Hypoxia-inducible factor 1-alpha (HIF-1α) as a factor mediating the relationship between obesity and heart failure with preserved ejection fraction.
Warbrick Ian,Rabkin Simon W
Obesity reviews : an official journal of the International Association for the Study of Obesity
Heart failure with preserved ejection fraction (HFpEF), a common condition with an increased mortality, is strongly associated with obesity and the metabolic syndrome. The latter two conditions are associated with increased epicardial fat that can extend into the heart. This review advances the proposition that hypoxia-inhibitory factor-1α (HIF-1α) maybe a key factor producing HFpEF. HIF-1α, a highly conserved transcription factor that plays a key role in tissue response to hypoxia, is increased in adipose tissue in obesity. Increased HIF-1α expression leads to expression of a potent profibrotic transcriptional programme involving collagen I, III, IV, TIMP, and lysyl oxidase. The net effect is the formation of collagen fibres leading to fibrosis. HIF-1α is also responsible for recruiting M1 macrophages that mediate obesity-associated inflammation, releasing IL-6, MCP-1, TNF-α, and IL-1β with increased expression of thrombospondin, pro α2 (I) collagen, transforming growth factor β, NADPH oxidase, and connective tissue growth factor. These factors can accelerate cardiac fibrosis and impair cardiac diastolic function. Inhibition of HIF-1α expression in adipose tissue of mice fed a high-fat diet suppressed fibrosis and reduces inflammation in adipose tissue. Delineation of the role played by HIF-1α in obesity-associated HFpEF may lead to new potential therapies.
Endoplasmic reticulum stress in perivascular adipose tissue promotes destabilization of atherosclerotic plaque by regulating GM-CSF paracrine.
Ying Ru,Li Sheng-Wei,Chen Jia-Yuan,Zhang Hai-Feng,Yang Ying,Gu Zhen-Jie,Chen Yang-Xin,Wang Jing-Feng
Journal of translational medicine
BACKGROUND:Perivascular adipose tissue (PVAT) accelerates plaque progression and increases cardiovascular risk. We tested the hypothesis that PVAT contributed to plaque vulnerability and investigated whether endoplasmic reticulum stress (ER stress) in PVAT played an important role in vulnerable plaque. METHODS:We transplanted thoracic aortic PVAT or subcutaneous adipose tissue as a control, from donor mice to carotid arteries of recipient apolipoprotein E deficient (apoE) mice after removing carotid artery collar placed for 6 weeks. Two weeks after transplantation, ER stress inhibitor 4-phenyl butyric acid (4-PBA) was locally administrated to the transplanted PVAT and then animals were euthanized after 4 weeks. Immunohistochemistry was performed to quantify plaque composition and neovascularization. Mouse angiogenesis antibody array kit was used to test the angiogenic factors produced by transplanted adipose tissue. In vitro tube formation assay, scratch wound migration assay and mouse aortic ring assay were used to assess the angiogenic capacity of supernatant of transplanted PVAT. RESULTS:Ultrastructural detection by transmission electron microscopy showed transplanted PVAT was a mixed population of white and brown adipocytes with abundant mitochondria. Transplanted PVAT increased the intraplaque macrophage infiltration, lipid core, intimal and vasa vasorum neovascularization and MMP2/9 expression in plaque while decreased smooth muscle cells and collagen in atherosclerotic plaque, which were restored by local 4-PBA-treatment. Antibody array analysis showed that 4-PBA reduced several angiogenic factors [Granulocyte Macrophage Colony Stimulating Factor (GM-CSF), MCP-1, IL-6] secreted by PVAT. Besides, conditioned medium from 4-PBA treated-PVAT inhibited tube formation and migration capacity of endothelial cells and ex vivo mouse aortic ring angiogenesis compared to conditioned medium from transplanted PVAT. mRNA expression and protein levels of GM-CSF were markedly elevated in adipocytes under ER stress which would be suppressed by 4-PBA. In addition, ER stress enhanced NF-κB binding to the promoter of the mouse GM-CSF gene in adipocytes confirmed by Chromatin immunoprecipitation analyses. CONCLUSIONS:Our findings demonstrate that ER stress in PVAT destabilizes atherosclerotic plaque, in part through increasing GM-CSF paracrine via transcription factor NF-κB.
