LncRNA CAIF suppresses LPS-induced inflammation and apoptosis of cardiomyocytes through regulating miR-16 demethylation.
Wang Yan,Zhang Yi
Immunity, inflammation and disease
BACKGROUND:The long noncoding RNA, cardiac autophagy inhibitory factor (CAIF), and microRNA (miR)-16 are reported to be involved in lipopolysaccharide (LPS)-induced inflammatory responses and cell apoptosis in many diseases. Herein, we investigated the interaction between CAIF and miR-16 in sepsis-induced chronic heart failure (CHF). METHODS:The expression of CAIF and miR-16 in plasma samples from sepsis-induced CHF patients (n = 60) and healthy controls (n = 60) were measured using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The correlations between CAIF and miR-16 across plasma samples from patients with sepsis-induced CHF and healthy controls were analyzed using linear regression. The messenger RNA (mRNA) levels of inducible nitric oxide synthase, C-C motif chemokine 2 (CCL2), growth-regulated alpha protein (CXCL1), and interleukin-6 (IL-6) were evaluated using qRT-PCR while nuclear factor κB activation was evaluated using luciferase assay. RESULTS:The expression levels of CAIF and miR-16 were downregulated in the plasma of sepsis-induced CHF patients and were positively correlated in these patients. In cardiomyocytes, LPS treatment dose-dependently decreased CAIF and miR-16 levels. CAIF overexpression increased miR-16 expression by demethylating miR-16. CAIF and/or miR-16 overexpression suppressed LPS-induced CCL2, CXCL1, and IL-6 expression at both the mRNA and protein levels. Analysis of cell apoptosis and western blot analysis showed that CAIF and/or miR-16 overexpression inhibited LPS-induced cardiomyocyte apoptosis by reducing Bax and cleaved caspase 3 levels and enhancing Bcl-2 levels. CONCLUSION:Our study is the first to report the abnormal expression of CAIF and miR-16 in heart disease. CAIF plays a protective role in sepsis-induced CHF by inhibiting cardiomyocyte apoptosis and inflammation, possibly by regulating miR-16 demethylation.
10.1002/iid3.498
Kombucha ameliorates LPS-induced sepsis in a mouse model.
Wang Penghui,Feng Zhihua,Sang Xiao,Chen Wenzhi,Zhang Xiaoni,Xiao Jianbin,Chen Youqiang,Chen Qi,Yang Minhe,Su Jingqian
Food & function
As a popular traditional fermented beverage, kombucha has been extensively studied for its health benefits. However, the science behind the anti-inflammatory effect of kombucha has not been well studied, and there is an urgent need to uncover the secrets of the anti-inflammatory properties of kombucha. Here, we investigate kombucha's protective effects against lipopolysaccharide (LPS)-induced sepsis and on the intestinal microecology in mice. The contents of reducing sugars, polyphenols, catechins, and organic acids in the kombucha group were identified using various methods. The results showed that the concentrations of acetic acid, gluconic acid, polyphenol, and glucuronic acid in the kombucha group were 55.70 ± 2.57 g L, 50.20 ± 1.92 g L, 2.36 ± 0.31, and 1.39 ± 0.22 g L, respectively. The result also demonstrated that kombucha effectively improves the survival rate from 0% to 40%, and increases the thermoregulation in LPS-treated mice, which showed decreased mobility and had lost their appetite for food. Furthermore, kombucha reduced the levels of tumor necrosis factor-α and interleukins (IL)-1β and IL-6, restored the levels of T cells and macrophages in LPS-challenged mice, alleviated the histopathological damage, and inhibited NF-κB signaling in mice with LPS-induced sepsis. We demonstrated that kombucha effectively prevents cellular immune function disorder in mice at the initial stage of sepsis and exerts an immunomodulatory effect. In addition, the effect of kombucha on the gut microbiota was investigated during sepsis. Kombucha supplementation altered the diversity of the gut microbiota and promoted the growth of butyrate-producing bacteria, which exert anti-inflammatory effects. Our results illustrate the potential of kombucha as a novel anti-inflammatory agent against the development of systemic inflammatory responses associated with sepsis.
10.1039/d1fo01839f
Mitoquinone mesylate (MitoQ) prevents sepsis-induced diaphragm dysfunction.
Supinski Gerald S,Schroder Elizabeth A,Wang Lin,Morris Andrew J,Callahan Leigh Ann P
Journal of applied physiology (Bethesda, Md. : 1985)
Sepsis-induced diaphragm dysfunction is a major contributor to respiratory failure in mechanically ventilated patients. There are no pharmacological treatments for this syndrome, but studies suggest that diaphragm weakness is linked to mitochondrial free radical generation. We hypothesized that administration of mitoquinone mesylate (MitoQ), a mitochondrially targeted free radical scavenger, would prevent sepsis-induced diaphragm dysfunction. We compared diaphragm function in 4 groups of male mice: ) sham-operated controls treated with saline (0.3 mL ip), ) sham-operated treated with MitoQ (3.5 mg/kg/day given intraperitoneally in saline), ) cecal ligation puncture (CLP) mice treated with saline, and ) CLP mice treated with MitoQ. Forty-eight hours after surgery, we assessed diaphragm force generation, myosin heavy chain content, state 3 mitochondrial oxygen consumption (OCR), and aconitase activity. We also determined effects of MitoQ in female mice with CLP sepsis and in mice with endotoxin-induced sepsis. CLP decreased diaphragm specific force generation and MitoQ prevented these decrements (e.g. maximal force averaged 30.2 ± 1.3, 28.0 ± 1.3, 12.8 ± 1.9, and 30.0 ± 1.0 N/cm for sham, sham + MitoQ, CLP, and CLP + MitoQ groups, respectively, < 0.001). CLP also reduced diaphragm mitochondrial OCR and aconitase activity; MitoQ blocked both effects. Similar responses were observed in female mice and in endotoxin-induced sepsis. Moreover, delayed MitoQ treatment (by 6 h) was as effective as immediate treatment. These data indicate that MitoQ prevents sepsis-induced diaphragm dysfunction, preserving force generation. MitoQ may be a useful therapeutic agent to preserve diaphragm function in critically ill patients with sepsis. This is the first study to show that mitoquinone mesylate (MitoQ), a mitochondrially targeted antioxidant, treats sepsis-induced skeletal muscle dysfunction. This biopharmaceutical agent is without known side effects and is currently being used by healthy individuals and in clinical trials in patients with various diseases. When taken together, our results suggest that MitoQ has the potential to be immediately translated into treatment for sepsis-induced skeletal muscle dysfunction.
10.1152/japplphysiol.01053.2020
The lipid biology of sepsis.
Amunugama Kaushalya,Pike Daniel P,Ford David A
Journal of lipid research
Sepsis, defined as the dysregulated immune response to an infection leading to organ dysfunction, is one of the leading causes of mortality around the globe. Despite the significant progress in delineating the underlying mechanisms of sepsis pathogenesis, there are currently no effective treatments or specific diagnostic biomarkers in the clinical setting. The perturbation of cell signaling mechanisms, inadequate inflammation resolution, and energy imbalance, all of which are altered during sepsis, are also known to lead to defective lipid metabolism. The use of lipids as biomarkers with high specificity and sensitivity may aid in early diagnosis and guide clinical decision making. In addition, identifying the link between specific lipid signatures and their role in sepsis pathology may lead to novel therapeutics. In this review, we discuss the recent evidence on dysregulated lipid metabolism both in experimental and human sepsis focused on bioactive lipids, fatty acids, and cholesterol as well as the enzymes regulating their levels during sepsis. We highlight not only their potential roles in sepsis pathogenesis but also the possibility of using these respective lipid compounds as diagnostic and prognostic biomarkers of sepsis.
10.1016/j.jlr.2021.100090
Synthetic hydrogel nanoparticles for sepsis therapy.
Koide Hiroyuki,Okishima Anna,Hoshino Yu,Kamon Yuri,Yoshimatsu Keiichi,Saito Kazuhiro,Yamauchi Ikumi,Ariizumi Saki,Zhou Yuqi,Xiao Ting-Hui,Goda Keisuke,Oku Naoto,Asai Tomohiro,Shea Kenneth J
Nature communications
Sepsis is a life-threatening condition caused by the extreme release of inflammatory mediators into the blood in response to infection (e.g., bacterial infection, COVID-19), resulting in the dysfunction of multiple organs. Currently, there is no direct treatment for sepsis. Here we report an abiotic hydrogel nanoparticle (HNP) as a potential therapeutic agent for late-stage sepsis. The HNP captures and neutralizes all variants of histones, a major inflammatory mediator released during sepsis. The highly optimized HNP has high capacity and long-term circulation capability for the selective sequestration and neutralization of histones. Intravenous injection of the HNP protects mice against a lethal dose of histones through the inhibition of platelet aggregation and migration into the lungs. In vivo administration in murine sepsis model mice results in near complete survival. These results establish the potential for synthetic, nonbiological polymer hydrogel sequestrants as a new intervention strategy for sepsis therapy and adds to our understanding of the importance of histones to this condition.
10.1038/s41467-021-25847-2
Effects of circular RNA Ttc3/miR-148a/Rcan2 axis on inflammation and oxidative stress in rats with acute kidney injury induced by sepsis.
Ma Xu,Zhu Guizhen,Jiao Tiantian,Shao Fengmin
Life sciences
Aim Increasing evidence demonstrated circular RNAs (circRNAs) are involved in the development of various diseases, including sepsis-induced AKI. Although CIRC-Ttc3 has been proved to regulate cardiac function after myocardial infarction, its role in sepsis-induced AKI remains unclear. MATERIALS AND METHODS:The AKI rat model was firstly induced by sepsis through cecal ligation puncture (CLP). Serum levels of creatinine, BUN, NGAL, TNF-α, IL-6, SOD, MDA and IL-1β were measured through appropriate kits. The pathological alteration and renal microvascular permeability in renal tissues were determined by HE staining and Evans Blue assays. Cell apoptosis was detected by TUNEL assay. The expression levels of CIRC-Ttc3, miR-148a, TNF-α, IL-1β and iNOS in rats' renal samples were tested by qRT-PCR or/and western blot. The binding ability between CIRC-Ttc3 and miR-148a was evaluated through luciferase reporter, RIP and RNA pull-down assays. KEY FINDINGS:Kidney injury was found in CLP-treated rats. CIRC-Ttc3 expression was down-regulated, and upregulation of CIRC-Ttc3 improved inflammatory responses and oxidative stress in AKI rats. Mechanismly, CIRC-Ttc3 was confirmed to bind to and negatively regulate miR-148a. Further rescue assays revealed that overexpression of miR-148a rescued the improvement of CIRC-Ttc3 on sepsis-induced AKI. Then, it was illustrated that CIRC-Ttc3 regulated Rcan2 expression by binding to miR-148a. Finally, knockdown of Rcan2 reversed the effects of miR-148a inhibition on sepsis-induced AKI. SIGNIFICANCE:CIRC-Ttc3 relieved inflammation and oxidative stress through regulating the miR-148a/Rcan2 axis in rats with AKI induced by sepsis. Therefore, CIRC-Ttc3 may be a potential therapeutic target for sepsis-induced AKI.
10.1016/j.lfs.2021.119233
Cateslytin abrogates lipopolysaccharide-induced cardiomyocyte injury by reducing inflammation and oxidative stress through toll like receptor 4 interaction.
Rocca Carmine,De Bartolo Anna,Grande Fedora,Rizzuti Bruno,Pasqua Teresa,Giordano Francesca,Granieri Maria Concetta,Occhiuzzi Maria Antonietta,Garofalo Antonio,Amodio Nicola,Cerra Maria Carmela,Schneider Francis,Panno Maria Luisa,Metz-Boutigue Marie Hélène,Angelone Tommaso
International immunopharmacology
Global public health is threatened by new pathogens, antimicrobial resistant microorganisms and a rapid decline of conventional antimicrobials efficacy. Thus, numerous medical procedures become life-threating. Sepsis can lead to tissue damage such as myocardium inflammation, associated with reduction of contractility and diastolic dysfunction, which may cause death. In this perspective, growing interest and attention are paid on host defence peptides considered as new potential antimicrobials. In the present study, we investigated the physiological and biochemical properties of Cateslytin (Ctl), an endogenous antimicrobial chromogranin A-derived peptide, in H9c2 cardiomyocytes exposed to lipopolysaccharide (LPS) infection. We showed that both Ctl (L and D) enantiomers, but not their scrambled counterparts, significantly increased cardiomyocytes viability following LPS, even if L-Ctl was effective at lower concentration (1 nM) compared to D-Ctl (10 nM). L-Ctl mitigated LPS-induced LDH release and oxidative stress, as visible by a reduction of MDA and protein carbonyl groups content, and by an increase of SOD activity. Molecular docking simulations strongly suggested that L-Ctl modulates TLR4 through a direct binding to the partner protein MD-2. Molecular analyses indicated that the protection mediated by L-Ctl against LPS-evoked sepsis targeted the TLR4/ERK/JNK/p38-MAPK pathway, regulating NFkB p65, NFkB p52 and COX2 expression and repressing the mRNA expression levels of the LPS-induced proinflammatory factors IL-1β, IL-6, TNF-α and NOS2. These findings indicate that Ctl could be considered as a possible candidate for the development of new antimicrobials strategies in the treatment of myocarditis. Interestingly, L-enantiomeric Ctl showed remarkable properties in strengthening the anti-inflammatory and anti-oxidant effects on cardiomyocytes.
10.1016/j.intimp.2021.107487
Effect of serum high mobility group box 1 protein on immune function and autophagy level of myocardial cells in rats with sepsis.
Wu Y,Wang H-B,Yang Y,Dong Q-L
European review for medical and pharmacological sciences
OBJECTIVE:To investigate the effects of serum high mobility group box 1 protein (HMGB1) on immune function and autophagy level of myocardial cells in rats with sepsis. MATERIALS AND METHODS:Cecal ligation and perforation (CLP) was used to establish rat sepsis models. A total of 60 SD rats were selected and randomly divided into blank control group (BCG, n=20), sham group (SG, n=20) and cecal ligation and perforation group (CLPG, n=20). Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum HMGB1 level in sepsis rats. The expression levels of inflammatory factors in rats were detected, and the ratio of CD4+/CD8+ T cells was detected by flow cytometry. Western blot was used to detect the expression of autophagy-related protein microtubule-related protein 1 light chain 3 (LC3), Beclin-1 and apoptosis-related protein B lymphoblastoma-2 (Bcl-2), and cTnT protein, respectively. RESULTS:The level of serum HMGB1 in the CLPG was significantly higher than that in the BCG and the SG (p<0.05). Compared with BCG and the SG, the CLPG had lower peripheral blood T lymphocyte proliferation response, lower IL-6 and IL-10 levels, and lower CD4+/CD8+T lymphocyte ratio (p<0.05). Bcl-2 and cTnT in the CLPG and SG were higher than those in the BCG. LC3-11 and Beclin-1 expression in the CLPG were higher than those in the BCG and SG (p<0.05). After HMGB1 interference in the CLPG, CD4+/CD8+T and Bcl-2 were significantly increased, while the other indicators were significantly decreased (p<0.05). The level of serum HMGB1 is directly related to the severity of sepsis. CONCLUSIONS:The increase of serum HMGB1 level in sepsis has a significant impact on cellular immune dysfunction. Sepsis can effectively activate myocardial autophagy, and the level of autophagy shows an increasing trend.
10.26355/eurrev_202102_25111
Sepsis-induced myocardial dysfunction: the role of mitochondrial dysfunction.
Yang Hang,Zhang Zhaocai
Inflammation research : official journal of the European Histamine Research Society ... [et al.]
INTRODUCTION:Sepsis-induced myocardial dysfunction (SIMD) is a condition manifested by an intrinsic myocardial systolic and diastolic dysfunction during sepsis, which is associated with worse clinical outcomes and a higher mortality. MATERIALS AND METHODS:Several pathophysiological mechanisms including mitochondrial dysfunction, abnormal body immune reaction, metabolic reprogramming, excessive production of reactive oxygen species (ROS), and disorder of calcium regulation have been involved in SIMD. Mitophagy has potential role in protecting myocardial cells in sepsis, especially in survivors. CONCLUSION:In the current review, we focus on the role of mitochondrial dysfunction and other mitochondria-related mechanisms including immunologic imbalance, energetic reprogramming, mitophagy, and pyroptosis in the mechanisms of SIMD.
10.1007/s00011-021-01447-0
The effects of UCP2 on autophagy through the AMPK signaling pathway in septic cardiomyopathy and the underlying mechanism.
Mao Jia-Yu,Su Long-Xiang,Li Dong-Kai,Zhang Hong-Min,Wang Xiao-Ting,Liu Da-Wei
Annals of translational medicine
Background:Mitochondrial dysfunction plays an important role in the development of septic cardiomyopathy. This study aimed to reveal the protective role of uncoupling protein 2 (UCP2) in mitochondria through AMP-activated protein kinase (AMPK) on autophagy during septic cardiomyopathy. Methods:UCP2 knockout mice via a cecal ligation and puncture (CLP) model and the H9C2 cardiomyocyte cell line in response to lipopolysaccharide (LPS) were used to study the effect. The myocardial morphological alterations, indicators of mitochondrial injury and levels of autophagy-associated proteins (pAMPK, pmTOR, pULK1, pTSC2, Beclin-1, and LC3-I/II) were assessed. In addition, the mechanism of the interaction between UCP2 and AMPK was further studied through gain- and loss-of-function studies. Results:Compared with the wild-type mice, the UCP2 knockout mice exhibited more severe cardiomyocyte injury after CLP, and the AMPK agonist AICAR protected against such injury. Consistent with this result, silencing UCP2 augmented the LPS-induced pathological damage and mitochondrial injury in the H9C2 cells, limited the upregulation of autophagy proteins and reduced AMPK phosphorylation. AICAR protected the cells from morphological changes and mitochondrial membrane potential loss and promoted autophagy. The silencing and overexpression of UCP2 led to correlated changes in the AMPK upstream kinases pLKB1 and CAMKK2. Conclusions:UCP2 exerts cardioprotective effects on mitochondrial dysfunction during sepsis via the action of AMPK on autophagy.
10.21037/atm-20-4819
Zerumin A attenuates the inflammatory responses in LPS-stimulated H9c2 cardiomyoblasts.
Shyni G L,Renjitha J,B Somappa Sasidhar,Raghu K G
Journal of biochemical and molecular toxicology
Zerumin A (ZA) is one of the potential components of Curcuma amada rhizomes, and it has been shown to possess a variety of pharmacological activities. This study deals with the beneficial activity of ZA in lipopolysaccharide (LPS)-stimulated inflammation in H9c2 cardiomyoblasts. Herein, H9c2 cells were preincubated with ZA for 1 h and stimulated with LPS for 24 h. The cells were analyzed for the expression of various pro-inflammatory mediators and signaling molecules. Results showed that the cell viability was significantly improved and reactive oxygen species production was alleviated remarkably with ZA pretreatment. We also found that ZA pretreatment significantly suppressed the upregulation of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein levels, and nitric oxide (NO) release in LPS-stimulated cells. In addition, ZA significantly ameliorated LPS-elicited overexpression of pro-inflammatory chemokines and cytokines such as monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor α (TNF- α), interferon-γ (IFN-γ), and interleukin-1 (IL-1) in H9c2 cells, and it upregulated the synthesis of the anti-inflammatory cytokine interleukin-10 (IL-10). Moreover, pretreatment with ZA and the mitogen-activated protein kinases (MAPK) pathway inhibitors also reduced the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinases (JNK), and p38. ZA significantly inhibited IkB-a phosphorylation and nuclear factor (NF)-kB p65 subunit translocation into nuclei. Overall data demonstrated that ZA protects cardiomyocytes against LPS injury by inhibiting NF-kB p65 activation via the MAPK signaling pathway in vitro. These findings suggest that ZA may be a promising agent for a detailed study for the prevention or treatment of myocardial dysfunction in sepsis.
10.1002/jbt.22777
Methylation of miR-19b-3p promoter exacerbates inflammatory responses in sepsis-induced ALI via targeting KLF7.
Jiang Lingzhi,Wang Mingshan,Sun Renhua,Lin Zongbin,Liu Renyang,Cai Hanhui,Tang Zhiyun,Zhang Run
Cell biology international
Sepsis-induced acute lung injury is associated with dysregulated inflammatory reactions. MiR-19b-3p level was reported to be downregulated in patients with sepsis. To evaluate the role of miR-19b-3p in sepsis, cecum ligation and puncture-induced mouse sepsis model and lpopolysaccharide (LPS)-treated pulmonary microvascular endothelial cells (PMVECs) were used. For in vivo study, lung tissue was harvested for hematoxylin and eosin (H&E) staining, tumor necrosis factor-α, interleukin-6 (IL-6), IL-1β, and p-p65, p-IκB measuring. Cell apoptosis was assessed by TUNEL assay. For in vitro study, cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. Methylation of miR-19b-3p promoter was measured by methylation-specific PCR (MSP) assay. The target of miR-19b-3p was determined by dual-luciferase reporter gene assay. The level of miR-19b-3p was determined to be downregulated in vitro and in vivo. In addition, miR-19b-3p protected mice from inflammation injury through inhibiting NF-κB signaling pathway. Overexpression of miR-19b-3p increased cell viability, decreased apoptosis, and proinflammatory cytokines secretion in LPS-treated PMVECs. Besides these, Krüppel-like factor 7 (KLF7) was confirmed as the target of miR-19b-3p. And methylation of miR-19b-3p was the reason of decreased miR-19b-3p level. In conclusion, miR-19b-3p protected cells from sepsis-induced inflammation injury via inhibiting NF-κB signaling pathway, and KLF7 was a potential target.
10.1002/cbin.11601
Maresin 1 alleviates the inflammatory response, reduces oxidative stress and protects against cardiac injury in LPS-induced mice.
Li Dan,Wang Menglong,Ye Jing,Zhang Jishou,Xu Yao,Wang Zhen,Zhao Mengmeng,Ye Di,Wan Jun
Life sciences
BACKGROUND:Maresin 1 (MaR1) is a pro-resolving lipid mediator that has been reported to have strong regulatory effects on oxidative stress and inflammation. This study aimed to determine the effect of MaR1 on lipopolysaccharide (LPS)-induced sepsis-related cardiac injury and explore its possible mechanisms. METHODS:Mice were administered MaR1 or PBS and then treated with LPS or saline for 6 h. Then, cardiac function, cardiac injury markers, cardiac macrophage differentiation, oxidative stress and myocardial cell apoptosis in each group were measured. RESULTS:MaR1 treatment significantly decreased the serum levels of lactate dehydrogenase (LDH) and kinase isoenzyme (CK-MB) and improved cardiac function in LPS-induced mice. Treatment with MaR1 also inhibited LPS-induced M1 macrophage differentiation and reduced M1 macrophage-related cytokine secretion while promoting M2 macrophage differentiation and increasing M2 macrophage-related inflammatory mediator expression. In addition, MaR1 decreased serum malondialdehyde (MDA) levels and increased serum levels of superoxide dismutase (SOD) and glutathione (GSH), as well as cardiac expression of nuclear factor erythroid-2 related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1), in LPS-induced mice. Furthermore, fewer TUNEL-positive cells were observed in the LPS + MaR1 group than in the LPS group. CONCLUSIONS:Our experimental results show that MaR1 alleviates cardiac injury and protects against cardiac dysfunction and may be beneficial in reducing sepsis-induced cardiac injury.
10.1016/j.lfs.2021.119467
Dulaglutide Alleviates LPS-Induced Injury in Cardiomyocytes.
ACS omega
BACKGROUND AND PURPOSE:Sepsis is a severe infection-induced disease with multiple organ failure, and sepsis-induced cardiomyopathy is a fatal condition. Inflammatory response and oxidative stress are reported to be involved in the development of sepsis-induced cardiomyopathy. Dulaglutide is a novel antidiabetic agent that is currently reported to exert an anti-inflammatory effect. The present study aims to explore the potential protective property of dulaglutide on lipopolysaccharide (LPS)-induced injury on cardiomyocytes. METHODS:LPS was used to induce an injury model on cardiomyocytes. The mitochondrial reactive oxygen species (ROS) level was detected using MitoSOX red, and reduced glutathione (GSH) was measured to evaluate the status of oxidative stress in H9c2 myocardial cells. The expressions of NADPH oxidase-1 (NOX-1) and inducible nitric oxidesynthase (iNOS) were determined using real-time PCR and western blot analysis. Real-time PCR and enzyme-linked immunosorbent assay (ELISA) were both used to detect the expressions and concentrations of tumor necrosis factor-α, interleukin-1β, interleukin-17, matrix metalloproteinase-2, and matrix metalloproteinase-9 in H9c2 myocardial cells, respectively. The production of nitric oxide (NO) was measured using the Griess reagent. The levels of creatine kinase isoenzyme-MB (CK-MB) and cardiac troponin I (cTnI) were detected using ELISA. Western blot was utilized to determine the expressions of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and p-NF-κB p65 in H9c2 myocardial cells in the nucleus. RESULTS:First, dulaglutide ameliorated LPS-induced oxidative stress by suppressing the production of mitochondrial ROS and elevating the level of reduced GSH, as well as downregulating NOX-1. Second, the LPS-induced cardiomyocyte injury was alleviated by dulaglutide through downregulating CK-MB and cTnI, accompanied by inhibiting iNOS expression and NO production. Lastly, the production of inflammatory factors and upregulation of MMPs induced by LPS were both significantly reversed by dulaglutide through suppressing the TLR4/Myd88/NF-κB signaling pathway. CONCLUSIONS:Dulaglutide alleviated LPS-induced injury in cardiomyocytes by inhibiting inflammation and oxidative stress.
10.1021/acsomega.0c06326
FAM134B-mediated endoplasmic reticulum autophagy protects against sepsis myocardial injury in mice.
Aging
Reticulophagy regulator 1 (RETEG1, also known as FAM134B) plays a crucial role in endoplasmic reticulum autophagy. We aimed to explore the effect of FAM134B-mediated endoplasmic reticulum autophagy in sepsis myocardial injury in mice. Sepsis myocardial injury mice were established via cecal ligation and puncture procedures. The expression of FAM134B and LC3-II/I was determined using immunohistochemistry. Myocardial tissue morphological changes and apoptosis were examined using hematoxylin and eosin (H&E) staining and TUNEL analysis. The effects of FAM134B knockdown or overexpression on mice with sepsis myocardial injury were also studied. The levels of TNF-α, IL-6, IL-8, and IL-10 were evaluated using enzyme-linked immunosorbent assay (ELISA). Autophagy- and apoptosis-related protein expression was detected using western blotting. The effect of FAM134B on Lipopolysaccharide (LPS) -induced cardiomyocytes was also studied. The expression of FAM134B and LC3-II/I increased in sepsis mice and lipopolysaccharide (LPS)-treated cardiomyocytes. 3-Methyladenine (3-MA) significantly inhibited FAM134B and LC3-II/I expression and promoted myocardial injury, inflammation response, and cardiomyocyte apoptosis. The overexpression of FAM134B could minimize myocardial injury, inflammation, and apoptosis, whereas FAM134B knockdown showed opposite effects. FAM134B-mediated endoplasmic reticulum autophagy had a protective effect on sepsis myocardial injury in mice by reducing inflammation and tissue apoptosis, which may provide new insights for sepsis myocardial injury therapies.
10.18632/aging.202786
Endothelial-derived exosomes induced by lipopolysaccharide alleviate rat cardiomyocytes injury and apoptosis.
Cao Yu,Wang Yan,Xiao Ling,Xu Jia-Ying,Liu Ying,Jiang Rui,Li Tao,Jiang Jun
American journal of translational research
Sepsis-induced myocardial dysfunction (SIMD) is one of the leading causes of death in sepsis. We hypothesized that exosomes released from ECs exposed to bacterial lipopolysaccharides (LPS) have some regulatory effect on cardiomyocytes (CMs). In this study, cultured rat ECs were exposed to 0.5 µg/ml of LPS, and exosomes were isolated from the conditioned medium through ultra-high-speed centrifugation. The exosomes were given to the cultured neonatal rat CMs to test the potential effects and proceed to small RNA sequencing to identify their miRNA expression. We found exosomes from ECs under LPS stimulation (EC-Exo) enhanced the cell viability and attenuated the injury of CMs. The RNA sequencing depicted the expression of several miRNAs increased in EC-Exo compared with the exosomes from the control ECs (EC-Exo). Further analysis showed that some miRNAs could promote the survival of CMs by down-regulating the expression of apoptosis-related proteins such as BAK1, P53, and PTEN. This study showed that EC-Exo has a cardiac protective effect on CMs, which miRNAs may achieve.
Overexpression of miR-365a-3p relieves sepsis-induced acute myocardial injury by targeting MyD88/NF-κB pathway.
Lv Hong,Tian Meng,Hu Ping,Wang Bin,Yang Lin
Canadian journal of physiology and pharmacology
Sepsis often leads to systemic multiple organ dysfunction, with the majority of deaths attributable to acute myocardial injury (AMI). In this study, we aimed to explore the functional role of miR-365a-3p in sepsis-induced AMI. The sepsis myocardial injury model was constructed using lipopolysaccharide (LPS) both in vitro and in vivo with selective regulation of miR-365a-3p expression. Real-time PCR or Western blot was employed to detect the expressions of miR-365a-3p, inflammatory cytokines (tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and IL-6), and inflammation-related proteins (nuclear factor-κB (NF-κB), I-κB, myeloid differentiation factor 88 (MyD88)) in myocardial tissues and cells. Also, cell counting kit-8 (CCK8) and flow cytometry assays were used to measure cardiomyocyte proliferation and apoptosis, respectively. Furthermore, the targeting relationship between miR-365a-3p and MyD88 was verified with the dual luciferase activity assay. miR-365a-3p was downregulated in LPS-induced myocardial injury model. miR-365a-3p overexpression attenuated cardiomyocyte apoptosis and suppressed the expressions of inflammatory cytokines and proteins. Inhibiting miR-365a-3p, however, produced the opposite effects. Mechanistically, miR-365a-3p targeted the 3'-untranslated region of MyD88, thereby inactivating MyD88-mediated NF-κB pathway. miR-365a-3p overexpression mitigated sepsis-mediated myocardial injury by inhibiting MyD88-mediated NF-κB activation.
10.1139/cjpp-2020-0646
Left Ventricular Impaired Relaxation and Interstitial Myocarditis Identified in Sepsis-Associated Cardiac Dysfunction: Use of a Rodent Model.
Sturgess David J,Morrison Shannon,Haluska Brian,Gobe Glenda C,Jones Mark A,Volante Sonia,Venkatesh Bala
Medical science monitor : international medical journal of experimental and clinical research
BACKGROUND Sepsis is a serious clinical problem that results from the systemic response of the body to infection. Left ventricular (LV) diastolic dysfunction is increasingly appreciated as a contributor to morbidity and mortality in sepsis. Animal models may offer a method of studying diastolic dysfunction while controlling for many potential clinical confounders, such as sepsis duration, premorbid condition, and therapeutic interventions. This study sought to evaluate an endotoxemia (LPS) rodent model of sepsis, with regard to echocardiographic evidence, including tissue Doppler, of LV diastolic dysfunction and histopathology findings. MATERIAL AND METHODS Fourteen male Sprague-Dawley rats were randomly allocated (1: 1) to LPS or saline (control). Mean arterial blood pressure (MAP) was measured through cannulation of the carotid artery. After a 30-min stabilization, baseline assessment with echocardiography and blood collection was performed. Rats were administered 0.9% saline or LPS (10 mg/mL). Follow-up echocardiography and blood collection were performed after 2 h. Hearts were removed post-mortem and pathology studied using histology and immunohistochemistry. RESULTS LPS was associated with hypotension (MAP 81.86±31.67 mmHg; 124.29±20.16; p=0.02) and LV impaired relaxation (myocardial early diastolic velocity [e'] 0.06±0.02 m/s; 0.09±0.02; P=0.008). Histopathology and immunohistochemistry demonstrated evidence of interstitial myocarditis (hydropic changes and inflammation). CONCLUSIONS LPS was associated with both diastolic dysfunction (impaired relaxation) and interstitial myocarditis. These features may offer a link between the structural and functional changes that have previously been described separately in clinical sepsis. This may facilitate further studies focused upon the mechanism and potential benefit treatment of sepsis-associated cardiac dysfunction.
10.12659/MSM.929512
Hemodynamic clinical phenotyping in septic shock.
Daulasim Anousone,Vieillard-Baron Antoine,Geri Guillaume
Current opinion in critical care
PURPOSE OF REVIEW:Recent studies have failed to show significant benefit from a uniform strategy, suggesting that hemodynamic management must be individually adapted in septic shock depending on different phenotypes. Different approaches that may be used to this end will be discussed. RECENT FINDINGS:Fluid management is a cornerstone of resuscitation, as the positive fluid balance has been associated with higher mortality and right ventricular failure. Myocardial evaluation is mandatory, as sepsis patients may present with a hyperkinetic state, left ventricular (systolic and diastolic) and/or right ventricular dysfunction, the latter being associated with higher mortality. Statistical approaches with the identification of hemodynamic clusters based on echocardiographic and clinical parameters might be integrated into daily practice to develop precision medicine. Such approaches may also predict the progression of septic shock. SUMMARY:Different hemodynamic phenotypes can occur at any stage of sepsis and be associated with one another. The clinician must regularly assess dynamic changes in phenotypes in septic shock patients. Statistical approaches based on machine learning need to be validated by prospective studies.
10.1097/MCC.0000000000000834
Long Non-Coding RNA Small Nucleolar RNA Host Gene 1 Alleviates Sepsis-Associated Myocardial Injury by Modulating the miR-181a-5p/XIAP Axis .
Luo Sicong,Huang Xiaoyan,Liu Shuling,Zhang Lieyuan,Cai Xingui,Chen Bojun
Annals of clinical and laboratory science
OBJECTIVE:Sepsis is a systemic inflammatory response syndrome that results in severe myocardial injury. This study aimed to explore the role and mechanism of long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) in sepsis-induced myocardial injury . METHODS:Embryonic rat ventricular myocardial cell line (H9c2) was treated with lipopolysaccharide (LPS) to simulate sepsis-induced myocardial injury . A quantitative real-time polymerase chain reaction was executed to determine the expression of SNHG1 and microRNA (miR)-181a-5p. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-h-tetrazolium bromide assay was employed to measure cell viability. The levels of inflammatory factors (tumor necrosis factor alpha [TNF-α], interleukin 6 [IL-6], and IL-1β) were measured by enzyme-linked immunosorbent assay. Oxidative stress was assessed by measuring malondialdehyde, superoxide dismutase, and lactate dehydrogenase. The targeted interrelations among SNHG1, miR-181a-5p, and X-linked inhibitor of apoptosis protein (XIAP) were verified by dual-luciferase reporter assay. Relative protein expression of XIAP was detected by western blot. RESULTS:SNHG1 and XIAP were down-regulated, and miR-181a-5p was up-regulated in LPS-induced H9c2 cells. Overexpression of SNHG1 or inhibition of miR-181a-5p facilitated cell viability and repressed inflammation and oxidative stress in LPS-treated H9c2 cells. MiR-181a-5p was a target of and negatively regulated by SNHG1. At the same time, XIAP was a target gene of and inversely modulated by miR-181a-5p. In addition, XIAP was positively regulated by SNHG1. Up-regulation of miR-181a-5p or silencing of XIAP reversed the inhibitory effects of SNHG1 on inflammation and oxidative stress, as well as the promoting effects on cell viability in LPS-induced H9c2 cells. CONCLUSION:SNHG1 protected H9c2 cells against LPS-induced injury through modulating the miR-181a-5p/XIAP axis.
RETRACTED: MicroRNA-375-3p in endothelial progenitor cells-derived extracellular vesicles relieves myocardial injury in septic rats via BRD4-mediated PI3K/AKT signaling pathway.
International immunopharmacology
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief.Concern was raised about the reliability of the Western blot results in Figs. 1E, 4A+F, 5A+B and Supplementary Fig. 1O+P, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0 [docs.google.com]). The journal requested the corresponding author comment on these concerns and provide the raw data. However, the authors were not responsive to the request for comment. Since original data could not be provided, the overall validity of the results could not be confirmed. Therefore, the Editor-in-Chief decided to retract the article.
10.1016/j.intimp.2021.107740
Pathologic function and therapeutic potential of exosomes in cardiovascular disease.
Ailawadi Shaina,Wang Xiaohong,Gu Haitao,Fan Guo-Chang
Biochimica et biophysica acta
The heart is a very complex conglomeration of organized interactions between various different cell types that all aid in facilitating myocardial function through contractility, sufficient perfusion, and cell-to-cell reception. In order to make sure that all features of the heart work effectively, it is imperative to have a well-controlled communication system among the different types of cells. One of the most important ways that the heart regulates itself is by the use of extracellular vesicles, more specifically, exosomes. Exosomes are types of nano-vesicles, naturally released from living cells. They are believed to play a critical role in intercellular communication through the means of certain mechanisms including direct cell-to-cell contact, long-range signals as well as electrical and extracellular chemical molecules. Exosomes contain many unique features like surface proteins/receptors, lipids, mRNAs, microRNAs, transcription factors and other proteins. Recent studies indicate that the exosomal contents are highly regulated by various stress and disease conditions, in turn reflective of the parent cell status. At present, exosomes are well appreciated to be involved in the process of tumor and infection disease. However, the research on cardiac exosomes is just emerging. In this review, we summarize recent findings on the pathologic effects of exosomes on cardiac remodeling under stress and disease conditions, including cardiac hypertrophy, peripartum cardiomyopathy, diabetic cardiomyopathy and sepsis-induced cardiovascular dysfunction. In addition, the cardio-protective effects of stress-preconditioned exosomes and stem cell-derived exosomes are also summarized. Finally, we discuss how to epigenetically reprogram exosome contents in host cells which makes them beneficial for the heart.
10.1016/j.bbadis.2014.10.008
Blockade of exosome generation with GW4869 dampens the sepsis-induced inflammation and cardiac dysfunction.
Essandoh Kobina,Yang Liwang,Wang Xiaohong,Huang Wei,Qin Dongze,Hao Jiukuan,Wang Yigang,Zingarelli Basilia,Peng Tianqing,Fan Guo-Chang
Biochimica et biophysica acta
Sepsis is an infection-induced severe inflammatory disorder that leads to multiple organ failure. Amongst organs affected, myocardial depression is believed to be a major contributor to septic death. While it has been identified that large amounts of circulating pro-inflammatory cytokines are culprit for triggering cardiac dysfunction in sepsis, the underlying mechanisms remain obscure. Additionally, recent studies have shown that exosomes released from bacteria-infected macrophages are pro-inflammatory. Hence, we examined in this study whether blocking the generation of exosomes would be protective against sepsis-induced inflammatory response and cardiac dysfunction. To this end, we pre-treated RAW264.7 macrophages with GW4869, an inhibitor of exosome biogenesis/release, followed by endotoxin (LPS) challenge. In vivo, we injected wild-type (WT) mice with GW4869 for 1h prior to endotoxin treatment or cecal ligation/puncture (CLP) surgery. We observed that pre-treatment with GW4869 significantly impaired release of both exosomes and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) in RAW264.7 macrophages. At 12h after LPS treatment or CLP surgery, WT mice pre-treated with GW4869 displayed lower amounts of exosomes and pro-inflammatory cytokines in the serum than control PBS-injected mice. Accordingly, GW4869 treatment diminished the sepsis-induced cardiac inflammation, attenuated myocardial depression and prolonged survival. Together, our findings indicate that blockade of exosome generation in sepsis dampens the sepsis-triggered inflammatory response and thereby, improves cardiac function and survival.
