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    [Study on the activity of a therapeutic bacterial combination in intestinal motility disorders in the aged]. Motta L,Blancato G,Scornavacca G,De Luca M,Vasquez E,Gismondo M R,Lo Bue A,Chisari G La Clinica terapeutica The possible beneficial effects and changes in the histology of the duodenojejunal and colonic mucosa brought about by oral bacterial therapy were studied in 60 elderly patients (mean age +/- SD: 76.6 +/- 5.3 years) with bowel disorders mainly represented by diarrhea accompanied by abdominal pain and meteorism. All patients were submitted to a 7-day washout followed by treatment with 6 capsules daily, each capsule containing live, lyophilized Lactobacillus acidophilus (10(9) CFU/ml). The clinical course was observed in 50 patients while the remaining 10 were hospitalized and submitted to esophago-gastro-duodenoscopy and colonoscopy both before and after treatment for withdrawal of duodenal secretion and fragments of duodenojejunal and colonic mucosa biopsies. Duodenal secretion was examined bacteriologically, and after treatment an increase of the anaerobic flora at the expense of the aerobic one was found together with improved quality of the former. Histologic examination showed reduction of the inflammatory infiltration by lymphocytes and plasma cells and increased muciparous activity of the glands. Clinically, a marked improvement of the symptoms was observed in all 60 patients.
    Principles and clinical implications of the brain-gut-enteric microbiota axis. Rhee Sang H,Pothoulakis Charalabos,Mayer Emeran A Nature reviews. Gastroenterology & hepatology While bidirectional brain-gut interactions are well known mechanisms for the regulation of gut function in both healthy and diseased states, a role of the enteric flora--including both commensal and pathogenic organisms--in these interactions has only been recognized in the past few years. The brain can influence commensal organisms (enteric microbiota) indirectly, via changes in gastrointestinal motility and secretion, and intestinal permeability, or directly, via signaling molecules released into the gut lumen from cells in the lamina propria (enterochromaffin cells, neurons, immune cells). Communication from enteric microbiota to the host can occur via multiple mechanisms, including epithelial-cell, receptor-mediated signaling and, when intestinal permeability is increased, through direct stimulation of host cells in the lamina propria. Enterochromaffin cells are important bidirectional transducers that regulate communication between the gut lumen and the nervous system. Vagal, afferent innervation of enterochromaffin cells provides a direct pathway for enterochromaffin-cell signaling to neuronal circuits, which may have an important role in pain and immune-response modulation, control of background emotions and other homeostatic functions. Disruption of the bidirectional interactions between the enteric microbiota and the nervous system may be involved in the pathophysiology of acute and chronic gastrointestinal disease states, including functional and inflammatory bowel disorders. 10.1038/nrgastro.2009.35
    Indications and challenges of probiotics, prebiotics, and synbiotics in the management of arthralgias and spondyloarthropathies in inflammatory bowel disease. Karimi Ouafae,Peña Amado Salvador Journal of clinical gastroenterology Arthralgia and spondyloarthropathy of the peripheral and the axial joints are common in patients with inflammatory bowel diseases. Evidence for this association has been provided by clinical, epidemiologic, and immunologic studies confirming the presence of shared inflammatory pathways in gut and joint. Bacterial gut infections such as Salmonella typhimurium, Yersinia enterocolitica, Shigella, Campylobacter jejuni may induce reactive peripheral arthritis and 20% of these patients may develop chronic spondyloarthropathy. It is not certain that arthralgias in inflammatory bowel diseases are more frequent than in the general population but clinical articular manifestations compatible with spondyloarthropathy are present in 10% to 40% of patients with inflammatory bowel diseases. These enteropathic peripheral arthropathies without axial involvement are subdivided into a pauciarticular of large joints and a bilateral symmetrical polyarthropathy. The rationale and the challenges of using prebiotics, probiotics, and synbiotics in the management of patients with inflammatory bowel diseases with arthralgias and spondyloarthropathy are briefly reviewed. The rationale is based on the modulation of the ubiquitous intestinal flora by bacteria and their products that have been proven to be safe. The challenge is to find the "window of opportunity" to treat the evolutionary stage of joint inflammation. It seems to us that the major aim is not to treat patients who have a self-limited inflammatory joint disorder, but those patients with persistent arthralgias in an early phase of the disease. Seronegative and seropositive patients with early arthritis, before damage may occur, could be managed by this approach to improve the quality of life and to positively influence the natural course of the disease. 10.1097/MCG.0b013e3181662455
    Age, Gender and Women's Health and the Patient. Houghton Lesley A,Heitkemper Margaret,Crowell Michael,Emmanuel Anton,Halpert Albena,McRoberts James A,Toner Brenda Gastroenterology Patients with functional gastrointestinal disorders (FGIDs) often experience distress, reduced quality of life, a perceived lack of validation, and an unsatisfactory experience with health care providers. A health care provider can provide the patient with a framework in which to understand and legitimize their symptoms, remove self-doubt or blame, and identify factors that contribute to symptoms that the patient can influence or control. This framework is implemented with the consideration of important factors that impact FGIDs, such as gender, age, society, and the patient's perspective. Although the majority of FGIDs, including globus, rumination syndrome, IBS, bloating, constipation, functional abdominal pain, sphincter of Oddi dyskinesia, pelvic floor dysfunction, and extra-intestinal manifestations, are more prevalent in women than men, functional chest pain, dyspepsia, vomiting, and anorectal pain do not appear to vary by gender. Studies suggest sex differences in somatic but not visceral pain perception, motility, and central processing of visceral pain; although further research is required in autonomic nervous system dysfunction, genetics and immunologic/microbiome. Gender differences in response to psychological treatments, antidepressants, fiber, probiotics, and anticholinergics have not been adequately studied. However, a greater clinical response to 5-HT antagonists but not 5-HT agonists has been reported in women compared with men. 10.1053/j.gastro.2016.02.017
    Gut microbes and the brain: paradigm shift in neuroscience. Mayer Emeran A,Knight Rob,Mazmanian Sarkis K,Cryan John F,Tillisch Kirsten The Journal of neuroscience : the official journal of the Society for Neuroscience The discovery of the size and complexity of the human microbiome has resulted in an ongoing reevaluation of many concepts of health and disease, including diseases affecting the CNS. A growing body of preclinical literature has demonstrated bidirectional signaling between the brain and the gut microbiome, involving multiple neurocrine and endocrine signaling mechanisms. While psychological and physical stressors can affect the composition and metabolic activity of the gut microbiota, experimental changes to the gut microbiome can affect emotional behavior and related brain systems. These findings have resulted in speculation that alterations in the gut microbiome may play a pathophysiological role in human brain diseases, including autism spectrum disorder, anxiety, depression, and chronic pain. Ongoing large-scale population-based studies of the gut microbiome and brain imaging studies looking at the effect of gut microbiome modulation on brain responses to emotion-related stimuli are seeking to validate these speculations. This article is a summary of emerging topics covered in a symposium and is not meant to be a comprehensive review of the subject. 10.1523/JNEUROSCI.3299-14.2014
    Anesthesia and surgery induce age-dependent changes in behaviors and microbiota. Liufu Ning,Liu Ling,Shen Shiqian,Jiang Zengliang,Dong Yuanlin,Wang Yanyan,Culley Deborah,Crosby Gregory,Cao Minghui,Shen Yuan,Marcantonio Edward,Xie Zhongcong,Zhang Yiying Aging The neuropathogenesis of postoperative delirium remains mostly unknown. The gut microbiota is implicated in the pathogenesis of neurological disorders. We, therefore, set out to determine whether anesthesia/surgery causes age-dependent gut microbiota dysbiosis, changes in brain IL-6 level and mitochondrial function, leading to postoperative delirium-like behavior in mice. Female 9 or 18 months old mice received abdominal surgery under 1.4% isoflurane for two hours. The postoperative delirium-like behavior, gut microbiota, levels of brain IL-6, PSD-95 and synaptophysin, and mitochondrial function were determined by a battery of behavioral tests, 16s rRNA sequencing, ELISA, Western blot and Seahorse XFp Extracellular Flux Analyzer. Intragastric administration of Lactobacillus (10 days) and probiotic (20 days) were used to mitigate the anesthesia/surgery-induced changes. Anesthesia/surgery caused different alterations in gut microbiota, including change rate of reduction in the levels of gut lactobacillus, between the 18 and 9 months old mice. The anesthesia/surgery induced greater postoperative delirium-like behavior, increased brain IL-6 levels, decreased PSD-95 and synaptophysin levels, and mitochondrial dysfunction in 18 than 9 months old mice. Treatments with Lactobacillus and probiotic mitigated the anesthesia/surgery-induced changes. These data suggest that microbiota dysbiosis may contribute to neuropathogenesis of postoperative delirium and treatment with Lactobacillus or a probiotic could mitigate postoperative delirium. 10.18632/aging.102736
    A Pilot Randomized Controlled Trial to Explore Cognitive and Emotional Effects of Probiotics in Fibromyalgia. Roman Pablo,Estévez Angeles F,Miras Alonso,Sánchez-Labraca Nuria,Cañadas Fernando,Vivas Ana B,Cardona Diana Scientific reports It has recently been found that microbes in the gut may regulate brain processes through the gut microbiota-brain axis, which modulates affection, motivation and higher cognitive functions. According to this finding, the use of probiotics may be a potential treatment to improve physical, psychological and cognitive status in clinical populations with altered microbiota balance such as those with fibromyalgia (FMS). Thus, the aim of the present pilot study with a double-blind, placebo-controlled, randomised design was to test whether a multispecies probiotic may improve cognition, emotional symptoms and functional state in a sample of patients diagnosed with FMS. Pain, impact of FMS, quality of life, anxiety and depressive symptoms were measured during the pre- and post-intervention phases; participants also completed two computerised cognitive tasks to assess impulsive choice and decision-making. Finally, urinary cortisol concentration was determined. To our knowledge, this is the first study that explore the effect of a multispecies probiotic in FMS patients. Our results indicated that probiotics improved impulsivity and decision-making in these patients. However, more research is needed to further explore the potential effects of probiotics on other cognitive functions affected in FMS as well as in other clinical populations. 10.1038/s41598-018-29388-5
    What the Gut Can Teach Us About Migraine. Hindiyeh Nada,Aurora Sheena K Current pain and headache reports During gestation, cells of the brain and gut develop almost simultaneously into the central nervous system (CNS) and enteric nervous system (ENS), respectively. They remain connected via the vagal nerve lifelong. While it is well known that the brain sends signal to the gut, communication is in fact bidirectional. Just as the brain can modulate gut functioning, the gut, and likely what we ingest, can in fact influence our brain functioning. We will first review both gastrointestinal (GI) function and migraine pathophysiology and then discuss evidence linking the migraine brain to various GI disorders. Lastly, we discuss the effects of gut microbiota on brain functioning and speculate how the gut and particularly diet may affect migraine. 10.1007/s11916-015-0501-4
    Gut nociceptors: sentinels promoting host defense. Brierley Stuart M Cell research 10.1038/s41422-020-0278-9
    Estrous cycle and ovariectomy-induced changes in visceral pain are microbiota-dependent. Tramullas Mónica,Collins James M,Fitzgerald Patrick,Dinan Timothy G,O' Mahony Siobhain M,Cryan John F iScience Visceral hypersensitivity (VH) is a hallmark of many functional gastrointestinal disorders including irritable bowel syndrome and is categorized by a dull, diffuse sensation of abdominal pain. Recently, the gut microbiota has been implicated in VH in male mice, but the effects in females have yet to be explored fully. To this end, we now show that somewhat surprisingly, female germ-free mice have similar visceral pain responses to colorectal distension (CRD) as their conventional controls. However, we show that although sensitivity to CRD is estrous cycle stage-dependent in conventional mice, it is not in germ-free mice. Further, ovariectomy (OVX) induced VH in conventional but not germ-free mice, and induced weight gain regardless of microbiota status. Finally, we show that estrogen-replacement ameliorated OVX-induced VH. Taken together, this study provides evidence for a major role of female sex hormones and the gut microbiota in sensation of visceral pain in females. 10.1016/j.isci.2021.102850
    A Descriptive Review on the Prevalence of Gastrointestinal Disturbances and Their Multiple Associations in Autism Spectrum Disorder. Lefter Radu,Ciobica Alin,Timofte Daniel,Stanciu Carol,Trifan Anca Medicina (Kaunas, Lithuania) Gastrointestinal disturbances have been frequently, but not unanimously, reported in autism spectrum disorder (ASD) individuals. Thus, digestive symptoms, such as constipation, diarrhea, abdominal bloating, and pain have been reported to correlate to the various maladaptive behaviors in ASD children, such as irritability, social withdrawal, stereotypy, hyperactivity, and even language regression. In this context, the present study provides an overview on the prevalence of the gastrointestinal (GI) disorders in ASD and the correlation between these and ASD symptoms and comorbidities and subsequently discusses the metabolic and microbiome factors underlying the effects of GI disorders in ASD. For our analysis of GI symptoms in children with ASD, we have searched peer-reviewed journals from 2005 to 2017 in PubMed databases that addressed the specificity of GI symptoms in ASD and included correlations of GI and ASD symptoms. The criteria for inclusion were clear quantitative mentioning of GI modifications, GI symptoms correlation with specific ASD symptoms or comorbidities, an appropriate methodology for defining ASD, and larger size samples. For this topic, only studies on human patients and original research were considered. A subsequent search in PubMed databases in journals from 2000 to 2017 we analyzed 13 articles on the mechanisms underlying the impact of GI dysfunctions in ASD, including gut microbial dysbiosis, immune reactivity, genetics, and altered neurotransmitters on the gut-brain axis. In the 18 original research studies that we selected out of an initial 327 studies, despite the different methodology, a predominant 83% highlighted the increased prevalence of GI symptoms in ASD patients. Constipation was most frequently cited, appearing in 12 of the studies (80%), followed by diarrhea reports in eight studies (53%). The association between cognitive and behavioral deficits and GI disorders was suggested in certain groups of ASD individuals. The evidence presented so far by numerous studies seems to indicate that GI dysfunctions are of particular relevance in ASD, underlined by various abnormalities along the nervous connections between the central nervous system and the gut, such as impaired parasympathetic activity and increased endocrine stress response. Sufficiently large size samples and standardized methodology are required for future studies to clarify the complex interactions between GI disturbances and ASD symptoms. 10.3390/medicina56010011
    Opioids in Cancer Development, Progression and Metastasis: Focus on Colorectal Cancer. Szczepaniak Adrian,Fichna Jakub,Zielińska Marta Current treatment options in oncology OPINION STATEMENT:So far, opioids have been successfully used to reduce cancer pain in patients in order to improve their quality of life. However, the use of opioids leads to numerous side effects such as constipation, drowsiness, nausea, itching, increased sweating and hormonal changes. In this review, we described the action of opioids in several molecular pathways significant for maintenance of the intestinal homeostasis including the impact on the intestinal epithelium integrity, changes in microbiome composition, modulation of the immune system or induction of apoptosis and inhibition of angiogenesis. We summed up the role of individual opioids in the processes involved in the growth and development of cancer and elucidated if targeting opioid receptors may constitute novel therapeutic option in colon cancer. 10.1007/s11864-019-0699-1
    Role of Gut Microbiota in the Pathophysiology of Stress-Related Disorders: Evidence from Neuroimaging Studies. Izuno Satoshi,Yoshihara Kazufumi,Sudo Nobuyuki Annals of nutrition & metabolism BACKGROUND:The brain and gut communicate bidirectionally via immune, neurological, and endocrine pathways, which is termed the "brain-gut interaction." Recent studies of gut microbiota as a mediator of this interaction have provided a growing body of scientific evidence that suggests that the gut microbiota influences stress and emotional responses and stress-related disorders. SUMMARY:Major advances in analytical methods have led to an increased number of studies that combine gut microbiota and neuroimaging, mainly magnetic resonance imaging, to elucidate the mechanisms. Observational studies have been done to examine brain characteristics related to gut microbiota profiles, and intervention studies have examined brain changes related to probiotic intake. Studies of healthy subjects using negative emotional stimuli have shown that the pattern of emotional response differs depending on the gut microbiota profile and that probiotic intervention can modulate emotional response and be a buffer against the negative effects of stress. In studies on irritable bowel syndrome (IBS), a typical psychosomatic disorder, IBS-specific gut microbiota were reported to contribute to visceral irritability and pain by affecting the subcortical regions. Studies on psychiatric disorders revealed that a relative abundance of Bacteroides that produce γ-aminobutyric acid in feces was associated with a change in brain function specific to depression and that gut microbiota have an influence on abnormalities in the reward system of attention-deficit/hyperactivity disorder. 10.1159/000517420
    Repeated inflammatory dural stimulation-induced cephalic allodynia causes alteration of gut microbial composition in rats. The journal of headache and pain BACKGROUND:Gut microbial dysbiosis and gut-brain axis dysfunction have been implicated in the pathophysiology of migraine. However, it is unclear whether migraine-related cephalic allodynia could induce the alteration of gut microbial composition. METHODS:A classic migraine rat model was established by repeated dural infusions of inflammatory soup (IS). Periorbital mechanical threshold and nociception-related behaviors were used to evaluate IS-induced cephalic allodynia and the preventive effect of topiramate. The alterations in gut microbial composition and potential metabolic pathways were investigated based on the results of 16 S rRNA gene sequencing. Microbiota-related short-chain fatty acids and tryptophan metabolites were detected and quantified by mass spectrometry analysis. RESULTS:Repeated dural IS infusions induced cephalic allodynia (decreased mechanical threshold), migraine-like behaviors (increased immobility time and reduced moving distance), and microbial composition alteration, which were ameliorated by the treatment of topiramate. Decreased Lactobacillus was the most prominent biomarker genus in the IS-induced alteration of microbial composition. Additionally, IS infusions also enhanced metabolic pathways of the gut microbiota in butanoate, propanoate, and tryptophan, while the increased tryptophan-related metabolites indole-3-acetamide and tryptophol in feces could be the indicators. CONCLUSIONS:Inflammatory dural stimulation-induced cephalic allodynia causes the alterations of gut microbiota profile and microbial metabolic pathways. 10.1186/s10194-022-01441-9
    Precision medicine and gut dysbiosis. Harris Cailin,Kim Peter T,Waterhouse Dawn,Feng Zeny,Niergarth Jessmyn,Lee Christine H Healthcare management forum Infection (CDI) is a leading cause of healthcare-associated infections in Canada, affecting the gastrointestinal tract which can lead to fever, abdominal pain, and diarrhea. Effective treatment for patients with Recurrent CDI (rCDI) can be achieved by Fecal Microbiota Transplantation (FMT) by introducing the gut micro-organisms of a healthy person (donor) into the bowel of the affected individual. Research has shown that an increase in the specific bacterial phyla post-FMT may be partly responsible for this gut restoration and elimination of disease. Furthermore, in understanding the key bacteria associated with successful FMT, full treatment plans can be developed for the individual needs of the patient by matching an infected individual with a donor possessing ideal microbiota for the specific patient. This development of precision medicine and more systematic adoption of FMT can be the next step toward more rapid resolution of rCDI. 10.1177/0840470419899426