Cardioprotective Heme Oxygenase-1-PGC1α Signaling in Epicardial Fat Attenuates Cardiovascular Risk in Humans as in Obese Mice.
Singh Shailendra P,McClung John A,Thompson Ellen,Glick Yosef,Greenberg Menachem,Acosta-Baez Giancarlo,Edris Basel,Shapiro Joseph I,Abraham Nader G
Obesity (Silver Spring, Md.)
OBJECTIVE:This study investigated whether levels of signaling pathways and inflammatory adipokines in epicardial fat regulate cardiovascular risks in humans and mice. METHODS:Epicardial fat was obtained from the hearts of patients with heart failure requiring coronary artery bypass surgery, and signaling pathways were compared with visceral fat. The genetic profile of epicardial and visceral fat from humans was also compared with genetic profiles of epicardial and visceral fat in obese mice. Left ventricular (LV) fractional shortening was measured in obese mice before and after treatment with inducers of mitochondrial signaling heme oxygenase 1 (HO-1)-peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α). An RNA array/heat map on 88 genes that regulate adipose tissue function was used to identify a target gene network. RESULTS:Human epicardial fat gene profiling showed decreased levels of mitochondrial signaling of HO-1-PGC1α and increased levels of the inflammatory adipokine CCN family member 3. Similar observations were seen in epicardial and visceral fat of obese mice. Improvement in LV function was linked to the increase in mitochondrial signaling in epicardial fat of obese mice. CONCLUSIONS:There is a link between cardiac ectopic fat deposition and cardiac function in humans that is similar to that which is described in obese mice. An increase of mitochondrial signaling pathway gene expression in epicardial fat attenuates cardiometabolic dysfunction and LV fractional shortening in obese mice.
Epicardial fat in heart failure patients with mid-range and preserved ejection fraction.
van Woerden Gijs,Gorter Thomas M,Westenbrink B Daan,Willems Tineke P,van Veldhuisen Dirk J,Rienstra Michiel
European journal of heart failure
AIMS:Adipose tissue and inflammation may play a role in the pathophysiology of patients with heart failure (HF) with mildly reduced or preserved ejection fraction. We therefore investigated epicardial fat in patients with HF with preserved (HFpEF) and mid-range ejection fraction (HFmrEF), and related this to co-morbidities, plasma biomarkers and cardiac structure. METHODS AND RESULTS:A total of 64 HF patients with left ventricular ejection fraction >40% and 20 controls underwent routine cardiac magnetic resonance examination. Epicardial fat volume was quantified on short-axis cine stacks covering the entire epicardium and was related to clinical correlates, biomarkers associated with inflammation and myocardial injury, and cardiac function and contractility on cardiac magnetic resonance. HF patients and controls were of comparable age, sex and body mass index. Total epicardial fat volume was significantly higher in HF patients compared to controls (107 mL/m vs. 77 mL/m , P <0.0001). HF patients with atrial fibrillation and/or type 2 diabetes mellitus had more epicardial fat than HF patients without these co-morbidities (116 vs. 100 mL/m , P =0.03, and 120 vs. 97 mL/m , P =0.001, respectively). Creatine kinase-MB, troponin T and glycated haemoglobin in patients with HF were positively correlated with epicardial fat volume (R =0.37, P =0.006; R =0.35, P =0.01; and R =0.42, P =0.002, respectively). CONCLUSION:Heart failure patients had more epicardial fat compared to controls, despite similar body mass index. Epicardial fat volume was associated with the presence of atrial fibrillation and type 2 diabetes mellitus and with biomarkers related to myocardial injury. The clinical implications of these findings are unclear, but warrant further investigation.
Correlation between adiponectin, chemerin, vascular endothelial growth factor and epicardial fat volume in patients with coronary artery disease.