10.1016/j.bbadis.2015.08.010
Prognostic impact of isolated right ventricular dysfunction in sepsis and septic shock: an 8-year historical cohort study.
Vallabhajosyula Saraschandra,Kumar Mukesh,Pandompatam Govind,Sakhuja Ankit,Kashyap Rahul,Kashani Kianoush,Gajic Ognjen,Geske Jeffrey B,Jentzer Jacob C
Annals of intensive care
BACKGROUND:Echocardiographic myocardial dysfunction is reported commonly in sepsis and septic shock, but there are limited data on sepsis-related right ventricular dysfunction. This study sought to evaluate the association of right ventricular dysfunction with clinical outcomes in patients with severe sepsis and septic shock. METHODS:Historical cohort study of adult patients admitted to all intensive care units at the Mayo Clinic from January 1, 2007 through December 31, 2014 for severe sepsis and septic shock, who had an echocardiogram performed within 72 h of admission. Patients with prior heart failure, cor-pulmonale, pulmonary hypertension and valvular disease were excluded. Right ventricular dysfunction was defined by the American Society of Echocardiography criteria. Outcomes included 1-year survival, in-hospital mortality and length of stay. RESULTS:Right ventricular dysfunction was present in 214 (55%) of 388 patients who met the inclusion criteria-isolated right ventricular dysfunction was seen in 100 (47%) and combined right and left ventricular dysfunction in 114 (53%). The baseline characteristics were similar between cohorts except for the higher mechanical ventilation use in patients with isolated right ventricular dysfunction. Echocardiographic findings demonstrated lower right ventricular and tricuspid valve velocities in patients with right ventricular dysfunction and lower left ventricular ejection fraction and increased mitral E/e' ratios in patients with combined right and left ventricular dysfunction. After adjustment for age, comorbidity, illness severity, septic shock and use of mechanical ventilation, isolated right ventricular dysfunction was independently associated with worse 1-year survival-hazard ratio 1.6 [95% confidence interval 1.2-2.1; p = 0.002) in patients with sepsis and septic shock. CONCLUSIONS:Isolated right ventricular dysfunction is seen commonly in sepsis and septic shock and is associated with worse long-term survival.
10.1186/s13613-017-0319-9
A multiplex analysis of sepsis mediators during human septic shock: a preliminary study on myocardial depression and organ failures.
Razazi Keyvan,Boissier Florence,Surenaud Mathieu,Bedet Alexandre,Seemann Aurélien,Carteaux Guillaume,de Prost Nicolas,Brun-Buisson Christian,Hue Sophie,Mekontso Dessap Armand
Annals of intensive care
BACKGROUND:The mechanisms of organ failure during sepsis are not fully understood. The hypothesis of circulating factors has been suggested to explain septic myocardial dysfunction. We explored the biological coherence of a large panel of sepsis mediators and their clinical relevance in septic myocardial dysfunction and organ failures during human septic shock. METHODS:Plasma concentrations of 24 mediators were assessed on the first day of septic shock using a multi-analyte cytokine kit. Septic myocardial dysfunction and organ failures were assessed using left ventricle ejection fraction (LVEF) and the Sequential Organ Failure Assessment score, respectively. RESULTS:Seventy-four patients with septic shock (and without immunosuppression or chronic heart failure) were prospectively included. Twenty-four patients (32%) had septic myocardial dysfunction (as defined by LVEF < 45%) and 30 (41%) died in ICU. Hierarchical clustering identified three main clusters of sepsis mediators, which were clinically meaningful. One cluster involved inflammatory cytokines of innate immunity, most of which were associated with septic myocardial dysfunction, organ failures and death; inflammatory cytokines associated with septic myocardial dysfunction had an additive effect. Another cluster involving adaptive immunity and repair (with IL-17/IFN pathway and VEGF) correlated tightly with a surrogate of early sepsis resolution (lactate clearance) and ICU survival. CONCLUSIONS:In this preliminary study, we identified a cluster of cytokines involved in innate inflammatory response associated with septic myocardial dysfunction and organ failures, whereas the IL-17/IFN pathway was associated with a faster sepsis resolution and a better survival.
10.1186/s13613-019-0538-3
The Anti-inflammatory Mediator Resolvin E1 Protects Mice Against Lipopolysaccharide-Induced Heart Injury.
Frontiers in pharmacology
BACKGROUND:Sepsis-induced cardiomyopathy () is a common severe complication of sepsis that contributes to mortality. is closely associated with excessive inflammatory responses, failed inflammation resolution, and apoptotic damage. Resolvin E1 (RvE1), an omega-3 polyunsaturated fatty acid (PUFA)-derived metabolite, has been reported to exert anti-inflammatory or proresolving activity in multiple animal models of inflammatory disease. However, the therapeutic potential of RvE1 in remains undetermined, which was, therefore, the aim of the present study. METHODS:C57BL/6J mice were randomly divided into three groups: control, lipopolysaccharide (LPS), and LPS + RvE1. Echocardiography, Western blotting (WB), quantitative real-time (QRT)-PCR, histological analyses, and flow cytometry were used to evaluate cardiac function, myocardial inflammation, and the underlying mechanisms. RESULTS:The RvE1-injected group showed improved left ventricular (LV) function and reduced serum lactate dehydrogenase (LDH) and creatine kinase myocardial bound (CK-MB) levels. Compared to LPS treatment alone, RvE1 treatment inhibited the infiltration of neutrophils and macrophages into the heart and spleen and suppressed the secretion of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and monocyte chemoattractant protein (MCP)-1, in the heart. We also observed that the activation of the mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB signaling pathways was blocked by RvE1 treatment, and this inhibition contributed to the improvement in the inflammatory response induced by LPS. RvE1 inhibited LPS-induced M1 macrophage polarization and promoted macrophage polarization toward the M2-like phenotype in both the heart and spleen. In addition, LPS administration dysregulated cyclooxygenase (COX) and lipoxygenase (LOX) in the heart, which were rectified by RvE1 treatment. RvE1 also reduced myocardial apoptosis rate in response to LPS-induced heart injury. CONCLUSION:RvE1 protects the heart against possibly through the inhibition of the MAPK and NF-κB inflammatory signaling pathways, modulation of macrophage polarization, and reduction in myocardial apoptosis. RvE1 may be a novel lipid mediator for the treatment of .
10.3389/fphar.2020.00203
The Natural Polypeptides as Significant Elastase Inhibitors.
Ahmad Shabir,Saleem Muhammad,Riaz Naheed,Lee Yong Sup,Diri Reem,Noor Ahmad,Almasri Diena,Bagalagel Alaa,Elsebai Mahmoud Fahmi
Frontiers in pharmacology
Human neutrophil elastase (HNE) is a major cause of the destruction of tissues in cases of several different chronic andinflammatory diseases. Overexpression of the elastase enzyme plays a significant role in the pathogenesis of various diseases including chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome, rheumatoid arthritis, the rare disease cyclic hematopoiesis (or cyclic neutropenia), infections, sepsis, cystic fibrosis, myocardial ischemia/reperfusion injury and asthma, inflammation, and atherosclerosis. Human neutrophil elastase is secreted by human neutrophils due to different stimuli. Medicine-based inhibition of the over-activation of neutrophils or production and activity of elastase have been suggested to mend inflammatory diseases. Although the development of new elastase inhibitors is an essential strategy for treating the different inflammatory diseases, it has been a challenge to specifically target the activity of elastase because of its overlapping functions with those of other serine proteases. This review article highlights the reported natural polypeptides as potential inhibitors of elastase enzyme. The mechanism of action, structural features, and activity of the polypeptides have also been correlated wherever they were available.
10.3389/fphar.2020.00688
Capsaicin protects cardiomyocytes against lipopolysaccharide-induced damage via 14-3-3γ-mediated autophagy augmentation.
Qiao Yang,Wang Liang,Hu Tianhong,Yin Dong,He Huan,He Ming
Frontiers in pharmacology
The myocardium is susceptible to lipopolysaccharide (LPS)-induced damage in sepsis, and cardiac dysfunction is a leading cause of mortality in patients with sepsis. The changes in cardiomyocyte autophagy in sepsis and the effects and mechanism of action of capsaicin (Cap) remain unclear. The potential pathway of 14-3-3γ-dependent autophagy and the effects and mechanisms of Cap were studied in LPS-induced injury to primary cultured neonatal rat cardiomyocytes. The results showed that cardiomyocyte viability decreased, lactate dehydrogenase and creatine kinase activities increased, 14-3-3γ expression was downregulated, and autophagy was inhibited after LPS challenge. Cap pretreatment augmented autophagy by upregulating 14-3-3γ expression and activating AMP-activated protein kinase (AMPK) and unc-51 like autophagy-activating kinase 1 (ULK1), suppressing mammalian target of rapamycin (mTOR), alleviating cardiac dysfunction and improving the inflammation response, whereas pAD/14-3-3γ-shRNA nullified the above effects. Cap pretreatment also decreased the levels of IL-1β, TNF-α, IL-6, and IL-10; suppressed intracellular oxidative stress; reduced the intracellular/mitochondrial reactive oxygen species (ROS); balanced GSH/GSSG; increased GSH-Px, catalase, and SOD activities; and decreased MDA contents. It also increased ATP content, activated complex Ⅰ and complex Ⅲ, stabilized the mitochondrial membrane potential, and decreased the mitochondrial permeability transition pore opening, thereby improving mitochondrial function. Pretreatment with Cap can regulate autophagy by upregulating 14-3-3γ expression, inhibiting oxidative stress and inflammation, maintaining mitochondrial function, and protecting cardiomyocytes against LPS-induced injury.
10.3389/fphar.2021.659015
Aldehyde Dehydrogenase 2 Protects Against Lipopolysaccharide-Induced Myocardial Injury by Suppressing Mitophagy.
Ji Wenqing,Wan Tiantian,Zhang Fang,Zhu Xiaomei,Guo Shubin,Mei Xue
Frontiers in pharmacology
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis-induced circulatory and cardiac dysfunction is associated with high mortality rates. Mitophagy, a specific form of autophagy, is excessively activated in lipopolysaccharide-induced myocardial injury. The present study investigated whether aldehyde dehydrogenase 2 (ALDH2) regulates mitophagy in sepsis-induced myocardial dysfunction. After lipopolysaccharide administration, cardiac dysfunction, inflammatory cell infiltration, biochemical indicators of myocardial cell injury, and cardiomyocyte apoptosis were ameliorated in mice by ALDH2 activation or overexpression. In contrast, cardiac dysfunction and cardiomyocyte apoptosis were exacerbated in mice followed ALDH2 inhibition. Moreover, ALDH2 activation or overexpression regulated mitophagy by suppressing the expression of phosphatase and tensin homolog-induced putative kinase 1 (PINK1)/Parkin, by preventing the accumulation of 4-hydroxy-trans-nonenal. Conversely, ALDH2 inhibition promoted the expression of LC3B by increasing 4-hydroxy-trans-2-nonenal accumulation. Consequently, ALDH2 may protect the heart from lipopolysaccharide-induced injury by suppressing PINK1/Parkin-dependent mitophagy.
10.3389/fphar.2021.641058
Sepsis and the heart.
Merx M W,Weber C
Circulation
Sepsis is generally viewed as a disease aggravated by an inappropriate immune response encountered in the afflicted individual. As an important organ system frequently compromised by sepsis and always affected by septic shock, the cardiovascular system and its dysfunction during sepsis have been studied in clinical and basic research for more than 5 decades. Although a number of mediators and pathways have been shown to be associated with myocardial depression in sepsis, the precise cause remains unclear to date. There is currently no evidence supporting global ischemia as an underlying cause of myocardial dysfunction in sepsis; however, in septic patients with coexistent and possibly undiagnosed coronary artery disease, regional myocardial ischemia or infarction secondary to coronary artery disease may certainly occur. A circulating myocardial depressant factor in septic shock has long been proposed, and potential candidates for a myocardial depressant factor include cytokines, prostanoids, and nitric oxide, among others. Endothelial activation and induction of the coagulatory system also contribute to the pathophysiology in sepsis. Prompt and adequate antibiotic therapy accompanied by surgical removal of the infectious focus, if indicated and feasible, is the mainstay and also the only strictly causal line of therapy. In the presence of severe sepsis and septic shock, supportive treatment in addition to causal therapy is mandatory. The purpose of this review is to delineate some characteristics of septic myocardial dysfunction, to assess the most commonly cited and reported underlying mechanisms of cardiac dysfunction in sepsis, and to briefly outline current therapeutic strategies and possible future approaches.
10.1161/CIRCULATIONAHA.106.678359
Is myocardial adrenergic responsiveness depressed in human septic shock?
Cariou Alain,Pinsky Michael R,Monchi Mehran,Laurent Ivan,Vinsonneau Christophe,Chiche Jean-Daniel,Charpentier Julien,Dhainaut Jean-François
Intensive care medicine
OBJECTIVE:To assess left ventricular (LV) contractile function and adrenergic responsiveness in septic patients. METHODS:We used echocardiographically defined fractional area of contraction (FAC), and LV area to end-systolic arterial pressure estimates of end-systolic elastance (E'es) and its change in response to dobutamine (5 microg/kg/min) in 10 subjects in septic shock admitted to an intensive care unit of an academic medical center. Subjects were studied on admission and again at both 5 days and 8-10 days after admission. RESULTS:Three of the 10 subjects died as a result of their acute process, while the others were discharged from hospital. Nine out of 10 subjects required intravenous vasopressor therapy on day 1, while only 1 of 9 subjects required vasopressor support at day 5. LV end-diastolic area (EDA) increased from day 1 to day 5 and days 8-10 (p<0.05), but neither FAC nor E'es was altered by time (EDA 15.7+/-5.8, 21.4+/-5.1, and 19.4+/-5.6 cm2; FAC 0.46+/-0.19, 0.50+/-0.20, and 0.48+/-0.15%; E'es 21.6+/-12.6, 23.2+/-8.5, and 19.2+/-6.3 mmHg/cm2, mean+/-SD, for days 1, 5 and 8-10 respectively). Although dobutamine did not alter E'es on day 1 or day 5, E'es increased in all of the 5 subjects studied on days 8-10 (p<0.05). CONCLUSIONS:Adrenergic hyporesponsiveness is present in septic shock and persists for at least 5 days into recovery, resolving by days 8-10 in survivors.
10.1007/s00134-008-1022-y
Anti-inflammatory properties of omega-3 fatty acids in critical illness: novel mechanisms and an integrative perspective.
Singer Pierre,Shapiro Haim,Theilla Miryam,Anbar Ronit,Singer Joelle,Cohen Jonathan
Intensive care medicine
INTRODUCTION:Fish oil-based nutrition is protective in severe critical care conditions. Regulation of the activity of transcription factor NF-kappaB is an important therapeutic effect of the major omega-3 fatty acids in fish oil, eicosapentaenoic and docosahexaenoic acid (EPA and DHA). METHODS AND RESULTS:Using the articles obtained by a Pubmed research, this article reviews three aspects of NF-kappaB/inflammatory inhibition by fish oil. (1) Inhibition of the NF-kappaB pathway at several subsequent steps: extracellular, free omega-3 inhibits the activation of the Toll-like receptor 4 by endotoxin and free saturated fatty acids. In addition, EPA/DHA blocks the signaling cascade between Toll-like/cytokine receptors and the activator of NF-kappaB, IKK. Oxidized omega-3 also interferes with the initiation of transcription by NF-kappaB. (2) The altered profile of lipid mediators generated during inflammation, with production of the newly identified, DHA-derived inflammation-resolving mediator classes (in addition to the formation of less pro-inflammatory eicosanoids from EPA). Resolvin D1 and Protectin D1 are potent, endogenous, DHA-derived lipid mediators that attenuate neutrophil migration and tissue injury in peritonitis and ischemia-reperfusion injury. Their production is increased in the later stages of an inflammatory response, at which time they enhance the removal of neutrophils. (3) Modulation of vagal tone with potential anti-inflammatory effects: vagal fibers innervating the viscera down-regulate inflammation by activating nicotinic receptors upon infiltrating and resident macrophages. Stimulation of the efferent vagus is therapeutic in experimental septic shock. Fish oil supplementation increases vagal tone following myocardial infarction and in experimental human endotoxinemia. CONCLUSION:It remains to be shown whether these pleiotropic actions of EPA/DHA contribute to fish oil's therapeutic effect in sepsis.
10.1007/s00134-008-1142-4
The RAGE axis in systemic inflammation, acute lung injury and myocardial dysfunction: an important therapeutic target?
Creagh-Brown Benedict C,Quinlan Gregory J,Evans Timothy W,Burke-Gaffney Anne
Intensive care medicine
BACKGROUND:The sepsis syndromes, frequently complicated by pulmonary and cardiac dysfunction, remain a major cause of death amongst the critically ill. Targeted therapies aimed at ameliorating the systemic inflammation that characterises the sepsis syndromes have largely yielded disappointing results in clinical trials. Whilst there are many potential reasons for lack of success of clinical trials, one possibility is that the pathways targeted, to date, are only modifiable very early in the course of the illness. More recent approaches have therefore attempted to identify pathways that could offer a wider therapeutic window, such as the receptor for advanced glycation end-products (RAGE) and its ligands. PURPOSE:The objectives of this study were to review the evidence supporting the role of the RAGE axis in systemic inflammation and associated acute lung injury and myocardial dysfunction, to explore some of the problems and conflicts that these RAGE studies have raised and to consider strategies by which they might be resolved. METHODS:MEDLINE was searched (1990-2010) and relevant literature collected and reviewed. RESULTS AND CONCLUSION:RAGE is an inflammation-perpetuating receptor with a diverse range of ligands. Evidence supporting a role of the RAGE axis in the pathogenesis of systemic inflammation, ALI and myocardial dysfunction is compelling with numerous animal experiments showing the beneficial effects of inhibiting the RAGE axis. Despite a number of unanswered questions that need to be further addressed, the potential for inhibiting RAGE-mediated inflammation in humans undoubtedly exists.
10.1007/s00134-010-1952-z
Mechanisms of cardiac and renal dysfunction in patients dying of sepsis.
Takasu Osamu,Gaut Joseph P,Watanabe Eizo,To Kathleen,Fagley R Eliot,Sato Brian,Jarman Steve,Efimov Igor R,Janks Deborah L,Srivastava Anil,Bhayani Sam B,Drewry Anne,Swanson Paul E,Hotchkiss Richard S
American journal of respiratory and critical care medicine
RATIONALE:The mechanistic basis for cardiac and renal dysfunction in sepsis is unknown. In particular, the degree and type of cell death is undefined. OBJECTIVES:To evaluate the degree of sepsis-induced cardiomyocyte and renal tubular cell injury and death. METHODS:Light and electron microscopy and immunohistochemical staining for markers of cellular injury and stress, including connexin-43 and kidney-injury-molecule-1 (Kim-1), were used in this study. MEASUREMENTS AND MAIN RESULTS:Rapid postmortem cardiac and renal harvest was performed in 44 septic patients. Control hearts were obtained from 12 transplant and 13 brain-dead patients. Control kidneys were obtained from 20 trauma patients and eight patients with cancer. Immunohistochemistry demonstrated low levels of apoptotic cardiomyocytes (<1-2 cells per thousand) in septic and control subjects and revealed redistribution of connexin-43 to lateral membranes in sepsis (P < 0.020). Electron microscopy showed hydropic mitochondria only in septic specimens, whereas mitochondrial membrane injury and autophagolysosomes were present equally in control and septic specimens. Control kidneys appeared relatively normal by light microscopy; 3 of 20 specimens showed focal injury in approximately 1% of renal cortical tubules. Conversely, focal acute tubular injury was present in 78% of septic kidneys, occurring in 10.3 ± 9.5% and 32.3 ± 17.8% of corticomedullary-junction tubules by conventional light microscopy and Kim-1 immunostains, respectively (P < 0.01). Electron microscopy revealed increased tubular injury in sepsis, including hydropic mitochondria and increased autophagosomes. CONCLUSIONS:Cell death is rare in sepsis-induced cardiac dysfunction, but cardiomyocyte injury occurs. Renal tubular injury is common in sepsis but presents focally; most renal tubular cells appear normal. The degree of cell injury and death does not account for severity of sepsis-induced organ dysfunction.
10.1164/rccm.201211-1983OC
Diastolic dysfunction and mortality in septic patients: a systematic review and meta-analysis.
Sanfilippo Filippo,Corredor Carlos,Fletcher Nick,Landesberg Giora,Benedetto Umberto,Foex Pierre,Cecconi Maurizio
Intensive care medicine
BACKGROUND:Myocardial dysfunction may contribute to the haemodynamic instability which accompanies sepsis, and may result in circulatory failure. There is no association between systolic dysfunction (SD) and mortality in septic patients and there is conflicting evidence regarding the effects of diastolic dysfunction (DD) on mortality in septic patients. METHODS:We conducted a systematic review and meta-analysis to investigate DD and mortality in septic patients. We included studies conducted in this patient population which investigated the association between DD reported according to tissue Doppler imaging (TDI) criteria and mortality, using the longest reported follow-up. As a secondary endpoint, we evaluated the association between SD and mortality according to the results reported by the retrieved studies. RESULTS:We included seven studies in our meta-analysis with 636 septic patients, 48% of them were found to have DD. We found a significant association between DD and mortality (RR 1.82, 95% CI 1.12-2.97, p = 0.02). This finding remained valid in a further analysis which including an older study reporting DD without TDI criteria. Five studies reported data on SD for a total of 581 patients, 29.6% of them with SD. No association was found between SD and mortality (RR 0.93, 95% CI 0.62-1.39, p = 0.73). Looking at subgroups, there was a trend towards higher mortality comparing isolated DD or combined SD-DD vs normal heart function (p = 0.10 and p = 0.05, respectively). CONCLUSIONS:Diastolic dysfunction is common in septic patients and it is associated with mortality. Systolic dysfunction is less common and is not associated with mortality in this group of patients.
10.1007/s00134-015-3748-7
Cardiac Myocyte KLF5 Regulates Ppara Expression and Cardiac Function.
Circulation research
RATIONALE:Fatty acid oxidation is transcriptionally regulated by peroxisome proliferator-activated receptor (PPAR)α and under normal conditions accounts for 70% of cardiac ATP content. Reduced Ppara expression during sepsis and heart failure leads to reduced fatty acid oxidation and myocardial energy deficiency. Many of the transcriptional regulators of Ppara are unknown. OBJECTIVE:To determine the role of Krüppel-like factor 5 (KLF5) in transcriptional regulation of Ppara. METHODS AND RESULTS:We discovered that KLF5 activates Ppara gene expression via direct promoter binding. This is blocked in hearts of septic mice by c-Jun, which binds an overlapping site on the Ppara promoter and reduces transcription. We generated cardiac myocyte-specific Klf5 knockout mice that showed reduced expression of cardiac Ppara and its downstream fatty acid metabolism-related targets. These changes were associated with reduced cardiac fatty acid oxidation, ATP levels, increased triglyceride accumulation, and cardiac dysfunction. Diabetic mice showed parallel changes in cardiac Klf5 and Ppara expression levels. CONCLUSIONS:Cardiac myocyte KLF5 is a transcriptional regulator of Ppara and cardiac energetics.
10.1161/CIRCRESAHA.115.306383
Non-invasive detection of human cardiomyocyte death using methylation patterns of circulating DNA.
Zemmour Hai,Planer David,Magenheim Judith,Moss Joshua,Neiman Daniel,Gilon Dan,Korach Amit,Glaser Benjamin,Shemer Ruth,Landesberg Giora,Dor Yuval
Nature communications
Detection of cardiomyocyte death is crucial for the diagnosis and treatment of heart disease. Here we use comparative methylome analysis to identify genomic loci that are unmethylated specifically in cardiomyocytes, and develop these as biomarkers to quantify cardiomyocyte DNA in circulating cell-free DNA (cfDNA) derived from dying cells. Plasma of healthy individuals contains essentially no cardiomyocyte cfDNA, consistent with minimal cardiac turnover. Patients with acute ST-elevation myocardial infarction show a robust cardiac cfDNA signal that correlates with levels of troponin and creatine phosphokinase (CPK), including the expected elevation-decay dynamics following coronary angioplasty. Patients with sepsis have high cardiac cfDNA concentrations that strongly predict mortality, suggesting a major role of cardiomyocyte death in mortality from sepsis. A cfDNA biomarker for cardiomyocyte death may find utility in diagnosis and monitoring of cardiac pathologies and in the study of normal human cardiac physiology and development.
10.1038/s41467-018-03961-y
Opportunities for microRNAs in the Crowded Field of Cardiovascular Biomarkers.
Halushka Perry V,Goodwin Andrew J,Halushka Marc K
Annual review of pathology
Cardiovascular diseases exist across all developed countries. Biomarkers that can predict or diagnose diseases early in their pathogeneses can reduce their morbidity and mortality in afflicted individuals. microRNAs are small regulatory RNAs that modulate translation and have been identified as potential fluid-based biomarkers across numerous maladies. We describe the current state of cardiovascular disease biomarkers across a range of diseases, including myocardial infarction, acute coronary syndrome, myocarditis, hypertension, heart failure, heart transplantation, aortic stenosis, diabetic cardiomyopathy, atrial fibrillation, and sepsis. We present the current understanding of microRNAs as possible biomarkers in these categories and where their best opportunities exist to enter clinical practice.
10.1146/annurev-pathmechdis-012418-012827
Pathophysiology of sepsis-induced cardiomyopathy.
Nature reviews. Cardiology
Sepsis is the life-threatening organ dysfunction caused by a dysregulated host response to infection and is the leading cause of death in intensive care units. Cardiac dysfunction caused by sepsis, usually termed sepsis-induced cardiomyopathy, is common and has long been a subject of interest. In this Review, we explore the definition, epidemiology, diagnosis and pathophysiology of septic cardiomyopathy, with an emphasis on how best to interpret this condition in the clinical context. Advances in diagnostic techniques have increased the sensitivity of detection of myocardial abnormalities but have posed challenges in linking those abnormalities to therapeutic strategies and relevant clinical outcomes. Sophisticated methodologies have elucidated various pathophysiological mechanisms but the extent to which these are adaptive responses is yet to be definitively answered. Although the indications for monitoring and treating septic cardiomyopathy are clinical and directed towards restoring tissue perfusion, a better understanding of the course and implications of septic cardiomyopathy can help to optimize interventions and improve clinical outcomes.
10.1038/s41569-020-00492-2
Left ventricular mitogen activated protein kinase signaling following polymicrobial sepsis during streptozotocin-induced hyperglycemia.
Gupta Akanksha,Brahmbhatt Sachin,Sharma Avadhesh C
Biochimica et biophysica acta
We hypothesized that sepsis during hyperglycemia would activate left ventricular (LV) mitogen activated protein kinase (MAPK) signaling mechanisms and modulate generation of endothelin-1 (ET-1) and nitric oxide (NO) that can contribute to the progression of LV dysfunction. A single injection of streptozotocin (STZ, 60 mg/kg, via tail vein) was used to produce type 2 diabetes in male SD rats. Polymicrobial sepsis and sham-sepsis were induced using single i.p. injection of cecal inoculum and sterile 5% dextrose water, respectively, on the 13th and 27th day following STZ injection. Both 2-week (2-wk) and 4-wk diabetes groups were associated with hyperglycemia and weight loss. LV end diastolic pressure (LVEDP) was significantly increased in 4-wk diabetes but not in 2-wk diabetes group. Plasma concentration of tumor necrosis factor-alpha (TNF-alpha) was significantly increased in 4-wk diabetes+sepsis group as compared to sham, 2-wk diabetes+sepsis and sepsis groups. Elevated plasma and LV ET-1 and NO byproducts (NOx) along with LV preproET-1 and inducible nitric oxide synthase (iNOS) protein expression were observed in 4-wk but not in 2-wk diabetes group. Sepsis further elevated LV iNOS and preproET-1 in 4-wk diabetes group. Up-regulated phosphorylation of LV p38-MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2) and heat shock protein-27 (Hsp27) was observed in 4-wk diabetes group. Sepsis caused a factorial increase in LV p38-MAPK and Hsp27 phosphorylation and iNOS up-regulation but not ERK1/2 following progression from 2-wk to 4-wk diabetes. The study provides evidence that sepsis up-regulated LV iNOS, p38-MAPK phosphorylation and elevated LVEDP during 4-wk diabetes. We concluded that sepsis contributes in the development of LVEDP dysfunction and alteration in signaling mechanisms depending upon the progression from 2-wk to 4-wk diabetes in the rat.
10.1016/j.bbadis.2004.05.001
Bigendothelin-1 via p38-MAPK-dependent mechanism regulates adult rat ventricular myocyte contractility in sepsis.
Gupta Akanksha,Aberle Nicholas S,Kapoor Ruchita,Ren Jun,Sharma Avadhesh C
Biochimica et biophysica acta
We tested the hypothesis that exogenous administration of the ET-1 precursor, bigET-1, would regulate adult rat ventricular myocyte (ARVM) contractility in a p38-mitogen activated protein kinase (p38-MAPK)-dependent mechanism during sepsis. Ventricular myocytes from adult rat hearts (both sham and septic) were stimulated to contract at 0.5 Hz and mechanical properties were evaluated using an IonOptix Myocam system. Immunoblot analysis was used to determine the phosphorylation of p38-MAPK and extracellular signal-regulated kinase 1/2 (ERK1/2). ARVMs were treated with vehicle, bigET-1 and inhibitors for 24 h and then subjected to functional and biochemical estimations. Septic ARVM displayed a distorted cell membrane and irregular network within the cells along with increased cell contractility as evidenced by elevated peak shortening (PS), maximal velocity of shortening (+dL/dt) and relengthening (-dL/dt) in comparison to sham ARVM. BigET-1 treatment caused ARVM enlargement in both sham and sepsis groups. BigET-1 (100 nM) produced an increase in ARVM contractility in sham group as compared to vehicle treatment. However, septic ARVM treated with bigET-1 exhibited unaltered ARVM contractility, and upregulated ET(B) receptors as compared to respective sham group. BigET-1 increased the concentration of ET-1 and upregulated phosphorylation of p38-MAPK but not of ERK1/2 in sham and septic ARVM. Furthermore, inhibition of p38-MAPK by SB203580 (10 microM) increased ARVM contractility in sham but not in sepsis group. BigET-1 reversed SB203580-induced increase in PS in sham group but accentuated it in sepsis group. BigET-1 also reversed SB203580-induced inhibition of p38-MAPK phosphorylation in sham but not in septic ARVM. SB203580 pretreatment followed by bigET-1 administration significantly decreased p38-MAPK phosphorylation and downregulated ET(B) receptor expression as compared to bigET-1 treatment per se in sepsis group but not in sham. We concluded that a bigET-1-induced non-responsive effect on septic ARVM contractile function could be due to upregulation of p38-MAPK phosphorylation and ET(B) receptor expression.
10.1016/j.bbadis.2005.03.006
TNF-alpha and IL-1beta increase Ca2+ leak from the sarcoplasmic reticulum and susceptibility to arrhythmia in rat ventricular myocytes.
Duncan David J,Yang Zhaokang,Hopkins Philip M,Steele Derek S,Harrison Simon M
Cell calcium
Sepsis is associated with ventricular dysfunction and increased incidence of atrial and ventricular arrhythmia however the underlying pro-arrhythmic mechanisms are unknown. Serum levels of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) are elevated during sepsis and affect Ca2+ regulation. We investigated whether pro-inflammatory cytokines disrupt cellular Ca2+ cycling leading to reduced contractility, but also increase the probability of pro-arrhythmic spontaneous Ca2+ release from the sarcoplasmic reticulum (SR). Isolated rat ventricular myocytes were exposed to TNF-alpha (0.05 ng ml(-1)) and IL-1beta (2 ng ml(-1)) for 3 hr and then loaded with fura-2 or fluo-3 to record the intracellular Ca2+ concentration ([Ca2+](i)). Cytokine treatment decreased the amplitude of the spatially averaged Ca2+ transient and the associated contraction, induced asynchronous Ca2+ release during electrical stimulation, increased the frequency of localized Ca2+ release events, decreased the SR Ca2+ content and increased the frequency of spontaneous Ca2+ waves at any given cytoplasmic Ca2+. These data suggest that TNF-alpha and IL-1beta increase the SR Ca2+ leak from the SR, which contributes to the depressed Ca2+ transient and contractility. Increased susceptibility to spontaneous SR Ca2+ release may contribute to arrhythmias in sepsis as the resulting Ca2+ extrusion via NCX is electrogenic, leading to cell depolarisation.
10.1016/j.ceca.2010.02.002
Riboflavin protects mice against liposaccharide-induced shock through expression of heat shock protein 25.
Shih Chun-Kuang,Chen Chiao-Ming,Chen C-Y Oliver,Liu Jen-Fang,Lin Hui-Wen,Chou Hung-Tsung,Li Sing-Chung
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
Riboflavin (vitamin B2) is a water-soluble vitamin essential for normal cellular functions, growth and development. This study aimed to investigate the effects of vitamin B2 on the survival rate, and expressions of tissue heat shock protein 25 (HSP25) and heat shock factor 1 (HSF1) in mice undergoing lipopolysaccharide (LPS) induced shock. Mice were assigned to four groups, saline vehicle, LPS, LPS plus low dose of vitamin B2 (LB2) and LPS plus high dose of vitamin B2 (HB2). Vitamin B2 (1 and 10mg/kg BW) was administered intraperitoneally at 2 and 0 h before the i.p. administration of LPS. At the end of the experiment, the survival rate monitored was 10, 20, 60, and 100% for LPS, LB2, HB2, and saline mice, respectively. HSP25 expressions in the heart and lung were significantly enhanced in a time-dependent manner in the HB2 mice as compared to the saline mice (p < 0.05), but not altered in the LB2 mice. In the HB2 mice, plasma riboflavin concentrations reached 300 nM at 6h post LPS and returned to the 0 h level at 72 h. The results showed that high dose of riboflavin could decrease LPS-induced mortality through an increased expression of HSP25.
10.1016/j.fct.2010.04.033
Apelin antagonizes myocardial impairment in sepsis.
Pan Chun-Shui,Teng Xu,Zhang Jing,Cai Yan,Zhao Jing,Wu Wei,Wang Xian,Tang Chao-Shu,Qi Yong-Fen
Journal of cardiac failure
BACKGROUND:Apelin is a cardiovascular peptide with multiple functions regulating homeostasis of the circulatory system and is the endogenous ligand of angiotensin II receptor like-1 (AGTRL1). Apelin has anti-inflammatory and inhibitory effects on release of inflammatory mediators. We aimed to analyze whether apelin antagonizes myocardial impairment in sepsis by attenuating inflammatory responses. METHODS AND RESULTS:Male rats underwent sepsis by cecal ligation and puncture (CLP) after receiving low- or high-dose apelin for 3 days. Twenty hours later, rats with sepsis showed severe disturbance of hemodynamic features. Reverse transcription-polymerase chain reaction revealed decreased mRNA levels of apelin and AGTRL1 in myocardia of rats with sepsis. Enzyme immune assay detected a lower level of apelin in plasma and myocardia. Western blot analysis revealed decreased level of myocardial AGTRL1 protein. Low- and high-dose apelin administration ameliorated disorders of cardiac function: increased mean arterial blood pressure, attenuated heart rate, elevated +LVdp/dt(max) and LVdp/dt(max), and lowered left ventricular end-diastolic pressure. Rats treated with low- or high-dose apelin showed lower content of plasma monocyte chemoattractant protein 1 and interleukin 8. In cultured rat peritoneal macrophages, apelin directly inhibited the production of monocyte chemoattractant protein 1 and interleukin-8 induced by lipopolysaccharide. CONCLUSIONS:These results suggest that apelin antagonizes cardiac impairment in sepsis by attenuating inflammatory responses and might be a promising therapeutic target for severe sepsis and septic shock.
10.1016/j.cardfail.2010.02.002
Chronic Akt activation attenuated lipopolysaccharide-induced cardiac dysfunction via Akt/GSK3β-dependent inhibition of apoptosis and ER stress.
Biochimica et biophysica acta
Sepsis is characterized by systematic inflammation and contributes to cardiac dysfunction. This study was designed to examine the effect of protein kinase B (Akt) activation on lipopolysaccharide-induced cardiac anomalies and underlying mechanism(s) involved. Mechanical and intracellular Ca²⁺ properties were examined in myocardium from wild-type and transgenic mice with cardiac-specific chronic Akt overexpression following LPS (4 mg/kg, i.p.) challenge. Akt signaling cascade (Akt, phosphatase and tensin homologue deleted on chromosome ten, glycogen synthase kinase 3 beta), stress signal (extracellular-signal-regulated kinases, c-Jun N-terminal kinases, p38), apoptotic markers (Bcl-2 associated X protein, caspase-3/-9), endoplasmic reticulum (ER) stress markers (glucose-regulated protein 78, growth arrest and DNA damage induced gene-153, eukaryotic initiation factor 2α), inflammatory markers (tumor necrosis factor α, interleukin-1β, interleukin-6) and autophagic markers (Beclin-1, light chain 3B, autophagy-related gene 7 and sequestosome 1) were evaluated. Our results revealed that LPS induced marked decrease in ejection fraction, fractional shortening, cardiomyocyte contractile capacity with dampened intracellular Ca²⁺ release and clearance, elevated reactive oxygen species (ROS) generation and decreased glutathione and glutathione disulfide (GSH/GSSG) ratio, increased ERK, JNK, p38, GRP78, Gadd153, eIF2α, BAX, caspase-3 and -9, downregulated B cell lymphoma 2 (Bcl-2), the effects of which were significantly attenuated or obliterated by Akt activation. Akt activation itself did not affect cardiac contractile and intracellular Ca²⁺ properties, ROS production, oxidative stress, apoptosis and ER stress. In addition, LPS upregulated levels of Beclin-1, LC3B and Atg7, while suppressing p62 accumulation. Akt activation did not affect Beclin-1, LC3B, Atg7 and p62 in the presence or absence of LPS. Akt overexpression promoted phosphorylation of Akt and GSK3β. In vitro study using the GSK3β inhibitor SB216763 mimicked the response elicited by chronic Akt activation. Taken together, these data showed that Akt activation ameliorated LPS-induced cardiac contractile and intracellular Ca²⁺ anomalies through inhibition of apoptosis and ER stress, possibly involving an Akt/GSK3β-dependent mechanism.
10.1016/j.bbadis.2013.02.023
Loss of duplexmiR-223 (5p and 3p) aggravates myocardial depression and mortality in polymicrobial sepsis.