    Serotonin, tryptophan metabolism and the brain-gut-microbiome axis. O'Mahony S M,Clarke G,Borre Y E,Dinan T G,Cryan J F Behavioural brain research The brain-gut axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract. Serotonin functions as a key neurotransmitter at both terminals of this network. Accumulating evidence points to a critical role for the gut microbiome in regulating normal functioning of this axis. In particular, it is becoming clear that the microbial influence on tryptophan metabolism and the serotonergic system may be an important node in such regulation. There is also substantial overlap between behaviours influenced by the gut microbiota and those which rely on intact serotonergic neurotransmission. The developing serotonergic system may be vulnerable to differential microbial colonisation patterns prior to the emergence of a stable adult-like gut microbiota. At the other extreme of life, the decreased diversity and stability of the gut microbiota may dictate serotonin-related health problems in the elderly. The mechanisms underpinning this crosstalk require further elaboration but may be related to the ability of the gut microbiota to control host tryptophan metabolism along the kynurenine pathway, thereby simultaneously reducing the fraction available for serotonin synthesis and increasing the production of neuroactive metabolites. The enzymes of this pathway are immune and stress-responsive, both systems which buttress the brain-gut axis. In addition, there are neural processes in the gastrointestinal tract which can be influenced by local alterations in serotonin concentrations with subsequent relay of signals along the scaffolding of the brain-gut axis to influence CNS neurotransmission. Therapeutic targeting of the gut microbiota might be a viable treatment strategy for serotonin-related brain-gut axis disorders. 10.1016/j.bbr.2014.07.027
    Gut-brain Axis and migraine headache: a comprehensive review. Arzani Mahsa,Jahromi Soodeh Razeghi,Ghorbani Zeinab,Vahabizad Fahimeh,Martelletti Paolo,Ghaemi Amir,Sacco Simona,Togha Mansoureh, The journal of headache and pain The terminology "gut-brain axis "points out a bidirectional relationship between the GI system and the central nervous system (CNS). To date, several researches have shown that migraine is associated with some gastrointestinal (GI) disorders such as Helicobacter pylori (HP) infection, irritable bowel syndrome (IBS), and celiac disease (CD). The present review article aims to discuss the direct and indirect evidence suggesting relationships between migraine and the gut-brain axis. However, the mechanisms explaining how the gut and the brain may interact in patients with migraine are not entirely clear. Studies suggest that this interaction seems to be influenced by multiple factors such as inflammatory mediators (IL-1β, IL-6, IL-8, and TNF-α), gut microbiota profile, neuropeptides and serotonin pathway, stress hormones and nutritional substances. Neuropeptides including CGRP, SP, VIP, NPY are thought to have antimicrobial impact on a variety of the gut bacterial strains and thus speculated to be involved in the bidirectional relationship between the gut and the brain. According to the current knowledge, migraine headache in patients harboring HP might be improved following the bacteria eradication. Migraineurs with long headache history and high headache frequency have a higher chance of being diagnosed with IBS. IBS and migraine share some similarities and can alter gut microflora composition and thereby may affect the gut-brain axis and inflammatory status. Migraine has been also associated with CD and the condition should be searched particularly in patients with migraine with occipital and parieto-occipital calcification at brain neuroimaging. In those patients, gluten-free diet can also be effective in reducing migraine frequency. It has also been proposed that migraine may be improved by dietary approaches with beneficial effects on gut microbiota and gut-brain axis including appropriate consumption of fiber per day, adhering to a low glycemic index diet, supplementation with vitamin D, omega-3 and probiotics as well as weight loss dietary plans for overweight and obese patients. 10.1186/s10194-020-1078-9
    Spinal cord injury and gut microbiota: A review. Jing Yingli,Bai Fan,Yu Yan Life sciences After spinal cord injury (SCI), intestinal dysfunction has a serious impact on physical and mental health, quality of life, and social participation. Recent data from rodent and human studies indicated that SCI causes gut dysbiosis. Remodeling gut microbiota could be beneficial for the recovery of intestinal function and motor function after SCI. However, few studies have explored SCI with focus on the gut microbiota and "microbiota-gut-brain" axis. In this review, the complications following SCI, including intestinal dysfunction, anxiety and depression, metabolic disorders, and neuropathic pain, are directly or indirectly related to gut dysbiosis, which may be mediated by "gut-brain" interactions. Furthermore, we discuss the research strategies that can be beneficial in this regard, including germ-free animals, fecal microbiota transplantation, probiotics, phages, and brain imaging techniques. The current microbial research has shifted from descriptive to mechanismal perspective, and future research using new technologies may further demonstrate the pathophysiological mechanism of association of SCI with gut microbiota, elucidate the mode of interaction of gut microbiota and hosts, and help develop personalized microbiota-targeted therapies and drugs based on microbiota or corresponding metabolites. 10.1016/j.lfs.2020.118865
    Opioid-induced gut microbial disruption and bile dysregulation leads to gut barrier compromise and sustained systemic inflammation. Banerjee S,Sindberg G,Wang F,Meng J,Sharma U,Zhang L,Dauer P,Chen C,Dalluge J,Johnson T,Roy S Mucosal immunology Morphine and its pharmacological derivatives are the most prescribed analgesics for moderate to severe pain management. However, chronic use of morphine reduces pathogen clearance and induces bacterial translocation across the gut barrier. The enteric microbiome has been shown to have a critical role in the preservation of the mucosal barrier function and metabolic homeostasis. Here, we show for the first time, using bacterial 16s rDNA sequencing, that chronic morphine treatment significantly alters the gut microbial composition and induces preferential expansion of Gram-positive pathogenic and reduction in bile-deconjugating bacterial strains. A significant reduction in both primary and secondary bile acid levels was seen in the gut, but not in the liver with morphine treatment. Morphine-induced microbial dysbiosis and gut barrier disruption was rescued by transplanting placebo-treated microbiota into morphine-treated animals, indicating that microbiome modulation could be exploited as a therapeutic strategy for patients using morphine for pain management. 10.1038/mi.2016.9
    The Gut Metagenome Changes in Parallel to Waist Circumference, Brain Iron Deposition, and Cognitive Function. Blasco Gerard,Moreno-Navarrete José Maria,Rivero Mireia,Pérez-Brocal Vicente,Garre-Olmo Josep,Puig Josep,Daunis-I-Estadella Pepus,Biarnés Carles,Gich Jordi,Fernández-Aranda Fernando,Alberich-Bayarri Ángel,Moya Andrés,Pedraza Salvador,Ricart Wifredo,López Miguel,Portero-Otin Manuel,Fernandez-Real José-Manuel The Journal of clinical endocrinology and metabolism Context:Microbiota perturbations seem to exert modulatory effects on emotional behavior, stress-, and pain-modulation systems in adult animals; however, limited information is available in humans. Objective:To study potential relationships among the gut metagenome, brain microstructure, and cognitive performance in middle-aged, apparently healthy, obese and nonobese subjects after weight changes. Design:This is a longitudinal study over a 2-year period. Setting:A tertiary public hospital. Patients or Other Participants:Thirty-five (18 obese) apparently healthy subjects. Intervention(s):Diet counseling was provided to all subjects. Obese subjects were followed every 6 months. Main Outcome Measure(s):Brain relaxometry (using magnetic resonance R2*), cognitive performance (by means of cognitive tests), and gut microbiome composition (shotgun). Results:R2* increased in both obese and nonobese subjects, independent of weight variations. Changes in waist circumference, but not in body mass index, were associated with brain iron deposition (R2*) in the striatum, amygdala, and hippocampus in parallel to visual-spatial constructional ability and circulating beta amyloid Aβ42 levels. These changes were linked to shifts in gut microbiome in which the relative abundance of bacteria belonging to Caldiserica and Thermodesulfobacteria phyla were reciprocally associated with raised R2* in different brain nuclei. Of note, the increase in bacteria belonging to Tenericutes phylum was parallel to decreased R2* gain in the striatum, serum Aβ42 levels, and spared visual-spatial constructional ability. Interestingly, metagenome functions associated with circulating and brain iron stores are involved in bacterial generation of siderophores. Conclusions:Changes in the gut metagenome are associated longitudinally with cognitive function and brain iron deposition. 10.1210/jc.2017-00133
    Antibiotic-induced dysbiosis alters host-bacterial interactions and leads to colonic sensory and motor changes in mice. Aguilera M,Cerdà-Cuéllar M,Martínez V Gut microbes Alterations in the composition of the commensal microbiota (dysbiosis) seem to be a pathogenic component of functional gastrointestinal disorders, mainly irritable bowel syndrome (IBS), and might participate in the secretomotor and sensory alterations observed in these patients.We determined if a state antibiotics-induced intestinal dysbiosis is able to modify colonic pain-related and motor responses and characterized the neuro-immune mechanisms implicated in mice. A 2-week antibiotics treatment induced a colonic dysbiosis (increments in Bacteroides spp, Clostridium coccoides and Lactobacillus spp and reduction in Bifidobacterium spp). Bacterial adherence was not affected. Dysbiosis was associated with increased levels of secretory-IgA, up-regulation of the antimicrobial lectin RegIIIγ, and toll-like receptors (TLR) 4 and 7 and down-regulation of the antimicrobial-peptide Resistin-Like Molecule-β and TLR5. Dysbiotic mice showed less goblet cells, without changes in the thickness of the mucus layer. Neither macroscopical nor microscopical signs of inflammation were observed. In dysbiotic mice, expression of the cannabinoid receptor 2 was up-regulated, while the cannabinoid 1 and the mu-opioid receptors were down-regulated. In antibiotic-treated mice, visceral pain-related responses elicited by intraperitoneal acetic acid or intracolonic capsaicin were significantly attenuated. Colonic contractility was enhanced during dysbiosis. Intestinal dysbiosis induce changes in the innate intestinal immune system and modulate the expression of pain-related sensory systems, an effect associated with a reduction in visceral pain-related responses. Commensal microbiota modulates gut neuro-immune sensory systems, leading to functional changes, at least as it relates to viscerosensitivity. Similar mechanisms might explain the beneficial effects of antibiotics or certain probiotics in the treatment of IBS. 10.4161/19490976.2014.990790
    Gut-Brain Axis and Behavior. Martin Clair R,Mayer Emeran A Nestle Nutrition Institute workshop series In the last 5 years, interest in the interactions among the gut microbiome, brain, and behavior has exploded. Preclinical evidence supports a role of the gut microbiome in behavioral responses associated with pain, emotion, social interactions, and food intake. Limited, but growing, clinical evidence comes primarily from associations of gut microbial composition and function to behavioral and clinical features and brain structure and function. Converging evidence suggests that the brain and the gut microbiota are in bidirectional communication. Observed dysbiotic states in depression, chronic stress, and autism may reflect altered brain signaling to the gut, while altered gut microbial signaling to the brain may play a role in reinforcing brain alterations. On the other hand, primary dysbiotic states due to Western diets may signal to the brain, altering ingestive behavior. While studies performed in patients with depression and rodent models generated by fecal microbial transfer from such patients suggest causation, evidence for an influence of acute gut microbial alterations on human behavioral and clinical parameters is lacking. Only recently has an open-label microbial transfer therapy in children with autism tentatively validated the gut microbiota as a therapeutic target. The translational potential of preclinical findings remains unclear without further clinical investigation. 10.1159/000461732
    Alterations in the fecal microbiota and serum metabolome in unstable angina pectoris patients. Liu Langsha,Luo Fanyan Frontiers in bioscience (Landmark edition) BACKGROUND:Unstable angina pectoris (UAP) is a type of Coronary artery disease (CAD) characterized by a series of angina symptoms. Insulin-like growth factor 1 (IGF-1) system may be related to CAD. However, the correlation between the IGF-1 system, metabolism, and gut microbiota has not been studied. In the present study, we investigated the alterations of serum IGF-1 system, metabolomics, and gut microbiota in patients with UAP. METHODS:Serum and stool samples from healthy volunteers and UAP patients were collected. Serum metabolomics, PAPP-A, IGF-1, IGFBP-4, STC2, hs-CRP, TNF-α, and IL-6 were detected in serum samples by LC-MS, and commercial ELISA kits, respectively. Fecal short-chain fatty acids (SCFAs) were measured by gas chromatography. 16S rDNA was used to measure the changes of the gut microbiota. The correlation of the above indicators was analyzed. RESULTS:There were 24 upregulated and 31 downregulated metabolites in the serum of UAP patients compared to those in the controls. Pathway analysis showed that these metabolites were enriched in pathways including linoleic acid metabolism, amino acid metabolism, starch metabolism, sucrose metabolism, and citrate cycle (TCA cycle), . Additionally, the UAP patients had lower fecal levels of 2-hydroxyisobutyric acid and succinic acid. 16S rDNA sequencing results showed that the relative abundances of , , , , Synergistaceae, and were significantly higher in the UAP patients than the healthy subjects. Moreover, the UAP patients had lower serum IGF-1, IGFBP-4, and STC2 and higher serum inflammatory cytokines (hs-CRP, TNF-α, and IL-6) levels than the healthy controls. Furthermore, there was a strong correlation between serum amino acids and IL-6, which played an important role in the development of UAP. CONCLUSIONS:These results indicated that the UAP patients had decreased serum IGF-1 level and imbalanced amino acids metabolism, which may be caused by the altered gut microbiota. It may provide a new therapeutic strategy for unstable angina pectoris. 10.31083/j.fbl2703100
    Mucosal Serotonin Reuptake Transporter Expression in Irritable Bowel Syndrome Is Modulated by Gut Microbiota Via Mast Cell-Prostaglandin E2. Gastroenterology BACKGROUND & AIMS:Increased colonic serotonin (5-HT) level and decreased serotonin reuptake transporter (SERT) expression in irritable bowel syndrome (IBS) may contribute to diarrhea and visceral hypersensitivity. We investigated whether mucosal SERT is modulated by gut microbiota via a mast cell-prostaglandin E2 (PGE2) pathway. METHODS:C57Bl/6 mice received intracolonic infusion of fecal supernatant (FS) from healthy controls or patients with diarrhea-predominant irritable bowel syndrome (IBS-D). The role of mast cells was studied in mast cell-deficient mice. Colonic organoids and/or mast cells were used for in vitro experiments. SERT expression was measured by quantitative polymerase chain reaction and Western blot. Visceromotor responses to colorectal distension and colonic transit were assessed. RESULTS:Intracolonic infusion of IBS-D FS in mice caused an increase in mucosal 5-HT compared with healthy control FS, accompanied by ∼50% reduction in SERT expression. Mast cell stabilizers, cyclooxygenase-2 inhibitors, and PGE2 receptor antagonist prevented SERT downregulation. Intracolonic infusion of IBS-D FS failed to reduce SERT expression in mast cell-deficient (W/Wv) mice. This response was restored by mast cell reconstitution. The downregulation of SERT expression evoked by IBS FS was prevented by lipopolysaccharide (LPS) antagonist LPS from Rhodobacter sphaeroides and a bacterial trypsin inhibitor. In vitro LPS treatment caused increased cyclooxygenase-2 expression and PGE2 release from cultured mouse mast cells. Intracolonic infusion of IBS-D FS in mice reduced colonic transit, increased fecal water content, and increased visceromotor responses to colorectal distension. Ondansetron prevented these changes. CONCLUSIONS:Fecal LPS acting in concert with trypsin in patients with IBS-D stimulates mucosal mast cells to release PGE2, which downregulates mucosal SERT, resulting in increased mucosal 5-HT. This may contribute to diarrhea and abdominal pain common in IBS. 10.1053/j.gastro.2022.02.016
    [Irritable bowel syndrome: New pathophysiological hypotheses and practical issues]. Duboc H,Dior M,Coffin B La Revue de medecine interne In 2015, besides the fact that it still fills the gastroenterologists' offices and impairs patient's quality of life, the irritable bowel syndrome has considerably evolved on several points. The pathophysiology is now organized around a consensual hypothesis called the "brain-gut axis", which gather all the influences of peripheral factors as gut microbiota or local serotonin secretion, on the central pain perception, contributing to visceral hypersensitivity and transit modifications. About the diagnosis, the key message is "avoid over-prescription" of additional tests, and reminds that a positive clinical diagnosis based on Rome III criteria is possible after the elimination of simple clinical warning signs. Finally, the food component, a neglected and historical claim of patients, finally finds a strong scientific rational, with a diet low in fermentable sugar and polyols, that gives positive and reproducible results. 10.1016/j.revmed.2015.12.030
    [Effect of acupuncture therapy on gut microbiota and fecal short-chain fatty acids in patients with diarrhea type irritable bowel syndrome]. Chen Lu,Xu Wan-Li,Pei Li-Xia,Wu Xiao-Liang,Geng Hao,Guo Jing,Sun Jian-Hua Zhongguo zhen jiu = Chinese acupuncture & moxibustion OBJECTIVE:To observe the clinical therapeutic effect of acupuncture therapy (acupuncture for regulating the mind and strengthening the spleen) on the gut microbiota and the content of fecal short-chain fatty acids (SCFAs) in patients with diarrhea type irritable bowel syndrome (IBS-D). METHODS:A total of 20 patients with IBS-D and 20 healthy subjects were included. The patients with IBS-D were treated with acupuncture therapy at Baihui (GV 20), Yintang (GV 29), Tianshu (ST 25), Shangjuxu (ST 37), Zusanli (ST 36), Sanyinjiao (SP 6) and Taichong (LR 3). The treatment was given once every two days, 3 times weekly, consecutively for 6 weeks. No intervention was provided for the healthy subjects. Before and after treatment, the IBS symptom severity score (IBS-SSS) was observed in the patients. The fecal samples were collected before and after treatment separately in the patients and in the healthy subjects. Using 16S rRNA sequencing technique, the structure and diversity of gut microbiota were analyzed. Using high-performance liquid chromatography, the content of SCFAs was detected. RESULTS:After treatment, the abdominal pain severity score, the abdominal pain days score, the satisfaction in bowel movement score, the life interference score and the total IBS-SSS score were all lower than those before treatment in the patients with IBS-D (<0.05). Compared with the healthy subjects, Firmicutes was increased (<0.05), Bacteroidetes and Proteobacteria were decreased (<0.05), and Shannon index was reduced (<0.05) and Simpson index was increased in patients with IBS-D before treatment (<0.05). Compared before treatment, Firmicutes was decreased (<0.05), Bacteroidetes and Proteobacteria were increased (<0.05), and Shannon index was increased (<0.05) and Simpson index was reduced in the patients with IBS-D after treatment (<0.05). Besides, the content of SCFAs was reduced after treatment (<0.05). CONCLUSION: acupuncture therapy relieves abdominal pain and diarrhea, which may be related to regulating the structure and diversity of gut microbiota and reducing the content of fecal SCFAs in the patients with IBS-D. 10.13703/j.0255-2930.20200205-k0002
    Novel directions in the study of osteoporosis: focus on gut microbiota as a potential therapeutic target. Bizzoca D,Solarino G,Vicenti G,Moretti L,Nappi V S,Belluati A,Moretti B Journal of biological regulators and homeostatic agents Osteoporosis is a significant social health problem, not only in terms of pain and disability but also in terms of mortality rate. In recent years, there is an increasing interest in studying the relationship between gut dysmicrobiosis, immune system and bone health, therefore the term "osteomicrobiology" has been recently coined. This review aims to summarize the current knowledge about the link between gut dysbiosis and osteoporosis, in order to define a potential preventive and therapeutic strategy. Gut microbiota (GM) plays a major role in maintaining body homeostasis, since it is involved in several physiological processes; in recent years, the gut microbiota has shown to modulate not only local processes but also systemic responses including bone metabolism. Several potential mechanisms may explain how gut microorganisms could affect bone metabolism, i.e. influencing the host metabolism, immune system and hormone secretion. The relationship between gut dysbiosis, immunological dysfunction and bone loss could be explained by mainly focusing on T cells. Moreover, it should be noted that the relationship between GM and the endocrine system could also explicate how the microbiome influences bone status. In this context, Insulin-Like Growth Factor-1 (IGF-1), vitamin D, serotonin and leptin might play a central role. GM could have a significant impact on bone metabolism, therefore future clinical studies are necessary to develop a new multidisciplinary approach for osteoporosis treatment and prevention.