Wu Qixin,Chen Yuxiang,Chen Song,Wu Xiaoqiu,Nong Weixia
Experimental and therapeutic medicine
Epicardial fat, a local visceral fat depot surrounded by visceral pericardial sac, surrounds the coronary arteries for most of their course and may contribute to the development of coronary atherosclerosis by local production of inflammatory cytokines. Some studies on non-invasive measurement of epicardial fat mass have shown that epicardial fat mass is associated with the increased incidence of coronary artery disease (CAD), onset and progression of coronary plaque, mainly including major adverse cardiovascular events, myocardial ischemia, and atrial fibrillation. In the present study the correlation of adiponectin, chemerin, and vascular endothelial growth factor (VEGF) with the epicardial fat volume in patients with coronary artery disease was explored, and the risk factors for vascular remodeling of CAD patients were analyzed. A total of 50 CAD patients, treated in Chongzuo People's Hospital from August 2017 to September 2018, were enrolled as the observation group, and further 50 healthy individuals, who underwent physical examinations in the hospital at the same period, were enrolled as the control group. RT-qPCR was adopted to detect the expression levels of adiponectin, chemerin and VEGF in the two groups, a 64-slice dual-source CT to detect epicardial fat volume, and Pearson's correlation to analyze adiponectin, chemerin, VEGF and epicardial fat volume. Logistic regression analysis was performed to analyze the risk factors for vascular remodeling in CAD patients, and a receiver operating characteristic (ROC) curve analysis was used to analyze the value of indexes with multifactorial significance in vascular remodeling. The observation group showed obviously larger epicardial fat volume than the control group (P<0.001), lower adiponectin expression than the control group (P<0.001), and higher chemerin and VEGF expression than the control group (P<0.001). In the observation group, adiponectin expression decreased with the increase of epicardial fat volume (P<0.001), while the expression of chemerin and VEGF increased with the increase of epicardial fat volume (P<0.001). Remodeling occurred in 27 of the 50 patients. ROC curve analysis showed that the areas under the curves of adiponectin, chemerin, VEGF and epicardial fat volume were 0.697, 0.652, 0.696 and 0.689, respectively. Epicardial fat volume, adiponectin, chemerin and VEGF are independent risk factors for vascular remodeling and the expression of adiponectin, chemerin and VEGF can reflect epicardial fat volume.
Epicardial Adipose Tissue May Mediate Deleterious Effects of Obesity and Inflammation on the Myocardium.
Journal of the American College of Cardiology
Epicardial adipose tissue has unique properties that distinguish it from other depots of visceral fat. Rather than having distinct boundaries, the epicardium shares an unobstructed microcirculation with the underlying myocardium, and in healthy conditions, produces cytokines that nourish the heart. However, in chronic inflammatory disorders (especially those leading to heart failure with preserved ejection fraction), the epicardium becomes a site of deranged adipogenesis, leading to the secretion of proinflammatory adipokines that can cause atrial and ventricular fibrosis. Accordingly, in patients at risk of heart failure with preserved ejection fraction, drugs that promote the accumulation or inflammation of epicardial adipocytes may lead to heart failure, whereas treatments that ameliorate the proinflammatory characteristics of epicardial fat may reduce the risk of heart failure. These observations suggest that epicardial adipose tissue is a transducer of the adverse effects of systemic inflammation and metabolic disorders on the heart, and thus, represents an important target for therapeutic interventions.
Targeting perivascular and epicardial adipose tissue inflammation: therapeutic opportunities for cardiovascular disease.
Rafeh Rim,Viveiros Anissa,Oudit Gavin Y,El-Yazbi Ahmed F
Clinical science (London, England : 1979)
Major shifts in human lifestyle and dietary habits toward sedentary behavior and refined food intake triggered steep increase in the incidence of metabolic disorders including obesity and Type 2 diabetes. Patients with metabolic disease are at a high risk of cardiovascular complications ranging from microvascular dysfunction to cardiometabolic syndromes including heart failure. Despite significant advances in the standards of care for obese and diabetic patients, current therapeutic approaches are not always successful in averting the accompanying cardiovascular deterioration. There is a strong relationship between adipose inflammation seen in metabolic disorders and detrimental changes in cardiovascular structure and function. The particular importance of epicardial and perivascular adipose pools emerged as main modulators of the physiology or pathology of heart and blood vessels. Here, we review the peculiarities of these two fat depots in terms of their origin, function, and pathological changes during metabolic deterioration. We highlight the rationale for pharmacological targeting of the perivascular and epicardial adipose tissue or associated signaling pathways as potential disease modifying approaches in cardiometabolic syndromes.