Wang Xiaohong,Huang Wei,Yang Yang,Wang Yigang,Peng Tianqing,Chang Jiang,Caldwell Charles C,Zingarelli Basilia,Fan Guo-Chang
Biochimica et biophysica acta
Sepsis is the leading cause of death in critically ill patients. While myocardial dysfunction has been recognized as a major manifestation in severe sepsis, the underlying molecular mechanisms associated with septic cardiomyopathy remain unclear. In this study, we performed a miRNA array analysis in hearts collected from a severe septic mouse model induced by cecal ligation and puncture (CLP). Among the 19 miRNAs that were dys-regulated in CLP-mouse hearts, miR-223(3p) and miR-223*(5p) were most significantly downregulated, compared with sham-operated mouse hearts. To test whether a drop of miR-223 duplex plays any roles in sepsis-induced cardiac dysfunction and inflammation, a knockout (KO) mouse model with a deletion of the miR-223 gene locus and wild-type (WT) mice were subjected to CLP or sham surgery. We observed that sepsis-induced cardiac dysfunction, inflammatory response and mortality were remarkably aggravated in CLP-treated KO mice, compared with control WTs. Using Western-blotting and luciferase reporter assays, we identified Sema3A, an activator of cytokine storm and a neural chemorepellent for sympathetic axons, as an authentic target of miR-223* in the myocardium. In addition, we validated that miR-223 negatively regulated the expression of STAT-3 and IL-6 in mouse hearts. Furthermore, injection of Sema3A protein into WT mice revealed an exacerbation of sepsis-triggered inflammatory response and myocardial depression, compared with control IgG1 protein-treated WT mice following CLP surgery. Taken together, these data indicate that loss of miR-223/-223* causes an aggravation of sepsis-induced inflammation, myocardial dysfunction and mortality. Our study uncovers a previously unrecognized mechanism underlying septic cardiomyopathy and thereby, may provide a new strategy to treat sepsis.
10.1016/j.bbadis.2014.01.012
Energy crisis: the role of oxidative phosphorylation in acute inflammation and sepsis.
Lee Icksoo,Hüttemann Maik
Biochimica et biophysica acta
Mitochondrial dysfunction is increasingly recognized as an accomplice in most of the common human diseases including cancer, neurodegeneration, diabetes, ischemia/reperfusion injury as seen in myocardial infarction and stroke, and sepsis. Inflammatory conditions, both acute and chronic, have recently been shown to affect mitochondrial function. We here discuss the role of oxidative phosphorylation (OxPhos), focusing on acute inflammatory conditions, in particular sepsis and experimental sepsis models. We discuss mitochondrial alterations, specifically the suppression of oxidative metabolism and the role of mitochondrial reactive oxygen species in disease pathology. Several signaling pathways including metabolic, proliferative, and cytokine signaling affect mitochondrial function and appear to be important in inflammatory disease conditions. Cytochrome c oxidase (COX) and cytochrome c, the latter of which plays a central role in apoptosis in addition to mitochondrial respiration, serve as examples for the entire OxPhos system since they have been studied in more detail with respect to cell signaling. We propose a model in which inflammatory signaling leads to changes in the phosphorylation state of mitochondrial proteins, including Tyr304 phosphorylation of COX catalytic subunit I. This results in an inhibition of OxPhos, a reduction of the mitochondrial membrane potential, and consequently a lack of energy, which can cause organ failure and death as seen in septic patients.
10.1016/j.bbadis.2014.05.031
Cortistatin Inhibits NLRP3 Inflammasome Activation of Cardiac Fibroblasts During Sepsis.
Zhang Bo,Liu Yue,Sui Yu-Bin,Cai Huai-Qiu,Liu Wen-Xiu,Zhu Minling,Yin Xin-Hua
Journal of cardiac failure
BACKGROUND:Cortistatin is a recently discovered neuropeptide that has emerged as a potential endogenous antiinflammatory peptide. As a clinical syndrome, sepsis occurs when an infection becomes amplified, leading to organ dysfunction or risk for secondary infection. Human septic shock involves excessive inflammatory cytokine production. Interleukin (IL) 1β is one of these cytokines, and it plays a pivotal role in sepsis-induced myocardial dysfunction. The aim of the present study is to evaluate whether cortistatin inhibits nucleotide-binding oligomerization domain-like receptor with a pyrin-domain 3 (NLRP3) inflammasome/caspase-1/IL-1β pathway in cardiac fibroblasts (CFs) and whether this role can subsequently affect myocardial injury. METHODS AND RESULTS:To test these processes, a murine model of cecal ligation and puncture in vivo and lipopolysaccharide-induced cardiac fibroblasts were used in vitro. We found that pretreatment with cortistatin inhibited NLRP3-mediated ASC pyroptosome formation, caspase-1 activation, and IL-1β secretion. Additionally cortistatin inhibits proinflammatory pathways (nuclear factor κB and pro-IL-1β). CONCLUSIONS:This work provided the first evidence of cortistatin as a new immunomodulatory factor with the capacity to deactivate NLRP3 inflammasome activity and to protect against the myocardial injury induced by sepsis. This study has important implications for the design of new strategies to control NLRP3-related diseases.
10.1016/j.cardfail.2015.01.002
Colon Ascendens Stent Peritonitis (CASP) Induces Excessive Inflammation and Systemic Metabolic Dysfunction in a Septic Rat Model.
Zhang Limin,Tian Yuan,Yang Jianfen,Li Jieshou,Tang Huiru,Wang Yulan
Journal of proteome research
The colon ascendens stent peritonitis (CASP) surgery induces a leakage of gut contents, causing polymicrobial sepsis related to post-operative multiple organ failure and death in surgical patient. To evaluate the effects of CASP on multiple organs, we analyzed the systemic metabolic consequences in liver, kidney, lung, and heart of rats after CASP by employing a combination of metabolomics, clinical chemistry, and biological assays. We found that CASP surgery after 18 h resulted in striking elevations of lipid, amino acids, acetate, choline, PC, and GPC in rat liver together with significant depletion of glucose and glycogen. Marked elevations of organic acids including lactate, acetate, and creatine and amino acids accompanied by decline of glucose, betaine, TMAO, choline metabolites (PC and GPC) nucleotides, and a range of organic osmolytes such as myo-inositol are observed in the kidney of 18 h post-operative rat. Furthermore, 18 h post-operative rats exhibited accumulations of lipid, amino acids, and depletions of taurine, myo-inositol, choline, PC, and GPC and some nucleotides including uridine, inosine, and adenosine in the lung. In addition, significant elevations of some amino acids, uracil, betaine, and choline metabolites, together with depletion of inosine-5'-monophosphate, were only observed in the heart of 18 h post-operative rats. These results provide new insights into pathological consequences of CASP surgery, which are important for timely prognosis of sepsis.
10.1021/acs.jproteome.7b00730
Cyanidin ameliorates endotoxin-induced myocardial toxicity by modulating inflammation and oxidative stress through mitochondria and other factors.
Li Fang,Lang Fangfang,Wang Yidan,Zhai Chunxiao,Zhang Chuanbei,Zhang Liping,Hao Enkui
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
Cyanidin, an anthocyanin pigment, demonstrates anti-oxidant and anti-inflammatory properties. Here, we examined the mechanistic role of cyanidin in endotoxin induced myocardial injury in inflammation and oxidative stress. In lipopolysaccharide (LPS) induced myocardial injury model, cyanidin ameliorated cardiac injury (Lactate dehydrogenase or LDH, Creatine Kinase or CK, cardiac troponin I or cTnI and cardiac myosin light chains 1 or cMLC1), cell death (caspase 3 activity and PARP activity), and improved cardiac function (ejection fraction or EF and end diastolic left ventricular inner dimension or LVID). Cyanidin also attenuated endotoxin induced myocardial injury by modulating inflammatory cytokines (Tumor necrosis factor alpha or TNFα, Interleukin-1 beta or IL-1β, macrophage inflammatory protein 2 or MIP-2 and chemokine (C-C motif) ligand 2 also known as monocyte chemoattractant protein 1 or MCP1) and oxidative stress (protein nitration). Cyanidin modulated redox homeostasis through intracellular oxidized/reduced glutathione. The most striking properties of cyanidin in endotoxin induced mediated myocardial injury was the modulation of mitochondria, its oxidative damage and associated factor Opa1 and Trx1. Thus, our study demonstrated that cyanidin as a constituent of our food chain may be beneficial and has therapeutic potential in sepsis treatment or other myocardial oxidative and/or inflammation induced injuries.
10.1016/j.fct.2018.05.053
Acacetin, a flavone with diverse therapeutic potential in cancer, inflammation, infections and other metabolic disorders.
Singh Shilpi,Gupta Pratima,Meena Abha,Luqman Suaib
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
BACKGROUND:Acacetin is a di-hydroxy and mono-methoxy flavone present in various plants, including black locust, Damiana, Silver birch. Literature information revealed that acacetin exhibits an array of pharmacological potential including chemopreventive and cytotoxic properties in cancer cell lines, prevents ischemia/reperfusion/myocardial infarction-induced cardiac injury, lipopolysaccharide (LPS), 1-methyl-4-phenyl pyridinium ion (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced neuroinflammation, LPS and sepsis-induced lung injury, rheumatoid and collagen-induced arthritis, inhibit the microbial growth, obesity, viral-mediated infections as well as hepatic protection. PURPOSE:This review highlights the therapeutic potential of acacetin, with updated and comprehensive information on the biological sources, chemistry, and pharmacological properties along with the possible mechanism of action, safety aspects, and future research opportunities. STUDY DESIGN:The information was retrieved from various search engines, including Pubmed, SciFinder, Science direct, Inxight:drugs, Google scholar, and Meta cyc. RESULT:The first section of this review focuses on the detailed biological source of acacetin, chromatographic techniques used for isolation, chemical characteristics, the method for the synthesis of acacetin, and the available natural and synthetic derivatives. Subsequently, the pharmacological activities, including anti-cancer, anti-inflammatory, anti-viral, anti-microbial, anti-obesity, have been discussed. The pharmacokinetics data and toxicity profile of acacetin are also discussed. CONCLUSION:Acacetin is a potent molecule reported for its strong anti-inflammatory and anti-cancer activity, however further scientific evidence is essential to validate its potency in disease models associated with inflammation and cancer. There is limited information available for toxicity profiling of acacetin; therefore, further studies would aid in establishing this natural flavone as a potent candidate for research studies at clinical setup.
10.1016/j.fct.2020.111708
Vesnarinone restores contractility and calcium handling in early endotoxemia.
Takeuchi K,del Nido P J,Poutias D N,Cowan D B,Munakata M,McGowan F X
Circulation
BACKGROUND:Endotoxin (lipopolysaccharide, LPS) is a trigger of the systemic inflammatory response. We have previously found that vesnarinone and amrinone, when given before LPS, prevented cytokine production and LPS-related cardiac dysfunction. We tested the hypothesis that vesnarinone would improve intracellular Ca(2+) handling and calcium-activated contractile force after the onset of endotoxemia. METHODS AND RESULTS:Adult rabbits received a bolus injection of LPS or vehicle. Vesnarinone (3 mg/kg) was given intravenously 90 minutes later. Two hours after LPS administration, hearts were perfused in the isolated Langendorff mode. Peak left ventricular developed pressure, +/-dp/dt, oxygen consumption (MVO(2)), and ratexpressure product were evaluated in conjunction with fluorescent spectroscopic determinations of intracellular calcium concentrations (Ca(i)) and the rate of Ca(i) transient decline during diastole (tauCa). Peak left ventricular developed pressure and +/-dp/dt were significantly lower in the LPS group. These were completely restored by vesnarinone. There was significantly slower diastolic calcium removal (increased tauCa) in LPS hearts that was also corrected by vesnarinone; however, the cytosolic calcium overload characteristic of LPS hearts was only partially improved. Reduced mechanical inefficiency (the ratio of rate-pressure product to MVO(2)) and myofilament sensitivity to Ca(i) were also significantly improved by vesnarinone. CONCLUSIONS:Acute endotoxemia caused contractile protein calcium insensitivity, oxygen wastage, and abnormal calcium cycling. Vesnarinone, given in the rescue mode, normalized LPS-induced myocardial dysfunction and partially restored abnormal calcium cycling. Although the mechanisms responsible for these effects require further clarification, it appears that agents such as vesnarinone may be useful to treat inflammatory-induced myocardial dysfunction.
10.1161/01.cir.102.suppl_3.iii-365
Aerosolized linear polyethylenimine-nitric oxide/nucleophile adduct attenuates endotoxin-induced lung injury in sheep.
Kirov Mikhail Y,Evgenov Oleg V,Kuklin Vladimir N,Virag Laszlo,Pacher Pal,Southan Garry J,Salzman Andrew L,Szabo Csaba,Bjertnaes Lars J
American journal of respiratory and critical care medicine
Pulmonary hypertension and edema are mainstays of acute lung injury (ALI). We synthesized linear polyethylenimine-nitric oxide/nucleophile adduct (DS-1), a water-soluble nitric oxide donor, and demonstrated that it is a potent relaxant of precontracted rat aortic rings without inducing desensitization. Moreover, DS-1 does not suppress the viability of human pulmonary epithelial cells in vitro. We also tested whether DS-1 counteracts ALI in endotoxemic sheep. Animals were instrumented for a chronic study. In 16 awake, spontaneously breathing sheep, Escherichia coli endotoxin (10 ng/kg/minute) was infused for 8 hours. From 2 hours of endotoxemia, sheep received either nebulized DS-1 (1 mg/kg/hour) or isotonic saline. DS-1 reduced endotoxin-induced rises in pulmonary arterial and microwedge pressures and vascular resistance index by 40-70%. In parallel, DS-1 decreased the accumulation of extravascular lung water by 60-70% and reduced the increment in right ventricle stroke work index and the falls in right ventricle ejection fraction, stroke volume, and left ventricle stroke work indices. Furthermore, DS-1 reduced venous admixture and improved arterial oxygen saturation. In four healthy animals, DS-1 alone slightly increased arterial oxygenation but had no other effects. Thus, aerosolized DS-1 attenuates endotoxin-induced ALI in sheep by reducing pulmonary hypertension and edema and improving myocardial function and gas exchange.
10.1164/rccm.2202021
C1-Esterase inhibitor: an anti-inflammatory agent and its potential use in the treatment of diseases other than hereditary angioedema.
Caliezi C,Wuillemin W A,Zeerleder S,Redondo M,Eisele B,Hack C E
Pharmacological reviews
C1-esterase inhibitor (C1-Inh) therapy was introduced in clinical medicine about 25 years ago as a replacement therapy for patients with hereditary angioedema caused by a deficiency of C1-Inh. There is now accumulating evidence, obtained from studies in animals and observations in patients, that administration of C1-Inh may have a beneficial effect as well in other clinical conditions such as sepsis, cytokine-induced vascular leak syndrome, acute myocardial infarction, or other diseases. Activation of the complement system, the contact activation system, and the coagulation system has been observed in these diseases. A typical feature of the contact and complement system is that on activation they give rise to vasoactive peptides such as bradykinin or the anaphylatoxins, which in part explains the proinflammatory effects of either system. C1-Inh, belonging to the superfamily of serine proteinase inhibitors (serpins), is a major inhibitor of the classical complement pathway, the contact activation system, and the intrinsic pathway of coagulation, respectively. It is, therefore, endowed with anti-inflammatory properties. However, inactivation of C1-Inh occurs locally in inflamed tissues by proteolytic enzymes (e.g., elastase) released from activated neutrophils or bacteria thereby leading to increased local activation of the various host defense systems. Here we will give an overview on the biochemistry and biology of C1-Inh. We will discuss studies addressing therapeutic administration of C1-Inh in experimental and clinical conditions. Finally, we will provide an explanation for the therapeutic benefit of C1-Inh in so many different diseases.
Endotoxin and thrombin elevate rodent endothelial cell protein C receptor mRNA levels and increase receptor shedding in vivo.
Gu J M,Katsuura Y,Ferrell G L,Grammas P,Esmon C T
Blood
The endothelial cell protein C receptor (EPCR) facilitates protein C activation by the thrombin-thrombomodulin complex. Protein C activation has been shown to be critical to the host defense against septic shock. In cell culture, tumor necrosis factor-alpha (TNF-alpha) down-regulates EPCR expression, raising the possibility that EPCR might be down-regulated in septic shock. We examined EPCR mRNA and soluble EPCR levels in mice and rats challenged with lethal dose 95 levels of endotoxin. Toxic doses of TNF-alpha failed to alter EPCR mRNA levels in mice. Rather than EPCR mRNA levels falling in response to endotoxin, as predicted from cell-culture experiments, they rose approximately 3-fold 6 hours after exposure to endotoxin before returning toward baseline levels at 24 hours after exposure. Soluble EPCR levels rose approximately 4-fold. Infusion of hirudin, a specific thrombin inhibitor, before endotoxin exposure almost completely blocked the increase in EPCR mRNA and soluble EPCR. Consistent with the idea that the responses were mediated by thrombin, thrombin infusion (5 U/kg of body weight for 3 hours) resulted in an approximately 2-fold increase in EPCR mRNA and soluble EPCR. Incubation of rat endothelial cells with thrombin or murine protease-activated receptor 1 agonist peptide resulted in a 2-fold increase in EPCR mRNA. These results indicate that thrombin plays a major role in up-regulating EPCR mRNA and shedding in vivo. (Blood. 2000;95:1687-1693)
Protective role of heme oxygenases against endotoxin-induced diaphragmatic dysfunction in rats.
Taillé C,Foresti R,Lanone S,Zedda C,Green C,Aubier M,Motterlini R,Boczkowski J
American journal of respiratory and critical care medicine
Reactive oxygen species are strongly implicated in diaphragmatic dysfunction during sepsis. We investigated whether the heme oxygenase (HO) pathway, which is a powerful protective cellular system, protects the diaphragm against oxidative stress and contractile failure during sepsis. A basal expression of both the inducible and constitutive HO protein isoforms (HO-1 and HO-2, respectively) was found in the diaphragm. Enhanced HO-1 expression in diaphragmatic myocytes was observed 24 h after Escherichia coli endotoxin (lipopolysaccharide, LPS) inoculation and remained elevated for at least 96 h. Enhanced HO-1 expression was also observed in the rectus abdominis and soleus muscles and in the left ventricular myocardium of endotoxemic animals. Diaphragmatic HO-2 expression was not modified by endotoxin. Diaphragmatic HO activity exhibited a biphasic time course characterized by a transient decrease during the first 12 h followed by a significant increase at 24 h, corresponding to HO-1 induction. Diaphragmatic force was significantly reduced 24 h after LPS, concomitantly with muscular oxidative stress. Administation of an inhibitor of heme oxygenase activity, zinc protoporphyrin IX (ZnPP-IX), further impaired muscular oxidative stress and contractile failure. By contrast, increased levels of HO-1 expression obtained by pretreatment of rats with hemin, a powerful inducer of HO-1, completely prevented LPS-mediated diaphragmatic oxidative stress and contractile failure. This protective effect was reversed by ZnPP-IX. These results show an important protective role for the HO pathway against sepsis-induced diaphragmatic dysfunction, which could be related to its antioxidant properties.
10.1164/ajrccm.163.3.2004202
Staphylococcal alpha-toxin provokes coronary vasoconstriction and loss in myocardial contractility in perfused rat hearts: role of thromboxane generation.
Sibelius U,Grandel U,Buerke M,Mueller D,Kiss L,Kraemer H J,Braun-Dullaeus R,Haberbosch W,Seeger W,Grimminger F
Circulation
BACKGROUND:Cardiac performance is severely depressed in septic shock. Endotoxin has been implicated as the causative agent in Gram-negative sepsis, but similar abnormalities are encountered in Gram-positive sepsis. We investigated the influence of the major exotoxin of Staphylococcus aureus, staphylococcal alpha-toxin, in isolated perfused rat hearts. METHODS AND RESULTS:Alpha-toxin 0.25 to 1 microg/mL caused a dose-dependent increase in coronary perfusion pressure that more than doubled. In parallel, we noted a decrease in left ventricular developed pressure and the maximum rate of left ventricular pressure rise (dP/dt(max)), dropping to a minimum of <60% of control. These changes were accompanied by a liberation of thromboxane A(2) and prostacyclin into the coronary effluent. The release of creatine kinase, lactate dehydrogenase, potassium, and lactate did not surpass control heart values, and leukotrienes were also not detected. Indomethacin, acetylsalicylic acid, and the thromboxane receptor antagonist daltroban fully blocked the alpha-toxin-induced coronary vasoconstrictor response and the decrease in left ventricular developed pressure and dP/dt(max), whereas the lipoxygenase inhibitor nordihydroguaiaretic acid, the platelet activating factor antagonist WEB 2086, and the alpha-adrenergic antagonist phentolamine were entirely ineffective. Inhibition of nitric oxide synthase even enhanced the alpha-toxin-induced increase in coronary perfusion pressure and the loss in myocardial performance. CONCLUSIONS:Purified staphylococcal alpha-toxin provokes coronary vasoconstriction and loss in myocardial contractility. The responses appear to be largely attributable to the generation of thromboxane and are even enhanced when the endogenous nitric oxide synthesis is blocked. Bacterial exotoxins, such as staphylococcal alpha-toxin, may thus be implicated in the loss of cardiac performance encountered in Gram-positive septic shock.
10.1161/01.cir.101.1.78
A circulating myocardial depressant substance in humans with septic shock. Septic shock patients with a reduced ejection fraction have a circulating factor that depresses in vitro myocardial cell performance.
Parrillo J E,Burch C,Shelhamer J H,Parker M M,Natanson C,Schuette W
The Journal of clinical investigation
We have previously described a subpopulation of patients with septic shock who had a reversible depression of radionuclide-determined left ventricular ejection fraction (EF). To investigate the mechanism of this myocardial depression, an in vitro model of mammalian myocardial cell performance was established employing primary spontaneously beating rat myocardial cells. The contraction of a single cardiac cell was quantitated by recording the changes in area occupied by the cell during contraction and relaxation. In 20 septic shock patients during the acute phase, the mean left ventricular EF was decreased (mean = 0.33, normal mean = 0.50), and serum obtained during this acute phase induced a mean (+/- standard error of the mean) 33 +/- 4% decrease in extent and 25 +/- 4% decrease in velocity of myocardial cell shortening during contraction (P less than 0.001). In contrast, serum obtained from 11 of these same patients before shock (n = 2) or after recovery (n = 9) of the left ventricular EF (mean = 0.50) showed a return toward normal in extent and velocity of shortening (P less than 0.001). Sera from 17 critically ill nonseptic patients, from 10 patients with structural heart disease as a cause for a depressed EF, and from 12 healthy laboratory personnel, induced no significant changes in in vitro myocardial cell performance. In 20 patients during the acute phase of septic shock, the decreased EF in vivo demonstrated a significant correlation (r = +0.52, P less than 0.01) with a decrease in the extent of myocardial cell shortening in vitro. The quantitative and temporal correlation between the decreased left ventricular EF and this serum myocardial depressant substance argues for a pathophysiologic role for this depressant substance in producing the reversible cardiomyopathy seen during septic shock in humans.
10.1172/JCI112135
Sepsis depresses the metabolic oxygen reserve of the coronary circulation in mature sheep.
Bloos F M,Morisaki H M,Neal A M,Martin C M,Ellis C G,Sibbald W J,Pitt M L
American journal of respiratory and critical care medicine
This study was undertaken to describe the metabolic O2 reserve of the coronary circulation in an awake sheep model of hyperdynamic sepsis. Forty-eight hours after sheep were randomized to either a SHAM group (n = 8) or a cecal ligation and perforation (CLP) group (n = 8), we measured hemodynamics, organ blood flows, and systemic and myocardial O2 metabolism variables at baseline and through four stages of progressive hypoxia. A significant elevation in arterial lactate levels occurred at a higher O2 delivery in the CLP group (527 +/- 55 ml/min/m2) than in the SHAM group (357 +/- 29 ml/min/m2, p < 0.05). The heart's metabolic O2 reserve (difference in circulatory determinants of O2 availability between baseline and where O2 uptake could not be sustained) was exhausted at an O2 content of 56.9 +/- 4.2 ml O2/L in SHAM sheep and 79.6 +/- 7.2 ml O2/L (p < 0.05) in CLP sheep. An increase in coronary blood flow was three times greater in SHAM than in CLP animals. Myocardial O2 extraction increased in hypoxia in SHAM sheep (0.78 +/- 0.03 to 0.88 +/- 0.02, p < 0.05), but not in CLP sheep (0.79 +/- 0.02 to 0.80 +/- 0.04). We conclude that the metabolic O2 reserve of the coronary circulation is depressed in this model of hyperdynamic sepsis as the ability to increase both coronary blood flows and myocardial O2 extraction was significantly limited.
10.1164/ajrccm.153.5.8630605
Cardiac myocytes activated by septic plasma promote neutrophil transendothelial migration: role of platelet-activating factor and the chemokines LIX and KC.
Madorin W Sean,Rui Tao,Sugimoto Naohito,Handa Osamu,Cepinskas Gediminas,Kvietys Peter R
Circulation research
Cardiac myocytes isolated from rats with peritonitis (cecal ligation and perforation; CLP) promote PMN transendothelial migration. Herein, we assessed (1) the mechanisms involved in cardiac myocyte activation during peritonitis and (2) the means by which these activated myocytes promote PMN transendothelial migration. Plasma obtained from mice subjected to CLP (septic plasma) activated isolated cardiac myocytes as evidenced by (1) increased nuclear levels of nuclear factor-kappaB (NF-kappaB) and (2) their ability to promote PMN migration across endothelial cell monolayers. Pretreatment of septic plasma with an antibody against tumor necrosis factor-alpha (TNF-alpha), but not interleukin-1beta (IL-1beta), blunted the ability of septic plasma to activate the myocytes. However, septic plasma obtained from TNF-alpha-deficient mice could still activate the myocytes; an effect attenuated by an antibody against IL-1beta. If the myocytes were pretreated with a proteasome inhibitor (MG 132) to prevent NF-kappaB activation, the myocyte-induced PMN transendothelial migration was compromised. The activated myocytes released platelet-activating factor (PAF), and myocyte-induced PMN migration was abrogated by a PAF receptor antagonist (WEB 2086). These myocytes also released the CXC chemokines LIX and KC; an event prevented by MG 132. Antibodies against LIX and KC abrogated the myocyte-induced PMN migration. However, LIX and KC, but not PAF, could promote PMN migration when used at concentrations produced by activated myocytes. These observations indicate that TNF-alpha and IL-1beta are, in part, responsible for the ability of septic plasma to activate cardiac myocytes. The activated myocytes promote PMN transendothelial migration, an effect attributable to LIX and KC, and possibly, PAF.
10.1161/01.RES.0000124395.20249.AE
Effects of epinephrine and norepinephrine on hemodynamics, oxidative metabolism, and organ energetics in endotoxemic rats.
Levy Bruno,Mansart Arnaud,Bollaert Pierre-Edouard,Franck Patricia,Mallie Jean-Pierre
Intensive care medicine
OBJECTIVE:To determine whether epinephrine increases lactate concentration in sepsis through hypoxia or through a particular thermogenic or metabolic pathway. DESIGN:Prospective, controlled experimental study in rats. SETTING:Experimental laboratory in a university teaching hospital. INTERVENTIONS:Three groups of anesthetized, mechanically ventilated male Wistar rats received an intravenous infusion of 15 mg/kg Escherichia coli O127:B8 endotoxin. Rats were treated after 90 min by epinephrine ( n=14), norepinephrine ( n=14), or hydroxyethyl starch ( n=14). Three groups of six rats served as time-matched control groups and received saline, epinephrine, or norepinephrine from 90 to 180 degrees min. Mean arterial pressure, aortic, renal, mesenteric and femoral blood flow, arterial blood gases, lactate, pyruvate, and nitrate were measured at baseline and 90 and 180 min after endotoxin challenge. At the end of experiments biopsy samples were taken from the liver, heart, muscle, kidney, and small intestine for tissue adenine nucleotide and lactate/pyruvate measurements. MEASUREMENTS AND RESULTS:Endotoxin induced a decrease in mean arterial pressure and in aortic, mesenteric, and renal blood flow. Plasmatic and tissue lactate increased with a high lactate/pyruvate (L/P) ratio. ATP decreased in liver, kidney, and heart. The ATP/ADP ratio did not change, and phosphocreatinine decreased in all organs. Epinephrine and norepinephrine increased mean arterial pressure to baseline values. Epinephrine increased aortic blood flow while renal blood low decreased with both drugs. Plasmatic lactate increased with a stable L/P ratio with epinephrine and did not change with norepinephrine compared to endotoxin values. Nevertheless epinephrine and norepinephrine when compared to endotoxin values did not change tissue L/P ratios or ATP concentration in muscle, heart, gut, or liver. In kidney both drugs decreased ATP concentration. CONCLUSIONS:Our data demonstrate in a rat model of endotoxemia that epinephrine-induced hyperlactatemia is not related to cellular hypoxia.
10.1007/s00134-002-1611-0
Early but not delayed continuous arteriovenous hemofiltration improves cardiovascular function in sepsis in dogs.
Mink S N,Li X,Bose D,Gu M,Liu G,Jacobs H,Light R B
Intensive care medicine
OBJECTIVE:Continuous arteriovenous hemofiltration (CAVH) has been advocated as treatment to remove inflammatory mediators and thereby to improve hemodynamic parameters in sepsis. However, the results obtained with CAVH have been inconsistent. In a canine model of bacteremic Pseudomonas aeruginosa pneumonia, we tested the hypothesis that the time course of the institution of CAVH may be important in obtaining a beneficial treatment effect. METHODS:Two protocols were performed in phenobarbital-anesthetized dogs. In the early hemofiltration study (EHS), CAVH for 3 h was initiated 2 h post-pneumonia before mean arterial pressure (MAP) fell. In the late hemofiltration study (LHS), CAVH for 3 h was initiated at 5 h post-pneumonia when a decrease in MAP had already occurred. Hemodynamic measurements included cardiac output (CO), stroke volume (SV), and stroke work (SW). Myocardial depressant activity [filterable cardiodepressant substance (FCS)] found in plasma was assessed by bioassay at each measurement interval. RESULTS:In EHS, after 5 h of sepsis, SW, CO, and SV in the hemofiltered pneumonia group were higher as compared with the nonhemofiltered pneumonia group. In contrast, in LHS, no differences in hemodynamic parameters were found between the two pneumonia groups. In both EHS and LHS, plasma FCS activity was decreased to similar extents by CAVH. CONCLUSION:These results suggest the time course of institution of CAVH may be important in obtaining a beneficial treatment effect in sepsis.
The endothelial glycocalyx protects against myocardial edema.
van den Berg Bernard M,Vink Hans,Spaan Jos A E
Circulation research
Myocardial tissue edema attributable to increased microvascular fluid loss contributes to cardiac dysfunction after myocardial ischemia, cardiopulmonary bypass, hypertension, and sepsis. Recent studies suggest that carbohydrate structures on the luminal surface of microvascular endothelium are essential to prevent tissue edema. We carefully preserved these structures for visualization with electron microscopy, revealing that the rat myocardial capillary endothelial surface is coated with a 0.2- to 0.5-microm-thick carbohydrate layer and that its degradation instantly results in notable myocardial tissue edema.
10.1161/01.RES.0000065917.53950.75
Sequential changes in autonomic regulation of cardiac myocytes after in vivo endotoxin injection in rat.
Abi-Gerges N,Tavernier B,Mebazaa A,Faivre V,Paqueron X,Payen D,Fischmeister R,Méry P F
American journal of respiratory and critical care medicine
We report that in vivo injection of endotoxin (EDTX, 6 mg. kg(-)(1)) induces cardiovascular alterations in rats that closely mimic the clinical situation, as assessed by in vivo hemodynamic measurements in anesthetized and conscious, chronically instrumented animals. The patch-clamp technique was used to characterize the L-type calcium current (I(Ca)) and its autonomic regulation in isolated cardiac myocytes. The density of I(Ca) progressively decreased at 12 and 36 h after EDTX injection. However, the dihydropyridine (+/-)Bay K 8644 (100 nM) enhanced I(Ca) to levels similar to those in control and EDTX-treated myocytes. In addition, the net stimulatory effect of a beta-adrenergic agonist (isoproterenol) on I(Ca) was increased 12 h after EDTX injection. This change in the beta-adrenergic effect declined 24 h later. The potentiation in the beta-adrenergic stimulation of I(Ca) was mimicked by L858051 (10 microM), a direct activator of adenylyl cyclase, but not by IBMX (200 microM), a phosphodiesterase inhibitor. Besides, the antiadrenergic effect of acetylcholine on I(Ca) was unchanged 12 h after EDTX injection, but increased 36 h after EDTX injection. These results support the hypothesis that time-dependent changes in the adenylyl cyclase pathway in cardiac myocytes may contribute, via the autonomic regulation of I(Ca), to the severity of myocardial dysfunction during sepsis.
10.1164/ajrccm.160.4.9808149
Phosphorylation-dependent alteration in myofilament ca2+ sensitivity but normal mitochondrial function in septic heart.
Tavernier B,Mebazaa A,Mateo P,Sys S,Ventura-Clapier R,Veksler V
American journal of respiratory and critical care medicine
The subcellular mechanisms responsible for myocardial depression during sepsis remain unclear. Recent data suggest a role for impaired energy generation and utilization, resulting in altered contractile function. Here, we studied the energetic and mechanical properties of skinned fibers isolated from rabbit ventricle in a nonlethal but hypotensive model of endotoxemia. Thirty-six hours after lipopolysaccharide (LPS) injection (in the presence of altered myocardial contractility), mitochondrial respiration, coupling between oxidation and phosphorylation, and creatine kinase function were similar in preparations from endotoxemic (LPS) and control animals. The maximal Ca2+-activated force was similar in LPS and control preparations. However, the Ca2+ concentration corresponding to half-maximal force (pCa50, where pCa = -log10[Ca2+]) was 5.55 +/- 0.01 (n = 11) in LPS fibers versus 5.61 +/- 0.01 (n = 10) in control fibers (p < 0.01). Both protein kinase A (PKA) and alkaline phosphatase treatment led to the disappearance in the difference between control and LPS pCa50 values. Incubation of control fibers with the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) did not change the Ca2+ sensitivity after subsequent skinning, whereas isoproterenol decreased pCa50 from 5.62 +/- 0.01 to 5.55 +/- 0.01 (p < 0.01). These data suggest that during sepsis, cardiac mitochondrial and creatine kinase systems remain unaltered, whereas protein phosphorylation decreases myofibrillar Ca2+ sensitivity and may contribute to the depression of cardiac contractility.
10.1164/ajrccm.163.2.2002128
Apoptosis: target for novel drugs.
Alam John J
Trends in biotechnology
Targeting apoptotic cell death pathways provides wide-ranging opportunities for the discovery and development of novel drugs. Some targeted therapies that selectively induce apoptosis in cancer cells are already marketed, and numerous pro-apoptotic drugs for treating cancer are currently being developed. The anti-apoptotic drugs that are most advanced in development are targeting acute disease indications such as stroke, myocardial infarction and sepsis, in which the role of apoptosis has been best defined and inhibitors of the apoptotic pathway have shown activity in various animal models. In the future, novel drugs might also result from an understanding of apoptotic pathways in chronic disorders.
10.1016/j.tibtech.2003.08.006
Role of interleukin 6 in myocardial dysfunction of meningococcal septic shock.
Pathan Nazima,Hemingway Cheryl A,Alizadeh Ash A,Stephens Alick C,Boldrick Jennifer C,Oragui Emmanuelle E,McCabe Colm,Welch Steven B,Whitney Adeline,O'Gara Peter,Nadel Simon,Relman David A,Harding Sian E,Levin Michael
Lancet (London, England)
BACKGROUND:Myocardial failure has a central role in the complex pathophysiology of septic shock and contributes to organ failure and death. During the sepsis-induced inflammatory process, specific factors are released that depress myocardial contractile function. We aimed to identify these mediators of myocardial depression in meningococcal septic shock. METHODS:We combined gene-expression profiling with protein and cellular methods to identify a serum factor causing cardiac dysfunction in meningococcal septic shock. We identified genes that were significantly upregulated in blood after exposure to meningococci. We then selected for further analysis those genes whose protein products had properties of a myocardial depressant factor--specifically a 12-25 kDa heat-stable protein that is released into serum shortly after onset of meningococcal infection. FINDINGS:We identified 174 significantly upregulated genes in meningococcus-infected blood: six encoded proteins that were of the predicted size and had characteristics of a myocardial depressant factor. Of these, interleukin 6 caused significant myocardial depression in vitro. Removal of interleukin 6 from serum samples of patients with meningococcaemia and from supernatants of inflammatory cells stimulated by meningococci in vitro abolished the negative inotropic activity. Furthermore, concentrations in serum of interleukin 6 strongly predicted degree of myocardial dysfunction and severity of disease in children with meningococcal septic shock. INTERPRETATION:Interleukin 6 is a mediator of myocardial depression in meningococcal disease. This cytokine and its downstream mediators could be a target for future treatment strategies.
10.1016/S0140-6736(03)15326-3
HMG-CoA reductase inhibitor simvastatin profoundly improves survival in a murine model of sepsis.
Merx Marc W,Liehn Elisa A,Janssens Uwe,Lütticken Rudolf,Schrader Jürgen,Hanrath Peter,Weber Christian
Circulation
BACKGROUND:HMG-CoA reductase inhibitors, such as simvastatin, have been shown to exhibit pronounced immunomodulatory effects independent of lipid lowering but to date have not been used to treat severe inflammatory disease such as sepsis. We thus approached the question of whether treatment with simvastatin might improve cardiovascular function and survival in sepsis. METHODS AND RESULTS:Mice treated with simvastatin and rendered septic by cecal ligation and perforation (CLP) show a mean survival time close to 4 times the value found in untreated mice. This dramatic improvement is based on a complete preservation of cardiac function and hemodynamic status, which are severely impaired in untreated CLP mice [eg, 20 hours after CLP, cardiac output declined from 1.24+/-0.09 to 0.87+/-0.11 mL x min(-1) x g(-1) in untreated mice (P<0.005; n=12), while remaining unaltered (1.21+/-0.08 mL x min(-1) x g(-1) at baseline and 1.15+/-0.1 mL x min(-1) x g(-1) 20 hours after CLP, P=NS, n=12) in CLP mice treated with simvastatin]. Untreated CLP mice remained refractory to beta-stimulation, whereas the responsiveness to dobutamine was restored by treatment with simvastatin. Susceptibility of coronary flow to endothelial nitric oxide synthase (eNOS) stimulation by bradykinin was close to 3 times as pronounced in untreated CLP mice as in untreated sham-operated mice, indicating a high level of eNOS activation secondary to sepsis. In addition, treatment with simvastatin reversed inflammatory alterations in CLP mice, namely, increased monocyte adhesion to endothelium. CONCLUSIONS:Simvastatin, which is well established in the treatment of lipid disorders and coronary artery disease, might have the additional potential of being an effective agent in sepsis treatment.
10.1161/01.CIR.0000129774.09737.5B
Peroxynitrite decomposition catalysts prevent myocardial dysfunction and inflammation in endotoxemic rats.
Lancel Steve,Tissier Stéphanie,Mordon Serge,Marechal Xavier,Depontieu Florence,Scherpereel Arnaud,Chopin Claude,Neviere Remi
Journal of the American College of Cardiology
OBJECTIVES:The aim of this study was to test whether peroxynitrite neutralizers would reduce peroxynitrite accumulation and improve myocardial contractile dysfunction and inflammation in endotoxin-treated rats. BACKGROUND:Release of endogenous proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha in response to endotoxin is responsible for the production of large amounts of nitric oxide (NO), which may exert detrimental effects on the myocardium in animal models, isolated hearts, and isolated cardiac myocytes. Recent studies have indicated that many of the deleterious effects of NO are mediated by peroxynitrite, a powerful oxidant generated from a fast diffusion-limited reaction of NO and superoxide anion. METHODS:We studied the effects of peroxynitrite neutralizers, such as mercaptoethylguanidine (MEG) sodium succinate (10 mg/kg) and 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrinato iron (III) (FeTPPS) (30 mg/kg) on peroxynitrite accumulation, in vivo endothelial cell-leukocyte activation on the mesenteric venule, and myocardial contractile dysfunction and inflammation in a model of sepsis induced by injection of endotoxin (10 mg/kg) in rats. RESULTS:Mercaptoethylguanidine sodium succinate and FeTPPS largely prevented the accumulation of peroxynitrite as measured by plasma rhodamine fluorescence and heart nitrotyrosine staining. Interestingly, MEG sodium succinate and FeTPPS improved endotoxin-induced myocardial contractile dysfunction, which was associated with reduced degradation of nuclear factor kappa B inhibitory protein I-kappa-B, plasma TNF-alpha levels, and microvascular endothelial cell-leukocyte activation. CONCLUSIONS:These observations suggest that the beneficial effects of MEG and FeTPPS on endotoxin-induced myocardial contractile dysfunction could be related to the unique effects of these compounds on cardiovascular inflammation processes.