    The Relationship Between the Serotonin Metabolism, Gut-Microbiota and the Gut-Brain Axis. Stasi Cristina,Sadalla Sinan,Milani Stefano Current drug metabolism BACKGROUND:Serotonin (5-HT) has a pleiotropic function in gastrointestinal, neurological/psychiatric and liver diseases. The aim of this review was to elucidate whether the gut-microbiota played a critical role in regulating peripheral serotonin levels. METHODS:We searched for relevant studies published in English using the PubMed database from 1993 to the present. RESULTS:Several studies suggested that alterations in the gut-microbiota may contribute to a modulation of serotonin signalling. The first indication regarded the changes in the composition of the commensal bacteria and the intestinal transit time caused by antibiotic treatment. The second indication regarded the changes in serotonin levels correlated to specific bacteria. The third indication regarded the fact that decreased serotonin transporter expression was associated with a shift in gut-microbiota from homeostasis to inflammatory type microbiota. Serotonin plays a key role in the regulation of visceral pain, secretion, and initiation of the peristaltic reflex; however, its altered levels are also detected in many different psychiatric disorders. Symptoms of some gastrointestinal functional disorders may be due to deregulation in central nervous system activity, dysregulation at the peripheral level (intestine), or a combination of both (brain-gut axis) by means of neuro-endocrine-immune stimuli. Moreover, several studies have demonstrated the profibrogenic role of 5-HT in the liver, showing that it works synergistically with platelet-derived growth factor in stimulating hepatic stellate cell proliferation. CONCLUSION:Although the specific interaction mechanisms are still unclear, some studies have suggested that there is a correlation between the gut-microbiota, some gastrointestinal and liver diseases and the serotonin metabolism. 10.2174/1389200220666190725115503
    Gut-brain axis: A matter of concern in neuropsychiatric disorders…! Naveed Muhammad,Zhou Qi-Gang,Xu Chu,Taleb Abdoh,Meng Fan,Ahmed Bilal,Zhang Yu,Fukunaga Kohji,Han Feng Progress in neuro-psychopharmacology & biological psychiatry The gut microbiota is composed of a large number of microbes, usually regarded as commensal bacteria. It has become gradually clear that gastrointestinal microbiota affects gut pathophysiology and the central nervous system (CNS) function by modulating the signaling pathways of the microbiota-gut-brain (MGB) axis. This bidirectional MGB axis communication primarily acts through neuroendocrine, neuroimmune, and autonomic nervous systems (ANS) mechanisms. Accumulating evidence reveals that gut microbiota interacts with the host brain, and its modulation may play a critical role in the pathology of neuropsychiatric disorders. Recently, neuroscience research has established the significance of gut microbiota in the development of brain systems that are essential to stress-related behaviors, including depression and anxiety. Application of modulators of the MGB, such as psychobiotics (e.g., probiotics), prebiotics, and specific diets, may be a promising therapeutic approach for neuropsychiatric disorders. The present review article primarily focuses on the relevant features of the disturbances of the MGB axis in the pathophysiology of neuropsychiatric disorders and its potential mechanisms. 10.1016/j.pnpbp.2020.110051
    Gut-Innervating Nociceptor Neurons Regulate Peyer's Patch Microfold Cells and SFB Levels to Mediate Salmonella Host Defense. Lai Nicole Y,Musser Melissa A,Pinho-Ribeiro Felipe A,Baral Pankaj,Jacobson Amanda,Ma Pingchuan,Potts David E,Chen Zuojia,Paik Donggi,Soualhi Salima,Yan Yiqing,Misra Aditya,Goldstein Kaitlin,Lagomarsino Valentina N,Nordstrom Anja,Sivanathan Kisha N,Wallrapp Antonia,Kuchroo Vijay K,Nowarski Roni,Starnbach Michael N,Shi Hailian,Surana Neeraj K,An Dingding,Wu Chuan,Huh Jun R,Rao Meenakshi,Chiu Isaac M Cell Gut-innervating nociceptor sensory neurons respond to noxious stimuli by initiating protective responses including pain and inflammation; however, their role in enteric infections is unclear. Here, we find that nociceptor neurons critically mediate host defense against the bacterial pathogen Salmonella enterica serovar Typhimurium (STm). Dorsal root ganglia nociceptors protect against STm colonization, invasion, and dissemination from the gut. Nociceptors regulate the density of microfold (M) cells in ileum Peyer's patch (PP) follicle-associated epithelia (FAE) to limit entry points for STm invasion. Downstream of M cells, nociceptors maintain levels of segmentous filamentous bacteria (SFB), a gut microbe residing on ileum villi and PP FAE that mediates resistance to STm infection. TRPV1+ nociceptors directly respond to STm by releasing calcitonin gene-related peptide (CGRP), a neuropeptide that modulates M cells and SFB levels to protect against Salmonella infection. These findings reveal a major role for nociceptor neurons in sensing and defending against enteric pathogens. 10.1016/j.cell.2019.11.014
    Concomitant use of analgesics and immune checkpoint inhibitors in non-small cell lung cancer: A pharmacodynamics perspective. Prasetya Rahmad Aji,Metselaar-Albers Marjolein,Engels Ferdi European journal of pharmacology The invention of immunotherapy, such as immune checkpoint inhibitors (ICIs) for advanced-stage non-small cell lung cancer (NSCLC), has become a new standard of care for a defined group of NSCLC patients. However, the possible impacts of ICI interactions with analgesics for alleviating cancer-related pain are unclear and lack clinical evidence. Many studies have indicated that opioids detrimentally affect the immune system, possibly harming patients of ongoing immunotherapy. Opioids may repress the immune system in various ways, including impairing T cell function, upregulating immunosuppressor Treg cells, and interrupting intestinal microflora composition that disrupts the entire immune system. Furthermore, opioids can influence tumor progression and metastasis directly as opioid receptors are overexpressed in several types of NSCLC. In contrast, another analgesic acting on cyclooxygenase (COX) inhibition (i.e., NSAIDs) may be a candidate for adjuvant therapy since COX-2 is also expressed in the tumor cells of NSCLC patients. In addition, COX-2 is associated with tumor proliferation and metastasis. Therefore, both prospective and retrospective studies should confirm the advantages and disadvantages of the concurrent use of analgesics and ICIs in a clinical setting. 10.1016/j.ejphar.2021.174284
    Preventing and Treating Colic. Indrio Flavia,Dargenio Vanessa Nadia,Giordano Paola,Francavilla Ruggiero Advances in experimental medicine and biology Colic is a common and distressing functional gastrointestinal disorder during infancy. It is a behavioral phenomenon in infants aged 1-4 months involving prolonged inconsolable crying and agitated status with multifactorial etiology. Colic can be considered as a benign, self-limited process because the baby normally grows and feeds even with transient irritable mood. Nevertheless, infantile colic is a common difficulty causing anxiety during parenthood and a recurrent reason for them to seek medical help, especially if it is the first child. The causes of colic can be classified as non-gastrointestinal or gastrointestinal. The former includes altered feeding techniques, modified child-parent relationship, immaturity of central nervous system, behavioral etiology, and maternal smoking or nicotine replacement therapy. Instead, the latter involves inadequate production of lactase enzyme, cow's milk protein intolerance, alteration of intestinal microbiota, gastrointestinal immaturity, or inflammation which causes intestinal hyperperistalsis due to increase in serotonin secretion and motilin receptor expression.Probiotics may play a crucial part in the manipulation of the microbiota. Probiotic administration is likely to maintain intestinal homeostasis through the modulation of permeability and peristalsis, influencing the gut-brain axis and inhibiting hypersensitivity. This is a decisive field in the development of preventive and therapeutic strategies for infantile colic. However, further studies are needed for each specific formulation in order to better characterize pharmacodynamic and pharmacokinetic properties and to evaluate their application as a possible preventive strategy if administered early during infancy against the later development of pain-related FGIDs. 10.1007/5584_2018_315
    Effect of Electroacupuncture on Gut Microbiota in Participants With Knee Osteoarthritis. Wang Tian-Qi,Li Ling-Ru,Tan Chun-Xia,Yang Jing-Wen,Shi Guang-Xia,Wang Li-Qiong,Hu Hui,Liu Zhi-Shun,Wang Jun,Wang Tong,Yuan Yong,Jia Wen-Rui,Li Hua,Wang Xin-Wei,Wu Bin,Tu Jian-Feng,Liu Cun-Zhi Frontiers in cellular and infection microbiology A close relationship between knee osteoarthritis (KOA) and gut microbiota has recently been described. Herein, we aim to investigate the effect of electroacupuncture (EA) on gut microbiota in participants with KOA. We conducted a study of 60 participants with KOA and 30 matched healthy controls (HCs). Sixty participants were allocated to either EA group (n=30) or sham acupuncture (SA) group (n=30). Five obligatory acupoints and three adjunct acupoints were punctured in the EA group. Eight non-acupoints that were separated from conventional acupoints or meridians were used for the SA group. Participants in both groups received 24 sessions within eight weeks. Fecal microbial analyses by 16S ribosomal RNA gene sequencing were carried out after collecting stools at and weeks (Four samples with changed defecation habits were excluded). The results showed that both Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score (0.043) and NRS score (0.002) decreased more in EA group than those in SA group. Moreover, EA could reverse more KOA-related bacteria including , , r . The number of significantly different genera between KOA patients and HCs were less after EA treatment than that after SA treatment. This meant that EA modified the composition of the gut microbiome, making it closer to healthy people, while not significantly affecting the microbial diversity. Two genera including (=0.0163), (=0.0144) were statistically increased than baseline in EA group (paired Wilcoxon rank sum test). After EA treatment, (0.0394) was more abundant and (0.0306) was significantly reduced in patients who demonstrated adequate response than in those with inadequate response (Wilcoxon rank-sum test). Spearman correlation test between gut microbe and KOA clinical outcomes indicated that and was negatively correlated with NRS score, WOMAC total score, and WOMAC pain, stiffness and pain scores (<0.001 or 0.05 or 0.01), while was positively correlated with them (<0.05 or 0.01). Our study suggests that EA contributes to the improvement of KOA and gut microbiota could be a potential therapeutic target. 10.3389/fcimb.2021.597431
    Paneth Cell Defects Induce Microbiota Dysbiosis in Mice and Promote Visceral Hypersensitivity. Riba Ambre,Olier Maïwenn,Lacroix-Lamandé Sonia,Lencina Corinne,Bacquié Valérie,Harkat Cherryl,Gillet Marion,Baron Marine,Sommer Caroline,Mallet Virginie,Salvador-Cartier Christel,Laurent Fabrice,Théodorou Vassilia,Ménard Sandrine Gastroenterology BACKGROUND & AIMS:Separation of newborn rats from their mothers induces visceral hypersensitivity and impaired epithelial secretory cell lineages when they are adults. Little is known about the mechanisms by which maternal separation causes visceral hypersensitivity or its relationship with defects in epithelial secretory cell lineages. METHODS:We performed studies with C3H/HeN mice separated from their mothers as newborns and mice genetically engineered (Sox9-vil-cre on C57BL/6 background) to have deficiencies in Paneth cells. Paneth cell deficiency was assessed by lysozyme staining of ileum tissues and lysozyme activity in fecal samples. When mice were 50 days old, their abdominal response to colorectal distension was assessed by electromyography. Fecal samples were collected and microbiota were analyzed using Gut Low-Density Array quantitative polymerase chain reaction. RESULTS:Mice with maternal separation developed visceral hypersensitivity and defects in Paneth cells, as reported from rats, compared with mice without maternal separation. Sox9-vil-Cre mice also had increased visceral hypersensitivity compared with control littermate Sox9 mice. Fecal samples from mice with maternal separation and from Sox9-vil-cre mice had evidence for intestinal dysbiosis of the microbiota, characterized by expansion of Escherichia coli. Daily gavage of conventional C3H/HeN adult mice with 10 commensal E coli induced visceral hypersensitivity. Conversely, daily oral administration of lysozyme prevented expansion of E coli during maternal separation and visceral hypersensitivity. CONCLUSIONS:Mice with defects in Paneth cells (induced by maternal separation or genetically engineered) have intestinal expansion of E coli leading to visceral hypersensitivity. These findings provide evidence that Paneth cell function and intestinal dysbiosis are involved in visceral sensitivity. 10.1053/j.gastro.2017.08.044
    Exploring the Potential Role of the Gut Microbiome in Chemotherapy-Induced Neurocognitive Disorders and Cardiovascular Toxicity. Ciernikova Sona,Mego Michal,Chovanec Michal Cancers Chemotherapy, targeting not only malignant but also healthy cells, causes many undesirable side effects in cancer patients. Due to this fact, long-term cancer survivors often suffer from late effects, including cognitive impairment and cardiovascular toxicity. Chemotherapy damages the intestinal mucosa and heavily disrupts the gut ecosystem, leading to gastrointestinal toxicity. Animal models and clinical studies have revealed the associations between intestinal dysbiosis and depression, anxiety, pain, impaired cognitive functions, and cardiovascular diseases. Recently, a possible link between chemotherapy-induced gut microbiota disruption and late effects in cancer survivors has been proposed. In this review, we summarize the current understanding of preclinical and clinical findings regarding the emerging role of the microbiome and the microbiota-gut-brain axis in chemotherapy-related late effects affecting the central nervous system (CNS) and heart functions. Importantly, we provide an overview of clinical trials evaluating the relationship between the gut microbiome and cancer survivorship. Moreover, the beneficial effects of probiotics in experimental models and non-cancer patients with neurocognitive disorders and cardiovascular diseases as well as several studies on microbiota modulations via probiotics or fecal microbiota transplantation in cancer patients are discussed. 10.3390/cancers13040782
    Targeting strategies for chemotherapy-induced peripheral neuropathy: does gut microbiota play a role? Zhong Shanshan,Zhou Zhike,Liang Yifan,Cheng Xi,Li Yong,Teng Weiyu,Zhao Mei,Liu Chang,Guan Meiting,Zhao Chuansheng Critical reviews in microbiology Chemotherapy-induced peripheral neuropathy (CIPN) is a progressive, often irreversible condition that produces severe neurological deficits. Emerging data suggest that chemotherapy also exerts detrimental effects on gut microbiota composition and intestinal permeability, contributing to dysbiosis and inflammation. Compared with other complications associated with chemotherapy, such as diarrhoea and mucositis, CIPN is of particular concern because it is the most common reason for terminating or suspending treatment. However, specific and effective curative treatment strategies are lacking. In this review, we provide an update on current preclinical and clinical understandings about the role of gut microbiota in CIPN. The gut microbiota serves as an intersection between the microbiome-gut-brain and the neuroimmune-endocrine axis, forming a complex network that can directly or indirectly affect key components involved in the manifestations of CIPN. Herein, we discuss several potential mechanisms within the context of the networks and summarize alterations in gut microbiome induced by chemotherapeutic drugs, providing great potential for researchers to target pathways associated with the gut microbiome and overcome CIPN. 10.1080/1040841X.2019.1608905
    Enterochromaffin Cells: Sentinels to Gut Microbiota in Hyperalgesia? Xu Xiaolin,Chen Rongmin,Zhan Gaofeng,Wang Danning,Tan Xi,Xu Hui Frontiers in cellular and infection microbiology In recent years, increasing studies have been conducted on the mechanism of gut microbiota in neuropsychiatric diseases and non-neuropsychiatric diseases. The academic community has also recognized the existence of the microbiota-gut-brain axis. Chronic pain has always been an urgent difficulty for human beings, which often causes anxiety, depression, and other mental symptoms, seriously affecting people's quality of life. Hyperalgesia is one of the main adverse reactions of chronic pain. The mechanism of gut microbiota in hyperalgesia has been extensively studied, providing a new target for pain treatment. Enterochromaffin cells, as the chief sentinel for sensing gut microbiota and its metabolites, can play an important role in the interaction between the gut microbiota and hyperalgesia through paracrine or neural pathways. Therefore, this systematic review describes the role of gut microbiota in the pathological mechanism of hyperalgesia, learns about the role of enterochromaffin cell receptors and secretions in hyperalgesia, and provides a new strategy for pain treatment by targeting enterochromaffin cells through restoring disturbed gut microbiota or supplementing probiotics. 10.3389/fcimb.2021.760076
    Gut microbiota-drug interactions in cancer pharmacotherapies: implications for efficacy and adverse effects. Expert opinion on drug metabolism & toxicology INTRODUCTION:The gut microbiota is involved in host physiology and health. Reciprocal microbiota-drug interactions are increasingly recognized as underlying some individual differences in therapy response and adverse events. Cancer pharmacotherapies are characterized by a high degree of interpatient variability in efficacy and side effect profile and recently, the microbiota has emerged as a factor that may underlie these differences. AREAS COVERED:The effects of cancer pharmacotherapy on microbiota composition and function are reviewed with consideration of the relationship between baseline microbiota composition, microbiota modification, antibiotics exposure, and cancer therapy efficacy. We assess the evidence implicating the microbiota in cancer therapy-related adverse events including impaired gut function, cognition, and pain perception. Finally, potential mechanisms underlying microbiota-cancer drug interactions are described, including direct microbial metabolism, and microbial modulation of liver metabolism and immune function. This review focused on preclinical and clinical studies conducted in the last 5 years. EXPERT OPINION:Preclinical and clinical research supports a role for baseline microbiota in cancer therapy efficacy, with emerging evidence that the microbiota modification may assist in side effect management. Future efforts should focus on exploiting this knowledge toward the development of microbiota-targeted therapies. Finally, a focus on specific drug-microbiota-cancer interactions is warranted. 10.1080/17425255.2022.2043849
    Editorial: The Promise of Psychiatric Translational Research: Exploring How the Gut Can Influence Brain Development. Szigethy Eva Journal of the American Academy of Child and Adolescent Psychiatry How the gastrointestinal (GI) tract can influence the development and functioning of the central nervous system is one of the hottest translational research topics today. In animal studies, GI infections have been linked to enteric inflammation, disrupted intestinal permeability, and changes in diversity in the gut microbiome as well as brain dysfunction. In humans, infectious gastroenteritis has been associated with modified composition of the gut microbiome and systemic inflammation. Although gastroenteritis has not been causally linked to dysregulation of the brain in humans, it has been associated with later chronic GI conditions such as irritable bowel syndrome, which is often accompanied by anxiety and depression. In other human studies, microbiome dysbiosis has been associated with significantly increased the risk for later systemic inflammation and brain dysfunction manifested as changes in emotions, behaviors, pain perception, and cognitions. Most studies investigating these relationships have focused on adult cohorts and are often cross-sectional in design nature. The study by Parent et al. is the first longitudinal study to evaluate whether repeated episodes of gastroenteritis during early childhood predicts behavioral problems in later childhood and mental illness during adolescence. In addition, it has an exploratory mechanistic objective: whether systemic inflammation in later childhood and adolescence moderates this brain-gut relationship. 10.1016/j.jaac.2019.05.021
    The Guts of the Opioid Crisis. Muchhala Karan H,Jacob Joanna C,Kang Minho,Dewey William L,Akbarali Hamid I Physiology (Bethesda, Md.) Bidirectional interactions of the gut epithelium with commensal bacteria are critical for maintaining homeostasis within the gut. Chronic opioid exposure perturbs gut homeostasis through a multitude of neuro-immune-epithelial mechanisms, resulting in the development of analgesic tolerance, a major underpinning of the current opioid crisis. Differences in molecular mechanisms of opioid tolerance between the enteric and central pain pathways pose a significant challenge for managing chronic pain without untoward gastrointestinal effects. 10.1152/physiol.00014.2021
    Brain to Belly: Abdominal Variants of Migraine and Functional Abdominal Pain Disorders Associated With Migraine. LenglarT Léa,Caula Caroline,Moulding Thomas,Lyles Annabel,Wohrer Delphine,Titomanlio Luigi Journal of neurogastroenterology and motility Migraine is one of the most frequent causes of primary headache and 9% of children suffer from migraines. Most children will continue to experience migraine attacks as adults, therefore it is imperative that we have a thorough understanding of this major health issue. This article considers the so-called abdominal variants of migraine, which are more commonly seen in children rather than adults: abdominal migraine, cyclic vomiting syndrome, and infantile colic. Other functional abdominal pain disorders such as irritable bowel syndrome and functional dyspepsia have also been linked to migraine in clinical studies. The common pathophysiological root of these diseases seems to be the gut-brain axis mechanism. Abdominal variants of migraine are considered pediatric precursors of migraine whereas the functional abdominal pain disorders related to migraine seem to share a pathophysiological root with no temporarily link as for today. In this review we aim to describe the epidemiological background, the current pathophysiological theories and the relationship of each disease to migraine. This review is the first to compile abdominal variants of migraine and functional abdominal pain disorders associated with migraine and we endeavor to elucidate the broad spectrum of migraine-related episodes in children. 10.5056/jnm20290
    Microbes, microglia, and pain. Dworsky-Fried Zoë,Kerr Bradley J,Taylor Anna M W Neurobiology of pain (Cambridge, Mass.) Globally, it is estimated that one in five people suffer from chronic pain, with prevalence increasing with age. The pathophysiology of chronic pain encompasses complex sensory, immune, and inflammatory interactions within both the central and peripheral nervous systems. Microglia, the resident macrophages of the central nervous system (CNS), are critically involved in the initiation and persistence of chronic pain. Microglia respond to local signals from the CNS but are also modulated by signals from the gastrointestinal tract. Emerging data from preclinical and clinical studies suggest that communication between the gut microbiome, the community of bacteria residing within the gut, and microglia is involved in producing chronic pain. Targeted strategies that manipulate or restore the gut microbiome have been shown to reduce microglial activation and alleviate symptoms associated with inflammation. These data indicate that manipulations of the gut microbiome in chronic pain patients might be a viable strategy in improving pain outcomes. Herein, we discuss the evidence for a connection between microglia and the gut microbiome and explore the mechanisms by which commensal bacteria might influence microglial reactivity to drive chronic pain. 10.1016/j.ynpai.2020.100045
    Bacterial modulation of visceral sensation: mediators and mechanisms. Lomax Alan E,Pradhananga Sabindra,Sessenwein Jessica L,O'Malley Dervla American journal of physiology. Gastrointestinal and liver physiology The potential role of the intestinal microbiota in modulating visceral pain has received increasing attention during recent years. This has led to the identification of signaling pathways that have been implicated in communication between gut bacteria and peripheral pain pathways. In addition to the well-characterized impact of the microbiota on the immune system, which in turn affects nociceptor excitability, bacteria can modulate visceral afferent pathways by effects on enterocytes, enteroendocrine cells, and the neurons themselves. Proteases produced by bacteria, or by host cells in response to bacteria, can increase or decrease the excitability of nociceptive dorsal root ganglion (DRG) neurons depending on the receptor activated. Short-chain fatty acids generated by colonic bacteria are involved in gut-brain communication, and intracolonic short-chain fatty acids have pronociceptive effects in rodents but may be antinociceptive in humans. Gut bacteria modulate the synthesis and release of enteroendocrine cell mediators, including serotonin and glucagon-like peptide-1, which activate extrinsic afferent neurons. Deciphering the complex interactions between visceral afferent neurons and the gut microbiota may lead to the development of improved probiotic therapies for visceral pain. 10.1152/ajpgi.00052.2019