Drugs That Ameliorate Epicardial Adipose Tissue Inflammation May Have Discordant Effects in Heart Failure With a Preserved Ejection Fraction as Compared With a Reduced Ejection Fraction.
Journal of cardiac failure
Heart failure with a preserved ejection fraction (HFpEF) and heart failure with a reduced ejection fraction (HFrEF) have distinctive pathophysiologies, and thus, therapeutic approaches to the 2 disorders should differ. Neurohormonal activation drives the progression of HFrEF, and neurohormonal antagonists are highly effective in HFrEF, but not in HFpEF. Conversely, a broad range of chronic systemic inflammatory or metabolic disorders cause an expansion and inflammation of epicardial adipose tissue; the secretion of adipocytokines may lead to microvascular dysfunction and fibrosis of the underlying myocardium, which (if the left atrium is affected) may lead to atrial fibrillation (AF) and (if the left ventricle is affected) may lead to HFpEF. Anti-inflammatory drugs (such as statins and anticytokine agents) can ameliorate epicardial adipose tissue dysfunction. Statins appear to ameliorate the development of atrial myopathy (both experimentally and clinically), and in randomized controlled trials, they reduce the incidence of new-onset and recurrent AF and decrease the risk of heart failure with the features of HFpEF; yet, they have no benefits in HFrEF. Similarly, anticytokine agents appear to prevent heart failure in patients with or prone to HFpEF, but adversely affect HFrEF. Several antihyperglycemic agents also reduce epicardial fat mass and inflammation, but this benefit may be offset by additional actions to cause sodium retention and neurohormonal activation. Thiazolidinediones have favorable effects on experimental AF and HFpEF, but their antinatriuretic actions negate these benefits, and they worsen the clinical course of HFrEF. Glucagon-like peptide-1 receptor agonists also ameliorate AF and HFpEF in laboratory models, but their positive inotropic and chronotropic effects may be deleterious in HFrEF. By contrast, metformin and sodium-glucose cotransporter 2 inhibitors alleviate epicardial adipose tissue dysfunction and may reduce the risk of AF and HFpEF; yet, they may have additional actions to promote cardiomyocyte survival that are useful in HFrEF. The concordance of the benefits of anti-inflammatory and antihyperglycemic drugs on AF and HFpEF (but not on HFrEF) supports the paradigm that epicardial adipose tissue is a central pathogenetic mechanism and therapeutic target for both AF and HFpEF in patients with chronic systemic inflammatory or metabolic diseases.
The Role of Inflammation in Epicardial Adipose Tissue in Heart Diseases.
Matloch Zdenek,Cinkajzlova Anna,Mraz Milos,Haluzik Martin
Current pharmaceutical design
Epicardial adipose tissue is not only a specific adipose tissue depot but also an active endocrine organ producing numerous substances with an important role in the development of obesity-related heart diseases. It is located between myocardium and visceral pericardium and consists predominantly of adipocytes, immunocompetent cells, ganglia and interconnecting nerve branches. Several studies documented a positive correlation between pericardial and epicardial fat and left ventricular hypertrophy and septal thickening, leading to diastolic dysfunction, electrocardiographic abnormalities and facilitating cardiac failure. The cellular cross-talks between epicardial fat and myocardium may include both the vasocrine and the paracrine mechanisms. Adipokines secreted from epicardial adipose tissue, vascular and stromal cells diffuse into interstitial fluid crossing the adventitia, media and intima and modulate cardiac function and cardiomyocyte phenotype and survival. In this article, we review the significance of epicardial adipose tissue and its association with cardiovascular diseases, cellular interactions between epicardial fat and myocardium, secretions of adipokines and inflammatory mediators and a potential of epicardial fat as a therapeutic target for the prevention of obesity-related heart diseases.