10.1016/j.jacc.2004.01.047
Immune cell Toll-like receptor 4 is required for cardiac myocyte impairment during endotoxemia.
Tavener Samantha A,Long Elizabeth M,Robbins Stephen M,McRae Krista M,Van Remmen Holly,Kubes Paul
Circulation research
The aim of this study was to investigate the importance of Toll-like receptor 4 (TLR4) signaling on cardiac myocytes versus immune cells in lipopolysaccharide (LPS)-induced cardiac dysfunction. Cardiac myocytes isolated from LPS-treated C57Bl/6 mice showed reduced shortening and calcium transients as compared with myocytes from untreated mice. In addition, LPS-treated C57Bl/6 mice showed impaired cardiac mitochondrial function, including reduced respiration and reduced time of induction of permeability transition. All of the aforementioned cardiac dysfunction was dependent on TLR4, because LPS-treated TLR4-deficient mice did not have reduced myocyte shortening or mitochondrial dysfunction. To evaluate the role of cardiac myocyte versus leukocyte TLR4, LPS was injected into chimeric mice with TLR4-positive leukocytes and TLR4-deficient myocytes. These mice showed reduced myocyte shortening in response to LPS. Myocytes from chimeric mice with TLR4-deficient leukocytes and TLR4-positive myocytes had no response to LPS. In addition, isolated myocytes from C57Bl/6 mice subsequently treated with LPS and serum for various times did not have reduced shortening, despite the presence of TLR4 mRNA and protein, as determined by reverse-transcription polymerase chain reaction and fluorescent-activated cell sorting. In fact, cardiac myocytes had equivalent amounts of TLR4 as endothelium; however, only the latter is responsive to LPS. Furthermore, signaling pathways downstream of TLR4 were not activated during direct LPS treatment of myocytes. In conclusion, TLR4 on leukocytes, and not on cardiac myocytes, is important for cardiac myocyte impairment during endotoxemia.
10.1161/01.RES.0000144175.70140.8c
A cardioprotective role for the endothelial protein C receptor in lipopolysaccharide-induced endotoxemia in the mouse.
Iwaki Takayuki,Cruz Diana T,Martin J Andrew,Castellino Francis J
Blood
A model of gram-negative lethal endotoxin shock, involving continuous peritoneal infusion of lipopolysaccharide (LPS), has been applied to wild-type (WT) mice and mice with a severe deficiency of endothelial protein C receptor (EPCR(delta/delta)). The survival of EPCR(delta/delta) mice was significantly diminished as compared to WT mice after administration of LPS via this route. Heart rates and central blood pressures also were significantly more depressed in EPCR(delta/delta) mice, indicating that the receptor-based protein C (PC) pathway functions in regulation of hemodynamic properties in the mouse. Further, heart muscle damage was more severe in EPCR(delta/delta) mice as compared to WT mice after endotoxin administration, as revealed by the more elevated plasma myoglobin levels in EPCR(delta/delta) mice and by microscopic examination of stained heart sections. Neutrophil infiltration was more pronounced in heart tissue of EPCR(delta/delta) mice, perhaps in response to the greatly increased expression level of the chemokine, MIP-2, which also significantly more up-regulated in the LPS-treated EPCR(delta/delta) mouse cohort. In conclusion, a severe deficiency of EPCR adversely affects survival of mice subjected to continuous infusion of endotoxin, via contributions of more responsive hemodynamic and cardiac alterations, thus suggesting that, among its other functions, the PC-based receptor system has a cardioprotective role after acute inflammatory challenge.
10.1182/blood-2004-06-2456
Toll-like receptor 2 mediates Staphylococcus aureus-induced myocardial dysfunction and cytokine production in the heart.
Knuefermann Pascal,Sakata Yasushi,Baker J Scott,Huang Chien-Hua,Sekiguchi Kenichi,Hardarson Hordur S,Takeuchi Osamu,Akira Shizuo,Vallejo Jesus G
Circulation
BACKGROUND:Staphylococcus aureus sepsis is associated with significant myocardial dysfunction. Toll-like receptor 2 (TLR2) mediates the inflammatory response to S aureus and may trigger an innate immune response in the heart. We hypothesized that a TLR2 deficiency would attenuate S aureus-induced cardiac proinflammatory mediator production and the development of cardiac dysfunction. METHODS AND RESULTS:Wild-type and TLR2-deficient (TLR2D) mice were studied. S aureus challenge significantly increased tumor necrosis factor, interleukin-1beta, and nitric oxide expression in hearts of wild-type mice. This response was significantly blunted in TLR2D mice. Hearts from TLR2D mice had impaired S aureus-induced activation of interleukin-1 receptor-associated kinase, c-Jun NH2 terminal kinase, nuclear factor-kappaB, and activator protein-1. Moreover, hearts from TLR2D mice were protected against S aureus-induced contractile dysfunction. CONCLUSIONS:These results show for the first time that TLR2 signaling contributes to the loss of myocardial contractility and cytokine production in the heart during S aureus sepsis.
10.1161/01.CIR.0000143081.13042.04
Characterization of membrane N-glycan binding sites of lysozyme for cardiac depression in sepsis.
Jacobs Hans,Mink Steven N,Duke Krika,Bose Deepak,Cheng Zhao-Qin,Howlett Susan,Ferrier Gregory R,Light R Bruce
Intensive care medicine
PURPOSE:In sepsis, reversible myocardial depression has been ascribed to the release of mediators of inflammation. We previously found that lysozyme released from leukocytes from the spleen and other organs mediated myocardial depression in an Escherichia coli model of septic shock in dogs. We hypothesize that lysozyme binds to or cleaves a cardiac surface membrane N-glycoprotein to cause depression. The objectives of the present study were: 1) to determine whether the binding of lysozyme is reversible; 2) to assess the N-glycan structure to which lysozyme binds; 3) to examine whether nonenzymatic proteins, termed lectins, with a binding specificity similar to that of lysozyme could also cause depression; and 4) to assess whether the membrane to which lysozyme binds is affected by the enzymes protease type XIV and collagenase A, that are used to prepare single cell myocyte experiments. METHODS:We measured isometric contraction in a right ventricular trabecular preparation. RESULTS:We found that lysozyme binds in a reversible manner to the Man beta(1-4) GlcNAc beta(1-4)GlcNAc moiety in the tri-mannosyl core structure of high mannose/hybrid and tri-antennary carbohydrate classes where GlcNAc is N-acetylglucosamine and Man is mannose. Lectins with a specificity similar to that of lysozyme also caused depression, and lysozyme's depressant activity was eliminated by protease type XIV and collagenase A. CONCLUSIONS:These results indicate that lysozyme reversibly binds to a membrane glycoprotein to cause myocardial depression in sepsis. We further localize its binding site to a variant of the chitotriose structure in the tri-mannosyl core of the membrane glycoprotein.
10.1007/s00134-004-2487-y
The haemodynamic and metabolic effects of epinephrine in experimental hyperdynamic septic shock.
Di Giantomasso David,Bellomo Rinaldo,May Clive N
Intensive care medicine
OBJECTIVE:To study the effect of epinephrine (EPI) infusion on vital organ blood flow and metabolic variables during sepsis. DESIGN AND SETTING:Randomised placebo-controlled animal trial in an animal laboratory. ANIMALS:Seven merino cross-ewes. INTERVENTIONS:Chronic implantation of flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous injection of E. coli. Random allocation of sheep to EPI (0.4 microg kg(-1) min(-1)) or vehicle for 6 h. MEASUREMENTS AND RESULTS:E. coli induced hypotension and hyperlactataemia and increased cardiac output, renal, mesenteric and coronary blood flows. Compared to vehicle, EPI restored mean arterial blood pressure (69 vs. 86 mmHg) and further increased cardiac output (6.4 vs. 7.1 l/min). EPI, however, decreased renal blood flow (330 vs. 247 ml/min) and renal conductance. EPI also reduced mesenteric and coronary conductance without changes in flows. Compared to vehicle, EPI increased urine output (293 vs. 544 ml/6 h) but not creatinine clearance. EPI increased lactate (1.8 vs. 15.7 mmol/l) with accompanying acidosis (serum bicarbonate: 25.2 vs. 15.7 mmol/l), hyperglycaemia (2.6 vs. 13.5 mmol/l) and hypokalaemia (4.3 vs. 3.0 mmol/l). CONCLUSIONS:Hyperdynamic sepsis increased blood flow to heart, gut and kidney. Although EPI infusion further increased cardiac output, blood pressure and myocardial performance, it was also associated with potent metabolic effects, decreased mesenteric, coronary and renal conductance and a significant reduction in renal blood flow.
10.1007/s00134-005-2580-x
Pivotal role of gp91phox-containing NADH oxidase in lipopolysaccharide-induced tumor necrosis factor-alpha expression and myocardial depression.
Peng Tianqing,Lu Xiangru,Feng Qingping
Circulation
BACKGROUND:Lipopolysaccharide (LPS) induces cardiomyocyte tumor necrosis factor-alpha (TNF-alpha) production, which is responsible for myocardial depression during sepsis. The aim of this study was to investigate the role of gp91phox-containing NADH oxidase signaling in cardiomyocyte TNF-alpha expression and myocardial dysfunction induced by LPS. METHODS AND RESULTS:In cultured mouse neonatal cardiomyocytes, LPS increased NADH oxidase (gp91phox subunit) expression and superoxide generation. Deficiency of gp91phox or inhibition of NADH oxidase blocked TNF-alpha expression stimulated by LPS. TNF-alpha induction was also inhibited by tempol, N-acetylcysteine, or 1,3-dimethyl-2-thiourea. NADH oxidase activation by LPS increased ERK1/2 and p38 phosphorylation, and inhibition of ERK1/2 and p38 phosphorylation blocked the effect of NADH oxidase on TNF-alpha expression. Isolated mouse hearts were perfused with LPS (5 microg/mL) alone or in the presence of apocynin for 1 hour. Myocardial TNF-alpha production was decreased in gp91phox-deficient or apocynin-treated hearts compared with those of wild type (P<0.05). To investigate the role of gp91phox-containing NADH oxidase in endotoxemia, mice were treated with LPS (4 mg/kg IP) for 4 and 24 hours, and their heart function was measured with a Langendorff system. Deficiency of gp91phox significantly attenuated LPS-induced myocardial depression (P<0.05). CONCLUSIONS:gp91phox-Containing NADH oxidase is pivotal in LPS-induced TNF-alpha expression and cardiac depression. Effects of NADH oxidase activation are mediated by ERK1/2 and p38 MAPK pathway. The present results suggest that gp91phox-containing NADH oxidase may represent a potential therapeutic target for myocardial dysfunction in sepsis.
10.1161/01.CIR.0000160366.50210.E9
Endotoxin-induced myocardial dysfunction: effects of macrophage migration inhibitory factor neutralization.
Chagnon Frederic,Metz Christine N,Bucala Richard,Lesur Olivier
Circulation research
The pathophysiology of sepsis-induced myocardial dysfunction still remains controversial. Macrophage migration inhibitory factor (MIF) has recently been identified as a cardiac-derived myocardial depressant factor in septic shock. Putative mechanisms by which MIF affects cardiac function are unknown. In an investigation of possible mechanisms of action, a rat model of endotoxin toxicity was designed using intraperitoneal (I/P) injection of lipopolysaccharides (LPS) with or without coinfusion of neutralizing anti-MIF or isotypic-matched antibodies. Echocardiographic evaluation revealed that MIF neutralization reversed endotoxin-induced myocardial dysfunction at 24 hours after injection. RNase protection assay (RPA) and Western blot established that MIF neutralization prevented LPS-induced mRNA expression and production of heart-derived inflammatory paracrine and autocrine cytokines such as IL-1s and IL-6. Moreover, MIF immunoneutralization increased heart Bcl-2/Bax protein ratio and suppressed endotoxin-induced release of mitochondrial cytochrome-c, as demonstrated by Western blotting. Inhibition of mitochondrial loss of cytochrome-c decreased in heart caspase-3 activity at 6 and 24 hours after injection. MIF neutralization also restored the LPS-induced deficient nuclear translocation of phospho-Akt and consequently the expression of the heart survival nuclear factor GATA-4. The restoration of the translocation/expression of survival factors by MIF inhibition resulted in lowered endotoxin-induced DNA fragmentation at 24 hours, a hallmark of downstream cardiomyocyte apoptosis. Our data indicate that early inactivation of MIF significantly reverses the imbalance of proapoptotic to prosurvival pathways and reduces acute inflammation of the heart thereby improving myocardial dysfunction induced by endotoxin.
10.1161/01.RES.0000168327.22888.4d
Ventricular myocyte caspases are directly responsible for endotoxin-induced cardiac dysfunction.
Lancel Steve,Joulin Olivier,Favory Raphael,Goossens Jean Francois,Kluza Jérome,Chopin Claude,Formstecher Pierre,Marchetti Philippe,Neviere Remi
Circulation
BACKGROUND:Although most of the deleterious effects of sepsis-induced apoptosis have been attributed to increased lymphocyte cell death, caspase activation may directly alter cell function of different organ systems. We postulated that left ventricular (LV) cardiomyocyte caspase activation is directly involved in sepsis-induced heart contractile dysfunction. METHODS AND RESULTS:LV cardiomyocytes isolated 4 hours after rat treatment with endotoxin injection (10 mg/kg) displayed major reductions in contractile reserve and myofilament response to Ca2+. Concomitantly, endotoxin also induced increases in LV cardiomyocyte caspase-3, -8, and -9-like activities, which were associated with sarcomeric structure destruction and cleavage of components of the cardiac myofilament. Interestingly, zVAD.fmk treatment of septic rat prevented LV cardiomyocyte contractile dysfunction, reductions in myofilament response to calcium, troponin T cleavage, and sarcomere destruction. Serum (10%) of endotoxin-treated rats induced contractile dysfunction, caspase-3-like activity increase, and troponin T cleavage of naive LV cardiomyocytes. The effects of septic serum were prevented in LV cardiomyocytes isolated from zVAD.fmk- or zDEVD.cmk-treated rats or LV cardiomyocytes preincubated with zVAD.fmk or zDEVD.cmk. CONCLUSIONS:The results show an important relationship between endotoxin-induced caspase activation and reduced contractile reserve and sarcomere disarray at the level of single LV cardiomyocytes.
10.1161/CIRCULATIONAHA.104.490979
Mechanisms of cardiac depression caused by lipoteichoic acids from Staphylococcus aureus in isolated rat hearts.
Grandel Ulrich,Hopf Michael,Buerke Michael,Hattar Katja,Heep Martina,Fink Ludger,Bohle Rainer M,Morath Siegfried,Hartung Thomas,Pullamsetti Soni,Schermuly Ralph T,Seeger Werner,Grimminger Friedrich,Sibelius Ulf
Circulation
BACKGROUND:Lipoteichoic acid (LTA) represents a major virulence factor in gram-positive sepsis. METHODS AND RESULTS:In the present study we perfused isolated rat hearts for 180 minutes with highly purified LTA from Staphylococcus aureus. A progressive decline of left ventricular contractile function paralleled by the expression of myocardial tumor necrosis factor-alpha (TNF-alpha) mRNA and protein as well as the release of TNF-alpha into the perfusate was observed in LTA-perfused hearts. Employment of an anti-TNF-alpha antibody completely prevented the loss in contractile function. When CD14, a prominent pathogen recognition receptor, was blocked by a specific antibody, induction of TNF-alpha mRNA and protein release as well as the associated cardiodepression was diminished in response to LTA. Synthesis of TNF-alpha protein was located to interstitial cells of LTA-challenged hearts as detected by immunohistochemistry. Besides progressive cardiodepression, coronary perfusion pressure (CPP) was moderately increased in LTA-perfused hearts. This was accompanied by the release of thromboxane A2 (TXA2) into the perfusate and the induction of cyclooxygenase (Cox)-2 mRNA and protein in the myocardium. Blocking of TXA2 by the nonspecific Cox inhibitor indomethacin, the thromboxane receptor antagonist daltroban, or the selective Cox-2 inhibitor NS-398 prevented the increase in CPP. CONCLUSIONS:LTA causes cardiac depression by activating myocardial TNF-alpha synthesis via CD14 and induces coronary vascular disturbances by activating Cox-2-dependent TXA2 synthesis. These phenomena may contribute to cardiac depression in gram-positive sepsis.
10.1161/CIRCULATIONAHA.104.503938
Protective effect of alpha-lipoic acid in lipopolysaccharide-induced endothelial fractalkine expression.
Sung Mi Jeong,Kim Won,Ahn So Young,Cho Chung-Hyun,Koh Gou Young,Moon Sang-Ok,Kim Duk Hoon,Lee Sik,Kang Kyung Pyo,Jang Kyu Yun,Park Sung Kwang
Circulation research
Fractalkine is a unique chemokine that functions as a chemoattractant as well as an adhesion molecule on endothelial cells activated by proinflammatory cytokines. Alpha-lipoic acid (LA), a naturally occurring dithiol compound, is an essential cofactor for mitochondrial bioenergetic enzymes. LA improves glycemic control, reduces diabetic polyneuropathies, and mitigates toxicity associated with heavy metal poisoning. The effects of LA on processes associated with sepsis, however, are unknown. We evaluated the antiinflammatory effect of LA on fractalkine expression in a lipopolysaccharide-induced endotoxemia model. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) significantly induced fractalkine mRNA and protein expression in endothelial cells. LA strongly suppressed TNF-alpha- or IL-1beta-induced fractalkine expression in endothelial cells by suppressing the activities of nuclear factor-kappaB and specificity protein-1. LA also decreased TNF-alpha- or IL-1beta-stimulated monocyte adhesion to human umbilical vein endothelial cells. As shown by immunohistochemistry, fractalkine protein expression was markedly increased by treatment with lipopolysaccharide in arterial endothelial cells, endocardium, and endothelium of intestinal villi. LA suppressed lipopolysaccharide-induced fractalkine protein expression and infiltration of endothelin 1-positive cells into the heart and intestine in vivo. LA protected against lipopolysaccharide-induced myocardial dysfunction and improved survival in lipopolysaccharide-induced endotoxemia. These results suggest that LA could be an effective agent to reduce fractalkine-mediated inflammatory processes in endotoxemia.
10.1161/01.RES.0000186522.89544.4D
Calcineurin regulates myocardial function during acute endotoxemia.
Joshi Mandar S,Julian Mark W,Huff Jennifer E,Bauer John A,Xia Yong,Crouser Elliott D
American journal of respiratory and critical care medicine
RATIONALE:Cyclosporin A (CsA) is known to preserve cardiac contractile function during endotoxemia, but the mechanism is unclear. Increased nitric oxide (NO) production and altered mitochondrial function are implicated as mechanisms contributing to sepsis-induced cardiac dysfunction, and CsA has the capacity to reduce NO production and inhibit mitochondrial dysfunction relating to the mitochondrial permeability transition (MPT). OBJECTIVES:We hypothesized that CsA would protect against endotoxin-mediated cardiac contractile dysfunction by attenuating NO production and preserving mitochondrial function. METHODS:Left ventricular function was measured continuously over 4 h in cats assigned as follows: control animals (n = 7); LPS alone (3 mg/kg, n = 8); and CsA (6 mg/kg, n = 7), a calcineurin inhibitor that blocks the MPT, or tacrolimus (FK506, 0.1 mg/kg, n = 7), a calcineurin inhibitor lacking MPT activity, followed in 30 min by LPS. Myocardial tissue was then analyzed for NO synthase-2 expression, tissue nitration, protein carbonylation, and mitochondrial morphology and function. MEASUREMENTS AND MAIN RESULTS:LPS treatment resulted in impaired left ventricular contractility, altered mitochondrial morphology and function, and increased protein nitration. As hypothesized, CsA pretreatment normalized cardiac performance and mitochondrial respiration and reduced myocardial protein nitration. Unexpectedly, FK506 pretreatment had similar effects, normalizing both cardiac and mitochondrial parameters. However, CsA and FK506 pretreatments markedly increased protein carbonylation in the myocardium despite elevated manganese superoxide dismutase activity during endotoxemia. CONCLUSIONS:Our data indicate that calcineurin is a critical regulator of mitochondrial respiration, tissue nitration, protein carbonylation, and contractile function in the heart during acute endotoxemia.
10.1164/rccm.200411-1507OC
Polyethylene glycol-superoxide dismutase prevents endotoxin-induced cardiac dysfunction.
Supinski Gerald S,Callahan Leigh A
American journal of respiratory and critical care medicine
RATIONALE:Sepsis produces significant mitochondrial and contractile dysfunction in the heart, but the role of superoxide-derived free radicals in the genesis of these abnormalities is not completely understood. OBJECTIVES:The study was designed to test the hypothesis that superoxide scavenger administration prevents endotoxin-induced cardiac mitochondrial and contractile dysfunction. METHODS:Four groups of rats were studied, and animals were injected with either saline, endotoxin, endotoxin plus polyethylene glycol-adsorbed-superoxide dismutase (PEG-SOD; a free-radical scavenger), or PEG-SOD alone. Animals were killed 48 h after injections. We then measured cardiac mitochondrial generation of reactive oxygen species (ROS), formation of free-radical reaction products (protein carbonyls, lipid aldehydes, nitrotyrosine), mitochondrial function, and cardiac contractile function. MEASUREMENTS AND MAIN RESULTS:Endotoxin elicited increases in cardiac mitochondrial ROS formation (p < 0.001), increases in cardiac levels of free-radical reaction products, reductions in mitochondrial ATP generation (p < 0.001), and decrements in cardiac pressure-generating capacity (p < 0.01). Administration of PEG-SOD blocked formation of free-radical reaction products, prevented mitochondrial dysfunction, and preserved cardiac contractility. For example, mitochondrial ATP generation was 923 +/- 50, 392 +/- 32, 753 +/- 25, and 763 +/- 36 nmol/min/mg, respectively, for control, endotoxin, endotoxin + PEG-SOD, and PEG-SOD groups (p < 0.001). In addition, cardiac systolic pressure generation at a diastolic pressure of 15 mm Hg averaged 110 +/- 11, 66 +/- 7, 129 +/- 10 and 124 +/- 5 mm Hg, respectively, for control, endotoxin, endotoxin + PEG-SOD, and PEG-SOD groups (p < 0.01). CONCLUSION:These data indicate that superoxide-derived oxidants play a critical role in the development of cardiac mitochondrial and contractile dysfunction in endotoxin-induced sepsis.
10.1164/rccm.200410-1346OC
Effects of 15-deoxy-Delta12,14-prostaglandin-J2 during hyperdynamic porcine endotoxemia.
Hauser Balázs,Kick Jochen,Iványi Zsolt,Asfar Pierre,Ehrmann Ulrich,Muth Claus-Martin,Albicini Maura,Wachter Ulrich,Vogt Josef,Bauer Michael,Brückner Uwe Bernd,Radermacher Peter,Bracht Hendrik
Intensive care medicine
OBJECTIVE:To investigate the hemodynamic and metabolic effects of the peroxisome proliferator-activated receptor (PPAR)-gamma ligand and nuclear-factor (NF)-kappa B inhibitor 15-deoxy-Delta12,14-prostaglandin-J2 (15d-PGJ2) during long-term, hyperdynamic porcine endotoxemia. DESIGN:Prospective, randomized, controlled experimental study with repeated measures. SETTING:Investigational animal laboratory. SUBJECTS:19 anesthetized, mechanically ventilated and instrumented pigs. INTERVENTIONS:At 12 h of continuous intravenous endotoxin and hydroxyethylstarch to keep mean arterial pressure (MAP)>60 mmHg, swine randomly received vehicle (control group, n=10) or 15-deoxy-Delta12,14-prostaglandin-J2 (15d-PGJ2 group, n=9; 1 microg kg(-1) min(-1) loading dose during 1 h; thereafter,0.25 microg kg(-1) min(-1) for 11 h). MEASUREMENTS AND RESULTS:Hemodynamic, metabolic and organ function parameters were assessed together with parameters of nitric oxide production and oxidative stress. 15d-PGJ2 prevented the endotoxin-induced progressive hypotension, due to a positive inotropic effect, which resulted in a significantly higher blood pressure during the treatment phase and prevented the rise in hepatic vein alanine-aminotransferase activity. It did not affect, however, any other parameter of organ function nor of nitric oxide production, proinflammatory cytokine release or lipid peroxidation (8-isoprostane). CONCLUSIONS:15d-PGJ2 stabilized systemic hemodynamics, due to improved myocardial performance, and resulted in an only transient effect on alanine-aminotransferase activity, without further beneficial effect on endotoxin-induced metabolic and organ function derangements. Low tissue 15d-PGJ2 concentrations and/or the delayed drug administration may explain these findings.
10.1007/s00134-006-0107-8
Cardiovascular protective role for activated protein C during endotoxemia in rats.
Favory Raphael,Lancel Steve,Maréchal Xavier,Tissier Stéphanie,Neviere Remi
Intensive care medicine
OBJECTIVE:We examined whether activated protein C (APC) treatment improves cardiovascular inflammation and dysfunction in endotoxemic rats. DESIGN AND SETTING:Randomized, controlled trial in an experimental laboratory of a university physiology department SUBJECTS:Male Sprague Dawley rats. INTERVENTIONS:Internal carotid artery and external jugular vein were catheterized under sterile conditions in rats. Instrumented rats infused or not with APC (240 microg/kg per hour) were challenged with E. coli endotoxin (10 mg/kg). Four hours after endotoxin challenge rats were prepared for cardiovascular functional studies and tissue and blood analyses. MEASUREMENTS AND RESULTS:Endotoxin administration induced systemic hypotension, depression of myocardial systolic performance and reduction in capillary density of the small intestine muscularis layer. Plasma levels of nitrite/nitrate, tumor necrosis factor alpha and macrophage migration inhibitory factor, mesentery venule leukocyte-endothelium interactions, heart and small intestine myeloperoxidase activities were increased in endotoxin-treated rats. APC largely prevented endotoxin-induced cardiovascular dysfunction with improved systemic hemodynamics, functional capillary density, and myocardial contractile performance. Beneficial cardiovascular effects of APC were associated with attenuation of entotoxin-induced inflammatory response in terms of plasma levels of nitrite/nitrate, tumor necrosis factor alpha, macrophage migration inhibitory factor, and endothelial cell-leukocyte activation. CONCLUSION:APC reduces systemic and tissue inflammation and preserves cardiovascular function during experimental endotoxemia.
10.1007/s00134-006-0166-x
Caspase inhibition prevents cardiac dysfunction and heart apoptosis in a rat model of sepsis.
Nevière R,Fauvel H,Chopin C,Formstecher P,Marchetti P
American journal of respiratory and critical care medicine
Despite intensive therapy, severe septic shock is commonly associated with myocardial dysfunction and death in humans. No new therapies have proven efficiency against cardiovascular alterations in sepsis. Here, we addressed the question of a beneficial effect of pharmacological inhibition of caspases on myocardial dysfunction following endotoxin treatment. Hearts from rats treated with endotoxin (10 mg/kg, intravenously) were isolated 4 h posttreatment for analysis. Assessment of myocardial contractility ex vivo and detection of apoptosis were performed. Hearts from endotoxin-treated rats displayed multiple caspase activities and also typical apoptosis pattern as detected by TUNEL, DNA fragmentation assays, and cytochrome c release as compared with control rats. z-VAD.fmk (3 mg/kg, intravenously), a broad spectrum caspase inhibitor (but not the irrelevant peptide z-FA.fmk), in coinjection with endotoxin, not only reduced caspase activities and nuclear apoptosis but also completely prevented endotoxin-induced myocardial dysfunction evaluated 4 h and even 14 h after endotoxin challenge. These data indicate that caspase activation plays an important role in myocardial cell dysfunction. Moreover, these results suggest that inhibitors of caspases may have important therapeutic applications in sepsis.
10.1164/ajrccm.163.1.2003109
Endotoxin-induced cardiomyopathy and systemic inflammation in mice is prevented by aldose reductase inhibition.
Ramana Kota V,Willis Monte S,White Michael D,Horton Jureta W,DiMaio J Michael,Srivastava Deepak,Bhatnagar Aruni,Srivastava Satish K
Circulation
BACKGROUND:Sepsis is a systemic inflammatory response syndrome characterized by excessive production of inflammatory cytokines and cardiovascular collapse. Postreceptor signaling events that lead to stress responses and cytokine production are sensitive to redox changes and products of lipid peroxidation. METHODS AND RESULTS:We tested the hypothesis that inflammatory signaling and cytokine generation during sepsis depend on the activity of the enzyme aldose reductase, which catalyzes the reduction of lipid peroxidation-derived aldehydes and their glutathione conjugates. The results of the present study show that pharmacological inhibition of aldose reductase by sorbinil or knockdown of the enzyme by small interfering RNA prevents the activation of nuclear factor-kappaB and the release of tumor necrosis factor-alpha from lipopolysaccharide-stimulated RAW264.7 or H9c2 cells. Increases in serum and cardiac cytokines in response to lipopolysaccharide challenge were suppressed by inhibition of aldose reductase. Treatment with sorbinil blunted the activation of protein kinase C, c-Jun NH2-terminal kinase, and p38, as well as phosphorylation of interleukin receptor-associated kinase, IkappaB-alpha, IkappaB kinase complex-alpha/beta, and phospholipase-gamma1 and -beta1. These changes were associated with decreased myocardial nuclear factor-kappaB and activating protein-1 activity, prostaglandin E2 production, induction of cyclooxygenase 2, and inducible nitric oxide synthase. Sorbinil treatment also induced functional recovery in myocardial fractional shortening in vivo and preserved contractile function of isolated perfused hearts. Inhibition of aldose reductase increased survival in mice injected with lethal doses of lipopolysaccharide. CONCLUSIONS:The present demonstration that aldose reductase mediates endotoxin-induced inflammation and cardiomyopathy suggests that inhibition of this enzyme may be useful to attenuate maladaptive host responses and to treat acute cardiovascular dysfunction associated with endotoxic shock.
10.1161/CIRCULATIONAHA.106.630830
Cardiomyocyte-specific overexpression of nitric oxide synthase 3 prevents myocardial dysfunction in murine models of septic shock.
Ichinose Fumito,Buys Emmanuel S,Neilan Tomas G,Furutani Elissa M,Morgan John G,Jassal Davinder S,Graveline Amanda R,Searles Robert J,Lim Chee C,Kaneki Masao,Picard Michael H,Scherrer-Crosbie Marielle,Janssens Stefan,Liao Ronglih,Bloch Kenneth D
Circulation research
Myocardial dysfunction contributes to the high mortality of patients with endotoxemia. Although nitric oxide (NO) has been implicated in the pathogenesis of septic cardiovascular dysfunction, the role of myocardial NO synthase 3 (NOS3) remains incompletely defined. Here we show that mice with cardiomyocyte-specific NOS3 overexpression (NOS3TG) are protected from myocardial dysfunction and death associated with endotoxemia. Endotoxin induced more marked impairment of Ca(2+) transients and cellular contraction in wild-type than in NOS3TG cardiomyocytes, in part, because of greater total sarcoplasmic reticulum Ca(2+) load and myofilament sensitivity to Ca(2+) in the latter during endotoxemia. Endotoxin increased reactive oxygen species production in wild-type but not NOS3TG hearts, in part, because of increased xanthine oxidase activity. Inhibition of NOS by N(G)-nitro-l-arginine-methyl ester restored the ability of endotoxin to increase reactive oxygen species production and xanthine oxidase activity in NOS3TG hearts to the levels measured in endotoxin-challenged wild-type hearts. Allopurinol, a xanthine oxidase inhibitor, attenuated endotoxin-induced reactive oxygen species accumulation and myocardial dysfunction in wild-type mice. The protective effects of cardiomyocyte NOS3 on myocardial function and survival were further confirmed in a murine model of polymicrobial sepsis. These results suggest that increased myocardial NO levels attenuate endotoxin-induced reactive oxygen species production and increase total sarcoplasmic reticulum Ca(2+) load and myofilament sensitivity to Ca(2+), thereby reducing myocardial dysfunction and mortality in murine models of septic shock.
10.1161/01.RES.0000253888.09574.7a
Myocardial lactate deprivation is associated with decreased cardiovascular performance, decreased myocardial energetics, and early death in endotoxic shock.
Levy Bruno,Mansart Arnauld,Montemont Chantal,Gibot Sebastien,Mallie Jean-Pierre,Regnault Veronique,Lecompte Thomas,Lacolley Patrick
Intensive care medicine
OBJECTIVE:We examined whether lactate availability is a limiting factor for heart function during endotoxic shock, and whether lactate deprivation thus induces heart energy depletion, thereby altering cardiovascular performance. The study goals were to determine whether muscle lactate production is linked to beta(2)-stimulation and to ascertain the effects of systemic lactate deprivation on hemodynamics, lactate metabolism, heart energetics, and outcome in a lethal model of rat's endotoxic shock. INTERVENTIONS:We modulated the adrenergic pathway in skeletal muscle using microdialysis with ICI-118551, a selective beta(2)-blocker. Muscle lactate formation in endotoxic shock was further inhibited by intravenous infusion of ICI-118551 or dichloroacetate (DCA), an activator of pyruvate dehydrogenase (DCA) and their combination. RESULTS:Muscle lactate formation was decreased by ICI-118551. During endotoxic shock both ICI-118151 and DCA decreased circulating and heart lactate concentrations in parallel with a decrease in tissue ATP content. The combination ICI-118551-DCA resulted in early cardiovascular collapse and death. The addition of molar lactate to ICI-1185111 plus DCA blunted the effects of ICI-118551+DCA on hemodynamics. Survival was markedly less with ICI-118551 than with endotoxin alone. CONCLUSION:Systemic lactate deprivation is detrimental to myocardial energetics, cardiovascular performance, and outcome.
10.1007/s00134-006-0523-9
Sepsis is associated with an upregulation of functional beta3 adrenoceptors in the myocardium.
Moniotte S,Belge C,Sekkali B,Massion P B,Rozec B,Dessy C,Balligand J-L
European journal of heart failure
OBJECTIVE:To analyze the implication of the beta3-adrenoceptor (beta3-AR) pathway in human septic myocardium and a murine model of sepsis, a condition associated with myocardial depression. METHODS AND RESULTS:beta3-AR and eNOS protein abundance were increased (332+/-66.4% and 218+/-39.3; P<0.05) in hearts from septic patients. The effect of BRL37344, a beta3-AR-preferential agonist, was analyzed by videomicroscopy on the contractility of neonatal mouse ventricular myocytes (NMVM) incubated with conditioned medium from LPS-stimulated cultured macrophages (Mc-LPS+ medium). Stimulation of untreated NMVM with BRL37344 dose-dependently decreased the amplitude of contractile shortening (P<0.05). This response was abolished by L-NAME (NOS inhibitor). Incubation in Mc-LPS+ medium potentiated the depressing effect of BRL37344 (P<0.05) as well as of SR58611A (P<0.05) in wild-type myocytes. Importantly, the contractile depression was abrogated in cardiomyocytes from beta3-AR KO mice. CONCLUSIONS:beta3-AR are upregulated during sepsis in the human myocardium and by cytokines in murine cardiomyocytes, where they mediate an increased negative inotropic response to beta3 agonists. Activation of the beta3-AR pathway by catecholamines may contribute to the myocardial dysfunction in sepsis.
10.1016/j.ejheart.2007.10.006
S100A8 and S100A9 mediate endotoxin-induced cardiomyocyte dysfunction via the receptor for advanced glycation end products.
Boyd John H,Kan Bernard,Roberts Haley,Wang Yingjin,Walley Keith R
Circulation research
Cardiovascular dysfunction as a result of sepsis is the leading cause of death in the critically ill. Cardiomyocytes respond to infectious pathogens with a Toll-like receptor-initiated proinflammatory response in conjunction with a decrease in contractility, although the downstream events linking Toll-like receptor activation and reduced cardiac contractility remain to be elucidated. Using microarray analysis of cardiac tissue exposed to systemic lipopolysaccharide (LPS), we discovered that 2 small calcium-regulating proteins (S100A8 and S100A9) are highly upregulated. HL-1 cardiomyocytes, isolated primary cardiomyocytes, and live mice were exposed to LPS, whereas beating HL-1 cells had S100A8 and S100A9 overexpressed and their calcium flux quantified. Using in vivo microbubble technology, we delivered S100A8 and S100A9 to normal mouse hearts; using the same technology, we inhibited S100A9 production in mouse hearts and subsequently exposed them to LPS. Coimmunoprecipitation of S100A8 and S100A9 identified interaction with RAGE (the receptor for advanced glycation end products), the cardiac function and postreceptor signaling of which were investigated. HL-1 cardiomyocytes, isolated primary cardiomyocytes, and whole hearts exposed to LPS have large increases in S100A8 and S100A9. Cardiac overexpression of S100A8 and S100A9 led to a RAGE-dependent decrease in calcium flux and, in the intact mouse, to a decreased cardiac ejection fraction, whereas knockdown of S100A9 attenuated LPS-induced cardiac dysfunction. Cardiomyocytes exposed to LPS express S100A8 and S100A9, leading to a RAGE-mediated decrease in cardiomyocyte contractility. This finding provides a novel mechanistic link between circulating pathogen-associated molecular products and subsequent cardiac dysfunction.
10.1161/CIRCRESAHA.107.167544
Effect of SOD-1 over-expression on myocardial function during resuscitated murine septic shock.
Baumgart Katja,Simkova Vladislava,Wagner Florian,Weber Sandra,Georgieff Michael,Radermacher Peter,Albuszies Gerd,Barth Eberhard
Intensive care medicine
PURPOSE:To test the hypothesis whether genetic over-expression of the Cu/Zn-superoxide dismutase (SOD-1) prevents the sepsis-related impairment of myocardial function and norepinephrine responsiveness in a resuscitated murine model of septic shock. METHODS:Fifteen hours after cecal ligation and puncture or sham-operation wild type, heterozygous and homozygous SOD-1 over-expressing mice were anesthetized, ventilated and instrumented with central venous and left ventricular pressure-conductance catheters, to assess heart function at 18, 21, and 24 h after CLP or sham-operation. Hydroxyethylstarch and noradrenaline (in the CLP-mice only) were infused to maintain normotensive hemodynamics. RESULTS:Fluid resuscitation and noradrenaline requirements did not differ between the mouse strains. While total myocardial SOD activity was five- and ninefold higher in the heterozygous and homozygous over-expressing animals, respectively, tissue catalase activity was not different. Anesthesia and fluid resuscitation alone caused left ventricular dilatation and a progressive fall in left ventricular end-systolic pressure and maximal systolic contraction (dp/dt (max)), while stroke volume and cardiac output increased. Due to the noradrenaline infusion heart rate, end-systolic pressure as well as dp/dt (max) and dp/dt (max) were significantly higher and relaxation time significantly lower in the CLP-mice, again without difference between the genetic strains. CONCLUSION:We conclude that neither hetero- nor homozygous SOD-1 over-expression caused a sustained improvement of the sepsis-related impairment of myocardial norepinephrine responsiveness, possibly due to the lacking increase of the tissue catalase and the mitochondrial SOD activity as well as the ongoing i.v. noradrenaline.