    Commentary on Ma et al. Resveratrol brings back happy bug's harmony. Ren Ke Brain, behavior, and immunity 10.1016/j.bbi.2020.03.005
    Association Between Gut Microbiota and Symptomatic Hand Osteoarthritis: Data From the Xiangya Osteoarthritis Study. Wei Jie,Zhang Chenhong,Zhang Yuqing,Zhang Weiya,Doherty Michael,Yang Tuo,Zhai Guangju,Obotiba Abasiama D,Lyu Houchen,Zeng Chao,Lei Guanghua Arthritis & rheumatology (Hoboken, N.J.) OBJECTIVE:Systemic inflammatory factors have been implicated in symptomatic hand osteoarthritis (OA). Gut microbiome dysbiosis promotes systemic inflammation. The aim of this study was to examine the association between the gut microbiome and the presence of symptomatic hand OA in a population-based study. METHODS:Study participants were subjects of the Xiangya Osteoarthritis Study, a community-based observational study conducted in the Hunan Province of China. Symptomatic hand OA was defined as the presence of both symptoms and radiographic OA in the same hand. The gut microbiome was analyzed using 16S ribosomal RNA gene sequencing in stool samples. We examined the relation of α-diversity, β-diversity, relative abundance of taxa, and potential bacterial functional pathways to symptomatic hand OA. RESULTS:A total of 1,388 participants (mean age 61.3 years, 57.4% women) were included in the study, of whom 72 had symptomatic hand OA (prevalence of symptomatic hand OA 5.2%). Beta-diversity of the gut microbiome, but not α-diversity, was significantly associated with the presence of symptomatic hand OA (P = 0.003). Higher relative abundance of the genera Bilophila and Desulfovibrio as well as lower relative abundance of the genus Roseburia was associated with symptomatic hand OA. Most functional pathways (i.e., those annotated in the KEGG Ortholog hierarchy) that were observed to be altered in participants with symptomatic hand OA belonged to the amino acid, carbohydrate, and lipid metabolic pathways. CONCLUSION:This large, population-based study provides the first evidence that alterations in the composition of the gut microbiome were observed among study participants who had symptomatic hand OA, and a low relative abundance of Roseburia but high relative abundance of Bilophila and Desulfovibrio at the genus level were associated with prevalent symptomatic hand OA. These findings may help investigators understand the role of the microbiome in the development of symptomatic hand OA and could contribute to potential translational opportunities. 10.1002/art.41729
    Gut-microbiota modulation: The impact of thegut-microbiotaon osteoarthritis. Arora Vipin,Singh Gurjit,O-Sullivan InSug,Ma Kaige,Natarajan Anbazhagan Arivarasu,Votta-Velis E Gina,Bruce Benjamin,Richard Ripper,van Wijnen Andre J,Im Hee-Jeong Gene Osteoarthritis (OA) is one of the most common medical conditions affecting > 300 million people globally which represents the formidable public health challenge. Despite its clinical and financial ramifications, there are currently no approved disease modifying OA drugs available and symptom palliation is the only alternative. Currently, the amount of data on the human intestinal microbiome is growing at a high rate, both in health and in various pathological conditions. With an increase in the amount of the accumulated data, there is an expanded understanding that the microbiome provides compelling evidence of a link between thegut microbiomeand development ofOA. The microbiota management tools of probiotics and/or prebiotics or symbiotic have been developed and indeed, commercialized over the past few decades with the expressed purpose of altering the microbiota within the gastrointestinal tract which could be a potentially novel intervention to tackle or prevent OA. However, the mechanisms how intestinal microbiota affects the OA pathogenesis are still not clear and further research targeting specific gut microbiota or its metabolites is still needed to advance OA treatment strategies from symptomatic management to individualized interventions of OA pathogenesis. This article provides an overview of the various preclinical and clinical studies using probiotics and prebiotics as plausible therapeutic options that can restore the gastrointestinal microbiota and its impact on the OA pathogenesis. May be in the near future the targeted alterations of gut microbiota may pave the way for developing new interventions to prevent and treat OA. 10.1016/j.gene.2021.145619
    [Investigating of Relation Between Fibromyalgia Syndrome and Intestinal Microbiota]. Albayrak Büşra,Süsgün Seda,Küçükakkaş Okan,Akbaş Fahri,Yabacı Ayşegül,Özçelik Semra Mikrobiyoloji bulteni Fibromyalgia syndrome (FMS) is one of the most frequent forms of chronic widespread pain, with a reported prevalence of 3-10% in the adult population. Clinical presentation of the typical pain and the presence of associated somatic and psychological symptoms form the basis of the diagnosis. FMS is associated with nervous system dysfunction and neurotransmitters act as targets of a number of drugs approved for fibromyalgia. However, although the underlying mechanisms in FMS are not yet known precisely, many hypotheses have been put forward. Considering the relation between fibromyalgia and irritable bowel syndrome (IBS), altered gut microbiome could be associated with fibromyalgia. In this study, it was aimed to investigate the variation of intestinal microbiome levels in patients with FMS compared to healthy controls. For the investigation of the microbiome, fecal samples were collected from a cohort of 54 patients with FMS and 36 healthy individuals. Those with any mental and/or physical illness in the control group were excluded from the study. The FMS patient group was determined according to the "American College of Rheumatology (ACR)" 2010 diagnostic criteria. The fecal samples were stored at -80°C until use and were thawed on ice; for each extraction, 0.3 g of faeces were weighed. Extraction of DNA was carried out with commercial kit according to the manufacturer's recommendations. Samples were compared using 16S rRNA gene amplification with specific primers of Bacteroidetes, Firmicutes, Enterobacter, Lactobacillus, Streptococcus and Bifidobacterium by the real-time PCR method. According to our results, while the increase of Bacteroidetes and Bifidobacterium was statistically significant (p<0.05), Firmicutes decreased (p<0.001) in the patient group. No statistically significant results were found for Enterobacter, Streptococcus and Lactobacillus (p> 0.05). When the relationship between bacteria was evaluated, a high statistically significance and negative correlation was found between Bacteroidetes and the percentage of Firmicutes (r= -0.778, p<0.001),while a moderate statistical significance and positive correlation was observed between the percentage of Enterobacter and Bifidobacterium (r= 0.460, p= 0.005). The results suggest that the gut microbiota may play a role in fibromyalgia. The balance of Firmicutes and Bacteroidetes phyla in the gut is known to have important effects on intestinal homeostasis. In summary, it is clear that large-scale further research in larger cohorts will be effective in understanding the relationship between the gut microbiome and FMS and evaluating possible treatment options. 10.5578/mb.20219903
    The gut microbiota mediates reward and sensory responses associated with regimen-selective morphine dependence. Lee Kevin,Vuong Helen E,Nusbaum David J,Hsiao Elaine Y,Evans Christopher J,Taylor Anna M W Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology Opioid use for long-term pain management is limited by adverse side effects, such as hyperalgesia and negative affect. Neuroinflammation in the brain and spinal cord is a contributing factor to the development of symptoms associated with chronic opioid use. Recent studies have described a link between neuroinflammation and behavior that is mediated by a gut-brain signaling axis, where alterations in indigenous gut bacteria contribute to several inflammation-related psychopathologies. As opioid receptors are highly expressed within the digestive tract and opioids influence gut motility, we hypothesized that systemic opioid treatment will impact the composition of the gut microbiota. Here, we explored how opioid treatments, and cessation, impacts the mouse gut microbiome and whether opioid-induced changes in the gut microbiota influences inflammation-driven hyperalgesia and impaired reward behavior. Male C57Bl6/J mice were treated with either intermittent or sustained morphine. Using 16S rDNA sequencing, we describe changes in gut microbiota composition following different morphine regimens. Manipulation of the gut microbiome was used to assess the causal relationship between the gut microbiome and opioid-dependent behaviors. Intermittent, but not sustained, morphine treatment was associated with microglial activation, hyperalgesia, and impaired reward response. Depletion of the gut microbiota via antibiotic treatment surprisingly recapitulated neuroinflammation and sequelae, including reduced opioid analgesic potency and impaired cocaine reward following intermittent morphine treatment. Colonization of antibiotic-treated mice with a control microbiota restored microglial activation state and behaviors. Our findings suggest that differing opioid regimens uniquely influence the gut microbiome that is causally related to behaviors associated with opioid dependence. 10.1038/s41386-018-0211-9
    The Effect of Multiprobiotics on Memory and Attention in Fibromyalgia: A Pilot Randomized Controlled Trial. Cardona Diana,Roman Pablo,Cañadas Fernando,Sánchez-Labraca Nuria International journal of environmental research and public health Fibromyalgia syndrome (FMS) is a chronic, generalized and diffuse pain disorder accompanied by cognitive deficits such as forgetfulness, concentration difficulties, loss of vocabulary and mental slowness, among others. In recent years, FMS has been associated with altered intestinal microbiota, suggesting that modulating gut microbiota (for example, through probiotics) could be an effective therapeutic treatment. Thus, the aim of the present study was to continue exploring the role of probiotics in cognitive processes in patients with FMS. A pilot randomized controlled trial was conducted in 31 patients diagnosed with FMS to compare the effects of a multispecies probiotic versus a placebo on cognitive variables (memory and attention) after eight weeks. Results showed that treatment with a multispecies probiotic produced an improvement in attention by reducing errors on an attention task, but it had no effect on memory. More specifically, a tendency to reduce errors of omission (Go trials) during the Go/No-Go Task was observed after treatment. These findings, along with our previous results in impulsivity, underline the relevance of using probiotics as a therapeutic option in FMS, although more research with a larger sample size is required. 10.3390/ijerph18073543
    Randomised clinical trial: linaclotide vs placebo-a study of bi-directional gut and brain axis. Rao Satish S C,Xiang Xuelian,Yan Yun,Rattanakovit Kulthep,Patcharatrakul Tanisa,Parr Rachael,Ayyala Deepak,Sharma Amol Alimentary pharmacology & therapeutics BACKGROUND:Linaclotide, a guanylate cyclase C agonist relieves irritable bowel syndrome with predominant constipation (IBS-C) symptoms, but how it improves pain in humans is unknown. AIMS:To investigate the effects of linaclotide and placebo on the afferent and efferent gut-brain-gut signalling in IBS-C patients, in a randomised clinical trial. METHODS:Patients with IBS-C (Rome III) and rectal hypersensitivity were randomised (2:1) to receive linaclotide (290 µg) or placebo for 10 weeks and undergo bi-directional gut and brain axis assessment using anorectal electrical stimulations and transcranial/transspinal-anorectal magnetic stimulations. Rectal sensations were examined by balloon distention. Assessments included abdominal pain, bowel symptoms and quality of life (QOL) scores. Primary outcomes were latencies of recto-cortical and cortico-rectal evoked potentials. RESULTS:Thirty-nine patients participated; 26 received linaclotide and 13 received placebo. Rectal cortical evoked potentials latencies (milliseconds) were significantly prolonged with linaclotide compared to baseline (P1:Δ 19 ± 6, P < 0.005; N1:Δ 20 ± 7, P < 0.02) but not with placebo (P1:Δ 3 ± 5; N1:Δ 4.7 ± 5,P = 0.3) or between groups. The efferent cortico-anorectal and spino-anorectal latencies were unchanged. The maximum tolerable rectal volume (cc) increased significantly with linaclotide compared to baseline (P < 0.001) and placebo (Δ 29 ± 10 vs 4 ± 20, (P < 0.03). Abdominal pain decreased (P < 0.001) with linaclotide but not between groups. Complete spontaneous bowel movement frequency increased (P < 0.001), and IBS-QOL scores improved (P = 0.01) with linaclotide compared to baseline and placebo. There was no difference in overall responders between linaclotide and placebo (54% vs 23%, P = 0.13). CONCLUSIONS:Linaclotide prolongs afferent gut-brain signalling from baseline but both afferent and efferent signalling were unaffected compared to placebo. Linaclotide significantly improves rectal hypersensitivity, IBS-C symptoms and QOL compared to placebo. These mechanisms may explain the effects of linaclotide on pain relief in IBS-C patients. ClinicalTrials.Gov: Registered at Clinical trials.gov no NCT02078323. 10.1111/apt.15772
    Irritable bowel syndrome. Ford Alexander C,Sperber Ami D,Corsetti Maura,Camilleri Michael Lancet (London, England) Irritable bowel syndrome is a functional gastrointestinal disorder with symptoms including abdominal pain associated with a change in stool form or frequency. The condition affects between 5% and 10% of otherwise healthy individuals at any one point in time and, in most people, runs a relapsing and remitting course. The best described risk factor is acute enteric infection, but irritable bowel syndrome is also more common in people with psychological comorbidity and in young adult women than in the rest of the general population. The pathophysiology of irritable bowel syndrome is incompletely understood, but it is well established that there is disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and altered CNS processing. Other less reproducible mechanisms might include genetic associations, alterations in gastrointestinal microbiota, and disturbances in mucosal and immune function. In most people, diagnosis can be made on the basis of clinical history with limited and judicious use of investigations, unless alarm symptoms such as weight loss or rectal bleeding are present, or there is a family history of inflammatory bowel disease or coeliac disease. Once the diagnosis is made, an empathetic approach is key and can improve quality of life and symptoms, and reduce health-care expenditure. The mainstays of treatment include patient education about the condition, dietary changes, soluble fibre, and antispasmodic drugs. Other treatments tend to be reserved for people with severe symptoms and include central neuromodulators, intestinal secretagogues, drugs acting on opioid or 5-HT receptors, or minimally absorbed antibiotics (all of which are selected according to predominant bowel habit), as well as psychological therapies. Increased understanding of the pathophysiology of irritable bowel syndrome in the past 10 years has led to a healthy pipeline of novel drugs in development. 10.1016/S0140-6736(20)31548-8
    Gut microbiota and its role in stress-induced hyperalgesia: Gender-specific responses linked to different changes in serum metabolites. Pharmacological research Long-term stress causes hyperalgesia; and there are gender differences in the mechanism of pain in male and female individuals. The role of gut microbiota in pain has also been verified. However, whether gut microbiota plays a role in hyperalgesia caused by chronic restraint stress (CRS) with gender differences has not been explored. This study investigated the role of gut microbiota in CRS-induced hyperalgesia gender-specifically through 16 S ribosomal RNA (16 S rRNA) gene sequencing and untargeted metabolomic analysis using liquid chromatography-mass spectrometry (LC-MS). The study found that both male and female mice experienced hyperalgesia after CRS and antibiotic treatment. 16 S rRNA gene sequencing reveals gender differences in the fecal microbiota induced by CRS. The pain threshold decreased after transplanting the fecal microbiota from the male and female CRS group to the corresponding pseudo-germ-free mice. In addition, this study detected gender differences in the host gut microbiota and serum metabolism induced by fecal microbiota transplantation (FMT). Specifically, the different serum metabolites between the pseudo-germ-free mice receiving FMT from the CRS group and those from the control group were mainly involved in bile secretion and steroid hormone biosynthesis for male mice, and in taurine and hypotaurine metabolism and tryptophan metabolism for female mice. In summary, the gut microbiota participates in stress-induced hyperalgesia (SIH) with gender differences by influencing the host's gut microbiota composition and serum metabolism. Therefore, our findings provided insights into developing novel gut microbiota-associated drugs for the management of gender-specific SIH. 10.1016/j.phrs.2022.106129
    Effect of ancient Khorasan wheat on gut microbiota, inflammation, and short-chain fatty acid production in patients with fibromyalgia. World journal of gastroenterology BACKGROUND:Fibromyalgia (FM) syndrome is mainly characterized by widespread pain, sleeping disorders, fatigue, and cognitive dysfunction. In many cases, gastrointestinal distress is also reported, suggesting the potential pathogenic role of the gut microbiota (GM). The GM is deeply influenced by several environmental factors, especially the diet, and recent findings highlighted significant symptom improvement in FM patients following various nutritional interventions such as vegetarian diet, low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols based diets, gluten-free diet, and especially an ancient grain supplementation. In particular, a recent study reported that a replacement diet with ancient Khorasan wheat led to an overall improvement in symptom severity of FM patients. AIM:To examine the effects of ancient Khorasan wheat on the GM, inflammation, and short-chain fatty acid production in FM patients. METHODS:After a 2-wk run-in period, 20 FM patients were enrolled in this randomized, double-blind crossover trial. In detail, they were assigned to consume either Khorasan or control wheat products for 8 wk and then, following an 8-wk washout period, crossed. Before and after treatments, GM characterization was performed by 16S rRNA sequencing while the fecal molecular inflammatory response and the short-chain fatty acids (SCFAs) were respectively determined with the Luminex MAGPIX detection system and a mass chromatography-mass spectrometry method. RESULTS:The Khorasan wheat replacement diet, in comparison with the control wheat diet, had more positive effects on intestinal microbiota composition and on both the fecal immune and SCFAs profiles such as the significant increase of butyric acid levels ( = 0.054), candidatus ( = 9.95e-06) and , and the reduction of ( = 4.97e-04). Moreover, the improvement of various FM symptoms along with the variation of some gut bacteria after the Khorasan wheat diet have been documented; in fact we reported positive correlations between and both Tiredness Symptoms Scale ( < 0.001) and Functional Outcome of Sleep Questionnaire ( < 0.05) scores, between and both Widespread Pain Index (WPI) + Symptom Severity scale (SS) ( < 0.05) and WPI ( < 0.05) scores, between candidatus and SS score ( < 0.05), and between and Sleep-Related and Safety Behaviour Questionnaire score ( < 0.05). CONCLUSION:The replacement diet based on ancient Khorasan wheat results in beneficial GM compositional and functional modifications that positively correlate with an improvement of FM symptomatology. 10.3748/wjg.v28.i18.1965
    Mechanisms of Stress-Induced Visceral Pain: Implications in Irritable Bowel Syndrome. Greenwood-Van Meerveld B,Moloney R D,Johnson A C,Vicario M Journal of neuroendocrinology Visceral pain is a term describing pain originating from the internal organs of the body and is a common feature of many disorders, including irritable bowel syndrome (IBS). Stress is implicated in the development and exacerbation of many visceral pain disorders. Recent evidence suggests that stress and the gut microbiota can interact through complementary or opposing factors to influence visceral nociceptive behaviours. The Young Investigator Forum at the International Society of Psychoneuroendocrinology (ISPNE) annual meeting reported experimental evidence suggesting the gut microbiota can affect the stress response to affect visceral pain. Building upon human imaging data showing abnormalities in the central processing of visceral stimuli in patients with IBS and knowledge that the amygdala plays a pivotal role in facilitating the stress axis, the latest experimental evidence supporting amygdala-mediated mechanisms in stress-induced visceral pain was reviewed. The final part of the session at ISPNE reviewed experimental evidence suggesting that visceral pain in IBS may be a result, at least in part, of afferent nerve sensitisation following increases in epithelial permeability and mucosal immune activation. 10.1111/jne.12361
    The gut-brain axis and beyond: Microbiome control of spinal cord injury pain in humans and rodents. Bannerman Courtney A,Douchant Katya,Sheth Prameet M,Ghasemlou Nader Neurobiology of pain (Cambridge, Mass.) Spinal cord injury (SCI) is a devastating injury to the central nervous system in which 60 to 80% of patients experience chronic pain. Unfortunately, this pain is notoriously difficult to treat, with few effective options currently available. Patients are also commonly faced with various compounding injuries and medical challenges, often requiring frequent hospitalization and antibiotic treatment. Change in the gut microbiome from the "normal" state to one of imbalance, referred to as gut dysbiosis, has been found in both patients and rodent models following SCI. Similarities exist in the bacterial changes observed after SCI and other diseases with chronic pain as an outcome. These changes cause a shift in the regulation of inflammation, causing immune cell activation and secretion of inflammatory mediators that likely contribute to the generation/maintenance of SCI pain. Therefore, correcting gut dysbiosis may be used as a tool towards providing patients with effective pain management and improved quality of life. 10.1016/j.ynpai.2020.100059
    Food for thought about the immune drivers of gut pain. Brierley Stuart M Nature 10.1038/d41586-020-03661-y
    Changes in Gut and Plasma Microbiome following Exercise Challenge in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Shukla Sanjay K,Cook Dane,Meyer Jacob,Vernon Suzanne D,Le Thao,Clevidence Derek,Robertson Charles E,Schrodi Steven J,Yale Steven,Frank Daniel N PloS one Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disease characterized by intense and debilitating fatigue not due to physical activity that has persisted for at least 6 months, post-exertional malaise, unrefreshing sleep, and accompanied by a number of secondary symptoms, including sore throat, memory and concentration impairment, headache, and muscle/joint pain. In patients with post-exertional malaise, significant worsening of symptoms occurs following physical exertion and exercise challenge serves as a useful method for identifying biomarkers for exertion intolerance. Evidence suggests that intestinal dysbiosis and systemic responses to gut microorganisms may play a role in the symptomology of ME/CFS. As such, we hypothesized that post-exertion worsening of ME/CFS symptoms could be due to increased bacterial translocation from the intestine into the systemic circulation. To test this hypothesis, we collected symptom reports and blood and stool samples from ten clinically characterized ME/CFS patients and ten matched healthy controls before and 15 minutes, 48 hours, and 72 hours after a maximal exercise challenge. Microbiomes of blood and stool samples were examined. Stool sample microbiomes differed between ME/CFS patients and healthy controls in the abundance of several major bacterial phyla. Following maximal exercise challenge, there was an increase in relative abundance of 6 of the 9 major bacterial phyla/genera in ME/CFS patients from baseline to 72 hours post-exercise compared to only 2 of the 9 phyla/genera in controls (p = 0.005). There was also a significant difference in clearance of specific bacterial phyla from blood following exercise with high levels of bacterial sequences maintained at 72 hours post-exercise in ME/CFS patients versus clearance in the controls. These results provide evidence for a systemic effect of an altered gut microbiome in ME/CFS patients compared to controls. Upon exercise challenge, there were significant changes in the abundance of major bacterial phyla in the gut in ME/CFS patients not observed in healthy controls. In addition, compared to controls clearance of bacteria from the blood was delayed in ME/CFS patients following exercise. These findings suggest a role for an altered gut microbiome and increased bacterial translocation following exercise in ME/CFS patients that may account for the profound post-exertional malaise experienced by ME/CFS patients. 10.1371/journal.pone.0145453
    What's in the pipeline for lower functional gastrointestinal disorders in the next 5 years? Camilleri Michael American journal of physiology. Gastrointestinal and liver physiology The overall objectives of this review are to summarize actionable biomarkers for organic etiology of lower functional gastrointestinal disorders (FGIDs) that lead to individualized treatment for their FGIDs and to assess the pipeline for novel approaches to the management of constipation, diarrhea, and chronic abdominal pain in lower FGIDs. The new approaches to therapy include ion exchangers/transporters for functional constipation (sodium-glucose cotransporter 1, Na/H exchanger 3, and solute carrier family 26 member 3 inhibitors), bile acid modulators for constipation such as ileal bile acid transporter inhibitors and fibroblast growth factor 19 analog for functional constipation, and bile acid sequestrants or farnesoid X receptor agonists for functional diarrhea. Treatment for chronic abdominal pain remains an unmet need in patients with lower FGIDs, and promising novel approaches include delayed-release linaclotide, nonclassical opioid visceral analgesics, and selective cannabinoid receptor agonists. The role of probiotics, fecal microbial transplantation, and possible future microbiome therapies is discussed. 10.1152/ajpgi.00205.2019
    Spinal cord injury in mice affects central and peripheral pathology in a severity-dependent manner. Pain ABSTRACT:Chronic pain is a common medical complication experienced by those living with spinal cord injury (SCI) and leads to worsened quality of life. The pathophysiology of SCI pain is poorly understood, hampering the development of safe and efficacious therapeutics. We therefore sought to develop a clinically relevant model of SCI with a strong pain phenotype and characterize the central and peripheral pathology after injury. A contusion (50 kdyn) injury, with and without sustained compression (60 seconds) of the spinal cord, was performed on female C57BL/6J mice. Mice with compression of the spinal cord exhibited significantly greater heat and mechanical hypersensitivity starting at 7 days postinjury, concomitant with reduced locomotor function, compared with those without compression. Immunohistochemical analysis of spinal cord tissue revealed significantly less myelin sparing and increased macrophage activation in mice with compression compared with those without. As measured by flow cytometry, immune cell infiltration and activation were significantly greater in the spinal cord (phagocytic myeloid cells and microglia) and dorsal root ganglia (Ly6C+ monocytes) after compression injury. We also decided to investigate the gastrointestinal microbiome, as it has been shown to be altered in patients with SCI and has recently been shown to play a role in immune system maturation and pain. We found increased dysbiosis of the gastrointestinal microbiome in an injury severity-dependent manner. The use of this contusion-compression model of SCI may help advance the preclinical assessment of acute and chronic SCI pain and lead to a better understanding of mechanisms contributing to this pain. 10.1097/j.pain.0000000000002471
    Gut Microbiota Influences Neuropathic Pain Through Modulating Proinflammatory and Anti-inflammatory T Cells: Erratum. Anesthesia and analgesia 10.1213/ANE.0000000000006043
    Tryptophan Metabolism and Gut-Brain Homeostasis. Roth William,Zadeh Kimia,Vekariya Rushi,Ge Yong,Mohamadzadeh Mansour International journal of molecular sciences Tryptophan is an essential amino acid critical for protein synthesis in humans that has emerged as a key player in the microbiota-gut-brain axis. It is the only precursor for the neurotransmitter serotonin, which is vital for the processing of emotional regulation, hunger, sleep, and pain, as well as colonic motility and secretory activity in the gut. Tryptophan catabolites from the kynurenine degradation pathway also modulate neural activity and are active in the systemic inflammatory cascade. Additionally, tryptophan and its metabolites support the development of the central and enteric nervous systems. Accordingly, dysregulation of tryptophan metabolites plays a central role in the pathogenesis of many neurologic and psychiatric disorders. Gut microbes influence tryptophan metabolism directly and indirectly, with corresponding changes in behavior and cognition. The gut microbiome has thus garnered much attention as a therapeutic target for both neurologic and psychiatric disorders where tryptophan and its metabolites play a prominent role. In this review, we will touch upon some of these features and their involvement in health and disease. 10.3390/ijms22062973
    A sexual advantage for pain in the gut? Costa Marcello The Journal of physiology 10.1113/JP281194
    Gut pain sensors help to combat infection. Gerner Romana R,Raffatellu Manuela Nature 10.1038/d41586-020-01105-1
    Pivotal role of the gut microbiota in congenital insensitivity to pain with anhidrosis. Zhang Mi,Hong Yishun,Wu Wenyao,Li Ningbo,Liu Baowen,Sun Jiaoli,Cao Xueqin,Ye Ting,Zhou Ling,Liu Cunming,Yang Chun,Zhang Xianwei Psychopharmacology BACKGROUND:Increasing evidence has shown that the occurrence and development of various human diseases are closely related to the gut microbiota. We compared the gut microbial communities of human subjects with congenital insensitivity to pain with anhidrosis (CIPA) and healthy controls (HCs) to assess whether fecal microbiota transplantation (FMT) into germ-free mice and mice in acute pain influenced the behaviors of the host. METHODS:We utilized 16 s rRNA analysis to compare the gut microbial communities of CIPA subjects and HCs and assessed whether FMT into germ-free mice and mice in acute pain influenced the behaviors of the host. RESULTS:In a 16 s RNA analysis, the CIPA group had significant decreases in the relative abundance of 11 bacteria, whereas 7 bacteria were significantly increased. In further animal experiments, the transplantation of fecal samples from CIPA patients to healthy mice significantly increased their scores on both the mechanical withdrawal test and the tail flick test; in an acute plantar incision model, scores were also significantly increased on the mechanical withdrawal test at 4 and 5 days after the operation. Moreover, pseudo-germ-free mice receiving fecal bacteria from patients with CIPA took significantly longer to escape and had a significantly longer path length on training days 1, 2, and 5 and also had fewer platform crossings and spent less time in the target quadrant in the probe trial. CONCLUSIONS:Our results suggest that the gut microbiota in CIPA subjects plays a key role in behaviors. Therapeutic strategies for improving the gut microbiota might alleviate CIPA symptoms. 10.1007/s00213-021-05930-8
    Paediatric functional abdominal pain disorders. Thapar Nikhil,Benninga Marc A,Crowell Michael D,Di Lorenzo Carlo,Mack Isabelle,Nurko Samuel,Saps Miguel,Shulman Robert J,Szajewska Hania,van Tilburg Miranda A L,Enck Paul Nature reviews. Disease primers Paediatric functional abdominal pain disorders, currently referred to as disorders of gut-brain interaction, comprise irritable bowel syndrome, functional dyspepsia, abdominal migraine and functional abdominal pain not otherwise specified, as defined by the Rome IV diagnostic criteria. Functional abdominal pain disorders are common disorders with a prevalence of 3-16% depending on country, age and sex. A greater understanding of aetiopathogenesis and pathophysiology is emerging and includes intestinal components (inflammation, motility and the microbiota), central factors (psychological aspects, sensitization and/or differences in connectivity or activity of certain brain regions) as well as extrinsic factors (infections). In particular, the timing of disruption of the microbiota-gut-brain axis seems to be important. Diagnosis is challenging but is primarily based on clinical symptoms and exclusion of other organic causes, with an emphasis on avoiding unnecessary invasive diagnostic procedures. The available pharmacological interventions are limited in children and, therefore, management has focused on combined approaches, including mind-targeted interventions (hypnotherapy and cognitive behavioural therapy), diet (probiotics) and percutaneous electrical nerve field stimulation. The evidence for their clinical efficacy, although limited, is favourable, with positive impacts on symptoms and overall quality of life. The coming decades hold promise for improved understanding and management of these enigmatic disorders. 10.1038/s41572-020-00222-5
    Key role of gut microbiota in anhedonia-like phenotype in rodents with neuropathic pain. Yang Chun,Fang Xi,Zhan Gaofeng,Huang Niannian,Li Shan,Bi Jiangjiang,Jiang Riyue,Yang Ling,Miao Liying,Zhu Bin,Luo Ailin,Hashimoto Kenji Translational psychiatry Patients with chronic neuropathic pain frequently suffer from symptoms of anhedonia, which is a core symptom of depression. Accumulating studies suggest that gut microbiota may play a role in depression via gut-microbiota-brain axis. However, it is unknown whether gut microbiota plays a role in neuropathic pain-associated anhedonia. Here, we used a rat model of spared nerve injury (SNI). Hierarchical cluster analysis of sucrose preference test (SPT) results was used to classify the SNI rats with or without anhedonia-like phenotype. The 16S ribosomal RNA sequencing analysis showed abnormal composition of gut microbiota in the anhedonia susceptible compared to sham-operated rats and resilient rats. Furthermore, antibiotics-treated mice showed pain as well as depression-like and anhedonia-like phenotypes, suggesting a role of gut microbiota in these abnormal behaviors. Transplantation of fecal microbiota from anhedonia susceptible rats into antibiotics-treated pseudo-germ-free mice significantly exaggerated pain and depression-like phenotypes, including anhedonia. In contrast, transplantation of fecal microbiota from resilient rats into antibiotics-treated pseudo-germ-free mice significantly improved pain and depression-like phenotypes, including anhedonia. In conclusion, this study suggests that abnormal composition of gut microbiota may contribute to anhedonia susceptibility post SNI surgery, and that gut microbiota also plays a role in the pain as well as depression-like phenotypes. Interestingly, fecal microbiota transplantation from SNI rats with or without anhedonia can alter pain, depression-like and anhedonia-like phenotypes in the pseudo-germ-free mice. Therefore, it is likely that gut microbiota plays a key role in the pain as well as depression-like phenotypes including anhedonia in rodents with neuropathic pain. 10.1038/s41398-019-0379-8
    GABA-producing Bifidobacterium dentium modulates visceral sensitivity in the intestine. Pokusaeva K,Johnson C,Luk B,Uribe G,Fu Y,Oezguen N,Matsunami R K,Lugo M,Major A,Mori-Akiyama Y,Hollister E B,Dann S M,Shi X Z,Engler D A,Savidge T,Versalovic J Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society BACKGROUND:Recurrent abdominal pain is a common and costly health-care problem attributed, in part, to visceral hypersensitivity. Increasing evidence suggests that gut bacteria contribute to abdominal pain perception by modulating the microbiome-gut-brain axis. However, specific microbial signals remain poorly defined. γ-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter and a key regulator of abdominal and central pain perception from peripheral afferent neurons. Although gut bacteria are reported to produce GABA, it is not known whether the microbial-derived neurotransmitter modulates abdominal pain. METHODS:To investigate the potential analgesic effects of microbial GABA, we performed daily oral administration of a specific Bifidobacterium strain (B. dentiumATCC 27678) in a rat fecal retention model of visceral hypersensitivity, and subsequently evaluated pain responses. KEY RESULTS:We demonstrate that commensal Bifidobacterium dentium produces GABA via enzymatic decarboxylation of glutamate by GadB. Daily oral administration of this specific Bifidobacterium (but not a gadB deficient) strain modulated sensory neuron activity in a rat fecal retention model of visceral hypersensitivity. CONCLUSIONS & INFERENCES:The functional significance of microbial-derived GABA was demonstrated by gadB-dependent desensitization of colonic afferents in a murine model of visceral hypersensitivity. Visceral pain modulation represents another potential health benefit attributed to bifidobacteria and other GABA-producing species of the intestinal microbiome. Targeting GABAergic signals along this microbiome-gut-brain axis represents a new approach for the treatment of abdominal pain. 10.1111/nmo.12904
    Dominant Role of the Gut Microbiota in Chemotherapy Induced Neuropathic Pain. Scientific reports Chemotherapy induced peripheral neuropathy (CIPN), a toxic side effect of some cancer treatments, negatively impacts patient outcomes and drastically reduces survivor's quality of life (QOL). Uncovering the mechanisms driving chemotherapy-induced CIPN is urgently needed to facilitate the development of effective treatments, as currently there are none. Observing that C57BL/6 (B6) and 129SvEv (129) mice are respectively sensitive and resistant to Paclitaxel-induced pain, we investigated the involvement of the gut microbiota in this extreme phenotypic response. Reciprocal gut microbiota transfers between B6 and 129 mice as well as antibiotic depletion causally linked gut microbes to Paclitaxel-induced pain sensitivity and resistance. Microglia proliferated in the spinal cords of Paclitaxel treated mice harboring the pain-sensitive B6 microbiota but not the pain-resistant 129 microbiota, which exhibited a notable absence of infiltrating immune cells. Paclitaxel decreased the abundance of Akkermansia muciniphila, which could compromise barrier integrity resulting in systemic exposure to bacterial metabolites and products - that acting via the gut-immune-brain axis - could result in altered brain function. Other bacterial taxa that consistently associated with both bacteria and pain as well as microglia and pain were identified, lending support to our hypothesis that microglia are causally involved in CIPN, and that gut bacteria are drivers of this phenotype. 10.1038/s41598-019-56832-x
    Integrative neuromuscular medicine: Neuropathy and neuropathic pain: Consider the alternatives. Rowin Julie Muscle & nerve Complementary and alternative treatment modalities are commonly utilized by patients for neuropathy and neuropathic pain due to perceived lack of benefit from conventional medical treatment. As the association between metabolic syndrome and neuropathy is increasingly recognized, diet and lifestyle interventions are becoming important components in the management of neuropathy. Progress in the understanding of the gut-immune interaction highlights the role the gut microbiome and inflammation plays in the modulation of neuropathy and neuropathic pain. Evidence for nutritional interventions, exercise, supplements, acupuncture, and mindfulness-based practices in the treatment of neuropathic pain is encouraging. This article reviews the available evidence to support the safe use of complementary and alternative treatments for commonly encountered conditions associated with neuropathy and neuropathic pain. Muscle Nerve 60: 124-136, 2019. 10.1002/mus.26510
    The gut microbiota as a key regulator of visceral pain. O' Mahony Siobhain M,Dinan Timothy G,Cryan John F Pain 10.1097/j.pain.0000000000000779
    Gut microbiota regulates neuropathic pain: potential mechanisms and therapeutic strategy. Lin Binbin,Wang Yuting,Zhang Piao,Yuan Yanyan,Zhang Ying,Chen Gang The journal of headache and pain Neuropathic pain (NP) is a sustained and nonreversible condition characterized by long-term devastating physical and psychological damage. Therefore, it is urgent to identify an effective treatment for NP. Unfortunately, the precise pathogenesis of NP has not been elucidated. Currently, the microbiota-gut-brain axis has drawn increasing attention, and the emerging role of gut microbiota is investigated in numerous diseases including NP. Gut microbiota is considered as a pivotal regulator in immune, neural, endocrine, and metabolic signaling pathways, which participates in forming a complex network to affect the development of NP directly or indirectly. In this review, we conclude the current understanding of preclinical and clinical findings regarding the role of gut microbiota in NP and provide a novel therapeutic method for pain relief by medication and dietary interventions. 10.1186/s10194-020-01170-x
    Stress and the Microbiota-Gut-Brain Axis in Visceral Pain: Relevance to Irritable Bowel Syndrome. Moloney Rachel D,Johnson Anthony C,O'Mahony Siobhain M,Dinan Timothy G,Greenwood-Van Meerveld Beverley,Cryan John F CNS neuroscience & therapeutics Visceral pain is a global term used to describe pain originating from the internal organs of the body, which affects a significant proportion of the population and is a common feature of functional gastrointestinal disorders (FGIDs) such as irritable bowel syndrome (IBS). While IBS is multifactorial, with no single etiology to completely explain the disorder, many patients also experience comorbid behavioral disorders, such as anxiety or depression; thus, IBS is described as a disorder of the gut-brain axis. Stress is implicated in the development and exacerbation of visceral pain disorders. Chronic stress can modify central pain circuitry, as well as change motility and permeability throughout the gastrointestinal (GI) tract. More recently, the role of the gut microbiota in the bidirectional communication along the gut-brain axis, and subsequent changes in behavior, has emerged. Thus, stress and the gut microbiota can interact through complementary or opposing factors to influence visceral nociceptive behaviors. This review will highlight the evidence by which stress and the gut microbiota interact in the regulation of visceral nociception. We will focus on the influence of stress on the microbiota and the mechanisms by which microbiota can affect the stress response and behavioral outcomes with an emphasis on visceral pain. 10.1111/cns.12490
    Microbiota regulates visceral pain in the mouse. Luczynski Pauline,Tramullas Monica,Viola Maria,Shanahan Fergus,Clarke Gerard,O'Mahony Siobhain,Dinan Timothy G,Cryan John F eLife The perception of visceral pain is a complex process involving the spinal cord and higher order brain structures. Increasing evidence implicates the gut microbiota as a key regulator of brain and behavior, yet it remains to be determined if gut bacteria play a role in visceral sensitivity. We used germ-free mice (GF) to assess visceral sensitivity, spinal cord gene expression and pain-related brain structures. GF mice displayed visceral hypersensitivity accompanied by increases in Toll-like receptor and cytokine gene expression in the spinal cord, which were normalized by postnatal colonization with microbiota from conventionally colonized (CC). In GF mice, the volumes of the anterior cingulate cortex (ACC) and periaqueductal grey, areas involved in pain processing, were decreased and enlarged, respectively, and dendritic changes in the ACC were evident. These findings indicate that the gut microbiota is required for the normal visceral pain sensation. 10.7554/eLife.25887
    Nutritional intervention in chronic pain: an innovative way of targeting central nervous system sensitization? Nijs Jo,Tumkaya Yilmaz Sevilay,Elma Ömer,Tatta Joe,Mullie Patrick,Vanderweeën Luc,Clarys Peter,Deliens Tom,Coppieters Iris,Weltens Nathalie,Van Oudenhove Lukas,Huysmans Eva,Malfliet Anneleen Expert opinion on therapeutic targets INTRODUCTION:Few treatment programs for chronic pain nowadays take a dietary pattern or adipose status into account. AREAS COVERED:An important role of neuroinflammation in chronic pain is now well established, at least in part due to increased central nervous system glial activation. Based on preclinical studies, it is postulated that the interaction between nutrition and central sensitization is mediated via bidirectional gut-brain interactions. This model of diet-induced neuroinflammation and consequent central sensitization generates a rationale for developing innovative treatments for patients with chronic pain. Methods: An umbrella approach to cover the authors' expert opinion within an evidence-based viewpoint. EXPERT OPINION:A low-saturated fat and low-added sugar dietary pattern potentially decreases oxidative stress, preventing Toll-like receptor activation and subsequent glial activation. A low-saturated fat and low-added sugar diet might also prevent afferent vagal nerve fibers sensing the pro-inflammatory mediators that come along with a high-(saturated) fat or energy-dense dietary pattern, thereby preventing them to signal peripheral inflammatory status to the brain. In addition, the gut microbiota produces polyamines, which hold the capacity to excite N-methyl-D-aspartate receptors, an essential component of the central nervous system sensitization. Hence, a diet reducing polyamine production by the gut microbiota requires exploration as a therapeutic target for cancer-related and non-cancer chronic pain. 10.1080/14728222.2020.1784142
    Human milk oligosaccharides alleviate stress-induced visceral hypersensitivity and associated microbiota dysbiosis. Ferrier Laurent,Eutamène Hélène,Siegwald Léa,Marquard Andrea M,Tondereau Valerie,Chevalier Julien,Jacot Guillaume E,Favre Laurent,Theodorou Vassilia,Vicario Maria,Rytz Andreas,Bergonzelli Gabriela,Garcia-Rodenas Clara L The Journal of nutritional biochemistry Pain-related functional gastrointestinal disorders (FGIDs) are characterized by visceral hypersensitivity (VHS) associated with alterations in the microbiota-gut-brain axis. Since human milk oligosaccharides (HMOs) modulate microbiota, gut and brain, we investigated whether HMOs impact VHS, and explored the role of gut microbiota. To induce VHS, C57BL/6JRj mice received hourly water avoidance stress (WAS) sessions for 10 d, or antibiotics (ATB) for 12 d. Challenged and unchallenged (Sham) animals were fed AIN93M diet (Cont) or AIN93M containing 1% of a 6-HMO mix (HMO6). VHS was assessed by monitoring the visceromotor response to colorectal distension. Fecal microbiome was analyzed by shotgun metagenomics. The effect of HMO6 sub-blends on VHS and nociceptive pathways was further tested using the WAS model. In mice fed Cont, WAS and ATB increased the visceromotor response to distension. HMO6 decreased WAS-mediated electromyographic rise at most distension volumes and overall Area Under Curve (AUC=6.12±0.50 in WAS/HMO6 vs. 9.46±0.50 in WAS/Cont; P<.0001). In contrast, VHS in ATB animals was not improved by HMO6. In WAS, HMO6 promoted most microbiota taxa and several functional pathways associated with low VHS and decreased those associated with high VHS. Among the sub-blends, 2'FL+DFL and LNT+6'SL reduced visceromotor response close to Sham/Cont values and modulated serotoninergic and CGRPα-related pathways. This research further substantiates the capacity of HMOs to modulate the microbiota-gut-brain communication and identifies mitigation of abdominal pain as a new HMO benefit. Ultimately, our findings suggest the value of specific HMO blends to alleviate pain associated FGIDs such as infantile colic or Irritable Bowel Syndrome. 10.1016/j.jnutbio.2021.108865
    Deciphering the Role of Human Gastrointestinal Microbiota in the Pathogenesis of Vaginal Infection and Cervical Cancer. Wang Jingyi,Yang Zhiling,Li Wen Journal of environmental pathology, toxicology and oncology : official organ of the International Society for Environmental Toxicology and Cancer The human microbiota typically contains symbionts and supports the host, although it can be commensal or reciprocal and pathogenic in its host function, immunity, and diet. Modern studies indicate that perturbations in the microbiome may be present in quite a few diseases, including inflammation and cancer. To be more specific, changes in the microbiomes of the gut and vagina may be related to various gynecologic cancers (cervical, uterine, and ovarian). Furthermore, the gastrointestinal microbiota can be altered by environmental factors and pre-existing morbidities and may cause nausea, vomiting, diarrhea, constipation, bloating, and abdominal pain. A healthy female gut microbiome is dominated by Bifidobacterium, Lactobacillus, Bacteroides, Clostridium, Escherichia, Streptococcus, and Ruminococcus; the vaginal microbiome includes Firmicutes, specifically Lactobacilli spp. However, the gram-variable coccobacillus Gardnerella vaginalis (previously known as Haemophilus vaginalis) dominates the microbiota of biological vaginosis (BV) and includes several anaerobic organisms. Vaginal microbiota perturbations can cause vaginal pain, sexual dysfunction, and urinary symptoms. In the current review paper, we explore recent research along with existing gaps in knowledge related to the association of changes in microbiota diversity and the pathogenesis of vaginal infection-associated cervical cancer. 10.1615/JEnvironPatholToxicolOncol.2020035637