10.1007/s00134-008-1319-x
Activation of endothelial intrinsic NF-{kappa}B pathway impairs protein C anticoagulation mechanism and promotes coagulation in endotoxemic mice.
Song Dongmei,Ye Xiaobing,Xu Honglei,Liu Shu Fang
Blood
Although the role of systemic activation of the nuclear factor kappaB (NF-kappaB) pathway in septic coagulation has been well documented, little is known about the contribution of endothelial-specific NF-kappaB signaling in this pathologic process. Here, we used transgenic mice that conditionally overexpress a mutant I-kappaBalpha, an inhibitor of NF-kappaB, selectively on endothelium, and their wild-type littermates to define the role of endothelial-specific NF-kappaB in septic coagulation. In wild-type mice, lipopolysaccharide (LPS) challenge (5 mg/kg intraperitoneally) caused markedly increased plasma markers of coagulation, decreased plasma fibrinogen level, and widespread tissue fibrin deposition, which were abrogated by endothelial NF-kappaB blockade in transgenic mice. Endothelial NF-kappaB blockade inhibited tissue factor expression in endothelial cells, but not in leukocytes. Endothelial NF-kappaB blockade did not inhibit LPS-induced tissue factor expression in heart, kidney, and liver. Endothelial NF-kappaB blockade prevented LPS down-regulation of endothelial protein C receptor (EPCR) and thrombomodulin protein expressions, inhibited tissue tumor necrosis factor-alpha converting enzyme activity, reduced EPCR shedding, and restored plasma protein C level. Our data demonstrate that endothelial intrinsic NF-kappaB signaling plays a pivotal role in septic coagulation and suggests a link between endothelial-specific NF-kappaB activation and the impairment of the thrombomodulin-protein C-EPCR anticoagulation pathway.
10.1182/blood-2009-02-205914
The emerging role of innate immunity in the heart and vascular system: for whom the cell tolls.
Mann Douglas L
Circulation research
Recent studies suggest that the heart possesses an innate immune system that is intended to delimit tissue injury, as well as orchestrate homoeostatic responses, within the heart. The extant literature suggests that this intrinsic stress response system is mediated, at least in part, by a family of pattern recognition receptors, most notably the Toll-like receptors. Although the innate immune system provides a short-term adaptive response to tissue injury, the beneficial effects of this phylogenetically ancient system may be lost if innate immune signaling becomes sustained and/or excessive; in which case, the salutary effects of activation of these pathways are contravened by the known deleterious effects of inflammatory signaling. Herein, the biology of innate immune signaling in the heart is reviewed, as well as the literature suggesting that the innate immune system is involved in the pathogenesis of atherosclerosis, acute coronary syndromes, stroke, viral myocarditis, sepsis, ischemia/reperfusion injury, and heart failure. The review concludes by discussing new therapies that are being developed to modulate the innate immune system.
10.1161/CIRCRESAHA.110.226936
Temporal changes in tissue cardiorespiratory function during faecal peritonitis.
Dyson Alex,Rudiger Alain,Singer Mervyn
Intensive care medicine
PURPOSE:Sepsis affects both macro- and micro-circulatory transport of oxygen to tissues, causing regional hypoxia. However, this relationship is poorly characterized with respect to inter-organ variability, disease severity and the evolution to organ dysfunction. We hypothesized that an early circulatory insult precedes the development of organ dysfunction, and is more severe in predicted non-survivors. Consequently, we assessed temporal changes in myocardial function and regional tissue oxygenation in peripheral and deep organs in a rat model of faecal peritonitis. We also examined the utility of a dynamic oxygen challenge test to assess the microcirculation. METHODS:Awake, tethered, fluid-resuscitated male Wistar rats were randomized to receive intraperitoneal injection of faecal slurry, or to act as controls. At either 6 or 24 h post insult, rats were anaesthetized and underwent echocardiography, arterial cannulation and placement of tissue oxygen probes in peripheral (muscle, bladder) and deep (liver and renal cortex) organ beds. Measurements were repeated during fluid loading and an oxygen challenge test (administration of high oxygen concentrations). RESULTS:Early sepsis (6 h) was characterized by a fall in global oxygen delivery with concurrent decreases in muscle, renal cortical and, especially, liver tissue PO2. By contrast, during established sepsis (24 h), myocardial and circulatory function had largely recovered despite increasing clinical unwellness, hyperlactataemia and biochemical evidence of organ failure. O2 challenge revealed an early depression of response that, by 24 h, had improved in all organ beds bar the kidney. CONCLUSIONS:This long-term septic model exhibited an early decline in tissue oxygenation, the degree of which related to predicted mortality. Clinical and biochemical deterioration, however, progressed despite cardiovascular recovery. Early circulatory dysfunction may thus be an important trigger for downstream processes that result in multi-organ failure. Furthermore, the utility of tissue PO2 monitoring to highlight the local oxygen supply-demand balance, and dynamic O2 challenge testing to assess microcirculatory function merit further investigation.
10.1007/s00134-011-2227-z
Inflammation in myocardial diseases.
Marchant David J,Boyd John H,Lin David C,Granville David J,Garmaroudi Farshid S,McManus Bruce M
Circulation research
Inflammatory processes underlie a broad spectrum of conditions that injure the heart muscle and cause both structural and functional deficits. In this article, we address current knowledge regarding 4 common forms of myocardial inflammation: myocardial ischemia and reperfusion, sepsis, viral myocarditis, and immune rejection. Each of these pathological states has its own unique features in pathogenesis and disease evolution, but all reflect inflammatory mechanisms that are partially shared. From the point of injury to the mobilization of innate and adaptive immune responses and inflammatory amplification, the cellular and soluble mediators and mechanisms examined in this review will be discussed with a view that both beneficial and adverse consequences arise in these human conditions.
10.1161/CIRCRESAHA.111.243170
The beneficial effects of melatonin against heart mitochondrial impairment during sepsis: inhibition of iNOS and preservation of nNOS.
Ortiz Francisco,García José A,Acuña-Castroviejo Darío,Doerrier Carolina,López Ana,Venegas Carmen,Volt Huayqui,Luna-Sánchez Marta,López Luis C,Escames Germaine
Journal of pineal research
While it is accepted that the high production of nitric oxide (NO˙) by the inducible nitric oxide synthase (iNOS) impairs cardiac mitochondrial function during sepsis, the role of neuronal nitric oxide synthase (nNOS) may be protective. During sepsis, there is a significantly increase in the expression and activity of mitochondrial iNOS (i-mtNOS), which parallels the changes in cytosolic iNOS. The existence of a constitutive NOS form (c-mtNOS) in heart mitochondria has been also described, but its role in the heart failure during sepsis remains unclear. Herein, we analyzed the changes in mitochondrial oxidative stress and bioenergetics in wild-type and nNOS-deficient mice during sepsis, and the role of melatonin, a known antioxidant, in these changes. Sepsis was induced by cecal ligation and puncture, and heart mitochondria were analyzed for NOS expression and activity, nitrites, lipid peroxidation, glutathione and glutathione redox enzymes, oxidized proteins, and respiratory chain activity in vehicle- and melatonin-treated mice. Our data show that sepsis produced a similar induction of iNOS/i-mtNOS and comparable inhibition of the respiratory chain activity in wild-type and in nNOS-deficient mice. Sepsis also increased mitochondrial oxidative/nitrosative stress to a similar extent in both mice strains. Melatonin administration inhibited iNOS/i-mtNOS induction, restored mitochondrial homeostasis in septic mice, and preserved the activity of nNOS/c-mtNOS. The effects of melatonin were unrelated to the presence or the absence of nNOS. Our observations show a lack of effect of nNOS on heart bioenergetic impairment during sepsis and further support the beneficial actions of melatonin in sepsis.
10.1111/jpi.12099
Parmodulins inhibit thrombus formation without inducing endothelial injury caused by vorapaxar.
Aisiku Omozuanvbo,Peters Christian G,De Ceunynck Karen,Ghosh Chandra C,Dilks James R,Fustolo-Gunnink Susanna F,Huang Mingdong,Dockendorff Chris,Parikh Samir M,Flaumenhaft Robert
Blood
Protease-activated receptor-1 (PAR1) couples the coagulation cascade to platelet activation during myocardial infarction and to endothelial inflammation during sepsis. This receptor demonstrates marked signaling bias. Its activation by thrombin stimulates prothrombotic and proinflammatory signaling, whereas its activation by activated protein C (APC) stimulates cytoprotective and antiinflammatory signaling. A challenge in developing PAR1-targeted therapies is to inhibit detrimental signaling while sparing beneficial pathways. We now characterize a novel class of structurally unrelated small-molecule PAR1 antagonists, termed parmodulins, and compare the activity of these compounds to previously characterized compounds that act at the PAR1 ligand-binding site. We find that parmodulins target the cytoplasmic face of PAR1 without modifying the ligand-binding site, blocking signaling through Gαq but not Gα13 in vitro and thrombus formation in vivo. In endothelium, parmodulins inhibit prothrombotic and proinflammatory signaling without blocking APC-mediated pathways or inducing endothelial injury. In contrast, orthosteric PAR1 antagonists such as vorapaxar inhibit all signaling downstream of PAR1. Furthermore, exposure of endothelial cells to nanomolar concentrations of vorapaxar induces endothelial cell barrier dysfunction and apoptosis. These studies demonstrate how functionally selective antagonism can be achieved by targeting the cytoplasmic face of a G-protein-coupled receptor to selectively block pathologic signaling while preserving cytoprotective pathways.
10.1182/blood-2014-09-599910
Cardiotoxicity during invasive pneumococcal disease.
American journal of respiratory and critical care medicine
Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and sepsis, with adult hospitalization linked to approximately 19% incidence of an adverse cardiac event (e.g., heart failure, arrhythmia, infarction). Herein, we review the specific host-pathogen interactions that contribute to cardiac dysfunction during invasive pneumococcal disease: (1) cell wall-mediated inhibition of cardiomyocyte contractility; (2) the new observation that S. pneumoniae is capable of translocation into the myocardium and within the heart, forming discrete, nonpurulent, microscopic lesions that are filled with pneumococci; and (3) the bacterial virulence determinants, pneumolysin and hydrogen peroxide, that are most likely responsible for cardiomyocyte cell death. Pneumococcal invasion of heart tissue is dependent on the bacterial adhesin choline-binding protein A that binds to laminin receptor on vascular endothelial cells and binding of phosphorylcholine residues on pneumococcal cell wall to platelet-activating factor receptor. These are the same interactions responsible for pneumococcal translocation across the blood-brain barrier during the development of meningitis. We discuss these interactions and how their neutralization, either with antibody or therapeutic agents that modulate platelet-activating factor receptor expression, may confer protection against cardiac damage and meningitis. Considerable collagen deposition was observed in hearts of mice that had recovered from invasive pneumococcal disease. We discuss the possibility that cardiac scar formation after severe pneumococcal infection may explain why individuals who are hospitalized for pneumonia are at greater risk for sudden death up to 1 year after infection.
10.1164/rccm.201411-1951PP
The Platelet Napoleon Complex-Small Cells, but Big Immune Regulatory Functions.
Morrell Craig N,Pariser Daphne N,Hilt Zachary T,Vega Ocasio Denisse
Annual review of immunology
Platelets have dual physiologic roles as both cellular mediators of thrombosis and immune modulatory cells. Historically, the thrombotic function of platelets has received significant research and clinical attention, but emerging research indicates that the immune regulatory roles of platelets may be just as important. We now know that in addition to their role in the acute thrombotic event at the time of myocardial infarction, platelets initiate and accelerate inflammatory processes that are part of the pathogenesis of atherosclerosis and myocardial infarction expansion. Furthermore, it is increasingly apparent from recent studies that platelets impact the pathogenesis of many vascular inflammatory processes such as autoimmune diseases, sepsis, viral infections, and growth and metastasis of many types of tumors. Therefore, we must consider platelets as immune cells that affect all phases of immune responses.
10.1146/annurev-immunol-042718-041607
Neutralizing the pathological effects of extracellular histones with small polyanions.
Meara Connor H O',Coupland Lucy A,Kordbacheh Farzaneh,Quah Benjamin J C,Chang Chih-Wei,Simon Davis David A,Bezos Anna,Browne Anna M,Freeman Craig,Hammill Dillon J,Chopra Pradeep,Pipa Gergely,Madge Paul D,Gallant Esther,Segovis Courtney,Dulhunty Angela F,Arnolda Leonard F,Mitchell Imogen,Khachigian Levon M,Stephens Ross W,von Itzstein Mark,Parish Christopher R
Nature communications
Extracellular histones in neutrophil extracellular traps (NETs) or in chromatin from injured tissues are highly pathological, particularly when liberated by DNases. We report the development of small polyanions (SPAs) (~0.9-1.4 kDa) that interact electrostatically with histones, neutralizing their pathological effects. In vitro, SPAs inhibited the cytotoxic, platelet-activating and erythrocyte-damaging effects of histones, mechanistic studies revealing that SPAs block disruption of lipid-bilayers by histones. In vivo, SPAs significantly inhibited sepsis, deep-vein thrombosis, and cardiac and tissue-flap models of ischemia-reperfusion injury (IRI), but appeared to differ in their capacity to neutralize NET-bound versus free histones. Analysis of sera from sepsis and cardiac IRI patients supported these differential findings. Further investigations revealed this effect was likely due to the ability of certain SPAs to displace histones from NETs, thus destabilising the structure. Finally, based on our work, a non-toxic SPA that inhibits both NET-bound and free histone mediated pathologies was identified for clinical development.
10.1038/s41467-020-20231-y
Liver X receptor agonist GW3965 protects against sepsis by promoting myeloid derived suppressor cells apoptosis in mice.
Zhang Wenqin,Luo Minjie,Zhou Yuexue,Hu Jie,Li Caiyan,Liu Ke,Liu Meidong,Zhu Yaxi,Chen Huan,Zhang Huali
Life sciences
AIMS:Immunosuppressive myeloid-derived suppressor cells (MDSCs) continuously expand and lead to poor outcome during sepsis. The activation of liver X receptor (LXR) can mitigate sepsis-induced liver and myocardial damage. This study aims to determine whether LXR plays a protective role in sepsis by regulating MDSCs. MAIN METHODS:Cecal ligation and puncture(CLP)was used to induce sepsis in mice. The mice were then treated with LXR agonist GW3965 (3 mg/kg) or vehicle 1 h, 6 h, 12 h, 24 h, 48 h, 72 h postoperatively. The effect of LXR on the survival rate and multi-organ injury induced by sepsis was evaluated by survival analysis, histological staining, biochemical analysis and ELISAs. The percentages of MDSCs and T cells were detected using flow cytometry. The mRNA expressions of LXR and ATP-binding cassette transporter A1 (ABCA1) were measured using real-time quantitative PCR (RT-qPCR). ABCA1 protein level was determined using immunofluorescence staining. KEY FINDINGS:LXR agonist GW3965 treatment improved the survival of septic mice, accompanied by reduced multi-organ injury and a decreased level of inflammatory cytokines. Furthermore, GW3965 treatment decreased MDSCs abundance in spleen by boosting the apoptosis of spleen MDSCs, therefore ameliorating their immunosuppressive activity. Meanwhile, bacteria clearance in tissues was enhanced after the GW3965 administration in septic mice. Mechanistically, GW3965 activated LXRβ and its downstream target ABCA1 to initiate the apoptosis of spleen MDSCs. SIGNIFICANCE:These findings provide new insights into the relationship between LXR and MDSCs in sepsis, thus revealing a potentially effective approach to target the immunosuppression of sepsis.
10.1016/j.lfs.2021.119434
Signaling by IL-6 promotes alternative activation of macrophages to limit endotoxemia and obesity-associated resistance to insulin.
Mauer Jan,Chaurasia Bhagirath,Goldau Julia,Vogt Merly C,Ruud Johan,Nguyen Khoa D,Theurich Sebastian,Hausen A Christine,Schmitz Joel,Brönneke Hella S,Estevez Emma,Allen Tamara L,Mesaros Andrea,Partridge Linda,Febbraio Mark A,Chawla Ajay,Wunderlich F Thomas,Brüning Jens C
Nature immunology
Obesity and resistance to insulin are closely associated with the development of low-grade inflammation. Interleukin 6 (IL-6) is linked to obesity-associated inflammation; however, its role in this context remains controversial. Here we found that mice with an inactivated gene encoding the IL-6Rα chain of the receptor for IL-6 in myeloid cells (Il6ra(Δmyel) mice) developed exaggerated deterioration of glucose homeostasis during diet-induced obesity, due to enhanced resistance to insulin. Tissues targeted by insulin showed increased inflammation and a shift in macrophage polarization. IL-6 induced expression of the receptor for IL-4 and augmented the response to IL-4 in macrophages in a cell-autonomous manner. Il6ra(Δmyel) mice were resistant to IL-4-mediated alternative polarization of macrophages and exhibited enhanced susceptibility to lipopolysaccharide (LPS)-induced endotoxemia. Our results identify signaling via IL-6 as an important determinant of the alternative activation of macrophages and assign an unexpected homeostatic role to IL-6 in limiting inflammation.
10.1038/ni.2865
A polyphenol-rich cranberry extract protects from diet-induced obesity, insulin resistance and intestinal inflammation in association with increased Akkermansia spp. population in the gut microbiota of mice.
Anhê Fernando F,Roy Denis,Pilon Geneviève,Dudonné Stéphanie,Matamoros Sébastien,Varin Thibault V,Garofalo Carole,Moine Quentin,Desjardins Yves,Levy Emile,Marette André
Gut
OBJECTIVE:The increasing prevalence of obesity and type 2 diabetes (T2D) demonstrates the failure of conventional treatments to curb these diseases. The gut microbiota has been put forward as a key player in the pathophysiology of diet-induced T2D. Importantly, cranberry (Vaccinium macrocarpon Aiton) is associated with a number of beneficial health effects. We aimed to investigate the metabolic impact of a cranberry extract (CE) on high fat/high sucrose (HFHS)-fed mice and to determine whether its consequent antidiabetic effects are related to modulations in the gut microbiota. DESIGN:C57BL/6J mice were fed either a chow or a HFHS diet. HFHS-fed mice were gavaged daily either with vehicle (water) or CE (200 mg/kg) for 8 weeks. The composition of the gut microbiota was assessed by analysing 16S rRNA gene sequences with 454 pyrosequencing. RESULTS:CE treatment was found to reduce HFHS-induced weight gain and visceral obesity. CE treatment also decreased liver weight and triglyceride accumulation in association with blunted hepatic oxidative stress and inflammation. CE administration improved insulin sensitivity, as revealed by improved insulin tolerance, lower homeostasis model assessment of insulin resistance and decreased glucose-induced hyperinsulinaemia during an oral glucose tolerance test. CE treatment was found to lower intestinal triglyceride content and to alleviate intestinal inflammation and oxidative stress. Interestingly, CE treatment markedly increased the proportion of the mucin-degrading bacterium Akkermansia in our metagenomic samples. CONCLUSIONS:CE exerts beneficial metabolic effects through improving HFHS diet-induced features of the metabolic syndrome, which is associated with a proportional increase in Akkermansia spp.
10.1136/gutjnl-2014-307142
ICAM-1-expressing neutrophils exhibit enhanced effector functions in murine models of endotoxemia.
Woodfin Abigail,Beyrau Martina,Voisin Mathieu-Benoit,Ma Bin,Whiteford James R,Hordijk Peter L,Hogg Nancy,Nourshargh Sussan
Blood
Intracellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein expressed on the cell surface of numerous cell types such as endothelial and epithelial cells, vascular smooth muscle cells, and certain leukocyte subsets. With respect to the latter, ICAM-1 has been detected on neutrophils in several clinical and experimental settings, but little is known about the regulation of expression or function of neutrophil ICAM-1. In this study, we report on the de novo induction of ICAM-1 on the cell surface of murine neutrophils by lipopolysaccharide (LPS), tumor necrosis factor, and zymosan particles in vitro. The induction of neutrophil ICAM-1 was associated with enhanced phagocytosis of zymosan particles and reactive oxygen species (ROS) generation. Conversely, neutrophils from ICAM-1-deficient mice were defective in these effector functions. Mechanistically, ICAM-1-mediated intracellular signaling appeared to support neutrophil ROS generation and phagocytosis. In vivo, LPS-induced inflammation in the mouse cremaster muscle and peritoneal cavity led to ICAM-1 expression on intravascular and locally transmigrated neutrophils. The use of chimeric mice deficient in ICAM-1 on myeloid cells demonstrated that neutrophil ICAM-1 was not required for local neutrophil transmigration, but supported optimal intravascular and extravascular phagocytosis of zymosan particles. Collectively, the present results shed light on regulation of expression and function of ICAM-1 on neutrophils and identify it as an additional regulator of neutrophil effector responses in host defense.
10.1182/blood-2015-08-664995
Same molecule but different expression: aging and sepsis trigger NLRP3 inflammasome activation, a target of melatonin.
Volt Huayqui,García José A,Doerrier Carolina,Díaz-Casado María E,Guerra-Librero Ana,López Luis C,Escames Germaine,Tresguerres Jesús A,Acuña-Castroviejo Darío
Journal of pineal research
The connection between the innate immune system, clock genes, and mitochondrial bioenergetics was analyzed during aging and sepsis in mouse heart. Our results suggest that the sole NF-κB activation does not explain the inflammatory process underlying aging; the former also triggers the NLRP3 inflammasome that enhances caspase-1-dependent maturation of IL-1β. In this way, aged mice enter into a vicious cycle as IL-1β further activates the NF-κB/NLRP3 inflammasome link. The origin of NF-κB activation was related to the age-dependent Bmal1/Clock/RORα/Rev-Erbα loop disruption, which lowers NAD(+) levels, reducing the SIRT1 deacetylase ability to inactivate NF-κB. Consequently, NF-κB binding to DNA increases, raising the formation of proinflammatory mediators and inducing mitochondrial impairment. The cycle is then closed with the subsequent NLRP3 inflammasome activation. This paired contribution of the innate immune pathways serves as a catalyst to magnify the response to sepsis in aged compared with young mice. Melatonin administration blunted the septic response, reducing inflammation and oxidative stress, and enhancing mitochondrial function at the levels of nonseptic aged mice, but it did not counteract the age-related inflammation. Together, our results suggest that, although with different strengths, chronoinflammaging constitutes the biochemical substrate of aging and sepsis, and identifies the NLRP3 inflammasome as a new molecular target for melatonin, providing a rationale for its use in NLRP3-dependent diseases.
10.1111/jpi.12303
Lipid Use and Misuse by the Heart.
Schulze P Christian,Drosatos Konstantinos,Goldberg Ira J
Circulation research
The heart utilizes large amounts of fatty acids as energy providing substrates. The physiological balance of lipid uptake and oxidation prevents accumulation of excess lipids. Several processes that affect cardiac function, including ischemia, obesity, diabetes mellitus, sepsis, and most forms of heart failure lead to altered fatty acid oxidation and often also to the accumulation of lipids. There is now mounting evidence associating certain species of these lipids with cardiac lipotoxicity and subsequent myocardial dysfunction. Experimental and clinical data are discussed and paths to reduction of toxic lipids as a means to improve cardiac function are suggested.
10.1161/CIRCRESAHA.116.306842
Autophagy Primes Neutrophils for Neutrophil Extracellular Trap Formation during Sepsis.
Park So Young,Shrestha Sanjeeb,Youn Young-Jin,Kim Jun-Kyu,Kim Shin-Yeong,Kim Hyun Jung,Park So-Hee,Ahn Won-Gyun,Kim Shin,Lee Myung Goo,Jung Ki-Suck,Park Yong Bum,Mo Eun-Kyung,Ko Yousang,Lee Suh-Young,Koh Younsuck,Park Myung Jae,Song Dong-Keun,Hong Chang-Won
American journal of respiratory and critical care medicine
RATIONALE:Neutrophils are key effectors in the host's immune response to sepsis. Excessive stimulation or dysregulated neutrophil functions are believed to be responsible for sepsis pathogenesis. However, the mechanisms regulating functional plasticity of neutrophils during sepsis have not been fully determined. OBJECTIVES:We investigated the role of autophagy in neutrophil functions during sepsis in patients with community-acquired pneumonia. METHODS:Neutrophils were isolated from patients with sepsis and stimulated with phorbol 12-myristate 13-acetate (PMA). The levels of reactive oxygen species generation, neutrophil extracellular trap (NET) formation, and granule release, and the autophagic status were evaluated. The effect of neutrophil autophagy augmentation was further evaluated in a mouse model of sepsis. MEASUREMENTS AND MAIN RESULTS:Neutrophils isolated from patients who survived sepsis showed an increase in autophagy induction, and were primed for NET formation in response to subsequent PMA stimulation. In contrast, neutrophils isolated from patients who did not survive sepsis showed dysregulated autophagy and a decreased response to PMA stimulation. The induction of autophagy primed healthy neutrophils for NET formation and vice versa. In a mouse model of sepsis, the augmentation of autophagy improved survival via a NET-dependent mechanism. CONCLUSIONS:These results indicate that neutrophil autophagy primes neutrophils for increased NET formation, which is important for proper neutrophil effector functions during sepsis. Our study provides important insights into the role of autophagy in neutrophils during sepsis.
10.1164/rccm.201603-0596OC
Melatonin administration to wild-type mice and nontreated NLRP3 mutant mice share similar inhibition of the inflammatory response during sepsis.
Rahim Ibtissem,Djerdjouri Bahia,Sayed Ramy K,Fernández-Ortiz Marisol,Fernández-Gil Beatriz,Hidalgo-Gutiérrez Agustín,López Luis C,Escames Germaine,Reiter Russel J,Acuña-Castroviejo Darío
Journal of pineal research
The NLRP3 inflammasome is involved in the innate immune response during inflammation. Moreover, melatonin blunts the NF-κB/NLRP3 connection during sepsis. Thus, we compared the roles of the NLRP3 inflammasome and/or melatonin treatment in the septic response of wild-type and NLRP3 mice. Mouse myocardial tissue was used for this purpose. The nuclear turnover of NF-κB was enhanced during sepsis, with an increase in TNFα, iNOS, and pro-IL-1β. The lack of inflammasome in NLRP3 mice significantly reduced that response and blunted IL-1β maturation due to the lack of caspase-1. Clock and Bmal1 did not change in both mouse strains, enhancing Chrono expression in mutants. RORα, which positively regulates Bmal1, was enhanced at a similar extend in both mouse strains, whereas the expression of the Bmal1 repressor, Rev-Erbα, increased in WT but was depressed in NLRP3 mice. Nampt, transcriptionally controlled by Bmal1, increased in WT mice together with Sirt1, whereas they remained unchanged in NLRP3 mice. Melatonin treatment reduced the septic response in a comparable manner as did the lack of NLRP3, but unlike the latter, it normalized the clock genes turnover through the induction of RORα and repression of Rev-Erbα and Per2, leading to enhanced Nampt and Sirt1. The lack of NLRP3 inflammasome converts sepsis to a moderate inflammatory disease and identifies NLRP3 as a main target for the treatment of sepsis. The efficacy of melatonin in counteracting the NLRP3 inflammasome activation further confirms the indoleamine as a useful therapeutic drug against this serious condition.
10.1111/jpi.12410
Heme Oxygenase-1 in Macrophages Drives Septic Cardiac Dysfunction via Suppressing Lysosomal Degradation of Inducible Nitric Oxide Synthase.
Jia Liangliang,Wang Yaping,Wang Yidong,Ma Yuankun,Shen Jian,Fu Zurong,Wu Yue,Su Sheng'an,Zhang Yuhao,Cai Zhejun,Wang Jian'an,Xiang Meixiang
Circulation research
RATIONALE:To date, our understanding of the role of HO-1 (heme oxygenase-1) in inflammatory diseases has mostly been limited to its catalytic function and the potential for its heme-related catabolic products to suppress inflammation and oxidative stress. Whether and how HO-1 in macrophages plays a role in the development of septic cardiac dysfunction has never been explored. OBJECTIVE:Here, we investigated the role of macrophage-derived HO-1 in septic cardiac dysfunction. METHODS AND RESULTS:Intraperitoneal injection of lipopolysaccharide significantly activated HO-1 expression in cardiac infiltrated macrophages. Surprisingly, we found that myeloid conditional HO-1 deletion in mice evoked resistance to lipopolysaccharide-triggered septic cardiac dysfunction and lethality in vivo, which was accompanied by reduced cardiomyocyte apoptosis in the septic hearts and decreased peroxynitrite production and iNOS (inducible NO synthase) in the cardiac infiltrated macrophages, whereas proinflammatory cytokine production and macrophage infiltration were unaltered. We further demonstrated that HO-1 suppression abolished the lipopolysaccharide-induced iNOS protein rather than mRNA expression in macrophages. Moreover, we confirmed that the inhibition of HO-1 promoted iNOS degradation through a lysosomal rather than proteasomal pathway in macrophages. Suppression of the lysosomal degradation of iNOS by bafilomycin A1 drove septic cardiac dysfunction in myeloid HO-1-deficient mice. Mechanistically, we demonstrated that HO-1 interacted with iNOS at the flavin mononucleotide domain, which further prevented iNOS conjugation with LC3 (light chain 3) and subsequent lysosomal degradation in macrophages. These effects were independent of HO-1's catabolic products: ferrous ion, carbon monoxide, and bilirubin. CONCLUSIONS:Our results indicate that HO-1 in macrophages drives septic cardiac dysfunction. The mechanistic insights provide potential therapeutic targets to treat septic cardiac dysfunction.
10.1161/CIRCRESAHA.118.312910
Beclin-1-Dependent Autophagy Protects the Heart During Sepsis.
Circulation
BACKGROUND:Cardiac dysfunction is a major component of sepsis-induced multiorgan failure in critical care units. Changes in cardiac autophagy and its role during sepsis pathogenesis have not been clearly defined. Targeted autophagy-based therapeutic approaches for sepsis are not yet developed. METHODS:Beclin-1-dependent autophagy in the heart during sepsis and the potential therapeutic benefit of targeting this pathway were investigated in a mouse model of lipopolysaccharide (LPS)-induced sepsis. RESULTS:LPS induced a dose-dependent increase in autophagy at low doses, followed by a decline that was in conjunction with mammalian target of rapamycin activation at high doses. Cardiac-specific overexpression of Beclin-1 promoted autophagy, suppressed mammalian target of rapamycin signaling, improved cardiac function, and alleviated inflammation and fibrosis after LPS challenge. Haplosufficiency for beclin 1 resulted in opposite effects. Beclin-1 also protected mitochondria, reduced the release of mitochondrial danger-associated molecular patterns, and promoted mitophagy via PTEN-induced putative kinase 1-Parkin but not adaptor proteins in response to LPS. Injection of a cell-permeable Tat-Beclin-1 peptide to activate autophagy improved cardiac function, attenuated inflammation, and rescued the phenotypes caused by beclin 1 deficiency in LPS-challenged mice. CONCLUSIONS:These results suggest that Beclin-1 protects the heart during sepsis and that the targeted induction of Beclin-1 signaling may have important therapeutic potential.
10.1161/CIRCULATIONAHA.117.032821
Unintended Consequences: Fluid Resuscitation Worsens Shock in an Ovine Model of Endotoxemia.
American journal of respiratory and critical care medicine
RATIONALE:Fluid resuscitation is widely considered a life-saving intervention in septic shock; however, recent evidence has brought both its safety and efficacy in sepsis into question. OBJECTIVES:In this study, we sought to compare fluid resuscitation with vasopressors with the use of vasopressors alone in a hyperdynamic model of ovine endotoxemia. METHODS:Endotoxemic shock was induced in 16 sheep, after which they received fluid resuscitation with 40 ml/kg of 0.9% saline or commenced hemodynamic support with protocolized noradrenaline and vasopressin. Microdialysis catheters were inserted into the arterial circulation, heart, brain, kidney, and liver to monitor local metabolism. Blood samples were recovered to measure serum inflammatory cytokines, creatinine, troponin, atrial natriuretic peptide, brain natriuretic peptide, and hyaluronan. All animals were monitored and supported for 12 hours after fluid resuscitation. MEASUREMENTS AND MAIN RESULTS:After resuscitation, animals that received fluid resuscitation required significantly more noradrenaline to maintain the same mean arterial pressure in the subsequent 12 hours (68.9 mg vs. 39.6 mg; P = 0.04). Serum cytokines were similar between groups. Atrial natriuretic peptide increased significantly after fluid resuscitation compared with that observed in animals managed without fluid resuscitation (335 ng/ml [256-382] vs. 233 ng/ml [144-292]; P = 0.04). Cross-sectional time-series analysis showed that the rate of increase of the glycocalyx glycosaminoglycan hyaluronan was greater in the fluid-resuscitated group over the course of the study (P = 0.02). CONCLUSIONS:Fluid resuscitation resulted in a paradoxical increase in vasopressor requirement. Additionally, it did not result in improvements in any of the measured microcirculatory- or organ-specific markers measured. The increase in vasopressor requirement may have been due to endothelial/glycocalyx damage secondary to atrial natriuretic peptide-mediated glycocalyx shedding.
10.1164/rccm.201801-0064OC
Treatment with camu camu () prevents obesity by altering the gut microbiota and increasing energy expenditure in diet-induced obese mice.
Anhê Fernando F,Nachbar Renato T,Varin Thibault V,Trottier Jocelyn,Dudonné Stéphanie,Le Barz Mélanie,Feutry Perrine,Pilon Geneviève,Barbier Olivier,Desjardins Yves,Roy Denis,Marette André
Gut
OBJECTIVE:The consumption of fruits is strongly associated with better health and higher bacterial diversity in the gut microbiota (GM). Camu camu () is an Amazonian fruit with a unique phytochemical profile, strong antioxidant potential and purported anti-inflammatory potential. DESIGN:By using metabolic tests coupled with 16S rRNA gene-based taxonomic profiling and faecal microbial transplantation (FMT), we have assessed the effect of a crude extract of camu camu (CC) on obesity and associated immunometabolic disorders in high fat/high sucrose (HFHS)-fed mice. RESULTS:Treatment of HFHS-fed mice with CC prevented weight gain, lowered fat accumulation and blunted metabolic inflammation and endotoxaemia. CC-treated mice displayed improved glucose tolerance and insulin sensitivity and were also fully protected against hepatic steatosis. These effects were linked to increased energy expenditure and upregulation of uncoupling protein 1 mRNA expression in the brown adipose tissue (BAT) of CC-treated mice, which strongly correlated with the mRNA expression of the membrane bile acid (BA) receptor TGR5. Moreover, CC-treated mice showed altered plasma BA pool size and composition and drastic changes in the GM (eg, bloom of and a strong reduction of ). Germ-free (GF) mice reconstituted with the GM of CC-treated mice gained less weight and displayed higher energy expenditure than GF-mice colonised with the FM of HFHS controls. CONCLUSION:Our results show that CC prevents visceral and liver fat deposition through BAT activation and increased energy expenditure, a mechanism that is dependent on the GM and linked to major changes in the BA pool size and composition.
10.1136/gutjnl-2017-315565
The Coagulation and Immune Systems Are Directly Linked through the Activation of Interleukin-1α by Thrombin.
Burzynski Laura C,Humphry Melanie,Pyrillou Katerina,Wiggins Kimberley A,Chan Julie N E,Figg Nichola,Kitt Lauren L,Summers Charlotte,Tatham Kate C,Martin Paul B,Bennett Martin R,Clarke Murray C H
Immunity
Ancient organisms have a combined coagulation and immune system, and although links between inflammation and hemostasis exist in mammals, they are indirect and slower to act. Here we investigated direct links between mammalian immune and coagulation systems by examining cytokine proproteins for potential thrombin protease consensus sites. We found that interleukin (IL)-1α is directly activated by thrombin. Thrombin cleaved pro-IL-1α at a site perfectly conserved across disparate species, indicating functional importance. Surface pro-IL-1α on macrophages and activated platelets was cleaved and activated by thrombin, while tissue factor, a potent thrombin activator, colocalized with pro-IL-1α in the epidermis. Mice bearing a mutation in the IL-1α thrombin cleavage site (R114Q) exhibited defects in efficient wound healing and rapid thrombopoiesis after acute platelet loss. Thrombin-cleaved IL-1α was detected in humans during sepsis, pointing to the relevance of this pathway for normal physiology and the pathogenesis of inflammatory and thrombotic diseases.
10.1016/j.immuni.2019.03.003
Inflammasome Activation Triggers Blood Clotting and Host Death through Pyroptosis.
Wu Congqing,Lu Wei,Zhang Yan,Zhang Guoying,Shi Xuyan,Hisada Yohei,Grover Steven P,Zhang Xinyi,Li Lan,Xiang Binggang,Shi Jumei,Li Xiang-An,Daugherty Alan,Smyth Susan S,Kirchhofer Daniel,Shiroishi Toshihiko,Shao Feng,Mackman Nigel,Wei Yinan,Li Zhenyu
Immunity
Inflammasome activation and subsequent pyroptosis are critical defense mechanisms against microbes. However, overactivation of inflammasome leads to death of the host. Although recent studies have uncovered the mechanism of pyroptosis following inflammasome activation, how pyroptotic cell death drives pathogenesis, eventually leading to death of the host, is unknown. Here, we identified inflammasome activation as a trigger for blood clotting through pyroptosis. We have shown that canonical inflammasome activation by the conserved type III secretion system (T3SS) rod proteins from Gram-negative bacteria or noncanonical inflammasome activation by lipopolysaccharide (LPS) induced systemic blood clotting and massive thrombosis in tissues. Following inflammasome activation, pyroptotic macrophages released tissue factor (TF), an essential initiator of coagulation cascades. Genetic or pharmacological inhibition of TF abolishes inflammasome-mediated blood clotting and protects against death. Our data reveal that blood clotting is the major cause of host death following inflammasome activation and demonstrate that inflammasome bridges inflammation with thrombosis.
10.1016/j.immuni.2019.04.003
GDF15 Is an Inflammation-Induced Central Mediator of Tissue Tolerance.
Cell
Growth and differentiation factor 15 (GDF15) is an inflammation-associated hormone with poorly defined biology. Here, we investigated the role of GDF15 in bacterial and viral infections. We found that inflammation induced GDF15, and that GDF15 was necessary for surviving both bacterial and viral infections, as well as sepsis. The protective effects of GDF15 were largely independent of pathogen control or the magnitude of inflammatory response, suggesting a role in disease tolerance. Indeed, we found that GDF15 was required for hepatic sympathetic outflow and triglyceride metabolism. Failure to defend the lower limit of plasma triglyceride levels was associated with impaired cardiac function and maintenance of body temperature, effects that could be rescued by exogenous administration of lipids. Together, we show that GDF15 coordinates tolerance to inflammatory damage through regulation of triglyceride metabolism.
10.1016/j.cell.2019.07.033
alleles modulate inflammation during microbial infection of mice in a sex-dependent manner.