    Altered gut microbiota and endocannabinoid system tone in vitamin D deficiency-mediated chronic pain. Guida Francesca,Boccella Serena,Belardo Carmela,Iannotta Monica,Piscitelli Fabiana,De Filippis Francesca,Paino Salvatore,Ricciardi Flavia,Siniscalco Dario,Marabese Ida,Luongo Livio,Ercolini Danilo,Di Marzo Vincenzo,Maione Sabatino Brain, behavior, and immunity Recent evidence points to the gut microbiota as a regulator of brain and behavior, although it remains to be determined if gut bacteria play a role in chronic pain. The endocannabinoid system is implicated in inflammation and chronic pain processing at both the gut and central nervous system (CNS) levels. In the present study, we used low Vitamin D dietary intake in mice and evaluated possible changes in gut microbiota, pain processing and endocannabinoid system signaling. Vitamin D deficiency induced a lower microbial diversity characterized by an increase in Firmicutes and a decrease in Verrucomicrobia and Bacteroidetes. Concurrently, vitamin D deficient mice showed tactile allodynia associated with neuronal hyperexcitability and alterations of endocannabinoid system members (endogenous mediators and their receptors) at the spinal cord level. Changes in endocannabinoid (anandamide and 2-arachidonoylglycerol) levels were also observed in the duodenum and colon. Remarkably, the anti-inflammatory anandamide congener, palmitoylethanolamide, counteracted both the pain behaviour and spinal biochemical changes in vitamin D deficient mice, whilst increasing the levels of Akkermansia, Eubacterium and Enterobacteriaceae, as compared with vehicle-treated mice. Finally, induction of spared nerve injury in normal or vitamin D deficient mice was not accompanied by changes in gut microbiota composition. Our data suggest the existence of a link between Vitamin D deficiency - with related changes in gut bacterial composition - and altered nociception, possibly via molecular mechanisms involving the endocannabinoid and related mediator signaling systems. 10.1016/j.bbi.2019.04.006
    Chronic Postoperative Pain and Microorganisms: The Good, the Bad, and the Ugly. Anesthesia and analgesia 10.1213/ANE.0000000000005769
    The Role of Bacteria and Its Derived Metabolites in Chronic Pain and Depression: Recent Findings and Research Progress. Li Shan,Hua Dongyu,Wang Qiaoyan,Yang Ling,Wang Xinlei,Luo Ailin,Yang Chun The international journal of neuropsychopharmacology BACKGROUND:Chronic pain is frequently comorbid with depression in clinical practice. Recently, alterations in gut microbiota and metabolites derived therefrom have been found to potentially contribute to abnormal behaviors and cognitive dysfunction via the "microbiota-gut-brain" axis. METHODS:PubMed was searched and we selected relevant studies before October 1, 2019. The search keyword string included "pain OR chronic pain" AND "gut microbiota OR metabolites"; "depression OR depressive disorder" AND "gut microbiota OR metabolites". We also searched the reference lists of key articles manually. RESULTS:This review systematically summarized the recent evidence of gut microbiota and metabolites in chronic pain and depression in animal and human studies. The results showed the pathogenesis and therapeutics of chronic pain and depression might be partially due to gut microbiota dysbiosis. Importantly, bacteria-derived metabolites, including short-chain fatty acids, tryptophan-derived metabolites, and secondary bile acids, offer new insights into the potential linkage between key triggers in gut microbiota and potential mechanisms of depression. CONCLUSION:Studying gut microbiota and its metabolites has contributed to the understanding of comorbidity of chronic pain and depression. Consequently, modulating dietary structures or supplementation of specific bacteria may be an available strategy for treating chronic pain and depression. 10.1093/ijnp/pyz061
    Animal models of visceral pain and the role of the microbiome. West Christine,McVey Neufeld Karen-Anne Neurobiology of pain (Cambridge, Mass.) Visceral pain refers to pain arising from the internal organs and is distinctly different from the expression and mechanisms of somatic pain. Diseases and disorders with increased visceral pain are associated with significantly reduced quality of life and incur large financial costs due to medical visits and lost work productivity. In spite of the notable burden of illness associated with those disorders involving increased visceral pain, and some knowledge regarding etiology, few successful therapeutics have emerged, and thus increased attention to animal models of visceral hypersensitivity is warranted in order to elucidate new treatment opportunities. Altered microbiota-gut-brain (MGB) axis communication is central to the comorbid gastrointestinal/psychiatric diseases of which increased visceral (intestinal) sensitivity is a hallmark. This has led to a particular focus on intestinal microbiome disruption and its potential role in the etiology of heightened visceral pain. Here we provide a review of studies examining models of heightened visceral pain due to altered bidirectional communication of the MGB axis, many of which are conducted on a background of stress exposure. We discuss work in which the intestinal microbiota has either been directly manipulated (as with germ-free, antibiotic, and fecal microbial transplantation studies) or indirectly affected through early life or adult stress, inflammation, and infection. Animal models of visceral pain alterations with accompanying changes to the intestinal microbiome have the highest face and construct validity to the human condition and are the focus of the current review. 10.1016/j.ynpai.2021.100064
    Gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy in the years 2000. Castagnola Elio,Ruberto Eliana,Guarino Alfredo World journal of gastroenterology AIM:To review gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy. To look at gut microflora features in oncology children. METHODS:We selected studies published after year 2000, excluding trials on transplanted pediatric patients. We searched English language publications in MEDLINE using the keywords: "gastrointestinal infection AND antineoplastic chemotherapy AND children", "gastrointestinal infection AND oncology AND children", "liver infection AND antineoplastic chemotherapy AND children", "liver abscess AND chemotherapy AND child", "neutropenic enterocolitis AND chemotherapy AND children", "thyphlitis AND chemotherapy AND children", "infectious diarrhea AND children AND oncology", "abdominal pain AND infection AND children AND oncology", "perianal sepsis AND children AND oncology", "colonic pseudo-obstruction AND oncology AND child AND chemotherapy", "microflora AND children AND malignancy", "microbiota AND children AND malignancy", "fungal flora AND children AND malignancy". We also analysed evidence from several articles and book references. RESULTS:Gastrointestinal and liver infections represent a major cause of morbidity and mortality in children undergoing antineoplastic chemotherapy. Antineoplastic drugs cause immunosuppression in addition to direct toxicity, predisposing to infections, although the specific risk is variable according to disease and host features. Common pathogens potentially induce severe diseases whereas opportunistic microorganisms may attack vulnerable hosts. Clinical manifestations can be subtle and not specific. In addition, several conditions are rare and diagnostic process and treatments are not standardized. Diagnosis may be challenging, however early diagnosis is needed for quick and appropriate interventions. Interestingly, the source of infection in those children can be exogenous or endogenous. Indeed, mucosal damage may allow the penetrance of endogenous microbes towards the bowel wall and their translocation into the bloodstream. However, only limited knowledge of intestinal dysbiosis in oncology children is available. CONCLUSION:The diagnostic work-up requires a multimodal approach and should be implemented (also by further studies on new biomarkers) for a prompt and individualized therapy. 10.3748/wjg.v22.i25.5853
    Altered Gut Microbiota Composition Is Associated With Back Pain in Overweight and Obese Individuals. Dekker Nitert Marloes,Mousa Aya,Barrett Helen L,Naderpoor Negar,de Courten Barbora Frontiers in endocrinology Back pain is the leading cause of disability worldwide and is associated with obesity and chronic low-grade inflammation. Alterations in intestinal microbiota may contribute to the pathogenesis of back pain through metabolites affecting immune and inflammatory responses. We compared the gut microbiota composition in a cohort of 36 overweight or obese individuals with or without self-reported back pain in the preceding month. Participants were characterized for anthropometry; bone health; metabolic health; inflammation; dietary intake; and physical activity. Demographic, clinical, biochemical characteristics, diet and physical activity were similar between participants with ( = 14) or without ( = 22) back pain. Individuals with back pain had a higher abundance of the genera ( = 0.0008; FDR = 0.027) ( = 0.0098; FDR = 0.17), and ( = 0.02; FDR = 0.27) than those without back pain. abundance remained higher in individuals with back pain in the past 2 weeks, 6 months, and 1 year. was positively correlated with BMI (rho = 0.35, = 0.03), serum adipsin (rho = 0.33, = 0.047), and serum leptin (rho = 0.38, = 0.02). Our findings suggest that back pain is associated with altered gut microbiota composition, possibly through increased inflammation. Further studies delineating the underlying mechanisms may identify strategies for lowering abundance to treat back pain. 10.3389/fendo.2020.00605
    A network approach to investigating the key microbes and stability of gut microbial communities in a mouse neuropathic pain model. Brandon-Mong Guo-Jie,Shaw Grace Tzun-Wen,Chen Wei-Hsin,Chen Chien-Chang,Wang Daryi BMC microbiology BACKGROUND:Neuropathic pain is an abnormally increased sensitivity to pain, especially from mechanical or thermal stimuli. To date, the current pharmacological treatments for neuropathic pain are still unsatisfactory. The gut microbiota reportedly plays important roles in inducing neuropathic pain, so probiotics have also been used to treat it. However, the underlying questions around the interactions in and stability of the gut microbiota in a spared nerve injury-induced neuropathic pain model and the key microbes (i.e., the microbes that play critical roles) involved have not been answered. We collected 66 fecal samples over 2 weeks (three mice and 11 time points in spared nerve injury-induced neuropathic pain and Sham groups). The 16S rRNA gene was polymerase chain reaction amplified, sequenced on a MiSeq platform, and analyzed using a MOTHUR- UPARSE pipeline. RESULTS:Here we show that spared nerve injury-induced neuropathic pain alters gut microbial diversity in mice. We successfully constructed reliable microbial interaction networks using the Metagenomic Microbial Interaction Simulator (MetaMIS) and analyzed these networks based on 177,147 simulations. Interestingly, at a higher resolution, our results showed that spared nerve injury-induced neuropathic pain altered both the stability of the microbial community and the key microbes in a gut micro-ecosystem. Oscillospira, which was classified as a low-abundance and core microbe, was identified as the key microbe in the Sham group, whereas Staphylococcus, classified as a rare and non-core microbe, was identified as the key microbe in the spared nerve injury-induced neuropathic pain group. CONCLUSIONS:In summary, our results provide novel experimental evidence that spared nerve injury-induced neuropathic pain reshapes gut microbial diversity, and alters the stability and key microbes in the gut. 10.1186/s12866-020-01981-7
    Alterations in the gut microbiota and metabolite profiles in the context of neuropathic pain. Chen Peng,Wang Chen,Ren Yan-Na,Ye Zeng-Jie,Jiang Chao,Wu Zhi-Bing Molecular brain The aim of this study was to explore the relationships among gut microbiota disturbances and serum and spinal cord metabolic disorders in neuropathic pain. 16S rDNA amplicon sequencing and serum and spinal cord metabolomics were used to identify alterations in the microbiota and metabolite profiles in the sham rats and the chronic constriction injury (CCI) model rats. Correlations between the abundances of gut microbiota components at the genus level, the levels of serum metabolites, and pain-related behavioural parameters were analysed. Ingenuity pathway analysis (IPA) was applied to analyse the interaction networks of the differentially expressed serum metabolites. First, we found that the composition of the gut microbiota was different between rats with CCI-induced neuropathic pain and sham controls. At the genus level, the abundances of Helicobacter, Phascolarctobacterium, Christensenella, Blautia, Streptococcus, Rothia and Lactobacillus were significantly increased, whereas the abundances of Ignatzschineria, Butyricimonas, Escherichia, AF12, and Corynebacterium were significantly decreased. Additionally, 72 significantly differentially expressed serum metabolites and 17 significantly differentially expressed spinal cord metabolites were identified between the CCI rats and the sham rats. Finally, correlation analysis showed that changes in the gut microbiota was significantly correlated with changes in serum metabolite levels, suggesting that dysbiosis of the gut microbiota is an important factor in modulating metabolic disturbances in the context of neuropathic pain. In conclusion, our research provides a novel perspective on the potential roles of the gut microbiota and related metabolites in neuropathic pain. 10.1186/s13041-021-00765-y
    Deepening the Mechanisms of Visceral Pain Persistence: An Evaluation of the Gut-Spinal Cord Relationship. Lucarini Elena,Parisio Carmen,Branca Jacopo J V,Segnani Cristina,Ippolito Chiara,Pellegrini Carolina,Antonioli Luca,Fornai Matteo,Micheli Laura,Pacini Alessandra,Bernardini Nunzia,Blandizzi Corrado,Ghelardini Carla,Di Cesare Mannelli Lorenzo Cells The management of visceral pain is a major clinical problem in patients affected by gastrointestinal disorders. The poor knowledge about pain chronicization mechanisms prompted us to study the functional and morphological alterations of the gut and nervous system in the animal model of persistent visceral pain caused by 2,4-dinitrobenzenesulfonic acid (DNBS). This agent, injected intrarectally, induced a colonic inflammation peaking on day 3 and remitting progressively from day 7. In concomitance with bowel inflammation, the animals developed visceral hypersensitivity, which persisted after colitis remission for up to three months. On day 14, the administration of pain-relieving drugs (injected intraperitoneally and intrathecally) revealed a mixed nociceptive, inflammatory and neuropathic pain originating from both the peripheral and central nervous system. At this time point, the colonic histological analysis highlighted a partial restitution of the , transmural collagen deposition, infiltration of mast cells and eosinophils, and upregulation of substance P (SP)-positive nerve fibers, which were surrounded by eosinophils and MHC-II-positive macrophages. A significant activation of microglia and astrocytes was observed in the dorsal and ventral horns of spinal cord. These results suggest that the persistence of visceral pain induced by colitis results from maladaptive plasticity of the enteric, peripheral and central nervous systems. 10.3390/cells9081772
    The "Culture" of Pain Control: A Review of Opioid-Induced Dysbiosis (OID) in Antinociceptive Tolerance. Mischel Ryan A,Muchhala Karan H,Dewey William L,Akbarali Hamid I The journal of pain It is increasingly recognized that chronic opioid use leads to maladaptive changes in the composition and localization of gut bacteria. Recently, this "opioid-induced dysbiosis" (OID) has been linked to antinociceptive tolerance development in preclinical models and may therefore identify promising targets for new opioid-sparing strategies. Such developments are critical to curb dose escalations in the clinical setting and combat the ongoing opioid epidemic. In this article, we review the existing literature that pertains to OID, including the current evidence regarding its qualitative nature, influence on antinociceptive tolerance, and future prospects. PERSPECTIVE: This article reviews the current literature on OID of gut bacteria, including its qualitative nature, influence on antinociceptive tolerance, and future prospects. This work may help identify targets for new opioid-sparing strategies. 10.1016/j.jpain.2019.11.015
    Predictive and Preventive Potential of Preoperative Gut Microbiota in Chronic Postoperative Pain in Breast Cancer Survivors. Anesthesia and analgesia BACKGROUND:Evidence suggests a potential relationship between gut microbiota and chronic postoperative pain (CPP). This study aimed to explore the predictive and preventive potential of preoperative gut microbiota in CPP in breast cancer survivors. METHODS:In the clinical experiments, we designed a nested case-control study to compared preoperative gut microbiota of breast cancer survivors with and without CPP using 16s rRNA sequencing. The primary outcome was clinically meaningful pain in or around the operative area 3 months after surgery. Logistic prediction models based on previously identified risk factors for CPP in breast cancer survivors were tested with and without differential bacteria to evaluate the model's potential for improvement with the addition of gut microbiota information. In the animal experiments, preoperative fecal microbiota was transplanted from patients with and without CPP to mice, and a spared nerve injury (SNI) model was used to mimic neuropathic pain in CPP. Mechanical hyperalgesia and the expression of markers of spinal microglia and peroxisome proliferator-activated receptor-γ (PPAR-γ) were assessed. RESULTS:Sixty-six CPP patients and 66 matched controls were analyzed. Preoperative gut microbiota composition was significantly different in the 2 groups at phylus, family, and genera levels. The discrimination of the clinical prediction model (determined by area under the receiver operating characteristic curve) improved by 0.039 and 0.099 after the involvement of differential gut microbiota at the family and genus levels, respectively. After fecal microbiota transplantation (FMT), "CPP microbiota" recipient mice exhibited significantly increased mechanical hyperalgesia and decreased expression of Ppar-γ and arginase-1 (Arg-1) in the spinal cord. CONCLUSIONS:Preoperative gut microbiota has the potential to predict and prevent the development of CPP and plays a causal role in its development via the PPAR-γ-microglia pathway in the spinal cord. Thus, it could be targeted to develop a prevention strategy for CPP in breast cancer survivors. 10.1213/ANE.0000000000005713
    Associations Between Dysmenorrhea Symptom-Based Phenotypes and Vaginal Microbiome: A Pilot Study. Chen Chen X,Carpenter Janet S,Gao Xiang,Toh Evelyn,Dong Qunfeng,Nelson David E,Mitchell Caroline,Fortenberry J Dennis Nursing research BACKGROUND:Dysmenorrhea is highly prevalent; it places women at risk for other chronic pain conditions. There is a high degree of individual variability in menstrual pain severity, the number of painful sites, and co-occurring gastrointestinal symptoms. Distinct dysmenorrhea symptom-based phenotypes were previously identified, but the biological underpinnings of these phenotypes are less known. One underexplored contributor is the vaginal microbiome. The vaginal microbiota differs significantly among reproductive-age women and may modulate as well as amplify reproductive tract inflammation, which may contribute to dysmenorrhea symptoms. OBJECTIVES:The objective of this study was to examine associations between dysmenorrhea symptom-based phenotypes and vaginal microbiome compositions on- and off-menses. METHODS:We conducted a prospective, longitudinal, pilot study of 20 women (aged 15-24 years) grouped into three dysmenorrhea symptom-based phenotypes: "mild localized pain," "severe localized pain," and "severe multiple pain and gastrointestinal symptoms." Over one menstrual cycle, participants provided vaginal swabs when they were on- and off-menses. We assayed the vaginal microbiome using 16S rRNA gene sequencing. Permutational multivariate analysis of variance tests were used to compare microbiome compositions across phenotypes, with heat maps generated to visualize the relative abundance of bacterial taxa. RESULTS:The vaginal microbiome compositions (n = 40) were different across the three phenotypes. After separating the on-menses (n = 20) and off-menses (n = 20) specimens, the statistically significant difference was seen on-menses, but not off-menses. Compared to the "mild localized pain" phenotype, participants in the "multiple severe symptoms" phenotype had a lower lactobacilli level and a higher abundance of Prevotella, Atopobium, and Gardnerella when on-menses. We also observed trends of differences across phenotypes in vaginal microbiome change from off- to on-menses. DISCUSSION:The study provides proof-of-concept data to support larger studies on associations between dysmenorrhea symptom-based phenotypes and vaginal microbiome that might lead to new intervention targets and/or biomarkers for dysmenorrhea. This line of research has the potential to inform precision dysmenorrhea treatment that can improve women's quality of life. 10.1097/NNR.0000000000000510
    Gut microbiota is critical for the induction of chemotherapy-induced pain. Shen Shiqian,Lim Grewo,You Zerong,Ding Weihua,Huang Peigen,Ran Chongzhao,Doheny Jason,Caravan Peter,Tate Samuel,Hu Kun,Kim Hyangin,McCabe Michael,Huang Bo,Xie Zhongcong,Kwon Douglas,Chen Lucy,Mao Jianren Nature neuroscience Chemotherapy-induced pain is a dose-limiting condition that affects 30% of patients undergoing chemotherapy. We found that gut microbiota promotes the development of chemotherapy-induced mechanical hyperalgesia. Oxaliplatin-induced mechanical hyperalgesia was reduced in germ-free mice and in mice pretreated with antibiotics. Restoring the microbiota of germ-free mice abrogated this protection. These effects appear to be mediated, in part, by TLR4 expressed on hematopoietic cells, including macrophages. 10.1038/nn.4606
    Microbiota: a novel regulator of pain. Defaye Manon,Gervason Sandie,Altier Christophe,Berthon Jean-Yves,Ardid Denis,Filaire Edith,Carvalho Frédéric Antonio Journal of neural transmission (Vienna, Austria : 1996) Among the various regulators of the nervous system, the gut microbiota has been recently described to have the potential to modulate neuronal cells activation. While bacteria-derived products can induce aversive responses and influence pain perception, recent work suggests that "abnormal" microbiota is associated with neurological diseases such as Alzheimer's, Parkinson's disease or autism spectrum disorder (ASD). Here we review how the gut microbiota modulates afferent sensory neurons function and pain, highlighting the role of the microbiota/gut/brain axis in the control of behaviors and neurological diseases. We outline the changes in gut microbiota, known as dysbiosis, and their influence on painful gastrointestinal disorders. Furthermore, both direct host/microbiota interaction that implicates activation of "pain-sensing" neurons by metabolites, or indirect communication via immune activation is discussed. Finally, treatment options targeting the gut microbiota, including pre- or probiotics, will be proposed. Further studies on microbiota/nervous system interaction should lead to the identification of novel microbial ligands and host receptor-targeted drugs, which could ultimately improve chronic pain management and well-being. 10.1007/s00702-019-02083-z
    The gastrointestinal microbiome and musculoskeletal diseases: a beneficial role for probiotics and prebiotics. Vitetta Luis,Coulson Samantha,Linnane Anthony W,Butt Henry Pathogens (Basel, Switzerland) Natural medicines are an attractive option for patients diagnosed with common and debilitating musculoskeletal diseases such as Osteoarthritis (OA) or Rheumatoid Arthritis (RA). The high rate of self-medication with natural products is due to (1) lack of an available cure and (2) serious adverse events associated with chronic use of pharmaceutical medications in particular non-steroidal anti-inflammatory drugs (NSAIDs) and high dose paracetamol. Pharmaceuticals to treat pain may disrupt gastrointestinal (GIT) barrier integrity inducing GIT inflammation and a state of and hyper-permeability. Probiotics and prebiotics may comprise plausible therapeutic options that can restore GIT barrier functionality and down regulate pro-inflammatory mediators by modulating the activity of, for example, Clostridia species known to induce pro-inflammatory mediators. The effect may comprise the rescue of gut barrier physiological function. A postulated requirement has been the abrogation of free radical formation by numerous natural antioxidant molecules in order to improve musculoskeletal health outcomes, this notion in our view, is in error. The production of reactive oxygen species (ROS) in different anatomical environments including the GIT by the epithelial lining and the commensal microbe cohort is a regulated process, leading to the formation of hydrogen peroxide which is now well recognized as an essential second messenger required for normal cellular homeostasis and physiological function. The GIT commensal profile that tolerates the host does so by regulating pro-inflammatory and anti-inflammatory GIT mucosal actions through the activity of ROS signaling thereby controlling the activity of pathogenic bacterial species. 10.3390/pathogens2040606