Shutinoski Bojan,Hakimi Mansoureh,Harmsen Irene E,Lunn Michaela,Rocha Juliana,Lengacher Nathalie,Zhou Yi Yuan,Khan Jasmine,Nguyen Angela,Hake-Volling Quinton,El-Kodsi Daniel,Li Juan,Alikashani Azadeh,Beauchamp Claudine,Majithia Jay,Coombs Kevin,Shimshek Derya,Marcogliese Paul C,Park David S,Rioux John D,Philpott Dana J,Woulfe John M,Hayley Shawn,Sad Subash,Tomlinson Julianna J,Brown Earl G,Schlossmacher Michael G
Science translational medicine
Variants in the leucine-rich repeat kinase-2 () gene are associated with Parkinson's disease, leprosy, and Crohn's disease, three disorders with inflammation as an important component. Because of its high expression in granulocytes and CD68-positive cells, LRRK2 may have a function in innate immunity. We tested this hypothesis in two ways. First, adult mice were intravenously inoculated with , resulting in sepsis. Second, newborn mouse pups were intranasally infected with reovirus (serotype 3 Dearing), which induced encephalitis. In both mouse models, wild-type Lrrk2 expression was protective and showed a sex effect, with female Lrrk2-deficient animals not controlling infection as well as males. Mice expressing Lrrk2 carrying the Parkinson's disease-linked p.G2019S mutation controlled infection better, with reduced bacterial growth and longer animal survival during sepsis. This gain-of-function effect conferred by the p.G2019S mutation was mediated by myeloid cells and was abolished in animals expressing a kinase-dead Lrrk2 variant, p.D1994S. Mouse pups with reovirus-induced encephalitis that expressed the p.G2019S Lrrk2 mutation showed increased mortality despite lower viral titers. The p.G2019S mutant Lrrk2 augmented immune cell chemotaxis and generated more reactive oxygen species during virulent infection. Reovirus-infected brains from mice expressing the p.G2019S mutant Lrrk2 contained higher concentrations of α-synuclein. Animals expressing one or two p.D1994S alleles showed lower mortality from reovirus-induced encephalitis. Thus, alleles may alter the course of microbial infections by modulating inflammation, and this may be dependent on the sex and genotype of the host as well as the type of pathogen.
10.1126/scitranslmed.aas9292
Low-grade endotoxaemia enhances artery thrombus growth via Toll-like receptor 4: implication for myocardial infarction.
European heart journal
AIMS:Low-grade endotoxaemia is detectable in human circulation but its role in thrombosis is still unclear. METHODS AND RESULTS:We measured serum lipopolysaccharide (LPS) concentration, soluble P-selectin (sP-selectin), a marker of platelet activation, and zonulin, a marker of gut permeability, in peripheral circulation, coronary thrombi, and intracoronary blood of patients with ST-elevation myocardial infarction (STEMI, n = 50) and stable angina (SA) (n = 50), respectively, and in controls (n = 50). Experimental study was carried out in mice to assess if Escherichia coli-LPS (E. coli-LPS) possess thrombotic property. Coronary thrombi from STEMI showed higher concentrations of LPS, sP-selectin vs. intracoronary blood of SA and peripheral blood of controls (P < 0.001). Zonulin was higher in STEMI compared to the other two groups [4.57 (3.34-5.22); 2.56 (0.41-4.36); 1.95 (1.22-2.65) ng/mL; P < 0.001] and correlated with LPS (Rs = 0.585; P < 0.001). Escherichia coli DNA was positive in 34% of STEMI vs. 12% of SA and 4% of controls (P < 0.001). In a subgroup of 12 STEMI, immunohistochemical analysis of coronary thrombi showed positivity for leucocyte Toll-like receptor 4 (TLR4), cathepsin G, and LPS from E. coli in 100%, 80%, and 25% of samples, respectively. E. coli-LPS injected in mice to reach LPS concentrations like those detected in coronary thrombi was associated with enhanced artery thrombosis and platelet activation, an effect blunted by TLR4 inhibitor co-administration. In vitro study demonstrated that LPS from E. coli enhanced platelet aggregation via TLR4-mediated leucocyte cathepsin G activation. CONCLUSION:ST-elevation myocardial infarction patients disclose an enhanced gut permeability that results in LPS translocation in human circulation and eventually thrombus growth at site of artery lesion via leucocyte-platelet interaction.
10.1093/eurheartj/ehz893
Vitamin lipid nanoparticles enable adoptive macrophage transfer for the treatment of multidrug-resistant bacterial sepsis.
Hou Xucheng,Zhang Xinfu,Zhao Weiyu,Zeng Chunxi,Deng Binbin,McComb David W,Du Shi,Zhang Chengxiang,Li Wenqing,Dong Yizhou
Nature nanotechnology
Sepsis, a condition caused by severe infections, affects more than 30 million people worldwide every year and remains the leading cause of death in hospitals. Moreover, antimicrobial resistance has become an additional challenge in the treatment of sepsis, and thus, alternative therapeutic approaches are urgently needed. Here, we show that adoptive transfer of macrophages containing antimicrobial peptides linked to cathepsin B in the lysosomes (MACs) can be applied for the treatment of multidrug-resistant bacteria-induced sepsis in mice with immunosuppression. The MACs are constructed by transfection of vitamin C lipid nanoparticles that deliver antimicrobial peptide and cathepsin B (AMP-CatB) mRNA. The vitamin C lipid nanoparticles allow the specific accumulation of AMP-CatB in macrophage lysosomes, which is the key location for bactericidal activities. Our results demonstrate that adoptive MAC transfer leads to the elimination of multidrug-resistant bacteria, including Staphylococcus aureus and Escherichia coli, leading to the complete recovery of immunocompromised septic mice. Our work provides an alternative strategy for overcoming multidrug-resistant bacteria-induced sepsis and opens up possibilities for the development of nanoparticle-enabled cell therapy for infectious diseases.
10.1038/s41565-019-0600-1
Systemic infection facilitates transmission of Pseudomonas aeruginosa in mice.
Nature communications
Health care-associated infections such as Pseudomonas aeruginosa bacteremia pose a major clinical risk for hospitalized patients. However, these systemic infections are presumed to be a "dead-end" for P. aeruginosa and to have no impact on transmission. Here, we use a mouse infection model to show that P. aeruginosa can spread from the bloodstream to the gallbladder, where it replicates to extremely high numbers. Bacteria in the gallbladder can then seed the intestines and feces, leading to transmission to uninfected cage-mate mice. Our work shows that the gallbladder is crucial for spread of P. aeruginosa from the bloodstream to the feces during bacteremia, a process that promotes transmission in this experimental system. Further research is needed to test to what extent these findings are relevant to infections in patients.
10.1038/s41467-020-14363-4
Assembly of alternative prothrombinase by extracellular histones initiates and disseminates intravascular coagulation.
Abrams Simon T,Su Dunhao,Sahraoui Yasmina,Lin Ziqi,Cheng Zhenxing,Nesbitt Kate,Alhamdi Yasir,Harrasser Micaela,Du Min,Foley Jonathan H,Lillicrap David,Wang Guozheng,Toh Cheng-Hock
Blood
Thrombin generation is pivotal to both physiological blood clot formation and pathological development of disseminated intravascular coagulation (DIC). In critical illness, extensive cell damage can release histones into the circulation, which can increase thrombin generation and cause DIC, but the molecular mechanism is not clear. Typically, thrombin is generated by the prothrombinase complex, comprising activated factor X (FXa), activated cofactor V (FVa), and phospholipids to cleave prothrombin in the presence of calcium. In this study, we found that in the presence of extracellular histones, an alternative prothrombinase could form without FVa and phospholipids. Histones directly bind to prothrombin fragment 1 (F1) and fragment 2 (F2) specifically to facilitate FXa cleavage of prothrombin to release active thrombin, unlike FVa, which requires phospholipid surfaces to anchor the classical prothrombinase complex. In vivo, histone infusion into mice induced DIC, which was significantly abrogated when prothrombin F1 + F2 were infused prior to histones, to act as decoy. In a cohort of intensive care unit patients with sepsis (n = 144), circulating histone levels were significantly elevated in patients with DIC. These data suggest that histone-induced alternative prothrombinase without phospholipid anchorage may disseminate intravascular coagulation and reveal a new molecular mechanism of thrombin generation and DIC development. In addition, histones significantly reduced the requirement for FXa in the coagulation cascade to enable clot formation in factor VIII (FVIII)- and FIX-deficient plasma, as well as in FVIII-deficient mice. In summary, this study highlights a novel mechanism in coagulation with therapeutic potential in both targeting systemic coagulation activation and correcting coagulation factor deficiency.
10.1182/blood.2019002973
Tissue factor pathway inhibitor reduces mortality from Escherichia coli septic shock.
Creasey A A,Chang A C,Feigen L,Wün T C,Taylor F B,Hinshaw L B
The Journal of clinical investigation
This study was designed to test the hypothesis that tissue factor pathway inhibitor (TFPI) plays a significant role in vivo in regulating coagulation that results from exposure of blood to tissue factor after vascular injury as in the case of gram negative sepsis. Highly purified recombinant TFPI (6 mg/kg) was administered either 30 min or 4 h after the start of a lethal intravenous Escherichia coli infusion in baboons. Early posttreatment of TFPI resulted in (a) permanent seven-day survivors (5/5) with significant improvement in quality of life, while the mean survival time for the controls (5/5) was 39.9 h (no survivors); and (b) significant attenuations of the coagulation response and various measures of cell injury, with significant reductions in pathology observed in E. coli sepsis target organs, including kidneys, adrenals, and lungs. TFPI administration did not affect the reduction in mean systemic arterial pressure, the increases in respiration and heart rate, or temperature changes associated with the bacterial infusion. TFPI treated E. coli infected baboons had significantly lower IL-6 levels than their phosphate buffered saline-treated controls, however tumor necrosis factor levels were similarly elevated in both groups. In contrast to the earlier 30-min treatment, the administration of TFPI at 4 h, i.e., 240 min, after the start of bacterial infusion resulted in prolongation of survival time, with 40% survival rate (2/5) and some attenuation of the coagulopathic response, especially in animals in which fibrinogen levels were above 10% of normal at the time of TFPI administration. Results provide evidence for the significance of tissue factor and tissue factor pathway inhibitor in bacterial sepsis, and suggest a role for blood coagulation in the regulation of the inflammatory response.
10.1172/JCI116529
Tyrphostin AG 556 improves survival and reduces multiorgan failure in canine Escherichia coli peritonitis.
Sevransky J E,Shaked G,Novogrodsky A,Levitzki A,Gazit A,Hoffman A,Elin R J,Quezado Z M,Freeman B D,Eichacker P Q,Danner R L,Banks S M,Bacher J,Thomas M L,Natanson C
The Journal of clinical investigation
Tyrosine kinase-dependent cell signaling is postulated to be a pivotal control point in inflammatory responses initiated by bacterial products and TNF. Using a canine model of gram-negative septic shock, we investigated the effect of tyrosine kinase inhibitors (tyrphostins) on survival. Animals were infected intraperitoneally with Escherichia coli 0111: B4, and then, in a randomized, blinded fashion, were treated immediately with one of two tyrphostins, AG 556 (n = 40) or AG 126 (n = 10), or with control (n = 50), and followed for 28 d or until death. All animals received supplemental oxygen, fluids, and antibiotics. Tyrphostin AG 556 improved survival times when compared to controls (P = 0.05). During the first 48 h after infection, AG 556 also improved mean arterial pressure, left ventricular ejection fraction, cardiac output, oxygen delivery, and alveolar-arterial oxygen gradient compared to controls (all P < or = 0.05). These improvements in organ injury were significantly predictive of survival. Treatment with AG 556 had no effect on clearance of endotoxin or bacteria from the blood (both P = NS); however, AG 556 did significantly lower serum TNF levels (P = 0.03). These data are consistent with the conclusion that AG 556 prevented cytokine-induced multiorgan failure and death during septic shock by inhibiting cell-signaling pathways without impairing host defenses as determined by clearance of bacteria and endotoxin.
10.1172/JCI119364
Structure-function relationships in the septic rat heart.
Piper R D,Li F Y,Myers M L,Sibbald W J
American journal of respiratory and critical care medicine
Myocardial edema and histologic changes consistent with tissue injury are reported in association with sepsis-induced myocardial depression. The objective of the present study was to determine whether, in the absence of shock, such changes (assessed by studying microvascular albumin flux, tissue edema, and morphometry) are prerequisites for the development of contractile dysfunction in sepsis. Sprague-Dawley rats were randomized into groups for either cecal ligation and perforation (CLP) or sham study. Twenty-four hours after entry of animals into the study, their myocardial function was assessed with the Langendorff isolated heart technique. Left-ventricular developed pressure (preload: 5 mm Hg) was reduced in CLP animals (34.9 +/- 3.3 mm Hg, n = 10) as compared with time-matched controls (46.4 +/- 4.0 mm Hg, n = 8, p < 0.05, unpaired t test). This was associated with a significant reduction in the maximal rate of increase (+ dP/dt(max)) and decrease (-dP/dt(max)) in left ventricular pressure in the CLP group (sham versus CLP, unpaired t test, p < 0.05). Upon reperfusion, after 30 min of ischemia, left ventricular resting tension was decreased in CLP as compared with sham-treated animals (sham versus CLP, analysis of variance (ANOVA) with repeated measures, p < 0.05). At 24 h, sepsis was not associated with myocardial edema (wet:dry weight ratio, sham = 4.094 +/- 0.098, n = 10; CLP = 4.185 +/- 0.066, n = 7), and tissue albumin flux was reduced (sham = 194 +/- 27 microliters. h-1. g dry wt-1, n = 10; CLP = 100 +/- 14 microliters. h-1. g dry wt-1, n = 7). In tissue processed for electron microscopy, we found no evidence of tissue injury or edema at either 24 or 48 h after CLP. We conclude that polymicrobial normotensive sepsis causes myocardial contractile depression in the absence of changes in myocardial structure.
10.1164/ajrccm.156.5.96-10085
Ischemic preconditioning decreases postischemic myocardial tumor necrosis factor-alpha production. Potential ultimate effector mechanism of preconditioning.
Meldrum D R,Dinarello C A,Shames B D,Cleveland J C,Cain B S,Banerjee A,Meng X,Harken A H
Circulation
BACKGROUND:Tumor necrosis factor-alpha (TNF-alpha) is an autocrine contributor to myocardial dysfunction and cardiomyocyte death in ischemia-reperfusion (I/R) injury, sepsis, chronic heart failure, and cardiac allograft rejection. Cardiac resident macrophages, infiltrating leukocytes, and cardiomyocytes themselves produce TNF-alpha. Although adenosine reduces macrophage TNF-alpha production and protects myocardium against I/R, it remains unknown whether ischemic preconditioning, which is mediated by adenosine, decreases postischemic myocardial TNF-alpha production. METHODS AND RESULTS:Isolated rat hearts were crystalloid perfused with the Langendorff method and subjected to global, normothermic I/R (20/40 minutes), with or without prior transient ischemic preconditioning (5 minutes) or adenosine pretreatment. Postischemic cardiac TNF-alpha (ELISA) and function were determined (Langendorff). I/R increased cardiac TNF-alpha and impaired myocardial function. Ischemic preconditioning or adenosine decreased myocardial TNF-alpha and improved postischemic functional recovery. Sequestration of myocardial TNF-alpha (TNF binding protein) during the I/R experiments similarly improved postischemic myocardial function. CONCLUSIONS:This study constitutes the initial demonstration that in addition to its other beneficial effects, preconditioning decreases postischemic myocardial TNF-alpha, an autocrine contributor to postischemic myocardial dysfunction. Reduced myocardial TNF-alpha production may represent the distal effector mechanism of preconditioning.
Inhibition of mitochondrial permeability transition prevents sepsis-induced myocardial dysfunction and mortality.
Larche Jérome,Lancel Steve,Hassoun Sidi Mohamed,Favory Raphael,Decoster Brigitte,Marchetti Philippe,Chopin Claude,Neviere Remi
Journal of the American College of Cardiology
OBJECTIVES:The purpose of this study was to test whether mitochondrial dysfunction is causative of sepsis sequelae, a mouse model of peritonitis sepsis induced by cecal ligation and perforation. Inhibition of mitochondrial permeability transition was achieved by means of pharmacological drugs and overexpression of the antiapoptotic protein B-cell leukemia (Bcl)-2. BACKGROUND:Sepsis is the leading cause of death in critically ill patients and the predominant cause of multiple organ failure. Although precise mechanisms by which sepsis leads to multiple organ dysfunction are unknown, growing evidence suggests that perturbations of key mitochondrial functions, including adenosine triphosphate production, Ca2+ homeostasis, oxygen-derived free radical production, and permeability transition, might be involved in sepsis pathophysiology. METHODS:Heart and lung functions were evaluated respectively by means of isolated heart preparation, bronchoalveolar lavage fluid protein concentration, lung wet/dry weight ratio, lung homogenate myeloperoxidase activity, and histopathologic grading. Respiratory fluxes, calcium uptake, and membrane potential were evaluated in isolated heart mitochondria. RESULTS:Peritonitis sepsis induced multiple organ dysfunction, mitochondrial abnormalities, and increased mortality rate, which were reduced by pharmacological inhibition of mitochondrial transition by cyclosporine derivatives and mitochondrial Bcl-2 overexpression. CONCLUSIONS:Our study provides strong evidence that mitochondrial permeability transition plays a critical role in septic organ dysfunction. These studies demonstrate that mitochondrial dysfunction in sepsis is causative rather than epiphenomenal and relevant in terms of vital organ function and outcome. Regarding the critical role of heart failure in the pathophysiology of septic shock, our study also indicates a potentially new therapeutic approach for treatment of sepsis syndrome.
10.1016/j.jacc.2006.02.069
Ceftazidime improves hemodynamics and oxygenation in ovine smoke inhalation injury and septic shock.
Maybauer Marc O,Maybauer Dirk M,Fraser John F,Traber Lillian D,Westphal Martin,Cox Robert A,Huda Ruksana,Nakano Yoshimitsu Y,Enkhbaatar Perenlei,Hawkins Hal K,Herndon David N,Traber Daniel L
Intensive care medicine
OBJECTIVE:To investigate ceftazidime in acute lung injury (ALI) and sepsis. DESIGN AND SETTING:Prospective, randomized, controlled animal study in an investigational ICU at a university hospital. INTERVENTIONS:Eighteen female Merino sheep were prepared for chronic study and subjected to smoke inhalation and septic challenge according to an established protocol. MEASUREMENTS AND RESULTS:Whereas global hemodynamics and oxygenation remained stable in sham animals (no injury, no treatment), the injury contributed to a hypotensive-hyperdynamic circulation in the control group (smoke inhalation and sepsis, no treatment), as indicated by a significant increase in cardiac index) and heart rate and a drop in mean arterial pressure. Treatment with ceftazidime (smoke inhalation and sepsis, treatment group) stabilized cardiac index and heart rate and attenuated the decrease in mean arterial pressure. The deterioration in PaO2/FiO2 ratio and pulmonary shunt fraction (Qs/Qt) was significantly delayed and blunted by ceftazidime. At 24 h after injury a significant increase in airway obstruction scores of bronchi and bronchioles in both injured groups was observed. Ceftazidime significantly reduced airway obstruction vs. control animals. Whereas plasma nitrate/nitrite levels increased similarly in the two injured groups, lung 3-nitrotyrosine content remained at the baseline level in the ceftazidime group. CONCLUSIONS:In ovine lung injury ceftazidime improves global hemodynamics and oxygenation not only by bacterial clearance but also via reduction in toxic nitrogen species such as 3-nitrotyrosine. Therefore ceftazidime appears as a clinically relevant adjunct in the common setting of sepsis-associated lung injury.
10.1007/s00134-007-0658-3
The protein C pathway in tissue inflammation and injury: pathogenic role and therapeutic implications.
Danese Silvio,Vetrano Stefania,Zhang Li,Poplis Victoria A,Castellino Francis J
Blood
Inflammation and coagulation are closely linked interdependent processes. Under physiologic conditions, the tissue microcirculation functions in anticoagulant and anti-inflammatory fashions. However, when inflammation occurs, coagulation is also set in motion and actively participates in enhancing inflammation. Recently, novel and unexpected roles of hemostasis in the humoral and cellular components of innate immunity have been described. In particular, the protein C system, besides its well-recognized role in anticoagulation, plays a crucial role in inflammation. Indeed, the protein C system is now emerging as a novel participant in the pathogenesis of acute and chronic inflammatory diseases, such as sepsis, asthma, inflammatory bowel disease, atherosclerosis, and lung and heart inflammation, and may emerge as unexpected therapeutic targets for intervention.
10.1182/blood-2009-09-201616
Essential role of CCR2 in neutrophil tissue infiltration and multiple organ dysfunction in sepsis.
Souto Fabricio O,Alves-Filho José C,Turato Walter M,Auxiliadora-Martins Maria,Basile-Filho Aníbal,Cunha Fernando Q
American journal of respiratory and critical care medicine
RATIONALE:Sepsis is defined as a systemic inflammatory response to infection, which in its severe form is associated with multiple organ dysfunction syndrome (MODS). The precise mechanisms by which MODS develops remain unclear. Neutrophils have a pivotal role in the defense against infections; however, overwhelming activation of neutrophils is known to elicit tissue damage. OBJECTIVES:We investigated the role of the chemokine receptor CCR2 in driving neutrophil infiltration and eliciting tissue damage in remote organs during sepsis. METHODS:Sepsis was induced in wild-type mice treated with CCR2 antagonist (RS504393) or CCR2(-/-) mice by cecal ligation and puncture (CLP) model. Neutrophil infiltration into the organs was measured by myeloperoxidase activity and fluorescence-activated cell sorter. CCR2 expression and chemotaxis were determined in neutrophils stimulated with Toll-like receptor agonists or isolated from septic mice and patients. MEASUREMENTS AND MAIN RESULTS:CCR2 expression and responsiveness to its ligands was induced in circulating neutrophils during CLP-induced sepsis by a mechanism dependent on Toll-like receptor/nuclear factor-κB pathway. Genetic or pharmacologic inhibition of CCR2 protected mice from CLP-induced mortality. This protection was associated with lower infiltration of neutrophils into the lungs, heart, and kidneys and reduced serum biochemical indicators of organ injury and dysfunction. Importantly, neutrophils from septic patients express high levels of CCR2, and the severity of patient illness correlated positively with increasing neutrophil chemotaxis to CCR2 ligands. CONCLUSIONS:Collectively, these data identify CCR2 as a key receptor that drives the inappropriate infiltration of neutrophils into remote organs during sepsis. Therefore, CCR2 blockade is a novel potential therapeutic target for treatment of sepsis-induced MODS.
10.1164/rccm.201003-0416OC
Cold-inducible RNA-binding protein (CIRP) triggers inflammatory responses in hemorrhagic shock and sepsis.
Qiang Xiaoling,Yang Weng-Lang,Wu Rongqian,Zhou Mian,Jacob Asha,Dong Weifeng,Kuncewitch Michael,Ji Youxin,Yang Huan,Wang Haichao,Fujita Jun,Nicastro Jeffrey,Coppa Gene F,Tracey Kevin J,Wang Ping
Nature medicine
A systemic inflammatory response is observed in patients undergoing hemorrhagic shock and sepsis. Here we report increased levels of cold-inducible RNA-binding protein (CIRP) in the blood of individuals admitted to the surgical intensive care unit with hemorrhagic shock. In animal models of hemorrhage and sepsis, CIRP is upregulated in the heart and liver and released into the circulation. In macrophages under hypoxic stress, CIRP translocates from the nucleus to the cytosol and is released. Recombinant CIRP stimulates the release of tumor necrosis factor-α (TNF-α) and HMGB1 from macrophages and induces inflammatory responses and causes tissue injury when injected in vivo. Hemorrhage-induced TNF-α and HMGB1 release and lethality were reduced in CIRP-deficient mice. Blockade of CIRP using antisera to CIRP attenuated inflammatory cytokine release and mortality after hemorrhage and sepsis. The activity of extracellular CIRP is mediated through the Toll-like receptor 4 (TLR4)-myeloid differentiation factor 2 (MD2) complex. Surface plasmon resonance analysis indicated that CIRP binds to the TLR4-MD2 complex, as well as to TLR4 and MD2 individually. In particular, human CIRP amino acid residues 106-125 bind to MD2 with high affinity. Thus, CIRP is a damage-associated molecular pattern molecule that promotes inflammatory responses in shock and sepsis.
10.1038/nm.3368
Activated protein C: biased for translation.
Griffin John H,Zlokovic Berislav V,Mosnier Laurent O
Blood
The homeostatic blood protease, activated protein C (APC), can function as (1) an antithrombotic on the basis of inactivation of clotting factors Va and VIIIa; (2) a cytoprotective on the basis of endothelial barrier stabilization and anti-inflammatory and antiapoptotic actions; and (3) a regenerative on the basis of stimulation of neurogenesis, angiogenesis, and wound healing. Pharmacologic therapies using recombinant human and murine APCs indicate that APC provides effective acute or chronic therapies for a strikingly diverse range of preclinical injury models. APC reduces the damage caused by the following: ischemia/reperfusion in brain, heart, and kidney; pulmonary, kidney, and gastrointestinal inflammation; sepsis; Ebola virus; diabetes; and total lethal body radiation. For these beneficial effects, APC alters cell signaling networks and gene expression profiles by activating protease-activated receptors 1 and 3. APC's activation of these G protein-coupled receptors differs completely from thrombin's activation mechanism due to biased signaling via either G proteins or β-arrestin-2. To reduce APC-associated bleeding risk, APC variants were engineered to lack >90% anticoagulant activity but retain normal cell signaling. Such a neuroprotective variant, 3K3A-APC (Lys191-193Ala), has advanced to clinical trials for ischemic stroke. A rich data set of preclinical knowledge provides a solid foundation for potential translation of APC variants to future novel therapies.
10.1182/blood-2015-02-355974
The podoplanin-CLEC-2 axis inhibits inflammation in sepsis.
Rayes Julie,Lax Siân,Wichaiyo Surasak,Watson Stephanie K,Di Ying,Lombard Stephanie,Grygielska Beata,Smith Stuart W,Skordilis Kassiani,Watson Steve P
Nature communications
Platelets play a critical role in vascular inflammation through the podoplanin and collagen/fibrin receptors, C-type-lectin-like-2 (CLEC-2) and glycoprotein VI (GPVI), respectively. Both receptors regulate endothelial permeability and prevent peri-vascular bleeding in inflammation. Here we show that platelet-specific deletion of CLEC-2 but not GPVI leads to enhanced systemic inflammation and accelerated organ injury in two mouse models of sepsis-intra-peritoneal lipopolysaccharide and cecal ligation and puncture. CLEC-2 deficiency is associated with reduced numbers of podoplanin-expressing macrophages despite increased cytokine and chemokine levels in the infected peritoneum. Pharmacological inhibition of the interaction between CLEC-2 and podoplanin regulates immune cell infiltration and the inflammatory reaction during sepsis, suggesting that activation of podoplanin underlies the anti-inflammatory action of platelet CLEC-2. We suggest podoplanin-CLEC-2 as a novel anti-inflammatory axis regulating immune cell recruitment and activation in sepsis.
10.1038/s41467-017-02402-6
Sox17 is required for endothelial regeneration following inflammation-induced vascular injury.
Liu Menglin,Zhang Lianghui,Marsboom Glenn,Jambusaria Ankit,Xiong Shiqin,Toth Peter T,Benevolenskaya Elizaveta V,Rehman Jalees,Malik Asrar B
Nature communications
Repair of the endothelial cell barrier after inflammatory injury is essential for tissue fluid homeostasis and normalizing leukocyte transmigration. However, the mechanisms of endothelial regeneration remain poorly understood. Here we show that the endothelial and hematopoietic developmental transcription factor Sox17 promotes endothelial regeneration in the endotoxemia model of endothelial injury. Genetic lineage tracing studies demonstrate that the native endothelium itself serves as the primary source of endothelial cells repopulating the vessel wall following injury. We identify Sox17 as a key regulator of endothelial cell regeneration using endothelial-specific deletion and overexpression of Sox17. Endotoxemia upregulates Hypoxia inducible factor 1α, which in turn transcriptionally activates Sox17 expression. We observe that Sox17 increases endothelial cell proliferation via upregulation of Cyclin E1. Furthermore, endothelial-specific upregulation of Sox17 in vivo enhances lung endothelial regeneration. We conclude that endotoxemia adaptively activates Sox17 expression to mediate Cyclin E1-dependent endothelial cell regeneration and restore vascular homeostasis.
10.1038/s41467-019-10134-y
Tissue-Specific Macrophage Responses to Remote Injury Impact the Outcome of Subsequent Local Immune Challenge.
Hoyer Friedrich Felix,Naxerova Kamila,Schloss Maximilian J,Hulsmans Maarten,Nair Anil V,Dutta Partha,Calcagno David M,Herisson Fanny,Anzai Atsushi,Sun Yuan,Wojtkiewicz Gregory,Rohde David,Frodermann Vanessa,Vandoorne Katrien,Courties Gabriel,Iwamoto Yoshiko,Garris Christopher S,Williams David L,Breton Sylvie,Brown Dennis,Whalen Michael,Libby Peter,Pittet Mikael J,King Kevin R,Weissleder Ralph,Swirski Filip K,Nahrendorf Matthias
Immunity
Myocardial infarction, stroke, and sepsis trigger systemic inflammation and organism-wide complications that are difficult to manage. Here, we examined the contribution of macrophages residing in vital organs to the systemic response after these injuries. We generated a comprehensive catalog of changes in macrophage number, origin, and gene expression in the heart, brain, liver, kidney, and lung of mice with myocardial infarction, stroke, or sepsis. Predominantly fueled by heightened local proliferation, tissue macrophage numbers increased systemically. Macrophages in the same organ responded similarly to different injuries by altering expression of tissue-specific gene sets. Preceding myocardial infarction improved survival of subsequent pneumonia due to enhanced bacterial clearance, which was caused by IFNɣ priming of alveolar macrophages. Conversely, EGF receptor signaling in macrophages exacerbated inflammatory lung injury. Our data suggest that local injury activates macrophages in remote organs and that targeting macrophages could improve resilience against systemic complications following myocardial infarction, stroke, and sepsis.
10.1016/j.immuni.2019.10.010
Melatonin improved rat cardiac mitochondria and survival rate in septic heart injury.
Zhang Hongmin,Liu Dawei,Wang Xiaoting,Chen Xiukai,Long Yun,Chai Wenzhao,Zhou Xiang,Rui Xi,Zhang Qing,Wang Hao,Yang Quanhui
Journal of pineal research
The pathogenesis of septic myocardial depression is complicated. Mitochondrial dysfunction has been suggested to be one of the main reasons for the reduced cardiac function. As melatonin is an antioxidant with the potential to scavenge radicals in mitochondria, we therefore employed a sepsis model, that is, cecal ligation and double puncture (CLP) in rats, to study the melatonin effects on: (i), myocardial mitochondrial function; (ii), heart systolic function; and (iii), prognosis of septic rats. We demonstrate that melatonin treatment (30 mg/kg, 3, 6, 12, 18, 24 hr after CLP) (i) improved myocardial cytochrome c oxidase (CcOX) activity and blood lactate level, (ii) attenuated heart dysfunction with a higher left ventricular ejection fraction (EF), and (iii) promoted 48-h survival of the rats compared to CLP animals with no melatonin treatment. In conclusion, our results show that rat myocardial mitochondrial CcOX activity was depressed during severe sepsis accompanied by myocardial depression characterized by the decline of EF. In septic rats, melatonin increased the CcOX activity, improved heart systolic function, and lowered mortality rate. The clinical use of melatonin in septic myocardial depression should be tested in the future.
10.1111/jpi.12033
Heparanase expression and activity are increased in platelets during clinical sepsis.
Journal of thrombosis and haemostasis : JTH
BACKGROUND:Heparanase (HPSE) is the only known mammalian enzyme that can degrade heparan sulfate. Heparan sulfate proteoglycans are essential components of the glycocalyx, and maintain physiological barriers between the blood and endothelial cells. HPSE increases during sepsis, which contributes to injurious glyocalyx degradation, loss of endothelial barrier function, and mortality. OBJECTIVES:As platelets are one of the most abundant cellular sources of HPSE, we sought to determine whether HPSE expression and activity increases in human platelets during clinical sepsis. We also examined associations between platelet HPSE expression and clinical outcomes. PATIENTS/METHODS:Expression and activity of HPSE was determined in platelets isolated from septic patients (n = 59) and, for comparison, sex-matched healthy donors (n = 46) using complementary transcriptomic, proteomic, and functional enzymatic assays. Septic patients were followed for the primary outcome of mortality, and clinical data were captured prospectively for septic patients. RESULTS:The mRNA expression of HPSE was significantly increased in platelets isolated from septic patients. Ribosomal footprint profiling, followed by [S35] methionine labeling assays, demonstrated that HPSE mRNA translation and HPSE protein synthesis were significantly upregulated in platelets during sepsis. While both the pro- and active forms of HPSE protein increased in platelets during sepsis, only the active form of HPSE protein significantly correlated with sepsis-associated mortality. Consistent with transcriptomic and proteomic upregulation, HPSE enzymatic activity was also increased in platelets during sepsis. CONCLUSIONS:During clinical sepsis HPSE, translation, and enzymatic activity are increased in platelets. Increased expression of the active form of HPSE protein is associated with sepsis-associated mortality.
10.1111/jth.15266
Monitoring circulating dipeptidyl peptidase 3 (DPP3) predicts improvement of organ failure and survival in sepsis: a prospective observational multinational study.
Blet Alice,Deniau Benjamin,Santos Karine,van Lier Dirk P T,Azibani Feriel,Wittebole Xavier,Chousterman Benjamin G,Gayat Etienne,Hartmann Oliver,Struck Joachim,Bergmann Andreas,Antonelli Massimo,Beishuizen Albertus,Constantin Jean-Michel,Damoisel Charles,Deye Nicolas,Di Somma Salvatore,Dugernier Thierry,François Bruno,Gaudry Stephane,Huberlant Vincent,Lascarrou Jean-Baptiste,Marx Gernot,Mercier Emmanuelle,Oueslati Haikel,Pickkers Peter,Sonneville Romain,Legrand Matthieu,Laterre Pierre-François,Mebazaa Alexandre,
Critical care (London, England)
BACKGROUND:Dipeptidyl peptidase 3 (DPP3) is a cytosolic enzyme involved in the degradation of various cardiovascular and endorphin mediators. High levels of circulating DPP3 (cDPP3) indicate a high risk of organ dysfunction and mortality in cardiogenic shock patients. METHODS:The aim was to assess relationships between cDPP3 during the initial intensive care unit (ICU) stay and short-term outcome in the AdrenOSS-1, a prospective observational multinational study in twenty-four ICU centers in five countries. AdrenOSS-1 included 585 patients admitted to the ICU with severe sepsis or septic shock. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by the Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use and need for renal replacement therapy. cDPP3 levels were measured upon admission and 24 h later. RESULTS:Median [IQR] cDPP3 concentration upon admission was 26.5 [16.2-40.4] ng/mL. Initial SOFA score was 7 [5-10], and 28-day mortality was 22%. We found marked associations between cDPP3 upon ICU admission and 28-day mortality (unadjusted standardized HR 1.8 [CI 1.6-2.1]; adjusted HR 1.5 [CI 1.3-1.8]) and between cDPP3 levels and change in renal and liver SOFA score (p = 0.0077 and 0.0009, respectively). The higher the initial cDPP3 was, the greater the need for organ support and vasopressors upon admission; the longer the need for vasopressor(s), mechanical ventilation or RRT and the higher the need for fluid load (all p < 0.005). In patients with cDPP3 > 40.4 ng/mL upon admission, a decrease in cDPP3 below 40.4 ng/mL after 24 h was associated with an improvement of organ function at 48 h and better 28-day outcome. By contrast, persistently elevated cDPP3 at 24 h was associated with worsening organ function and high 28-day mortality. CONCLUSIONS:Admission levels and rapid changes in cDPP3 predict outcome during sepsis. Trial Registration ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015.
10.1186/s13054-021-03471-2
Initial Characterization of Stressed Transgenic Mice With Cardiomyocyte-Specific Overexpression of Protein Phosphatase 2C.
Bollmann Paula,Werner Franziska,Jaron Marko,Bruns Tom A,Wache Hartmut,Runte Jochen,Boknik Peter,Kirchhefer Uwe,Müller Frank U,Buchwalow Igor B,Rothemund Sven,Neumann Joachim,Gergs Ulrich
Frontiers in pharmacology
As part of our ongoing studies on the potential pathophysiological role of serine/threonine phosphatases (PP) in the mammalian heart, we have generated mice with cardiac-specific overexpression of PP2Cβ (PP2C-TG) and compared them with littermate wild type mice (WT) serving as a control. Cardiac fibrosis was noted histologically in PP2C-TG. Collagen 1a, interleukin-6 and the natriuretic peptides ANP and BNP were augmented in PP2C-TG vs. WT ( < 0.05). Left atrial preparations from PP2C-TG were less resistant to hypoxia than atria from WT. PP2C-TG maintained cardiac function after the injection of lipopolysaccharide (LPS, a model of sepsis) and chronic isoproterenol treatment (a model of heart failure) better than WT. Crossbreeding of PP2C-TG mice with PP2A-TG mice (a genetic model of heart failure) resulted in double transgenic (DT) mice that exhibited a pronounced increase of heart weight in contrast to the mild hypertrophy noted in the mono-transgenic mice. The ejection fraction was reduced in PP2C-TG and in PP2A-TG mice compared with WT, but the reduction was the highest in DT compared with WT. PP2A enzyme activity was enhanced in PP2A-TG and DT mice compared with WT and PP2C-TG mice. In summary, cardiac overexpression of PP2Cβ and co-overexpression of both the catalytic subunit of PP2A and PP2Cβ were detrimental to cardiac function. PP2Cβ overexpression made cardiac preparations less resistant to hypoxia than WT, leading to fibrosis, but PP2Cβ overexpression led to better adaptation to some stressors, such as LPS or chronic β-adrenergic stimulation. Hence, the effect of PP2Cβ is context sensitive.
10.3389/fphar.2020.591773
miR-484 targeting of Yap1-induced LPS-inhibited proliferation, and promoted apoptosis and inflammation in cardiomyocyte.
Xu Ming,Li Xiao-Yong,Song Laichun,Tao Chao,Fang Jihui,Tao Liang
Bioscience, biotechnology, and biochemistry
Apoptosis and inflammation were the main hallmarks of sepsis-induced cardiomyopathy (SIC). Yes-associated protein isoform 1 (Yap1) and miR-484 were involved in mitochondrial fission and apoptosis, especially proapoptotic roles in SIC. Here, we investigated the role of Yap1 and miR-484 in lipopolysaccharide (LPS)-treated H9c2 cells. Yap1 was downregulated, while miR-484 was elevated by LPS treatment. Cell counting kit-8, flow cytometry, western blotting, and ELISA showed that miR-484 inhibitor significantly improved cell viability, decreased apoptosis, suppressed NLRP3 inflammasome formation, and reduced secretion of inflammatory cytokines TNF-α, IL-1β, and IL-6. Yap1, directly targeted by miR-484 shown in the luciferase assay, was more like a compensatory regulator of LPS stimulation. Knockdown of Yap1 inverted the effects of miR-484 inhibitor, including decreased cell viability, and promoted apoptosis and inflammation. These revealed miR-484 directly targeted mRNA of Yap1 to inhibit cell viability, and promote apoptosis and inflammation in LPS-treated H9c2 cells.