    Revealing the magic of acupuncture based on biological mechanisms: A literature review. Zhang Bo,Shi Haojun,Cao Shengnan,Xie Liangyu,Ren Pengcheng,Wang Jianmin,Shi Bin Bioscience trends Acupuncture has been used to treat various disease for more than 3,000 years in China and other Asian countries. As a complementary and alternative therapy, it has gained increasing popularity and acceptance among public and healthcare professionals in the West. Over the past few decades, basic and clinical research on acupuncture has made considerable progress. Internationally recognized evidence from clinical studies has been published, a preliminary system to clinically evaluate acupuncture has been created, and some clinical guidelines have been formulated. Moreover, scientists have strived to explore the physiological and biological mechanisms of acupuncture. Some basic studies have indicated that acupuncture has various actions, such as analgesic, muscle relaxing, anti-inflammatory, mild anxiolytic, and antidepressant actions, with possible biological mechanisms such as central sensitization, neurotransmitters, the intestinal flora, immune regulation, oxidative stress, and neuroinflammation. The current review describes the common indications for acupuncture recommended by the WHO and the use of acupuncture in China, the United States, Australia, and several other countries. This review then summarized the mechanisms by which acupuncture treats common conditions including lower back pain (LBP), ischemic stroke, depression, and irritable bowel syndrome (IBS) and it also cited specific acupuncture points for treating these conditions. The hope is that this review will provide useful information for both acupuncturists and researchers to better understand the mechanisms of acupuncture and reasons for its usage. 10.5582/bst.2022.01039
    Putative Probiotic Strains Isolated from Kefir Improve Gastrointestinal Health Parameters in Adults: a Randomized, Single-Blind, Placebo-Controlled Study. Wang Ming-Cheng,Zaydi Ahmad Imran,Lin Wei-Hung,Lin Jin-Seng,Liong Min-Tze,Wu Jiunn-Jong Probiotics and antimicrobial proteins The dairy products remain as the largest reservoir for isolation of probiotic microorganisms. While probiotics have been immensely reported to exert various health benefits, it is also a common notion that these health potentials are strain and host dependent, leading to the need of more human evidence based on specific strains, health targets, and populations. This randomized, single-blind, and placebo-controlled human study aimed to evaluate the potential benefits of putative probiotic strains isolated from kefir on gastrointestinal parameters in fifty-six healthy adults. The consumption of AB-kefir (Bifidobacterium longum, Lactobacillus acidophilus, L. fermentum, L. helveticus, L. paracasei, L. rhamnosus, and Streptococcus thermophiles; total 10 log CFU/sachet) daily for 3 week reduced symptoms of abdominal pain, bloating (P = 0.014), and appetite (P = 0.041) in male subjects as compared to the control. Gut microbiota distribution profiles were shifted upon consumption of AB-kefir compared to baseline, where the abundance of bifidobacteria was increased in male subjects and maintained upon cessation of AB-kefir consumption. The consumption of AB-kefir also increased gastrointestinal abundance of total anaerobes (P = 0.038) and total bacterial (P = 0.049) in female subjects compared to the control after 3 weeks. Our results indicated that AB-kefir could potentially be developed as a natural strategy to improve gastrointestinal functions in adults. 10.1007/s12602-019-09615-9
    Morphine induces changes in the gut microbiome and metabolome in a morphine dependence model. Wang Fuyuan,Meng Jingjing,Zhang Li,Johnson Timothy,Chen Chi,Roy Sabita Scientific reports Opioid analgesics are frequently prescribed in the United States and worldwide. However, serious comorbidities, such as dependence, tolerance, immunosuppression and gastrointestinal disorders limit their long-term use. In the current study, a morphine-murine model was used to investigate the role of the gut microbiome and metabolome as a potential mechanism contributing to the negative consequences associated with opioid use. Results reveal a significant shift in the gut microbiome and metabolome within one day following morphine treatment compared to that observed after placebo. Morphine-induced gut microbial dysbiosis exhibited distinct characteristic signatures, including significant increase in communities associated with pathogenic function, decrease in communities associated with stress tolerance and significant impairment in bile acids and morphine-3-glucuronide/morphine biotransformation in the gut. Moreover, expansion of Enterococcus faecalis was strongly correlated with gut dysbiosis following morphine treatment, and alterations in deoxycholic acid (DCA) and phosphatidylethanolamines (PEs) were associated with opioid-induced metabolomic changes. Collectively, these results indicate that morphine induced distinct alterations in the gut microbiome and metabolome, contributing to negative consequences associated with opioid use. Therapeutics directed at maintaining microbiome homeostasis during opioid use may reduce the comorbidities associated with opioid use for pain management. 10.1038/s41598-018-21915-8
    Gut microbiota depletion by antibiotics ameliorates somatic neuropathic pain induced by nerve injury, chemotherapy, and diabetes in mice. Journal of neuroinflammation BACKGROUND:Gut microbiota has been found involved in neuronal functions and neurological disorders. Whether and how gut microbiota impacts chronic somatic pain disorders remain elusive. METHODS:Neuropathic pain was produced by different forms of injury or diseases, the chronic constriction injury (CCI) of the sciatic nerves, oxaliplatin (OXA) chemotherapy, and streptozocin (STZ)-induced diabetes in mice. Continuous feeding of antibiotics (ABX) cocktail was used to cause major depletion of the gut microbiota. Fecal microbiota, biochemical changes in the spinal cord and dorsal root ganglion (DRG), and the behaviorally expressed painful syndromes were assessed. RESULTS:Under condition of gut microbiota depletion, CCI, OXA, or STZ treatment-induced thermal hyperalgesia or mechanical allodynia were prevented or completely suppressed. Gut microbiota depletion also prevented CCI or STZ treatment-induced glial cell activation in the spinal cord and inhibited cytokine production in DRG in OXA model. Interestingly, STZ treatment failed to induce the diabetic high blood glucose and painful hypersensitivity in animals with the gut microbiota depletion. ABX feeding starting simultaneously with CCI, OXA, or STZ treatment resulted in instant analgesia in all the animals. ABX feeding starting after establishment of the neuropathic pain in CCI- and STZ-, but not OXA-treated animals produced significant alleviation of the thermal hyeralgesia or mechanical allodynia. Transplantation of fecal bacteria from SPF mice to ABX-treated mice partially restored the gut microbiota and fully rescued the behaviorally expressed neuropathic pain, of which, Akkermansia, Bacteroides, and Desulfovibrionaceae phylus may play a key role. CONCLUSION:This study demonstrates distinct roles of gut microbiota in the pathogenesis of chronic painful conditions with nerve injury, chemotherapy and diabetic neuropathy and supports the clinical significance of fecal bacteria transplantation. 10.1186/s12974-022-02523-w
    Visceral pain: gut microbiota, a new hope? Pusceddu Matteo M,Gareau Melanie G Journal of biomedical science BACKGROUND:Visceral pain is a complex and heterogeneous disorder, which can range from the mild discomfort of indigestion to the agonizing pain of renal colic. Regulation of visceral pain involves the spinal cord as well as higher order brain structures. Recent findings have linked the microbiota to gastrointestinal disorders characterized by abdominal pain suggesting the ability of microbes to modulate visceral hypersensitivity and nociception to pain. MAIN BODY:In this review we describe the neuroanatomical basis of visceral pain signaling and the existing evidence of its manipulation exerted by the gut microbiota. We included an updated overview of the potential therapeutic effects of dietary intervention, specifically probiotics and prebiotics, in alleviating hypersensitivity to visceral pain stimuli. CONCLUSIONS:The gut microbiota dramatically impacts normal visceral pain sensation and affects the mechanisms mediating visceral nociception. Furthermore, manipulation of the gut microbiota using prebiotics and probiotics plays a potential role in the regulation of visceral pain disorders. 10.1186/s12929-018-0476-7
    Gut Microbiota Influences Neuropathic Pain Through Modulating Proinflammatory and Anti-inflammatory T Cells. Anesthesia and analgesia BACKGROUND:Gut microbiota, a consortium of diverse microorganisms residing in the gastrointestinal tract, has emerged as a key player in neuroinflammatory responses, supporting the functional relevance of the "gut-brain axis." Chronic-constriction injury of the sciatic nerve (CCI) is a commonly used animal model of neuropathic pain with a major input from T cell-mediated immune responses. In this article, we sought to examine whether gut microbiota influences CCI neuropathic pain, and, if so, whether T-cell immune responses are implicated. METHODS:We used a mixture of wide-spectrum oral antibiotics to perturbate gut microbiota in mice and then performed CCI in these animals. Nociceptive behaviors, including mechanical allodynia and thermal hyperalgesia, were examined before and after CCI. Additionally, we characterized the spinal cord infiltrating T cells by examining interferon (IFN)-γ, interleukin (IL)-17, and Foxp3. Using a Foxp3-GFP-DTR "knock-in" mouse model that allows punctual depletion of regulatory T cells, we interrogated the role of these cells in mediating the effects of gut microbiota in the context of CCI neuropathic pain. RESULTS:We found that oral antibiotics induced gut microbiota changes and attenuated the development of CCI neuropathic pain, as demonstrated by dampened mechanical allodynia and thermal hyperalgesia. Percentages of IFN-γ-producing Th1 cells and Foxp3+ regulatory T cells were significantly different between animals that received oral antibiotics (Th1 mean = 1.0, 95% confidence interval [CI], 0.9-1.2; Foxp3 mean = 8.1, 95% CI, 6.8-9.3) and those that received regular water (Th1 mean = 8.4, 95% CI, 7.8-9.0, P < .01 oral antibiotics versus water, Cohen's d = 18.8; Foxp 3 mean = 2.8, 95% CI, 2.2-3.3, P < .01 oral antibiotics versus water, Cohen's d = 6.2). These T cells characterized a skewing from a proinflammatory to an anti-inflammatory immune profile induced by gut microbiota changes. Moreover, we depleted Foxp3+ regulatory T cells and found that their depletion reversed the protection of neuropathic pain mediated by gut microbiota changes, along with a dramatic increase of IFN-γ-producing Th1 cell infiltration in the spinal cord (before depletion mean = 2.8%, 95% CI, 2.2-3.5; after depletion mean = 9.1%, 95% CI, 7.2-11.0, p < .01 before versus after, Cohen's d = 5.0). CONCLUSIONS:Gut microbiota plays a critical role in CCI neuropathic pain. This role is mediated, in part, through modulating proinflammatory and anti-inflammatory T cells. 10.1213/ANE.0000000000005155
    Supplementation with SCFAs Re-Establishes Microbiota Composition and Attenuates Hyperalgesia and Pain in a Mouse Model of NTG-Induced Migraine. International journal of molecular sciences Migraine is a common brain-disorder that affects 15% of the population. Converging evidence shows that migraine is associated with gastrointestinal disorders. However, the mechanisms underlying the interaction between the gut and brain in patients with migraine are not clear. In this study, we evaluated the role of the short-chain fatty acids (SCFAs) as sodium propionate (SP) and sodium butyrate (SB) on microbiota profile and intestinal permeability in a mouse model of migraine induced by nitroglycerine (NTG). The mice were orally administered SB and SP at the dose of 10, 30 and 100 mg/kg, 5 min after NTG intraperitoneal injections. Behavioral tests were used to evaluate migraine-like pain. Histological and molecular analyses were performed on the intestine. The composition of the intestinal microbiota was extracted from frozen fecal samples and sequenced with an Illumina MiSeq System. Our results demonstrated that the SP and SB treatments attenuated hyperalgesia and pain following NTG injection. Moreover, SP and SB reduced histological damage in the intestine and restored intestinal permeability and the intestinal microbiota profile. These results provide corroborating evidence that SB and SP exert a protective effect on central sensitization induced by NTG through a modulation of intestinal microbiota, suggesting the potential application of SCFAs as novel supportive therapies for intestinal disfunction associated with migraine. 10.3390/ijms23094847
    Gut-brain Axis: Role of Lipids in the Regulation of Inflammation, Pain and CNS Diseases. Russo Roberto,Cristiano Claudia,Avagliano Carmen,De Caro Carmen,La Rana Giovanna,Raso Giuseppina Mattace,Canani Roberto Berni,Meli Rosaria,Calignano Antonio Current medicinal chemistry The human gut is a composite anaerobic environment with a large, diverse and dynamic enteric microbiota, represented by more than 100 trillion microorganisms, including at least 1000 distinct species. The discovery that a different microbial composition can influence behavior and cognition, and in turn the nervous system can indirectly influence enteric microbiota composition, has significantly contributed to establish the well-accepted concept of gut-brain axis. This hypothesis is supported by several evidence showing mutual mechanisms, which involve the vague nerve, the immune system, the hypothalamic-pituitaryadrenal (HPA) axis modulation and the bacteria-derived metabolites. Many studies have focused on delineating a role for this axis in health and disease, ranging from stress-related disorders such as depression, anxiety and irritable bowel syndrome (IBS) to neurodevelopmental disorders, such as autism, and to neurodegenerative diseases, such as Parkinson Disease, Alzheimer's Disease etc. Based on this background, and considering the relevance of alteration of the symbiotic state between host and microbiota, this review focuses on the role and the involvement of bioactive lipids, such as the N-acylethanolamine (NAE) family whose main members are N-arachidonoylethanolamine (AEA), palmitoylethanolamide (PEA) and oleoilethanolamide (OEA), and short chain fatty acids (SCFAs), such as butyrate, belonging to a large group of bioactive lipids able to modulate peripheral and central pathologic processes. Their effective role has been studied in inflammation, acute and chronic pain, obesity and central nervous system diseases. A possible correlation has been shown between these lipids and gut microbiota through different mechanisms. Indeed, systemic administration of specific bacteria can reduce abdominal pain through the involvement of cannabinoid receptor 1 in the rat; on the other hand, PEA reduces inflammation markers in a murine model of inflammatory bowel disease (IBD), and butyrate, producted by gut microbiota, is effective in reducing inflammation and pain in irritable bowel syndrome and IBD animal models. In this review, we underline the relationship among inflammation, pain, microbiota and the different lipids, focusing on a possible involvement of NAEs and SCFAs in the gut-brain axis and their role in the central nervous system diseases. 10.2174/0929867324666170216113756
    Metabolomics: The Key to Unraveling the Role of the Microbiome in Visceral Pain Neurotransmission. Frontiers in neuroscience Inflammatory bowel disease (IBD), comprising Crohn's disease and Ulcerative colitis, is a relapsing and remitting disease of the gastrointestinal tract, presenting with chronic inflammation, ulceration, gastrointestinal bleeding, and abdominal pain. Up to 80% of patients suffering from IBD experience acute pain, which dissipates when the underlying inflammation and tissue damage resolves. However, despite achieving endoscopic remission with no signs of ongoing intestinal inflammation or damage, 30-50% of IBD patients in remission experience chronic abdominal pain, suggesting altered sensory neuronal processing in this disorder. Furthermore, effective treatment for chronic pain is limited such that 5-25% of IBD outpatients are treated with narcotics, with associated morbidity and mortality. IBD patients commonly present with substantial alterations to the microbial community structure within the gastrointestinal tract, known as dysbiosis. The same is also true in irritable bowel syndrome (IBS), a chronic disorder characterized by altered bowel habits and abdominal pain, in the absence of inflammation. An emerging body of literature suggests that the gut microbiome plays an important role in visceral hypersensitivity. Specific microbial metabolites have an intimate relationship with host receptors that are highly expressed on host cell and neurons, suggesting that microbial metabolites play a key role in visceral hypersensitivity. In this review, we will discuss the techniques used to analysis the metabolome, current potential metabolite targets for visceral hypersensitivity, and discuss the current literature that evaluates the role of the post-inflammatory microbiota and metabolites in visceral hypersensitivity. 10.3389/fnins.2022.917197
    Inflammasome Signaling Regulates the Microbial-Neuroimmune Axis and Visceral Pain in Mice. Aguilera Mònica,Rossini Valerio,Hickey Ana,Simnica Donjete,Grady Fiona,Felice Valeria D,Moloney Amy,Pawley Lauren,Fanning Aine,McCarthy Lorraine,O'Mahony Siobhan M,Cryan John F,Nally Ken,Shanahan Fergus,Melgar Silvia International journal of molecular sciences Interactions between the intestinal microbiota, immune system and nervous system are essential for homeostasis in the gut. Inflammasomes contribute to innate immunity and brain-gut interactions, but their role in microbiota-neuro-immune interactions is not clear. Therefore, we investigated the effect of the inflammasome on visceral pain and local and systemic neuroimmune responses after antibiotic-induced changes to the microbiota. Wild-type (WT) and caspase-1/11 deficient (Casp1 KO) mice were orally treated for 2 weeks with an antibiotic cocktail (Abx, Bacitracin A and Neomycin), followed by quantification of representative fecal commensals (by qPCR), cecal short chain fatty acids (by HPLC), pathways implicated in the gut-neuro-immune axis (by RT-qPCR, immunofluorescence staining, and flow cytometry) in addition to capsaicin-induced visceral pain responses. Abx-treatment in WT-mice resulted in an increase in colonic macrophages, central neuro-immune interactions, colonic inflammasome and nociceptive receptor gene expression and a reduction in capsaicin-induced visceral pain. In contrast, these responses were attenuated in Abx-treated Casp1 KO mice. Collectively, the data indicate an important role for the inflammasome pathway in functional and inflammatory gastrointestinal conditions where pain and alterations in microbiota composition are prominent. 10.3390/ijms22158336
    Evidence for an association of gut microbial Clostridia with brain functional connectivity and gastrointestinal sensorimotor function in patients with irritable bowel syndrome, based on tripartite network analysis. Labus Jennifer S,Osadchiy Vadim,Hsiao Elaine Y,Tap Julien,Derrien Muriel,Gupta Arpana,Tillisch Kirsten,Le Nevé Boris,Grinsvall Cecilia,Ljungberg Maria,Öhman Lena,Törnblom Hans,Simren Magnus,Mayer Emeran A Microbiome BACKGROUND AND AIMS:Evidence from preclinical and clinical studies suggests that interactions among the brain, gut, and microbiota may affect the pathophysiology of irritable bowel syndrome (IBS). As disruptions in central and peripheral serotonergic signaling pathways have been found in patients with IBS, we explored the hypothesis that the abundance of serotonin-modulating microbes of the order Clostridiales is associated with functional connectivity of somatosensory brain regions and gastrointestinal (GI) sensorimotor function. METHODS:We performed a prospective study of 65 patients with IBS and 21 healthy individuals (controls) recruited from 2011 through 2013 at a secondary/tertiary care outpatient clinic in Sweden. Study participants underwent functional brain imaging, rectal balloon distension, a nutrient and lactulose challenge test, and assessment of oroanal transit time within a month. They also submitted stool samples, which were analyzed by 16S ribosomal RNA gene sequencing. A tripartite network analysis based on graph theory was used to investigate the interactions among bacteria in the order Clostridiales, connectivity of brain regions in the somatosensory network, and GI sensorimotor function. RESULTS:We found associations between GI sensorimotor function and gut microbes in stool samples from controls, but not in samples from IBS patients. The largest differences between controls and patients with IBS were observed in the Lachnospiraceae incertae sedis, Clostridium XIVa, and Coprococcus subnetworks. We found connectivity of subcortical (thalamus, caudate, and putamen) and cortical (primary and secondary somatosensory cortices) regions to be involved in mediating interactions among these networks. CONCLUSIONS:In a comparison of patients with IBS and controls, we observed disruptions in the interactions between the brain, gut, and gut microbial metabolites in patients with IBS-these involve mainly subcortical but also cortical regions of brain. These disruptions may contribute to altered perception of pain in patients with IBS and may be mediated by microbial modulation of the gut serotonergic system. 10.1186/s40168-019-0656-z
    The progress of gut microbiome research related to brain disorders. Zhu Sibo,Jiang Yanfeng,Xu Kelin,Cui Mei,Ye Weimin,Zhao Genming,Jin Li,Chen Xingdong Journal of neuroinflammation There is increasing evidence showing that the dynamic changes in the gut microbiota can alter brain physiology and behavior. Cognition was originally thought to be regulated only by the central nervous system. However, it is now becoming clear that many non-nervous system factors, including the gut-resident bacteria of the gastrointestinal tract, regulate and influence cognitive dysfunction as well as the process of neurodegeneration and cerebrovascular diseases. Extrinsic and intrinsic factors including dietary habits can regulate the composition of the microbiota. Microbes release metabolites and microbiota-derived molecules to further trigger host-derived cytokines and inflammation in the central nervous system, which contribute greatly to the pathogenesis of host brain disorders such as pain, depression, anxiety, autism, Alzheimer's diseases, Parkinson's disease, and stroke. Change of blood-brain barrier permeability, brain vascular physiology, and brain structure are among the most critical causes of the development of downstream neurological dysfunction. In this review, we will discuss the following parts: Overview of technical approaches used in gut microbiome studiesMicrobiota and immunityGut microbiota and metabolitesMicrobiota-induced blood-brain barrier dysfunctionNeuropsychiatric diseases ■ Stress and depression■ Pain and migraine■ Autism spectrum disordersNeurodegenerative diseases ■ Parkinson's disease■ Alzheimer's disease■ Amyotrophic lateral sclerosis■ Multiple sclerosisCerebrovascular disease ■ Atherosclerosis■ Stroke■ Arteriovenous malformationConclusions and perspectives. 10.1186/s12974-020-1705-z
    Gut Microbiota Dysbiosis Enhances Migraine-Like Pain Via TNFα Upregulation. Tang Yuanyuan,Liu Sufang,Shu Hui,Yanagisawa Lora,Tao Feng Molecular neurobiology Migraine is one of the most disabling neurological diseases worldwide; however, the mechanisms underlying migraine headache are still not fully understood and current therapies for such pain are inadequate. It has been suggested that inflammation and neuroimmune modulation in the gastrointestinal tract could play an important role in the pathogenesis of migraine headache, but how gut microbiomes contribute to migraine headache is unclear. In the present study, we investigated the effect of gut microbiota dysbiosis on migraine-like pain using broad-spectrum antibiotics and germ-free (GF) mice. We observed that antibiotics treatment-prolonged nitroglycerin (NTG)-induced acute migraine-like pain in wild-type (WT) mice and the pain prolongation was completely blocked by genetic deletion of tumor necrosis factor-alpha (TNFα) or intra-spinal trigeminal nucleus caudalis (Sp5C) injection of TNFα receptor antagonist. The antibiotics treatment extended NTG-induced TNFα upregulation in the Sp5C. Probiotics administration significantly inhibited the antibiotics-produced migraine-like pain prolongation. Furthermore, NTG-induced migraine-like pain in GF mice was markedly enhanced compared to that in WT mice and gut colonization with fecal microbiota from WT mice robustly reversed microbiota deprivation-caused pain enhancement. Together, our results suggest that gut microbiota dysbiosis contributes to chronicity of migraine-like pain by upregulating TNFα level in the trigeminal nociceptive system. 10.1007/s12035-019-01721-7
    Gastrointestinal involvement of autism spectrum disorder: focus on gut microbiota. Expert review of gastroenterology & hepatology INTRODUCTION:Autism spectrum disorder (ASD) is a neurodevelopmental disorder typical of early age, characterized by impaired communication, social interaction, and repetitive behaviors. ASD patients frequently suffer from gastrointestinal (GI) symptoms. Neuro-psychological functions, intestinal homeostasis, and functional GI disturbances are modulated by the gut microbiota through the so-called 'microbiota-gut-brain axis'. AREAS COVERED:Literature regarding GI symptoms among the ASD community as well as the involvement and modulation of the gut microbiota in GI disturbances of ASD patients was searched. Constipation, diarrhea, reflux, abdominal bloating, pain, and discomfort are reported with variable prevalence. ASD is characterized by a reduction of /, of the abundance of and other imbalances. ASD patients with GI symptoms present microbial changes with plausible relation with deficiency of digestive enzymes, carbohydrate malabsorption, selective eating, bacterial toxins, serotonin metabolism, and inflammation. The strategies to mitigate the GI distress through the gut microbiota modulation comprise antimicrobials, probiotics, prebiotics, fecal microbiota transplantation, and dietary intervention. EXPERT OPINION:The modulation of the gut microbiota in ASD individuals with GI disturbances seems a promising target for the future medicine. A standardization of the research strategies for large-scale studies together with a focus on poorly explored fields is necessary to strengthen this hypothesis. 10.1080/17474124.2021.1869938