10.1093/bbb/zbaa009
Beneficial role of oleuropein in sepsis-induced myocardial injury. Possible Involvement of GSK-3β/NF-kB pathway.
Xing Conghui,Xu Li,Yao Yingjie
Acta cirurgica brasileira
PURPOSE:The present study explored the potential therapeutic role of oleuropein in sepsis-induced heart injury along with the role of GSK-3β/NF-kB signaling pathway. METHODS:Sepsis-induced myocardial injury was induced by cecal ligation and puncture (CLP) in rats. The cardiac injury was assessed by measuring the levels of cTnI and creatine kinase-MB (CK-MB). Sepsis-induced inflammation was assessed by measuring interleukin-6 (IL-6), IL-10 and HMGB1 levels. The different doses of oleuropein (5, 10, and 20 mg/kg) were given prior to CLP. Oleuropein (20 mg/kg) was administered after 6 hof CLP. The expressions of GSK-3β, p-GSK-3β (Ser9) and nuclear factor-κB (NF-κB) were measured in heart homogenates. RESULTS:Cecal ligation and puncture was associated with myocardial injury, an increase in IL-6, a decrease in IL-10 and an increase in HMGB1. Moreover, it decreased the ratio of p-GSK-3β/GSK-3β and increased the expression of p-NF-kB. Pretreatment with oleuropein attenuated CLP-induced myocardial injury and systemic inflammation in a dose-dependent manner. Administration of oleuropein after the onset of CLP also attenuated cardiac injury and inflammation. It also restored CLP-induced changes in the HMGB1 levels, the ratio of p-GSK-3β/GSK-3β and expression of p- NF-kB. CONCLUSIONS:Oleuropein attenuates sepsis-induced systemic inflammation and myocardial injury by inhibiting NF-kB and GSK-3β signaling.
10.1590/ACB360107
Comparative Effectiveness of Heart Rate Control Medications for the Treatment of Sepsis-Associated Atrial Fibrillation.
Chest
BACKGROUND:Atrial fibrillation (AF) with rapid ventricular response frequently complicates the management of critically ill patients with sepsis and may necessitate the initiation of medication to avoid hemodynamic compromise. However, the optimal medication to achieve rate control for AF with rapid ventricular response in sepsis is unclear. RESEARCH QUESTION:What is the comparative effectiveness of frequently used AF medications (β-blockers, calcium channel blockers, amiodarone, and digoxin) on heart rate (HR) reduction among critically ill patients with sepsis and AF with rapid ventricular response? STUDY DESIGN AND METHODS:We conducted a multicenter retrospective cohort study among patients with sepsis and AF with rapid ventricular response (HR > 110 beats/min). We compared the rate control effectiveness of β-blockers to calcium channel blockers, amiodarone, and digoxin using multivariate-adjusted, time-varying exposures in competing risk models (for death and addition of another AF medication), adjusting for fixed and time-varying confounders. RESULTS:Among 666 included patients, 50.6% initially received amiodarone, 10.1% received a β-blocker, 33.8% received a calcium channel blocker, and 5.6% received digoxin. The adjusted hazard ratio for HR of < 110 beats/min by 1 h was 0.50 (95% CI, 0.34-0.74) for amiodarone vs β-blocker, 0.37 (95% CI, 0.18-0.77) for digoxin vs β-blocker, and 0.75 (95% CI, 0.51-1.11) for calcium channel blocker vs β-blocker. By 6 h, the adjusted hazard ratio for HR < 110 beats/min was 0.67 (95% CI, 0.47-0.97) for amiodarone vs β-blocker, 0.60 (95% CI, 0.36-1.004) for digoxin vs β-blocker, and 1.03 (95% CI, 0.71-1.49) for calcium channel blocker vs β-blocker. INTERPRETATION:In a large cohort of patients with sepsis and AF with rapid ventricular response, a β-blocker treatment strategy was associated with improved HR control at 1 h, but generally similar HR control at 6 h compared with amiodarone, calcium channel blocker, or digoxin.
10.1016/j.chest.2020.10.049
Anti-Interleukin-16 Neutralizing Antibody Treatment Alleviates Sepsis-Induced Cardiac Injury and Dysfunction via the Nuclear Factor Erythroid-2 Related Factor 2 Pathway in Mice.
Zhang Jianwei,Yang Zicong,Liang Zhishan,Wang Mengjie,Hu Changxing,Chang Chao,Shi Lei,Ji Qingwei,Liu Ling
Oxidative medicine and cellular longevity
Several interleukin (IL) members have been reported to participate in sepsis. In this study, the effects of IL-16 on sepsis-induced cardiac injury and dysfunction were examined, and the related mechanisms were detected. IL-16 expression in septic mice was first measured, and the results showed that both cardiac and serum IL-16 expression levels were increased in mice with sepsis induced by LPS or cecal ligation and puncture (CLP) compared with control mice. Then, IL-16 was neutralized, and the effects on lipopolysaccharide- (LPS-) induced cardiac injury were detected. The results showed that an anti-IL-16 neutralizing antibody (nAb) significantly reduced mortality and increased serum lactate dehydrogenase (LDH), creatine kinase myocardial bound (CK-MB), and cardiac troponin T (cTnT) levels while improving cardiac function in mice with LPS-induced sepsis. Neutralization of IL-16 also increased the activation of antioxidant pathways and the expression of antioxidant factors in septic mice while decreasing the activation of prooxidant pathways and the expression of prooxidants. Treatment with the anti-IL-16 nAb increased mitochondrial apoptosis-inducing factor (AIF) expression, decreased nuclear AIF and cleaved poly-ADP-ribose polymerase (PARP) expression, and decreased TUNEL-positive cell percentages in LPS-treated mice. Additionally, treatment with CPUY192018, the nuclear factor erythroid-2 related factor 2 (Nrf2) pathway, significantly increased mortality and reversed the above effects in mice treated with LPS and the anti-IL-16 nAb. Our results showed that the anti-IL-16 nAb regulates oxidative stress through the Nrf2 pathway and participates in the regulation of cardiac injury in septic mice. Neutralization of IL-16 may be a beneficial strategy for the prevention of cardiac injury and dysfunction in sepsis patients.
10.1155/2021/6616422
mTOR inhibition as a possible pharmacological target in the management of systemic inflammatory response and associated neuroinflammation by lipopolysaccharide challenge in rats.
Guden Demet Sinem,Temiz-Resitoglu Meryem,Senol Sefika Pinar,Kibar Deniz,Yilmaz Sakir Necat,Tunctan Bahar,Malik Kafait U,Sahan-Firat Seyhan
Canadian journal of physiology and pharmacology
Neuroinflammation plays a critical role during sepsis triggered by microglial activation. Mammalian target of rapamycin (mTOR) has gained attraction in neuroinflammation, however, the mechanism remains unclear. Our goal was to assess the effects of mTOR inhibition by rapamycin on inflammation, microglial activation, oxidative stress, and apoptosis associated with the changes in the inhibitor-κB (IκB)-α/nuclear factor-κB (NF-κB)/hypoxia-inducible factor-1α (HIF-1α) pathway activity following a systemic challenge with lipopolysaccharide (LPS). Rats received saline (10 mL/kg), LPS (10 mg/kg), and (or) rapamycin (1 mg/kg) intraperitoneally. Inhibition of mTOR by rapamycin blocked phosphorylated form of ribosomal protein S6, NF-κB p65 activity by increasing degradation of IκB-α in parallel with HIF-1α expression increased by LPS in the kidney, heart, lung, and brain tissues. Rapamycin attenuated the increment in the expression of tumor necrosis factor-α and interleukin-1β, the inducible nitric oxide synthase, gp91, and p47 in addition to nitrite levels elicited by LPS in tissues or sera. Concomitantly, rapamycin treatment reduced microglial activation, brain expression of caspase-3, and Bcl-2-associated X protein while it increased expression of B cell lymphoma 2 induced by LPS. Overall, this study supports the hypothesis that mTOR contributes to the detrimental effect of LPS-induced systemic inflammatory response associated with neuroinflammation via IκB-α/NF-κB/HIF-1α signaling pathway.
10.1139/cjpp-2020-0487
Long non-coding RNA GAS5 aggravates myocardial depression in mice with sepsis via the microRNA-449b/HMGB1 axis and the NF-κB signaling pathway.
Gao Hongfeng,Ma Huijing,Gao Min,Chen Aichun,Zha Shujuan,Yan Jixi
Bioscience reports
Sepsis is a common cause of deaths of patients in intensive care unit. The study aims to figure out the role of long non-coding RNA (lncRNA) GAS5 in the myocardial depression in mice with sepsis. Cecal ligation and puncture (CLP) was applied to induce sepsis in mice, and then the heart function, myocardium structure, and the inflammatory response were evaluated. Differentially expressed lncRNAs in mice with sepsis were identified. Then gain- and loss-of-functions of GAS5 were performed in mice to evaluate its role in mouse myocardial depression. The lncRNA-associated microRNA (miRNA)-mRNA network was figured out via an integrative prediction and detection. Myocardial injury was observed by overexpression of high-mobility group box 1 (HMGB1) in septic mice with knockdown of GAS5 expression. Activity of NF-κB signaling was evaluated, and NF-κB inhibition was induced in mice with sepsis and overexpression of GAS5. Collectively, CLP resulted in myocardial depression and injury, and increased inflammation in mice. GAS5 was highly expressed in septic mice. GAS5 inhibition reduced myocardial depression, myocardial injury and inflammation responses in septic mice. GAS5 was identified to bind with miR-449b and to elevate HMGB1 expression, thus activating the NF-κB signaling. HMGB1 overexpression or NF-κB inactivation reduced the GAS5-induced myocardial depression and inflammation in septic mice. Our study suggested that GAS5 might promote sepsis-induced myocardial depression via the miR-449b/HMGB1 axis and the following NF-κB activation.
10.1042/BSR20201738
A venous-specific purinergic signaling cascade initiated by Pannexin 1 regulates TNFα-induced increases in endothelial permeability.
Science signaling
The endothelial cell barrier regulates the passage of fluid between the bloodstream and underlying tissues, and barrier function impairment exacerbates the severity of inflammatory insults. To understand how inflammation alters vessel permeability, we studied the effects of the proinflammatory cytokine TNFα on transendothelial permeability and electrophysiology in ex vivo murine veins and arteries. We found that TNFα specifically decreased the barrier function of venous endothelium without affecting that of arterial endothelium. On the basis of RNA expression profiling and protein analysis, we found that claudin-11 (CLDN11) was the predominant claudin in venous endothelial cells and that there was little, if any, CLDN11 in arterial endothelial cells. Consistent with a difference in claudin composition, TNFα increased the permselectivity of Cl over Na in venous but not arterial endothelium. The vein-specific effects of TNFα also required the activation of Pannexin 1 (Panx1) channels and the CD39-mediated hydrolysis of ATP to adenosine, which subsequently stimulated A adenosine receptors. Moreover, the increase in vein permeability required the activation of the Ca channel TRPV4 downstream of Panx1 activation. Panx1-deficient mice resisted the pathologic effects of sepsis induced by cecal ligation and puncture on life span and lung vascular permeability. These data provide a targetable pathway with the potential to promote vein barrier function and prevent the deleterious effects of vascular leak in response to inflammation.
10.1126/scisignal.aba2940
Fat-1 transgenic mice rich in endogenous omega-3 fatty acids are protected from lipopolysaccharide-induced cardiac dysfunction.
Mao Shuai,Ma Huan,Chen Peipei,Liang Yubin,Zhang Minzhou,Hinek Aleksander
ESC heart failure
AIMS:Cardiac malfunctions developing in result of sepsis are hard to treat so they eventually contribute to the increased mortality. Previous reports indicated for therapeutic potential of exogenous ω-3 polyunsaturated fatty acids (PUFA) in sepsis, but potential benefits of this compound on the malfunctional heart have not been explored yet. In the present study, we investigated whether the constantly elevated levels of endogenous ω-3 PUFA in transgenic fat-1 mice would alleviate the lipopolysaccharide (LPS)-induced cardiac failure and death. METHODS AND RESULTS:After both wild type (WT) and transgenic fat-1 mice were challenged with LPS, a Kaplan-Meier curve and echocardiography were performed to evaluate the survival rates and cardiac function. Proteomics analysis, RT-PCR, western blotting, immune-histochemistry, and transmission electron microscopy were further performed to investigate the underlying mechanisms. Results showed that transgenic fat-1 mice exhibited the significantly lower mortality after LPS challenge as compared with their WT counterparts (30% vs. 42.5%, P < 0.05). LPS injection consistently impaired the left ventricular contractile function and caused the cardiac injury in the wild type mice, but not significantly affected the fat-1 mice (P < 0.05). Proteomic analyses, ELISA, and immunohistochemistry further revealed that myocardium of the LPS-challenged fat-1 mice demonstrated the significantly lower levels of pro-inflammatory markers and ROS than WT mice. Meaningfully, the LPS-treated fat-1 mice also demonstrated a significantly higher levels of LC3 II/I and Atg7 expressions than the LPS-treated WT mice (P < 0.05), as well as displayed a selectively increased levels of peroxisome proliferator-activated receptor (PPAR) γ and sirtuin (Sirt)-1 expression, associated with a parallel decrease in NFκB activation. CONCLUSIONS:The fat-1 mice were protected from the detrimental LPS-induced inflammation and oxidative stress, and exhibited enhancement of the autophagic flux activities, associating with the increased Sirt-1 and PPARγ signals.
10.1002/ehf2.13262
Ablation of Aquaporin-9 Ameliorates the Systemic Inflammatory Response of LPS-Induced Endotoxic Shock in Mouse.
Tesse Angela,Gena Patrizia,Rützler Michael,Calamita Giuseppe
Cells
Septic shock is the most severe complication of sepsis, being characterized by a systemic inflammatory response following bacterial infection, leading to multiple organ failure and dramatically high mortality. Aquaporin-9 (AQP9), a membrane channel protein mainly expressed in hepatocytes and leukocytes, has been recently associated with inflammatory and infectious responses, thus triggering strong interest as a potential target for reducing septic shock-dependent mortality. Here, we evaluated whether AQP9 contributes to murine systemic inflammation during endotoxic shock. Wild type (; WT) and gene knockout (; KO) male mice were submitted to endotoxic shock by i.p. injection of lipopolysaccharide (LPS; 40 mg/kg) and the related survival times were followed during 72 h. The electronic paramagnetic resonance and confocal microscopy were employed to analyze the nitric oxide (NO) and superoxide anion (O) production, and the expression of inducible NO-synthase (iNOS) and cyclooxigenase-2 (COX-2), respectively, in the liver, kidney, aorta, heart and lung of the mouse specimens. LPS-treated KO mice survived significantly longer than corresponding WT mice, and 25% of the KO mice fully recovered from the endotoxin treatment. The LPS-injected KO mice showed lower inflammatory NO and O productions and reduced iNOS and COX-2 levels through impaired NF-κB p65 activation in the liver, kidney, aorta, and heart as compared to the LPS-treated WT mice. Consistent with these results, the treatment of FaO cells, a rodent hepatoma cell line, with the AQP9 blocker HTS13268 prevented the LPS-induced increase of inflammatory NO and O. A role for AQP9 is suggested in the early acute phase of LPS-induced endotoxic shock involving NF-κB signaling. The modulation of AQP9 expression/function may reveal to be useful in developing novel endotoxemia therapeutics.
10.3390/cells10020435
Inhibition of 5-lipoxygenase is associated with downregulation of the leukotriene B4 receptor 1/ Interleukin-12p35 pathway and ameliorates sepsis-induced myocardial injury.
Xie Saiyang,Qi Xiping,Wu Qingqing,Wei Li,Zhang Min,Xing Yun,Shi Wenke,Chen Si,Zeng Xiaofeng,Wang Shasha,Guo Haipeng,Deng Wei
Free radical biology & medicine
Sepsis rapidly contributed to multiorgan failure affecting most commonly of the cardiovascular and respiratory systems and yet there were no effective therapies. The current study aimed at providing evidence on the cardioprotection of suppression of 5-Lipoxygenase (5-Lox) and identifying the possible mechanism in the mouse model of sepsis. The cecal ligation-perforation (CLP) model was applied to C57BL/6 wild-type (WT) and 5-Lox deficient (5-Lox) mice to induce sepsis. 5-Lox expression was up-regulated in mouse myocardium and leukotriene B4 (LTB4) level was increased in serum after sepsis. Subsequently, we utilized a recombinant adenoviral expression vector (rAAV9) to overexpress Alox5 gene in adult mice. Compared to WT mice, 5-Lox overexpression accelerated CLP-induced myocardial injury and cardiac dysfunction. Oppositely, 5-Lox deficiency offered protection against myocardial injury in a mouse model of sepsis and attenuated sepsis-mediated inflammation, oxidative stress and apoptosis in the mouse heart. Mechanically, 5-Lox promoted LTB4 production, which in turn contributed to the activation of leukotriene B4 receptor 1 (BLT1)/interleukin-12p35 (IL-12p35) pathway and enhanced M1 macrophage polarization. However, the suppression of BLT1 by either gene mutation or antagonist U75302 significantly inhibited the adverse effect of 5-Lox in sepsis. Further study demonstrated that pharmacological inhibition of 5-Lox prevented CLP-induced septic cardiomyopathy (SCM). Our study identified 5-Lox exacerbated sepsis-associated myocardial injury through activation of LTB4 production and promoting BLT1/IL-12p35 pathway. Hence, inhibition of 5-Lox may be a potential candidate strategy for septic cardiac dysfunction treatment.
10.1016/j.freeradbiomed.2021.02.034
Profiles of differentially expressed long noncoding RNAs and messenger RNAs in the myocardium of septic mice.
Li Chengbao,Liu Yongchao,Qin Jing,Liu Yuhao,Ma Lijie,Zhang Shouqin,Wang Junjie,Wang Sheng
Annals of translational medicine
Background:Sepsis is the primary cause of mortality in the intensive care unit (ICU), mainly due to sepsis-induced dysfunction of essential organs such as the heart and lungs. This study investigated the myocardium's epigenetic characterization from septic mice to identify potential treatment targets for septic myocardial dysfunction. Methods:Cecal ligation and puncture (CLP) was used to induce sepsis in male C57BL/6 mice. Hearts were collected 24 h after surgery to determine the expression profiles of long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) by microarray. To validate the reliability of microarray results, we randomly chose six differentially expressed lncRNAs for qRT-PCR. Functional mapping of differentially expressed mRNAs was annotated with gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses; lncRNA-mRNA co-expression network was constructed to reveal connections between lncRNAs and mRNAs. Results:Microarray analysis indicated that 1,568 lncRNAs and 2,166 mRNAs were differentially expressed in the myocardium from septic mice, which was further confirmed by qRT-PCR. KEGG pathway analysis showed that numerous differentially expressed mRNAs were relevant to tumor necrosis factor (TNF) and phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signaling pathways. Moreover, according to the lncRNA-mRNA co-expression network constructed by the above six lncRNAs and their interacting mRNAs, the co-expression network profiles had 57 network nodes and 134 connections, including 76 positive interactions and 58 negative interactions. Conclusions:In mouse hearts, sepsis resulted in differential expression of lncRNAs and mRNAs related to TNF and PI3K-Akt signaling pathways, suggesting that lncRNAs and their interacting mRNAs may participate in the pathogenesis of septic myocardial dysfunction by regulating TNF and PI3K-Akt signaling pathways.
10.21037/atm-20-3830
Hypoxia-inducible factor-dependent induction of myeloid-derived netrin-1 attenuates natural killer cell infiltration during endotoxin-induced lung injury.
Berg Nathaniel K,Li Jiwen,Kim Boyun,Mills Tingting,Pei Guangsheng,Zhao Zhongming,Li Xiangyun,Zhang Xu,Ruan Wei,Eltzschig Holger K,Yuan Xiaoyi
FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Sepsis and sepsis-associated lung inflammation significantly contribute to the morbidity and mortality of critical illness. Here, we examined the hypothesis that neuronal guidance proteins could orchestrate inflammatory events during endotoxin-induced lung injury. Through a targeted array, we identified netrin-1 as the top upregulated neuronal guidance protein in macrophages treated with lipopolysaccharide (LPS). Furthermore, we found that netrin-1 is highly enriched in infiltrating myeloid cells, particularly in macrophages during LPS-induced lung injury. Transcriptional studies implicate hypoxia-inducible factor HIF-1α in the transcriptional induction of netrin-1 during LPS treatment. Subsequently, the deletion of netrin-1 in the myeloid compartment (Ntn1 LysM Cre) resulted in exaggerated mortality and lung inflammation. Surprisingly, further studies revealed enhanced natural killer cells (NK cells) infiltration in Ntn1 LysM Cre mice, and neutralization of NK cell chemoattractant chemokine (C-C motif) ligand 2 (CCL2) reversed the exaggerated lung inflammation. Together, these studies provide functional insight into myeloid cell-derived netrin-1 in controlling lung inflammation through the modulation of CCL2-dependent infiltration of NK cells.
10.1096/fj.202002407R
Cystatin Alleviates Sepsis Through Activating Regulatory Macrophages.
Xie Hong,Wu Lingqin,Chen Xingzhi,Gao Shifang,Li Huihui,Yuan Yuan,Liang Jinbao,Wang Xiaoli,Wang Shuying,Xu Changyan,Chu Liang,Zhan Bin,Zhou Rui,Yang Xiaodi
Frontiers in cellular and infection microbiology
Multi-organ failure caused by the inflammatory cytokine storm induced by severe infection is the major cause of death for sepsis. -Cys is a cysteine protease inhibitor secreted by with strong immunomodulatory functions on host immune system. Our previous studies have shown that treatment with -Cys recombinant protein (r-Cys) attenuated inflammation caused by sepsis. However, the immunological mechanism underlying the immunomodulation of -Cys for regulating inflammatory diseases is not yet known. In this study, we investigated the effect of -Cys on the macrophage M2 polarization and subsequent therapeutic effect on sepsis. The r-Cys was expressed in yeast . Incubation of mouse bone marrow-derived macrophages (BMDMs) with yeast-expressed r-Cys significantly activated the polarization of macrophages to M2 subtype characterized by the expression of F4/80 CD206 with the elated secretion of IL-10 and TGF-β. Adoptive transfer of r-Cys treated BMDMs to mice with sepsis induced by cecal ligation and puncture (CLP) significantly improved their survival rates and the systemic clinical manifestations of sepsis compared with mice receiving non-treated normal BMDMs. The therapeutic effect of -Cys-induced M2 macrophages on sepsis was also reflected by the reduced pathological damages in organs of heart, lung, liver and kidney and reduced serological levels of tissue damage-related ALT, AST, BUN and Cr, associated with downregulated pro-inflammatory cytokines (IFN-gamma and IL-6) and upregulated regulatory anti-inflammatory cytokines (IL-10 and TGF-β). Our results demonstrated that -Cys is a strong immunomodulatory protein with anti-inflammatory features through activating M2 macrophage polarization. The findings of this study suggested that -Cys itself or -Cys-induced M2 macrophages could be used as therapeutic agents in the treatment of sepsis or other inflammatory diseases.
10.3389/fcimb.2021.617461
A DARPin targeting activated Mac-1 is a novel diagnostic tool and potential anti-inflammatory agent in myocarditis, sepsis and myocardial infarction.
Siegel Patrick M,Bojti István,Bassler Nicole,Holien Jessica,Flierl Ulrike,Wang Xiaowei,Waggershauser Philipp,Tonnar Xavier,Vedecnik Christopher,Lamprecht Constanze,Stankova Ivana,Li Tian,Helbing Thomas,Wolf Dennis,Anto-Michel Nathaly,Mitre Lucia Sol,Ehrlich Julia,Orlean Lukas,Bender Ileana,Przewosnik Anne,Mauler Maximilian,Hollederer Laura,Moser Martin,Bode Christoph,Parker Michael W,Peter Karlheinz,Diehl Philipp
Basic research in cardiology
The monocyte β-integrin Mac-1 is crucial for leukocyte-endothelium interaction, rendering it an attractive therapeutic target for acute and chronic inflammation. Using phage display, a Designed-Ankyrin-Repeat-Protein (DARPin) was selected as a novel binding protein targeting and blocking the α I-domain, an activation-specific epitope of Mac-1. This DARPin, named F7, specifically binds to activated Mac-1 on mouse and human monocytes as determined by flow cytometry. Homology modelling and docking studies defined distinct interaction sites which were verified by mutagenesis. Intravital microscopy showed reduced leukocyte-endothelium adhesion in mice treated with this DARPin. Using mouse models of sepsis, myocarditis and ischaemia/reperfusion injury, we demonstrate therapeutic anti-inflammatory effects. Finally, the activated Mac-1-specific DARPin is established as a tool to detect monocyte activation in patients receiving extra-corporeal membrane oxygenation, as well as suffering from sepsis and ST-elevation myocardial infarction. The activated Mac-1-specific DARPin F7 binds preferentially to activated monocytes, detects inflammation in critically ill patients, and inhibits monocyte and neutrophil function as an efficient new anti-inflammatory agent.
10.1007/s00395-021-00849-9
Wnt/β-Catenin Antagonist Pyrvinium Exerts Cardioprotective Effects in Polymicrobial Sepsis Model by Attenuating Calcium Dyshomeostasis and Mitochondrial Dysfunction.
Cardiovascular toxicology
Calcium dysregulation and mitochondrial dysfunction are key elements in the development of sepsis-induced cardiac dysfunction. Evidences have suggested that inhibition of Wnt/β-Catenin signalling prevents cardiac dysfunction and remodelling in surgical, hypertension and pressure overload models. The present study investigated the effects of Wnt/β-Catenin inhibitor on calcium overload and mitochondrial dysfunction in rat sepsis model of cardiomyopathy. Induction of sepsis by cecal ligation puncture (CLP) resulted in the up-regulation of cardiac β-catenin transcriptional levels and cardiac dysfunction depicted by increased serum lactate dehydrogenase, CK-MB levels reduced maximum (dp/dt max.) and minimum developed pressure (dp/dt min.), increased LVEsDP and relaxation constant tau values. Moreover, oxidative and inflammatory stress, immune cell infiltration, increased myeloperoxidase activity, enhanced caspase-3 activity and fibronectin protein levels were observed in septic rat's heart. Also, septic rat's heart displayed mitochondrial dysfunction due to mPTP opening, increased calcium up-regulation in left ventricular apex tissues and whole heart, increased collagen staining, necrosis and structural damage. Pre-treatment with Wnt/β-Catenin antagonist attenuated sepsis-induced serum and tissue biochemical changes, cardiac dysfunction and structural alterations by inhibiting mitochondrial mPTP opening and restricting calcium overloading in cardiac tissue.
10.1007/s12012-021-09643-4
Beclin-1 improves mitochondria-associated membranes in the heart during endotoxemia.
Sun Yuxiao,Cai Ying,Qian Suhong,Chiou Hellen,Zang Qun S
FASEB bioAdvances
Mitochondria-associated membranes (MAMs) are essential to mitochondria. This study was to determine whether endotoxemia rearranges MAMs in the heart, and whether Beclin-1 regulates this process. Wild-type mice and mice with a cardiac-specific overexpression of Beclin-1 (-), or a heterozygous knockout of Beclin-1 ( ) were given lipopolysaccharide (LPS) challenge. In the heart, the ultrastructure of MAMs was examined by electron microscopy and the histology evaluated by immunostaining. Additionally, MAMs were isolated by ultracentrifugation, and their content and function were quantified. The effects of Beclin-1-activating peptide (TB-peptide) on MAMs were also examined. Data showed that endotoxemia decreased both the total mass and the function of MAMs, and these deficiencies became worse in mice but were alleviated in - and TB-peptide-treated mice. Responses of myocardial MAMs to LPS and to TB-peptide were additionally examined in AC16 human cardiomyocytes. findings recaptured the effects of LPS and TB-peptide in cardiomyocytes; the challenge of LPS reduced the level and activity of MAMs, and TB-peptide attenuated this defect. Together, the results suggest a new function of Beclin-1 in improving cardiac MAMs during endotoxemia, providing a mechanism for the previously identified role of Beclin-1 in protection of mitochondria and cardiac function.
10.1096/fba.2020-00039
The emerging role of the apelinergic system in kidney physiology and disease.
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association
The apelinergic system (AS) is a novel pleiotropic system with an essential role in renal and cardiovascular physiology and disease, including water homeostasis and blood pressure regulation. It consists of two highly conserved peptide ligands, apelin and apela, and a G-protein-coupled apelin receptor. The two ligands have many isoforms and a short half-life and exert both similar and divergent effects. Vasopressin, apelin and their receptors colocalize in hypothalamic regions essential for body fluid homeostasis and interact at the central and renal levels to regulate water homeostasis and diuresis in inverse directions. In addition, the AS and renin-angiotensin system interact both systemically and in the kidney, with implications for the cardiovascular system. A role for the AS in diverse pathological states, including disorders of sodium and water balance, hypertension, heart failure, pre-eclampsia, acute kidney injury, sepsis and diabetic nephropathy, has recently been reported. Furthermore, several metabolically stable apelin analogues have been developed, with potential applications in diverse diseases. We review here what is currently known about the physiological functions of the AS, focusing on renal, cardiovascular and metabolic homeostasis, and the role of the AS in associated diseases. We also describe several hurdles and research opportunities worthy of the attention of the nephrology community.
10.1093/ndt/gfab070
Regulatory role of the TLR4/JNK signaling pathway in sepsis‑induced myocardial dysfunction.
Chang Chao,Hu Liya,Sun Shanshan,Song Yanqiu,Liu Shan,Wang Jing,Li Peijun
Molecular medicine reports
Sepsis is a life‑threatening organ dysfunction caused by a dysregulated host response to infection, and is a leading cause of mortality worldwide. Myocardial dysfunction is associated with poor prognosis in patients with sepsis and contributes to a high risk of mortality. However, the pathophysiological mechanisms underlying sepsis‑induced myocardial dysfunction are not completely understood. The aim of the present study was to investigate the role of toll‑like receptor 4 (TLR4)/c‑Jun N‑terminal kinase (JNK) signaling in pro‑inflammatory cytokine expression and cardiac dysfunction during lipopolysaccharide (LPS)‑induced sepsis in mice. C57BL/6 mice were pretreated with TAK‑242 or saline for 1 h and then subjected to LPS (12 mg/kg, intraperitoneal) treatment. Cardiac function was assessed using an echocardiogram. The morphological changes of the myocardium were examined by hematoxylin and eosin staining and transmission electron microscopy. The serum protein levels of cardiac troponin I (cTnI) and tumor necrosis factor‑α (TNF‑α) were determined by an enzyme‑linked immunosorbent assay (ELISA). The TLR4 and JNK mRNA levels were analyzed via reverse transcription‑quantitative PCR. TLR4, JNK and phosphorylated‑JNK protein levels were measured by western blotting. In response to LPS, the activation of TLR4 and JNK in the myocardium was upregulated. There were significant increases in the serum levels of TNF‑α and cTnI, as well as histopathological changes in the myocardium and suppressed cardiac function, following LPS stimulation. Inhibition of TLR4 activation using TAK‑242 led to a decrease in the activation of JNK and reduced the protein expression of TNF‑α in plasma, and alleviated histological myocardial injury and improved cardiac function during sepsis in mice. The present data suggested that the TLR4/JNK signaling pathway played a critical role in regulating the production of pro‑inflammatory cytokines and myocardial dysfunction induced by LPS.
10.3892/mmr.2021.11973
Pinocembrin alleviates lipopolysaccharide-induced myocardial injury and cardiac dysfunction in rats by inhibiting p38/JNK MAPK pathway.
Li Chuang,Wan Weiguo,Ye Tianxin,Sun Yazhou,Chen Xiaoli,Liu Xin,Shi Shaobo,Zhang Yan,Qu Chuan,Yang Bo,Zhang Cui
Life sciences
AIM:Recent studies have shown that, with its excellent anti-inflammatory and antioxidant effects, pinocembrin can reduce the occurrence of arrhythmia in myocardial infarction rats. However, whether it can alleviate lipopolysaccharide (LPS)-induced myocardial injury in rats has not been reported. Therefore, the purpose of this study was to investigate whether pinocembrin could alleviate myocardial injury and arrhythmia in rats with sepsis. MATERIALS AND METHODS:Rats were intraperitoneally injected with LPS to simulate animal sepsis, and the caudal vein was injected with pinocembrin or normal saline for intervention. Transthoracic echocardiography, inflammatory factors, electrophysiological recording, histological analysis, and western-blot analysis were performed. KEY FINDINGS:Compared with the control group, the rats in the LPS group had myocardial injury and cardiac dysfunction, and the incidence of ventricular arrhythmia increased. In addition, LPS resulted in the increase of p-c-Jun N-terminal kinase (JNK), p-p38 proteins in the myocardium, the levels of inflammatory factors in the blood and the apoptosis rate of left ventricular cardiomyocytes. And all these adverse effects were eliminated, thus confirming that pinocembrin has an excellent protective effect on the heart. SIGNIFICANCE:Reducing the inflammatory response and cell apoptosis by inhibiting p38/JNK mitogen-activated protein kinase (MAPK) signaling pathway, pinocembrin can alleviate myocardial injury, cardiac dysfunction, and ventricular arrhythmia induced by LPS.
10.1016/j.lfs.2021.119418
Chrysin Ameliorates Sepsis-Induced Cardiac Dysfunction Through Upregulating Nfr2/Heme Oxygenase 1 Pathway.
Journal of cardiovascular pharmacology
ABSTRACT:The incidence of myocardial dysfunction caused by sepsis is high, and the mortality of patients with sepsis can be significantly increased. During sepsis, oxidative stress and inflammation can lead to severe organ dysfunction. Flavone chrysin is one of the indispensable biological active ingredients for different fruits and vegetables and has antioxidant and anti-inflammatory properties. However, it is not clear whether chrysin is an effective treatment for heart dysfunction caused by sepsis. We found that it had protective effects against the harmful effects caused by LPS, manifested in improved survival, normalized cardiac function, improved partial pathological scores of myocardial tissue, and remission of apoptosis, as well as reduced oxidative stress and inflammation. Mechanism studies have found that chrysin is an important antioxidant protein, a key regulator of heme oxygenase 1 (HO-1). We found that HO-1 levels were increased after LPS intervention, and chrysin further increased HO-1 levels, along with the addition of Nrf2, a regulator of antioxidant proteins. Pretreatment with PD98059, an extracellular signal-regulated kinase-specific inhibitor, blocked chrysin-mediated phosphorylation of Nrf2 and the nuclear translocation of Nrf2. The protective effect of chrysin on sepsis-induced cardiac dysfunction was blocked by ZnPP, which is a HO-1 blocker. Chrysin increased antioxidant activity and reduced markers of oxidative stress (SOD and MDA) and inflammation (MPO and IL-1β), all of which were blocked by ZnPP. This indicates that HO-1 is the upstream molecule regulating the protective effect of chrysin. Thus, by upregulation of HO-1, chrysin protects against LPS-induced cardiac dysfunction and inflammation by inhibiting oxidative stress.
10.1097/FJC.0000000000000989
Pralidoxime improves the hemodynamics and survival of rats with peritonitis-induced sepsis.
Mamadjonov Najmiddin,Jung Yong Hun,Jeung Kyung Woon,Lee Hyoung Youn,Lee Byung Kook,Youn Chun Song,Jeong In Seok,Heo Tag,Min Yong Il
PloS one
Several studies have suggested that sympathetic overstimulation causes deleterious effects in septic shock. A previous study suggested that pralidoxime exerted a pressor effect through a mechanism unrelated to the sympathetic nervous system; this effect was buffered by the vasodepressor action of pralidoxime mediated through sympathoinhibition. In this study, we explored the effects of pralidoxime on hemodynamics and survival in rats with peritonitis-induced sepsis. This study consisted of two sub-studies: survival and hemodynamic studies. In the survival study, 66 rats, which survived for 10 hours after cecal ligation and puncture (CLP), randomly received saline placebo, pralidoxime, or norepinephrine treatment and were monitored for up to 24 hours. In the hemodynamic study, 44 rats were randomly assigned to sham, CLP-saline placebo, CLP-pralidoxime, or CLP-norepinephrine groups, and hemodynamic measurements were performed using a conductance catheter placed in the left ventricle. In the survival study, 6 (27.2%), 15 (68.1%), and 5 (22.7%) animals survived the entire 24-hour monitoring period in the saline, pralidoxime, and norepinephrine groups, respectively (log-rank test P = 0.006). In the hemodynamic study, pralidoxime but not norepinephrine increased end-diastolic volume (P <0.001), stroke volume (P = 0.002), cardiac output (P = 0.003), mean arterial pressure (P = 0.041), and stroke work (P <0.001). The pressor effect of norepinephrine was short-lived, such that by 60 minutes after the initiation of norepinephrine infusion, it no longer had any significant effect on mean arterial pressure. In addition, norepinephrine significantly increased heart rate (P <0.001) and the ratio of arterial elastance to ventricular end-systolic elastance (P = 0.010), but pralidoxime did not. In conclusion, pralidoxime improved the hemodynamics and 24-hour survival rate in rats with peritonitis-induced sepsis, but norepinephrine did not.
10.1371/journal.pone.0249794
Cardiovascular complications of bacteraemia.
BMJ case reports
The incidence of bacteraemia has risen due to a worldwide increase in immunocompromised patients and antibiotic resistance. We describe three patients who experienced severe, including cardiovascular, complications of pneumococcal bacteraemia. Cardiovascular complications related to pneumococci may run a fulminant course. However, some of these life-threatening complications (eg, endocarditis and aortitis) may long remain unnoticed or be misdiagnosed and therefore delay correct treatment. We review the literature with regards to the incidence, diagnosis and treatment of these rare but possibly lethal and hence important cardiovascular complications.
10.1136/bcr-2020-240341
Comparative transcriptome analysis of transcripts of uncertain coding potential in septic myocardial depression.
BMC cardiovascular disorders
BACKGROUND:Septic shock with myocardial depression is very common in intensive care units. However, the exact molecular mechanisms underlying sepsis-induced myocardial depression remain unclear. Whether the profiles of transcripts of uncertain coding potential (TUCPs) differ between patients with and without myocardial depression is also unknown. Our study aimed to find expression differences between groups of TUCPs and determine their potential functions in a preclinical model. METHODS:We generated rat models of hypodynamic septic shock induced by lipopolysaccharide. A total of 12 rats were established and left ventricular tissue from each was collected. We performed RNA-seq to identify TUCPs in each sample. Transcripts with an corrected P value of < 0.05 were defined as differentially expressed (DE). We also performed GO terms and KEGG analysis to identify the potential functions of DE TUCPs. RESULTS:A total of 4,851 TUCPs were identified in heart samples, 85 of which were expressed differently between the sepsis and control groups. Further bioinformatic analyses suggested that TUCPs play important roles in myocardial contraction, energy regulation, and metabolic processes, and are also involved in the regulation of several pathways. CONCLUSION:Our results demonstrate that TUCPs both participate in and mediate the pathological process of myocardial depression. Our study improves the understanding of the basic molecular mechanisms underlying myocardial depression from a novel perspective.
10.1186/s12872-021-01973-z
Knockdown of lncRNA PVT1 attenuated macrophage M1 polarization and relieved sepsis induced myocardial injury via miR-29a/HMGB1 axis.
Cytokine
BACKGROUND:LncRNA PVT1 was reported to be elevated in septic myocardial tissue. The underlying mechanism by which PVT1 aggravated sepsis induced myocardial injury needs further investigation. METHODS:Mice was subjected to LPS injection to mimic in vivo sepsis model. HE staining was applied to observe tissue injury. Cardiac function of mice was determined by echocardiography. Bone marrow derived macrophage (BMDM) was used to confirm the regulatory effect of PVT1 in macrophage polarization. Western blotting or qRT-PCR were performed to evaluate protein or mRNA levels, respectively. ELISA was conducted to determine cytokine levels. Interaction between PVT1 and miR-29a, miR-29a and HMGB1 were accessed by dual luciferase assay. RESULTS:Expression of PVT1 was elevated in myocardial tissue and heart infiltrating macrophages of sepsis mice. PVT1 knockdown alleviated LPS induced myocardial injury and attenuated M1 macrophage polarization. The mechanic study suggested that PVT1 targeted miR-29a, thus elevated expression of HMGB1, which was repressed by miR-29a targeting. The effect of PVT1 on M1 macrophage polarization was dependent on targeting miR-29a. CONCLUSION:PVT1 promoted M1 polarization and aggravated LPS induced myocardial injury via miR-29a/HMGB1 axis.
10.1016/j.cyto.2021.155509
Melatonin alleviates lipopolysaccharide-induced myocardial injury by inhibiting inflammation and pyroptosis in cardiomyocytes.
Annals of translational medicine
BACKGROUND:Melatonin (MT) has been shown to protect against various cardiovascular diseases. However, the effect of MT on lipopolysaccharide (LPS)-induced myocardial injury is poorly understood. This study aims to evaluate the effects of MT on LPS-induced myocardial injury . METHODS:H9C2 cells were divided into a control group, MT group, LPS group, and MT + LPS group. The control group was treated with sterile saline solution, the LPS group received 8 µg/mL LPS for 24 h, MT + LPS cells were pretreated with 200 µmol/L MT for 2 h then with 8 µg/mL LPS for 24 h, and the MT group received only 200 µmol/L MT for 2 h. The CCK-8 assay and lactate dehydrogenase (LDH) activity assay were used to analyze cell viability and LDH release, respectively. Intracellular reactive oxygen species (ROS) and the rate of pyroptosis were measured using the fluorescent probe dichloro-dihydro-fluorescein diacetate (DCFH-DA) and propidium iodide (PI) staining, respectively. The cell supernatants were used to measure the levels of inflammatory cytokines, including IL-6, TNF-α, and IL-1β by enzyme-linked immunosorbent assay (ELISA). The protein levels of iNOS, COX-2, NF-κB, p-NF-κB, NLRP3, caspase-1, and GSDMD were detected by western blot. RESULTS:MT pretreatment significantly improved LPS-induced myocardial injury by inhibiting inflammation and pyroptosis in H9C2 cells. Moreover, MT inhibited the activation of the NF-κB pathway, and reduced the expression of inflammation-related proteins (iNOS and COX-2), and pyroptosis-related proteins (NLRP3, caspase-1, and GSDMD). CONCLUSIONS:Our data suggests that MT can alleviate LPS-induced myocardial injury, providing novel insights into the treatment of sepsis-induced myocardial dysfunction.
10.21037/atm-20-8196
NMR-based serum and urine metabolomic profile reveals suppression of mitochondrial pathways in experimental sepsis-associated acute kidney injury.
American journal of physiology. Renal physiology
Sepsis-associated acute kidney injury (SA-AKI) is a significant problem in the critically ill that causes increased death. Emerging understanding of this disease implicates metabolic dysfunction in its pathophysiology. This study sought to identify specific metabolic pathways amenable to potential therapeutic intervention. Using a murine model of sepsis, blood and tissue samples were collected for assessment of systemic inflammation, kidney function, and renal injury. Nuclear magnetic resonance (NMR)-based metabolomics quantified dozens of metabolites in serum and urine that were subsequently submitted to pathway analysis. Kidney tissue gene expression analysis confirmed the implicated pathways. Septic mice had elevated circulating levels of inflammatory cytokines and increased levels of blood urea nitrogen and creatinine, indicating both systemic inflammation and poor kidney function. Renal tissue showed only mild histological evidence of injury in sepsis. NMR metabolomic analysis identified the involvement of mitochondrial pathways associated with branched-chain amino acid metabolism, fatty acid oxidation, and de novo NAD biosynthesis in SA-AKI. Renal cortical gene expression of enzymes associated with those pathways was predominantly suppressed. Renal cortical fatty acid oxidation rates were lower in septic mice with high inflammation, and this correlated with higher serum creatinine levels. Similar to humans, septic mice demonstrated renal dysfunction without significant tissue disruption, pointing to metabolic derangement as an important contributor to SA-AKI pathophysiology. Metabolism of branched-chain amino acid and fatty acids and NAD synthesis, which all center on mitochondrial function, appeared to be suppressed. Developing interventions to activate these pathways may provide new therapeutic opportunities for SA-AKI. NMR-based metabolomics revealed disruptions in branched-chain amino acid metabolism, fatty acid oxidation, and NAD synthesis in sepsis-associated acute kidney injury. These pathways represent essential processes for energy provision in renal tubular epithelial cells and may represent targetable mechanisms for therapeutic intervention.
10.1152/ajprenal.00582.2020
Pgc-1α Promotes Phosphorylation, Inflammation, and Apoptosis in H9c2 Cells During the Early Stage of Lipopolysaccharide Induction.
Huang Qun,Liu De-Hong,Chen Chang-Feng,Han Yong,Huang Zhi-Qiang,Zhang Ji-Wen,Zeng Xiao-Mei
Inflammation
Cardiac dysfunction in severe sepsis is associated with increased mortality. However, the molecular mechanisms underlying septic heart dysfunction remain unclear. Expression of peroxisome proliferator-activated receptor-γ coactivator 1α (Pgc-1α), concentrations of inflammatory factors, and activation of the nuclear factor kappa-B (NF-κB) signaling pathway were examined in H9c2 cells after a 24-h lipopolysaccharide (LPS) stimulation period using qPCR, enzyme-linked immunosorbent assays (ELISAs), and western blots (WBs), respectively. Pgc-1α was overexpressed and suppressed in cells using a lentivirus vector and siRNA, respectively. The effects of Pgc-1α dysfunction on the release of inflammatory factors and apoptosis were analyzed. Pgc-1α expression was increased after LPS induction for 0.5 h and returned to the pre-induction level at 2 h. Levels of IL-1β, IL-6, and TNF-α increase after LPS induction for 0.5 h and accumulated in the culture supernatants over time. The WBs revealed the highest Pgc-1α and phospho (p)-p65 protein levels after LPS induction for 0.5 h, followed by a decrease; moreover, the cleaved-caspase-3 level increased after LPS induction for 0.5 h and increased gradually thereafter. A functional analysis of Pgc-1α revealed that overexpression of this protein enhanced LPS-induced inflammatory factors and p-p65 levels and inhibited apoptosis during the early stage after LPS induction (0.5 and 4 h). In contrast, the inhibition of Pgc-1α expression inhibited the LPS expression-associated increases in inflammatory factors and p-p65 and promoted apoptosis. Pgc-1α promoted LPS-induced p65 phosphorylation and inflammatory factor release while inhibiting apoptosis.
10.1007/s10753-021-01453-8
Acute Cardiac Injury in Coronavirus Disease 2019 and Other Viral Infections-A Systematic Review and Meta-Analysis.
Critical care medicine
OBJECTIVES:Severe acute respiratory syndrome-related coronavirus-2 binds and inhibits angiotensin-converting enzyme-2. The frequency of acute cardiac injury in patients with coronavirus disease 2019 is unknown. The objective was to compare the rates of cardiac injury by angiotensin-converting enzyme-2-binding viruses from viruses that do not bind to angiotensin-converting enzyme-2. DATA SOURCES:We performed a systematic review of coronavirus disease 2019 literature on PubMed and EMBASE. STUDY SELECTION:We included studies with ten or more hospitalized adults with confirmed coronavirus disease 2019 or other viral pathogens that described the occurrence of acute cardiac injury. This was defined by the original publication authors or by: 1) myocardial ischemia, 2) new cardiac arrhythmia on echocardiogram, or 3) new or worsening heart failure on echocardiogram. DATA EXTRACTION:We compared the rates of cardiac injury among patients with respiratory infections with viruses that down-regulate angiotensin-converting enzyme-2, including H1N1, H5N1, H7N9, and severe acute respiratory syndrome-related coronavirus-1, to those with respiratory infections from other influenza viruses that do not bind angiotensin-converting enzyme-2, including Influenza H3N2 and influenza B. DATA SYNTHESIS:Of 57 studies including 34,072 patients, acute cardiac injury occurred in 50% (95% CI, 44-57%) of critically ill patients with coronavirus disease 2019. The overall risk of acute cardiac injury was 21% (95% CI, 18-26%) among hospitalized patients with coronavirus disease 2019. In comparison, 37% (95% CI, 26-49%) of critically ill patients with other respiratory viruses that bind angiotensin-converting enzyme-2 (p = 0.061) and 12% (95% CI, 7-22%) of critically ill patients with other respiratory viruses that do not bind angiotensin-converting enzyme-2 (p < 0.001) experienced a cardiac injury. CONCLUSIONS:Acute cardiac injury may be associated with whether the virus binds angiotensin-converting enzyme-2. Acute cardiac injury occurs in half of critically ill coronavirus disease 2019 patients, but only 12% of patients infected by viruses that do not bind to angiotensin-converting enzyme-2.
10.1097/CCM.0000000000005026
Extracellular histones are a target in myocardial ischaemia-reperfusion injury.
Cardiovascular research
AIMS:Acute myocardial infarction causes lethal cardiomyocyte injury during ischaemia and reperfusion (I/R). Histones have been described as important Danger Associated Molecular Proteins (DAMPs) in sepsis. The objective of this study was to establish whether extracellular histone release contributes to myocardial infarction. METHODS AND RESULTS:Isolated, perfused rat hearts were subject to I/R. Nucleosomes and histone-H4 release was detected early during reperfusion. Sodium-β-O-Methyl cellobioside sulfate (mCBS), a newly developed histone-neutralizing compound, significantly reduced infarct size whilst also reducing the detectable levels of histones. Histones were directly toxic to primary adult rat cardiomyocytes in vitro. This was prevented by mCBS or HIPe, a recently described, histone-H4 neutralizing peptide, but not by an inhibitor of TLR4, a receptor previously reported to be involved in DAMP-mediated cytotoxicity. Furthermore, TLR4-reporter HEK293 cells revealed that cytotoxicity of histone H4 was independent of TLR4 and NF-κB. In an in vivo rat model of I/R, HIPe significantly reduced infarct size. CONCLUSION:Histones released from the myocardium are cytotoxic to cardiomyocytes, via a TLR4-independent mechanism. The targeting of extracellular histones provides a novel opportunity to limit cardiomyocyte death during I/R injury of the myocardium.
10.1093/cvr/cvab139
Platelet MHC class I mediates CD8+ T-cell suppression during sepsis.
Blood
Circulating platelets interact with leukocytes to modulate host immune and thrombotic responses. In sepsis, platelet-leukocyte interactions are increased and have been associated with adverse clinical events, including increased platelet-T-cell interactions. Sepsis is associated with reduced CD8+ T-cell numbers and functional responses, but whether platelets regulate CD8+ T-cell responses during sepsis remains unknown. In our current study, we systemically evaluated platelet antigen internalization and presentation through major histocompatibility complex class I (MHC-I) and their effects on antigen-specific CD8+ T cells in sepsis in vivo and ex vivo. We discovered that both human and murine platelets internalize and proteolyze exogenous antigens, generating peptides that are loaded onto MHC-I. The expression of platelet MHC-I, but not platelet MHC-II, is significantly increased in human and murine platelets during sepsis and in human megakaryocytes stimulated with agonists generated systemically during sepsis (eg, interferon-γ and lipopolysaccharide). Upregulation of platelet MHC-I during sepsis increases antigen cross-presentation and interactions with CD8+ T cells in an antigen-specific manner. Using a platelet lineage-specific MHC-I-deficient mouse strain (B2Mf/f-Pf4Cre), we demonstrate that platelet MHC-I regulates antigen-specific CD8+ T-cell proliferation in vitro, as well as the number and functional responses of CD8+ T cells in vivo, during sepsis. Loss of platelet MHC-I reduces sepsis-associated mortality in mice in an antigen-specific setting. These data identify a new mechanism by which platelets, through MHC-I, process and cross-present antigens, engage antigen-specific CD8+ T cells, and regulate CD8+ T-cell numbers, functional responses, and outcomes during sepsis.
10.1182/blood.2020008958
PVT1 knockdown inhibited the biological behavior of LPS-induced cardiac fibroblasts by regulating miR-24.
Dai Qing,Hong Yi,Li Jie
Genes & genomics
BACKGROUND:The heart is one of the target organs vulnerable to sepsis. About 50% of sepsis patients will suffer from myocardial injury and cardiac dysfunction, which will aggravate the sepsis and affect its prognosis. OBJECTIVES:Here, we attempt to investigate the function of long non coding RNA PVT1 in LPS-induced cardiac fibroblasts in vitro, and explore its potential mechanism. METHODS:The expression of PVT1 in LPS-induced cardiac fibroblasts was detected by qRT-PCR. CCK-8 assay, cell migration, qRT-PCR and western blotting analysis were applied to evaluating the effect of PVT1 knockdown on LPS-induced cardiac fibroblasts. The bioinformatics analysis and the rescue experiment were devoted to the underlying mechanism. RESULTS:PVT1 expression was up-regulated in LPS-induced cardiac fibroblasts. And knockdown of PVT1 inhibited cell viability and migration, alleviated inflammation cytokines production of LPS-treated cardiac fibroblasts. The bioinformatics analysis predicted PVT1 negatively regulates miR-24 and KLF6 is a direct target of miR-24. CONCLUSIONS:In a word, we observed PVT1 expression level was up-regulated in LPS- treated cardiac fibroblasts. PVT1 knockdown could alleviate LPS-induced biological behavior of cardiac fibroblasts through sponging miR-24 in vitro.
10.1007/s13258-021-01104-0
Cardiovascular and Renal Disease in Chronic Critical Illness.
Loftus Tyler J,Filiberto Amanda C,Ozrazgat-Baslanti Tezcan,Gopal Saraswathi,Bihorac Azra
Journal of clinical medicine
With advances in critical care, patients who would have succumbed in previous eras now survive through hospital discharge. Many survivors suffer from chronic organ dysfunction and induced frailty, representing an emerging chronic critical illness (CCI) phenotype. Persistent and worsening cardiovascular and renal disease are primary drivers of the CCI phenotype and have pathophysiologic synergy, potentiating one another and generating a downward spiral of worsening disease and clinical outcomes manifest as cardio-renal syndromes. In addition to pharmacologic therapies (e.g., diuretics, beta adrenergic receptor blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and blood pressure control), special consideration should be given to behavioral modifications that avoid the pitfalls of polypharmacy and suboptimal renal and hepatic dosing, to which CCI patients may be particularly vulnerable. Smoking cessation, dietary modifications (e.g., early high-protein nutrition and late low-sodium diets), and increased physical activity are advised. Select patients benefit from cardiac re-synchronization therapy or renal replacement therapy. Coordinated, patient-centered care bundles may improve compliance with standards of care and patient outcomes. Given the complex, heterogeneous nature of cardiovascular and renal disease in CCI and the dismal long-term outcomes, further research is needed to clarify pathophysiologic mechanisms of cardio-renal syndromes in CCI and develop targeted therapies.
10.3390/jcm10081601
Effect of Verapamil, an L-Type Calcium Channel Inhibitor, on Caveolin-3 Expression in Septic Mouse Hearts.
Rattis Bruna A C,Freitas Ana C,Oliveira Jordana F,Calandrini-Lima João L A,Figueiredo Maria J,Soave Danilo F,Ramos Simone G,Celes Mara R N
Oxidative medicine and cellular longevity
Sepsis-induced myocardial dysfunction considerably increases mortality risk in patients with sepsis. Previous studies from our group have shown that sepsis alters the expression of structural proteins in cardiac cells, resulting in cardiomyocyte degeneration and impaired communication between cardiac cells. Caveolin-3 (CAV3) is a structural protein present in caveolae, located in the membrane of cardiac muscle cells, which regulates physiological processes such as calcium homeostasis. In sepsis, there is a disruption of calcium homeostasis, which increases the concentration of intracellular calcium, which can lead to the activation of potent cellular enzymes/proteases which cause severe cellular injury and death. The purpose of the present study was to test the hypotheses that sepsis induces CAV3 overexpression in the heart, and the regulation of L-type calcium channels directly relates to the regulation of CAV3 expression. Severe sepsis increases the expression of CAV3 in the heart, as immunostaining in our study showed CAV3 presence in the cardiomyocyte membrane and cytoplasm, in comparison with our control groups (without sepsis) that showed CAV3 presence predominantly in the plasma membrane. The administration of verapamil, an L-type calcium channel inhibitor, resulted in a decrease in mortality rates of septic mice. This effect was accompanied by a reduction in the expression of CAV3 and attenuation of cardiac lesions in septic mice treated with verapamil. Our results indicate that CAV3 has a vital role in cardiac dysfunction development in sepsis and that the regulation of L-type calcium channels may be related to its expression.
10.1155/2021/6667074
Tumor necrosis factor-induced ArhGEF10 selectively activates RhoB contributing to human microvascular endothelial cell tight junction disruption.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Capillary endothelial cells (ECs) maintain a semi-permeable barrier between the blood and tissue by forming inter-EC tight junctions (TJs), regulating selective transport of fluid and solutes. Overwhelming inflammation, as occurs in sepsis, disrupts these TJs, leading to leakage of fluid, proteins, and small molecules into the tissues. Mechanistically, disruption of capillary barrier function is mediated by small Rho-GTPases, such as RhoA, -B, and -C, which are activated by guanine nucleotide exchange factors (GEFs) and disrupted by GTPase-activating factors (GAPs). We previously reported that a mutation in a specific RhoB GAP (p190BRhoGAP) underlays a hereditary capillary leak syndrome. Tumor necrosis factor (TNF) treatment disrupts TJs in cultured human microvascular ECs, a model of capillary leak. This response requires new gene transcription and involves increased RhoB activation. However, the specific GEF that activates RhoB in capillary ECs remains unknown. Transcriptional profiling of cultured tight junction-forming human dermal microvascular endothelial cells (HDMECs) revealed that 17 GEFs were significantly induced by TNF. The function of each candidate GEF was assessed by short interfering RNA depletion and trans-endothelial electrical resistance screening. Knockown of ArhGEF10 reduced the TNF-induced loss of barrier which was phenocopied by RhoB or dual ArhGEF10/RhoB knockdown. ArhGEF10 knockdown also reduced the extent of TNF-induced RhoB activation and disruption at tight junctions. In a cell-free assay, immunoisolated ArhGEF10 selectively catalyzed nucleotide exchange to activate RhoB, but not RhoA or RhoC. We conclude ArhGEF10 is a TNF-induced RhoB-selective GEF that mediates TJ disruption and barrier loss in human capillary endothelial cells.
10.1096/fj.202002783RR
PINK1 contained in huMSC-derived exosomes prevents cardiomyocyte mitochondrial calcium overload in sepsis via recovery of mitochondrial Ca efflux.
Stem cell research & therapy
BACKGROUND:Sepsis is a systemic inflammatory response to a local severe infection that may lead to multiple organ failure and death. Previous studies have shown that 40-50% of patients with sepsis have diverse myocardial injuries and 70 to 90% mortality rates compared to 20% mortality in patients with sepsis without myocardial injury. Therefore, uncovering the mechanism of sepsis-induced myocardial injury and finding a target-based treatment are immensely important. OBJECTIVE:The present study elucidated the mechanism of sepsis-induced myocardial injury and examined the value of human umbilical cord mesenchymal stem cells (huMSCs) for protecting cardiac function in sepsis. METHODS:We used cecal ligation and puncture (CLP) to induce sepsis in mice and detect myocardial injury and cardiac function using serological markers and echocardiography. Cardiomyocyte apoptosis and heart tissue ultrastructure were detected using TdT-mediated dUTP Nick-End Labeling (TUNEL) and transmission electron microscopy (TEM), respectively. Fura-2 AM was used to monitor Ca uptake and efflux in mitochondria. FQ-PCR and Western blotting detected expression of mitochondrial Ca distribution regulators and PTEN-induced putative kinase 1 (PINK1). JC-1 was used to detect the mitochondrial membrane potential (Δψm) of cardiomyocytes. RESULTS:We found that expression of PINK1 decreased in mouse hearts during sepsis, which caused cardiomyocyte mitochondrial Ca efflux disorder, mitochondrial calcium overload, and cardiomyocyte injury. In contrast, we found that exosomes isolated from huMSCs (huMSC-exo) carried Pink1 mRNA, which could be transferred to recipient cardiomyocytes to increase PINK1 expression. The reduction in cardiomyocyte mitochondrial calcium efflux was reversed, and cardiomyocytes recovered from injury. We confirmed the effect of the PINK1-PKA-NCLX axis on mitochondrial calcium homeostasis in cardiomyocytes during sepsis. CONCLUSION:The PINK1-PKA-NCLX axis plays an important role in mitochondrial calcium efflux in cardiomyocytes. Therefore, PINK1 may be a therapeutic target to protect cardiomyocyte mitochondria, and the application of huMSC-exo is a promising strategy against sepsis-induced heart dysfunction.
10.1186/s13287-021-02325-6
Feeding-induced resistance to acute lethal sepsis is dependent on hepatic BMAL1 and FXR signalling.
Nature communications
In mice, time of day strongly influences lethality in response to LPS, with survival greatest at the beginning compared to the end of the light cycle. Here we show that feeding, rather than light, controls time-of-day dependent LPS sensitivity. Mortality following LPS administration is independent of cytokine production and the clock regulator BMAL1 expressed in myeloid cells. In contrast, deletion of BMAL1 in hepatocytes globally disrupts the transcriptional response to the feeding cycle in the liver and results in constitutively high LPS sensitivity. Using RNAseq and functional validation studies we identify hepatic farnesoid X receptor (FXR) signalling as a BMAL1 and feeding-dependent regulator of LPS susceptibility. These results show that hepatocyte-intrinsic BMAL1 and FXR signalling integrate nutritional cues to regulate survival in response to innate immune stimuli. Understanding hepatic molecular programmes operational in response to these cues could identify novel pathways for targeting to enhance endotoxemia resistance.
10.1038/s41467-021-22961-z
Premorbid β1-selective (but not non-selective) β-blocker exposure reduces intensive care unit mortality among septic patients.
Kuo Ming-Jen,Chou Ruey-Hsing,Lu Ya-Wen,Guo Jiun-Yu,Tsai Yi-Lin,Wu Cheng-Hsueh,Huang Po-Hsun,Lin Shing-Jong
Journal of intensive care
BACKGROUND:β-blockers may protect against catecholaminergic myocardial injury in critically ill patients. Long-term β-blocker users are known to have lower lactate concentrations and favorable sepsis outcomes. However, the effects of β1-selective and nonselective β-blockers on sepsis outcomes have not been compared. This study was conducted to investigate the impacts of different β-blocker classes on the mortality rate in septic patients. METHODS:We retrospectively screened 2678 patients admitted to the medical or surgical intensive care unit (ICU) between December 2015 and July 2017. Data from patients who met the Sepsis-3 criteria at ICU admission were included in the analysis. Premorbid β-blocker exposure was defined as the prescription of any β-blocker for at least 1 month. Bisoprolol, metoprolol, and atenolol were classified as β1-selective β-blockers, and others were classified as nonselective β-blockers. All patients were followed for 28 days or until death. RESULTS:Among 1262 septic patients, 209 (16.6%) patients were long-term β-blocker users. Patients with premorbid β-blocker exposure had lower heart rates, initial lactate concentrations, and ICU mortality. After adjustment for disease severity, comorbidities, blood pressure, heart rate, and laboratory data, reduced ICU mortality was associated with premorbid β1-selective [adjusted hazard ratio, 0.40; 95% confidence interval (CI), 0.18-0.92; P = 0.030], but not non-selective β-blocker use. CONCLUSION:Premorbid β1-selective, but not non-selective, β-blocker use was associated with improved mortality in septic patients. This finding supports the protective effect of β1-selective β-blockers in septic patients. Prospective studies are needed to confirm it.
10.1186/s40560-021-00553-9
Paeoniflorin and Hydroxysafflor Yellow A in Xuebijing Injection Attenuate Sepsis-Induced Cardiac Dysfunction and Inhibit Proinflammatory Cytokine Production.
Wang Xin-Tong,Peng Zhen,An Ying-Ying,Shang Ting,Xiao Guangxu,He Shuang,Chen Xi,Zhang Han,Wang Yuefei,Wang Tao,Zhang Jun-Hua,Gao Xiumei,Zhu Yan,Feng Yuxin
Frontiers in pharmacology
Sepsis-induced myocardial dysfunction is a major contributor to the poor outcomes of septic shock. As an add-on with conventional sepsis management for over 15 years, the effect of Xuebijing injection (XBJ) on the sepsis-induced myocardial dysfunction was not well understood. The material basis of Xuebijing injection (XBJ) in managing infections and infection-related complications remains to be defined. A murine cecal ligation and puncture (CLP) model and cardiomyocytes culture were adopted to study the influence of XBJ on infection-induced cardiac dysfunction. XBJ significantly improved the survival of septic-mice and rescued cardiac dysfunction . RNA-seq revealed XBJ attenuated the expression of proinflammatory cytokines and related signalings in the heart which was further confirmed on the mRNA and protein levels. Xuebijing also protected cardiomyocytes from LPS-induced mitochondrial calcium ion overload and reduced the LPS-induced ROS production in cardiomyocytes. The therapeutic effect of XBJ was mediated by the combination of paeoniflorin and hydroxysafflor yellow A (HSYA) (C0127-2). C0127-2 improved the survival of septic mice, protected their cardiac function and cardiomyocytes while balancing gene expression in cytokine-storm-related signalings, such as TNF-α and NF-κB. In summary, Paeoniflorin and HSYA are key active compounds in XBJ for managing sepsis, protecting cardiac function, and controlling inflammation in the cardiac tissue partially by limiting the production of IL-6, IL-1β, and CXCL2.
10.3389/fphar.2020.614024
Mechanistic insights into cell-free hemoglobin-induced injury during septic shock.
Wang Jeffrey,Applefeld Willard N,Sun Junfeng,Solomon Steve B,Feng Jing,Couse Zoe G,Risoleo Thomas F,Danner Robert L,Tejero Jesús,Lertora Juan,Alipour Elmira,Basu Swati,Sachdev Vandana,Kim-Shapiro Daniel B,Gladwin Mark T,Klein Harvey G,Natanson Charles
American journal of physiology. Heart and circulatory physiology
Cell-free hemoglobin (CFH) levels are elevated in septic shock and are higher in nonsurvivors. Whether CFH is only a marker of sepsis severity or is involved in pathogenesis is unknown. This study aimed to investigate whether CFH worsens sepsis-associated injuries and to determine potential mechanisms of harm. Fifty-one, 10-12 kg purpose-bred beagles were randomized to receive intrapulmonary challenges or saline followed by CFH infusions (oxyhemoglobin >80%) or placebo. Animals received antibiotics and intensive care support for 96 h. CFH significantly increased mean pulmonary arterial pressures and right ventricular afterload in both septic and nonseptic animals, effects that were significantly greater in nonsurvivors. These findings are consistent with CFH-associated nitric oxide (NO) scavenging and were associated with significantly depressed cardiac function, and worsened shock, lactate levels, metabolic acidosis, and multiorgan failure. In septic animals only, CFH administration significantly increased mean alveolar-arterial oxygenation gradients, also to a significantly greater degree in nonsurvivors. CFH-associated iron levels were significantly suppressed in infected animals, suggesting that bacterial iron uptake worsened pneumonia. Notably, cytokine levels were similar in survivors and nonsurvivors and were not predictive of outcome. In the absence and presence of infection, CFH infusions resulted in pulmonary hypertension, cardiogenic shock, and multiorgan failure, likely through NO scavenging. In the presence of infection alone, CFH infusions worsened oxygen exchange and lung injury, presumably by supplying iron that promoted bacterial growth. CFH elevation, a known consequence of clinical septic shock, adversely impacts sepsis outcomes through more than one mechanism, and is a biologically plausible, nonantibiotic, noncytokine target for therapeutic intervention. Cell-free hemoglobin (CFH) elevations are a known consequence of clinical sepsis. Using a two-by-two factorial design and extensive physiological and biochemical evidence, we found a direct mechanism of injury related to nitric oxide scavenging leading to pulmonary hypertension increasing right heart afterload, depressed cardiac function, worsening circulatory failure, and death, as well as an indirect mechanism related to iron toxicity. These discoveries alter conventional thinking about septic shock pathogenesis and provide novel therapeutic approaches.
10.1152/ajpheart.00092.2021
MiR-210-3p Enhances Cardiomyocyte Apoptosis and Mitochondrial Dysfunction by Targeting the NDUFA4 Gene in Sepsis-Induced Myocardial Dysfunction.
International heart journal
Sepsis-induced myocardial dysfunction (SIMD) is a common complication with high incidence rates in sepsis patients. This study aimed to investigate the roles of miR-210-3p in regulating cardiomyocyte apoptosis and mitochondrial dysfunction associated with SIMD pathogenesis.A rat sepsis model was established by cecal ligation and puncture. Serum inflammatory factors, myocardial tissue apoptosis, and expression of miR-210-3p were evaluated. In vitro, miR-210-3p expression in H9C2 cells was altered by transfection with its mimics or inhibitors. H9C2 viability was assessed via CCK-8 assay, and reactive oxygen species (ROS) production and apoptosis were detected through flow cytometry. The targeting regulatory relations between miR-210-3p and NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4) were validated by dual luciferase reporter assay.The rat sepsis model showed increased serum TNF-α and IL-6 levels, significant myocardial tissue injuries and apoptosis with decreased Bcl-2 and increased Caspase-1 protein levels. In vitro, septic rat serum suppressed viability, promoted ROS production and apoptosis, impaired COX IV activities and increased cytochrome release in H9C2 cells. The expression of miR-210-3p was greatly increased in myocardial tissues of septic rats and septic serum-treated H9C2 cells. miR-210-3p directly binds to the 3' UTR of the NDUFA4 gene. Septic rat serum suppressed NDUFA4 and Iron-Sulfur Cluster Assembly Protein U gene expressions in H9C2 cells. The above cellular and molecular alterations in H9C2 cells induced by septic serum were enhanced by miR-210-3p mimics and abrogated by miR-210-3p inhibitors.miR-210-3p promoted SIMD pathogenesis by targeting NDUFA4 to enhance cardiomyocyte apoptosis and impair mitochondrial function.
10.1536/ihj.20-512
The autonomic nervous system in septic shock and its role as a future therapeutic target: a narrative review.
Carrara Marta,Ferrario Manuela,Bollen Pinto Bernardo,Herpain Antoine
Annals of intensive care
The autonomic nervous system (ANS) regulates the cardiovascular system. A growing body of experimental and clinical evidence confirms significant dysfunction of this regulation during sepsis and septic shock. Clinical guidelines do not currently include any evaluation of ANS function during the resuscitation phase of septic shock despite the fact that the severity and persistence of ANS dysfunction are correlated with worse clinical outcomes. In the critical care setting, the clinical use of ANS-related hemodynamic indices is currently limited to preliminary investigations trying to predict and anticipate imminent clinical deterioration. In this review, we discuss the evidence supporting the concept that, in septic shock, restoration of ANS-mediated control of the cardiovascular system or alleviation of the clinical consequences induced by its dysfunction (e.g., excessive tachycardia, etc.), may be an important therapeutic goal, in combination with traditional resuscitation targets. Recent studies, which have used standard and advanced monitoring methods and mathematical models to investigate the ANS-mediated mechanisms of physiological regulation, have shown the feasibility and importance of monitoring ANS hemodynamic indices at the bedside, based on the acquisition of simple signals, such as heart rate and arterial blood pressure fluctuations. During the early phase of septic shock, experimental and/or clinical studies have shown the efficacy of negative-chronotropic agents (i.e., beta-blockers or ivabradine) in controlling persistent tachycardia despite adequate resuscitation. Central α-2 agonists have been shown to prevent peripheral adrenergic receptor desensitization by reducing catecholamine exposure. Whether these new therapeutic approaches can safely improve clinical outcomes remains to be confirmed in larger clinical trials. New technological solutions are now available to non-invasively modulate ANS outflow, such as transcutaneous vagal stimulation, with initial pre-clinical studies showing promising results and paving the way for ANS modulation to be considered as a new potential therapeutic target in patients with septic shock.
10.1186/s13613-021-00869-7
Inhibition of micro RNA miR-122-5p prevents lipopolysaccharide-induced myocardial injury by inhibiting oxidative stress, inflammation and apoptosis via targeting GIT1.
Song Wenliang,Zhang Tiening,Yang Ni,Zhang Tao,Wen Ri,Liu Chunfeng
Bioengineered
Myocardial injury resulting from sepsis is the leading cause of death worldwide. Micro RNA miR-122-5p is involved in various physiological and pathological processes and is highly expressed in the heart of septic rats. However, its function in sepsis-caused myocardial injury remains elusive. Herein, a rat model of septic myocardial injury was established by intraperitoneal injection of lipopolysaccharide (LPS), and cardiomyocyte H9c2 was exposed to LPS to induce sepsis-related inflammatory injury . Inhibition of miR-122-5p suppressed LPS-triggered myocardial injury evidenced by decreased heart weight index (HWI), reduced inflammatory cell infiltration and cell rupture, and reduced cardiac marker enzymes cTnI and LDH. MiR-122-5p inhibition inhibited ROS production and enhanced the activities of antioxidant enzymes CAT, SOD and GSH-px in LPS-treated rats and H9c2 cells. MiR-122-5p inhibition reduced the production of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β, and inhibited cell apoptosis along with decreased cleaved-caspase 3 induced by LPS. Moreover, increased GIT1 expression was found following miR-122-5p inhibition. We further verified GIT1 as a target of miR-122-5p, and silencing GIT1 partially reversed the benefits of miR-122-5p loss in LPS-injured H9c2 cells. The HO-1 and NQO-1 expression and Nrf-2 activation were enhanced by miR-122-5p inhibition, which was reversed by GIT1 depletion, indicating the involvement of Nrf-2/HO-1 signaling in regulating miR-122-5p/GIT1-mediated cardioprotection. Taken together, our data suggest that inhibition of miR-122-5p may mitigate sepsis-triggered myocardial injury through inhibiting inflammation, oxidative stress and apoptosis via targeting GIT1, which provides a possible therapeutic target for sepsis.
10.1080/21655979.2021.1926201
Low-power infrared laser modulates telomere length in heart tissue from an experimental model of acute lung injury.
da Silva Neto Trajano Larissa Alexsandra,da Silva Sergio Luiz Philippe,de Oliveira Diego Sá Leal,Trajano Eduardo Tavares Lima,Dos Santos Silva Marco Aurélio,de Paoli Flavia,Mencalha André Luiz,de Souza da Fonseca Adenilson
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology
Acute lung injury and acute respiratory distress syndrome can occur as a result of sepsis. Cardiac dysfunction is a serious component of multi-organ failure caused by severe sepsis. Telomere shortening is related to several heart diseases. Telomeres are associated with the shelterin protein complex, which contributes to the maintenance of telomere length. Low-power infrared lasers modulate mRNA levels of shelterin complex genes. This study aimed to evaluate effects of a low-power infrared laser on mRNA relative levels of genes involved in telomere stabilization and telomere length in heart tissue of an experimental model of acute lung injury caused by sepsis. Animals were divided into six groups, treated with intraperitoneal saline solution, saline solution and exposed to a low-power infrared laser at 10 J cm and 20 J cm, lipopolysaccharide (LPS), and LPS and, after 4 h, exposed to a low-power infrared laser at 10 J cm and 20 J cm. The laser exposure was performed only once. Analysis of mRNA relative levels and telomere length by RT-qPCR was performed. Telomere shortening and reduction in mRNA relative levels of TRF1 mRNA in heart tissues of LPS-induced ALI animals were observed. In addition, laser exposure increased the telomere length at 10 J cm and modulated the TRF1 mRNA relative levels of at 20 J cm in healthy animals. Although the telomeres were shortened and mRNA levels of TRF1 gene were increased in nontreated controls, the low-power infrared laser irradiation increased the telomere length at 10 J cm in cardiac tissue of animals affected by LPS-induced acute lung injury, which suggests that telomere maintenance is a part of the photobiomodulation effect induced by infrared radiation.
10.1007/s43630-021-00051-9
The Role of Semaphorins and Their Receptors in Innate Immune Responses and Clinical Diseases of Acute Inflammation.
Kanth Shreya M,Gairhe Salina,Torabi-Parizi Parizad
Frontiers in immunology
Semaphorins are a group of proteins that have been studied extensively for their critical function in neuronal development. They have been shown to regulate airway development, tumorigenesis, autoimmune diseases, and the adaptive immune response. Notably, emerging literature describes the role of immunoregulatory semaphorins and their receptors, plexins and neuropilins, as modulators of innate immunity and diseases defined by acute injury to the kidneys, abdomen, heart and lungs. In this review we discuss the pathogenic functions of semaphorins in clinical conditions of acute inflammation, including sepsis and acute lung injury, with a focus on regulation of the innate immune response as well as potential future therapeutic targeting.
10.3389/fimmu.2021.672441
Anti-Septic Potential of 7-α-Obacunyl Acetate Isolated from the on Cecal Ligation/Puncture Mice via Suppression of JAK-STAT/NF-κB Signal Pathway.
Infection and drug resistance
PURPOSE:Sepsis is a life-threatening clinical syndrome and characterized by an inflammatory and innate immune response to infections. The current study was aimed to evaluate the anti-sepsis effect of 7-α-Obacunyl acetate (7-OBA), the abundant constituent isolated from (Meliaceae), in cecal ligation and puncture (CLP)-induced mice and to investigate the related molecular mechanisms. METHODS:The CLP operation was performed to establish the sepsis mice model, and the survival rate and temperature were measured after 7-OBA treatment (7.5, 15, and 30 mg/kg; i.p.). Inflammatory cytokines levels of TNF-α, IL-1β, IL-6, and IL-10 were detected by ELISA kits, and the kidney, liver, and heart function were measured using an automatic biochemistry analyzer. Effects of 7-OBA on NF-κB and JAK2-STAT3 signaling pathways were determined by Western blot analysis in a lipopolysaccharide (LPS) stimulated RAW264.7 cells model. RESULTS:7-OBA treatment significantly increased the survival rate (<0.05 and <0.01) and normalized temperature (<0.05 and <0.01) of sepsis mice. The levels of pro-inflammatory cytokines like TNF-α, IL-1β, and IL-6 in serum were obviously decreased, whereas the anti-inflammatory cytokines of IL-10 were increased. CLP-induced increases of the main markers of kidney, liver, and heart function in mice (<0.01) were also obviously reversed by 7-OBA. The anti-sepsis effect of 7-OBA might be associated with regulation of nuclear factor kappa-B (NF-κB) and Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) signal pathways. CONCLUSION:Our investigation indicated that 7-OBA can be developed as an effective agent for treating/curing sepsis in the future.
10.2147/IDR.S302853