    The role of the microbiome for human health: from basic science to clinical applications. Mohajeri M Hasan,Brummer Robert J M,Rastall Robert A,Weersma Rinse K,Harmsen Hermie J M,Faas Marijke,Eggersdorfer Manfred European journal of nutrition The 2017 annual symposium organized by the University Medical Center Groningen in The Netherlands focused on the role of the gut microbiome in human health and disease. Experts from academia and industry examined interactions of prebiotics, probiotics, or vitamins with the gut microbiome in health and disease, the development of the microbiome in early-life and the role of the microbiome on the gut-brain axis. The gut microbiota changes dramatically during pregnancy and intrinsic factors (such as stress), in addition to extrinsic factors (such as diet, and drugs) influence the composition and activity of the gut microbiome throughout life. Microbial metabolites, e.g. short-chain fatty acids affect gut-brain signaling and the immune response. The gut microbiota has a regulatory role on anxiety, mood, cognition and pain which is exerted via the gut-brain axis. Ingestion of prebiotics or probiotics has been used to treat a range of conditions including constipation, allergic reactions and infections in infancy, and IBS. Fecal microbiota transplantation (FMT) highly effective for treating recurrent Clostridium difficile infections. The gut microbiome affects virtually all aspects of human health, but the degree of scientific evidence, the models and technologies and the understanding of mechanisms of action vary considerably from one benefit area to the other. For a clinical practice to be broadly accepted, the mode of action, the therapeutic window, and potential side effects need to thoroughly be investigated. This calls for further coordinated state-of-the art research to better understand and document the human gut microbiome's effects on human health. 10.1007/s00394-018-1703-4
    Current Perspectives on Gut Microbiome Dysbiosis and Depression. Capuco Alexander,Urits Ivan,Hasoon Jamal,Chun Rebecca,Gerald Brittany,Wang Jason K,Kassem Hisham,Ngo Anh L,Abd-Elsayed Alaa,Simopoulos Thomas,Kaye Alan D,Viswanath Omar Advances in therapy The human gut microbiome partakes in a bidirectional communication pathway with the central nervous system (CNS), named the microbiota-gut-brain axis. The microbiota-gut-brain axis is believed to modulate various central processes through the vagus nerve as well as production of microbial metabolites and immune mediators which trigger changes in neurotransmission, neuroinflammation, and behavior. Little is understood about the utilization of microbiome manipulation to treat disease. Though studies exploring the role of the microbiome in various disease processes have shown promise, mechanisms remain unclear and evidence-based treatments for most illnesses have not yet been developed. The animal studies reviewed here offer an excellent array of basic science research that continues to clarify mechanisms by which the microbiome may affect mental health. More evidence is needed, particularly as it relates to translating this work to human subjects. The studies presented in this paper largely demonstrate encouraging results in the treatment of depression. Limitations include small sample sizes and heterogeneous methodology. The exact mechanism by which the gut microbiota causes or alters neuropsychiatric disease states is not fully understood. In this review, we focus on recent studies investigating the relationship between gut microbiome dysbiosis and the pathogenesis of depression. This article is based on previously conducted studies and does not contain any studies with human participants or animals performed by any of the authors. 10.1007/s12325-020-01272-7
    Gut microbiota, immunity and pain. Santoni Matteo,Miccini Francesca,Battelli Nicola Immunology letters The interplay between microbiota and nervous system has been associated with a variety of diseases, including stress, anxiety, depression and cognition. The growing body of evidences on the essential role of gut microbiota in modulating acute and chronic pain has opened a new frontier for pain management. Gut microbiota is involved in the development of visceral, inflammatory and neuropathic pain. Bacterial alterations due to chronic opioid administration have been directly related to the development of drug tolerance, which can be potentially restored by the use of probiotics and antibiotics. In this review we describe the mechanisms underlying the brain/gut axis and the relationship between gut microbiota, immunity and pain. 10.1016/j.imlet.2020.11.010
    The self-serving benefits of being a good host: A role for our micro-inhabitants in shaping opioids' function. Eitan Shoshana,Madison Caitlin A,Kuempel Jacob Neuroscience and biobehavioral reviews Opioids are highly efficacious in their ability to relieve pain, but they are liable for abuse, dependence, and addiction. Risk factors to develop opioid use disorders (OUD) include chronic stress, socio-environment, and preexisting major depressive disorders (MDD) and posttraumatic stress disorders (PTSD). Additionally, opioids reduce gut motility, induce loss of gut barrier function, and alter the composition of the trillions of microbes hosted in the gastrointestinal tract, known as the gut microbiota. The microbiota are significant contributors to the reciprocal communication between the central nervous system (CNS) and the gut, termed the gut-brain axis. They have strong influences on their host behaviors, including the ability to cope with stress, sociability, affect, mood, and anxiety. Thus, they are implicated in the etiology of MDD and PTSD. Here we review the latest studies demonstrating that intestinal flora can, directly and indirectly, by affecting sociability levels, responses to stress, and mental state, alter the responses to opioids. It suggests that microbiota can potentially be used to increase the resilience to develop analgesic tolerance and OUD. 10.1016/j.neubiorev.2021.04.019
    Microbiota and Pain: Save Your Gut Feeling. Cells Recently, a growing body of evidence has emerged regarding the interplay between microbiota and the nervous system. This relationship has been associated with several pathological conditions and also with the onset and regulation of pain. Dysregulation of the axis leads to a huge variety of diseases such as visceral hypersensitivity, stress-induced hyperalgesia, allodynia, inflammatory pain and functional disorders. In pain management, probiotics have shown promising results. This narrative review describes the peripheral and central mechanisms underlying pain processing and regulation, highlighting the role of the gut-brain axis in the modulation of pain. We summarized the main findings in regard to the stress impact on microbiota's composition and its influence on pain perception. We also focused on the relationship between gut microbiota and both visceral and inflammatory pain and we provided a summary of the main evidence regarding the mechanistic effects and probiotics use. 10.3390/cells11060971
    Role of gut microbiota in neuropathy and neuropathic pain states: A systematic preclinical review. Neurobiology of disease Gut microbiota has implications in Central Nervous System (CNS) disorders. Our study systematically identified preclinical studies aimed to investigate the possible gut microbiota contribution in neuropathy and neuropathic pain. The systematic review is reported in accordance with PRISMA checklist and guidelines outlined updated to 2020. We included research articles reporting neuropathy-related behavioral evaluations and/or neurological scores coupled to gut microbiota analysis performed by high-throughput technologies in the last ten years. Two investigators performed a search through 3 electronic bibliographic databases for full-text articles (PubMed, Scopus, and EMBASE) and three registries (Prospero, SyRF, and bioRxiv), cross-references, and linear searches. We assessed the methodological quality via the CAMARADES checklist and appraised the heterogeneous body of evidence by narrative synthesis. In total, there were 19 eligible studies. The most of these reports showed significant changes in gut microbiota setting in neuropathy conditions. The major gut microbiome remodeling was through fecal microbiome transplantation. Mechanistic proof of the gut-CNS communication was achieved by measuring inflammatory mediators, metabolic products, or neurotransmitters. As a limitation, we found considerable heterogeneity across eligible studies. We conclude that the current understanding of preclinical findings suggested an association between neuropathy and/or neuropathic pain and gut microbiota modifications. Our analysis provides the basis for further studies targeting microbiota for managing symptoms of neuropathy or other neuroinflammation-based CNS disorders. The systematic review protocol was registered on the international database Prospero under the registration number (257628). 10.1016/j.nbd.2022.105773
    Probiotics in digestive, emotional, and pain-related disorders. Roman Pablo,Abalo Raquel,Marco Eva M,Cardona Diana Behavioural pharmacology In recent years, interest in the relationship between gut microbiota and disease states has grown considerably. Indeed, several strategies have been employed to modify the microbiome through the administration of different diets, by the administration of antibiotics or probiotics, or even by transplantation of feces. In the present manuscript, we focus specifically on the potential application of probiotics, which seem to be a safe strategy, in the management of digestive, pain, and emotional disorders. We present evidence from animal models and human studies, notwithstanding that translation to clinic still deserves further investigation. The microbiome influences gut functions as well as neurological activity by a variety of mechanisms, which are also discussed. The design and performance of larger trials is urgently needed to verify whether these new strategies might be useful not only for the treatment of disorders affecting the gastrointestinal tract but also in the management of emotional and pain disorders not directly related to the gut. 10.1097/FBP.0000000000000385
    Relationships of sleep disturbance, intestinal microbiota, and postoperative pain in breast cancer patients: a prospective observational study. Yao Zhi-Wen,Zhao Bing-Cheng,Yang Xiao,Lei Shao-Hui,Jiang Yu-Mei,Liu Ke-Xuan Sleep & breathing = Schlaf & Atmung PURPOSE:Our study was designed to examine the possible relationship between gut microbiota, sleep disturbances, and acute postoperative pain. METHODS:Using 16S rRNA sequencing, we analyzed preoperative fecal samples from women undergoing breast cancer surgery. Preoperative sleep disturbance was evaluated with the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Peak and average pain at rest and movement were evaluated 24 h after surgery, using a numerical rating scale (NRS). Preoperative symptoms of depression and anxiety were assessed with the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), respectively. Inflammation was measured using white blood cell and neutrophil counts, together with platelet-lymphocyte ratio, and neutrophil-lymphocyte ratio. RESULTS:Preoperative sleep disturbance was associated with more severe acute postoperative pain. At the phylum level, women with poor sleep quality had higher relative abundance of Firmicutes (p = 0.021) and lower relative abundance of Bacteroidetes (p = 0.013). At the genus level, women with poor sleep quality harbored higher relative abundance of Acidaminococcus and lower relative abundance of several genera. The genus Alloprevotella was negatively associated with peak pain at movement during the first 24 h (r = - 0.592, p < 0.001). The genus Desulfovibrio was negatively associated with symptoms of anxiety (r = - 0.448, p = 0.006). However, partial correlations suggested that the relationship between Alloprevotella and peak pain at movement during the first 24 h was not statistically significant after controlling for sleep (r = - 0.134, p = 0.443). CONCLUSION:These findings suggest that the changed gut microbiota may be involved in sleep-pain interaction and could be applied as a potential preventive method for postoperative pain. TRIAL REGISTRATION:The present clinical study has been registered on Chinese Clinical Trial Registry ( www.chictr.org.cn ); the clinical trial registration number is ChiCTR1900021730; the date of registration is March 7, 2019. 10.1007/s11325-020-02246-3
    Pueraria lobata Targeted Preparation Improves the Clinical Symptoms of Cervical Spondylosis by Regulating the Balance of Gut Microbiota. Computational and mathematical methods in medicine BACKGROUND:Nanotargeted preparations can enhance the safety and effectiveness of medication by altering the pharmacokinetic behavior of drugs in the human body, and Pueraria lobata is shown to be effective in the treatment of neck and back pain. PURPOSE:This study prepared a nano-Pueraria targeted preparation, in order to analyze its effect on improving the clinical symptoms of cervical spondylosis by adjusting the balance of intestinal flora. METHODS:A total of 200 patients with cervical spondylosis admitted to the Affiliated Hospital of Nanjing University of Chinese Medicine were enrolled and divided into an observation group and a control group. The control group was given Tuina therapy, and the observation group was given nano-Pueraria targeted preparation + Tuina therapy. The clinical symptoms and intestinal microflora of the two groups were examined before intervention. RESULTS:It was found that the markedly effective of treatment efficacy of the observation group (98%) was higher than that of the control group (78%) after 15 days of intervention, and the clinical symptoms were obviously fewer than those of the control group. The distribution of gut microbiota showed that there were significant differences in the composition of gut microbiota between the two groups. Compared with the control group, the abundance of Firmicutes in the observation group was significantly higher, while the abundance of Bacteroidetes and Proteobacteria was significantly lower. CONCLUSION:The targeted preparation of nano-Pueraria can improve the clinical symptoms of patients with cervical spondylosis by adjusting the balance of gut microbiota. 10.1155/2022/2136807
    Fecal transplantation and butyrate improve neuropathic pain, modify immune cell profile, and gene expression in the PNS of obese mice. Bonomo Raiza R,Cook Tyler M,Gavini Chaitanya K,White Chelsea R,Jones Jacob R,Bovo Elisa,Zima Aleksey V,Brown Isabelle A,Dugas Lara R,Zakharian Eleonora,Aubert Gregory,Alonzo Francis,Calcutt Nigel A,Mansuy-Aubert Virginie Proceedings of the National Academy of Sciences of the United States of America Obesity affects over 2 billion people worldwide and is accompanied by peripheral neuropathy (PN) and an associated poorer quality of life. Despite high prevalence, the molecular mechanisms underlying the painful manifestations of PN are poorly understood, and therapies are restricted to use of painkillers or other drugs that do not address the underlying disease. Studies have demonstrated that the gut microbiome is linked to metabolic health and its alteration is associated with many diseases, including obesity. Pathologic changes to the gut microbiome have recently been linked to somatosensory pain, but any relationships between gut microbiome and PN in obesity have yet to be explored. Our data show that mice fed a Western diet developed indices of PN that were attenuated by concurrent fecal microbiome transplantation (FMT). In addition, we observed changes in expression of genes involved in lipid metabolism and calcium handling in cells of the peripheral nerve system (PNS). FMT also induced changes in the immune cell populations of the PNS. There was a correlation between an increase in the circulating short-chain fatty acid butyrate and pain improvement following FMT. Additionally, butyrate modulated gene expression and immune cells in the PNS. Circulating butyrate was also negatively correlated with distal pain in 29 participants with varied body mass index. Our data suggest that the metabolite butyrate, secreted by the gut microbiome, underlies some of the effects of FMT. Targeting the gut microbiome, butyrate, and its consequences may represent novel viable approaches to prevent or relieve obesity-associated neuropathies. 10.1073/pnas.2006065117
    Resveratrol alleviates temporomandibular joint inflammatory pain by recovering disturbed gut microbiota. Ma Yajing,Liu Sufang,Shu Hui,Crawford Joshua,Xing Ying,Tao Feng Brain, behavior, and immunity Patients with temporomandibular disorders (TMDs) often experience persistent facial pain. However, the treatment of TMD pain is still inadequate. In recent years, the disturbance of gut microbiota has been shown to play an important role in the pathogenesis of different neurological diseases including chronic pain. In the present study, we investigated the involvement of gut microbiota in the development of temporomandibular joint (TMJ) inflammation. Intra-temporomandibular joint injection of complete Freund's adjuvant (CFA) was employed to induce TMJ inflammation. Resveratrol (RSV), a natural bioactive compound with anti-inflammatory property, was used to treat the CFA-induced TMJ inflammation. We observed that CFA injection not only induces persistent joint pain, but also causes the reduction of short-chain fatty acids (SCFAs, including acetic acid, propionic acid and butyric acid) in the gut as well as decreases relevant gut bacteria Bacteroidetes and Lachnospiraceae. Interestingly, systemic administration of RSV (i.p.) dose-dependently inhibits CFA-induced TMJ inflammation, reverses CFA-caused reduction of SCFAs and these gut bacteria. Moreover, CFA injection causes blood-brain barrier (BBB) leakage, activates microglia and enhances tumor necrosis factor alpha (TNFα) release in the spinal trigeminal nucleus caudalis (Sp5C). The RSV treatment restores the BBB integrity, inhibits microglial activation and decreases the release of TNFα in the Sp5C. Furthermore, fecal microbiota transplantation with feces from RSV-treated mice significantly diminishes the CFA-induced TMJ inflammation. Taken together, our results suggest that gut microbiome perturbation is critical for the development of TMJ inflammation and that recovering gut microbiome to normal levels could be a new therapeutic approach for treating such pain. 10.1016/j.bbi.2020.01.016
    The gut microbiome-joint connection: implications in osteoarthritis. Current opinion in rheumatology PURPOSE OF REVIEW:Osteoarthritis is a debilitating disease leading to joint degeneration, inflammation, pain, and disability. Despite efforts to develop a disease modifying treatment, the only accepted and available clinical approaches involve palliation. Although many factors contribute to the development of osteoarthritis, the gut microbiome has recently emerged as an important pathogenic factor in osteoarthritis initiation and progression. This review examines the literature to date regarding the link between the gut microbiome and osteoarthritis. RECENT FINDINGS:Studies showing correlations between serum levels of bacterial metabolites and joint degeneration were the first links connecting a dysbiosis of the gut microbiome with osteoarthritis. Further investigations have demonstrated that microbial community shifts induced by antibiotics, a germ-free environment or high-fat are important underlying factors in joint homeostasis and osteoarthritis. It follows that strategies to manipulate the microbiome have demonstrated efficacy in mitigating joint degeneration in osteoarthritis. Moreover, we have observed that dietary supplementation with nutraceuticals that are joint protective may exert their influence via shifts in the gut microbiome. SUMMARY:Although role of the microbiome in osteoarthritis is an area of intense study, no clear mechanism of action has been determined. Increased understanding of how the two factors interact may provide mechanistic insight into osteoarthritis and lead to disease modifying treatments. 10.1097/BOR.0000000000000681
    Effect of herbal medicine daikenchuto on gastrointestinal symptoms following laparoscopic colectomy in patients with colon cancer: A prospective randomized study. Hanada Keita,Wada Toshiaki,Kawada Kenji,Hoshino Nobuaki,Okamoto Michio,Hirata Wataru,Mizuno Rei,Itatani Yoshiro,Inamoto Susumu,Takahashi Ryo,Yoshitomi Mami,Watanabe Takeshi,Hida Koya,Obama Kazutaka,Sakai Yoshiharu Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie We conducted a prospective randomized study to investigate the effect of daikenchuto (DKT) on abdominal symptoms following laparoscopic colectomy in patients with left-sided colon cancer. Patients who suffered from abdominal pain or distention on postoperative day 1 were randomized to either the DKT group or non-DKT group. The primary endpoints were the evaluation of abdominal pain, abdominal distention, and quality of life. The metabolome and gut microbiome analyses were conducted as secondary endpoints. A total of 17 patients were enrolled: 8 patients in the DKT group and 9 patients in the non-DKT group. There were no significant differences in the primary endpoints and postoperative adverse events between the two groups. The metabolome and gut microbiome analyses showed that the levels of plasma lipid mediators associated with the arachidonic acid cascade were lower in the DKT group than in the non-DKT group, and that the relative abundance of genera Serratia and Bilophila were lower in the DKT group than in the non-DKT group. DKT administration did not improve the abdominal symptoms following laparoscopic colectomy. The effects of DKT on metabolites and gut microbiome have to be further investigated. 10.1016/j.biopha.2021.111887
    Gut Microbiome Dysbiosis and Depression: a Comprehensive Review. Capuco Alexander,Urits Ivan,Hasoon Jamal,Chun Rebecca,Gerald Brittany,Wang Jason K,Ngo Anh L,Simopoulos Thomas,Kaye Alan D,Colontonio Matthew M,Parker-Actlis Tomasina Q,Fuller Mitchell C,Viswanath Omar Current pain and headache reports PURPOSE OF REVIEW:The human gut microbiome is involved in a bi-directional communication pathway with the central nervous system (CNS), termed the microbiota-gut-brain axis. The microbiota-gut-brain axis is believed to mediate or modulate various central processes through the vagus nerve. The microbiota-gut-brain axis is involved with the production of microbial metabolites and immune mediators which trigger changes in neurotransmission, neuroinflammation, and behavior. Little is understood about the utilization of microbiome manipulation to treat disease. RECENT FINDINGS:Though studies exploring the role of the microbiome in various disease processes have shown promise, mechanisms remain unclear and evidence-based treatments for most illnesses have not yet been developed. The animal studies reviewed in the present investigation include an array of basic science studies that clarify mechanisms by which the microbiome may affect mental health. More evidence is needed, particularly as it relates to translating this work to humans. The studies presented in this review demonstrate encouraging results in the treatment of depression. Limitations include small sample sizes and heterogeneous methodology. The exact mechanism by which the gut microbiota causes or alters neuropsychiatric disease states is not fully understood. In this review, we focus on recent studies investigating the relationship between gut microbiome dysbiosis and the pathogenesis of depression. 10.1007/s11916-020-00871-x
    Prolonged Impairment of Short-Chain Fatty Acid and L-Isoleucine Biosynthesis in Gut Microbiome in Patients With COVID-19. Zhang Fen,Wan Yating,Zuo Tao,Yeoh Yun Kit,Liu Qin,Zhang Lin,Zhan Hui,Lu Wenqi,Xu Wenye,Lui Grace C Y,Li Amy Y L,Cheung Chun Pan,Wong Chun Kwok,Chan Paul K S,Chan Francis K L,Ng Siew C Gastroenterology BACKGROUND AND AIMS:Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with altered gut microbiota composition. Phylogenetic groups of gut bacteria involved in the metabolism of short chain fatty acids (SCFAs) were depleted in SARS-CoV-2-infected patients. We aimed to characterize a functional profile of the gut microbiome in patients with COVID-19 before and after disease resolution. METHODS:We performed shotgun metagenomic sequencing on fecal samples from 66 antibiotics-naïve patients with COVID-19 and 70 non-COVID-19 controls. Serial fecal samples were collected (at up to 6 times points) during hospitalization and beyond 1 month after discharge. We assessed gut microbial pathways in association with disease severity and blood inflammatory markers. We also determined changes of microbial functions in fecal samples before and after disease resolution and validated these functions using targeted analysis of fecal metabolites. RESULTS:Compared with non-COVID-19 controls, patients with COVID-19 with severe/critical illness showed significant alterations in gut microbiome functionality (P < .001), characterized by impaired capacity of gut microbiome for SCFA and L-isoleucine biosynthesis and enhanced capacity for urea production. Impaired SCFA and L-isoleucine biosynthesis in gut microbiome persisted beyond 30 days after recovery in patients with COVID-19. Targeted analysis of fecal metabolites showed significantly lower fecal concentrations of SCFAs and L-isoleucine in patients with COVID-19 before and after disease resolution. Lack of SCFA and L-isoleucine biosynthesis significantly correlated with disease severity and increased plasma concentrations of CXCL-10, NT- proB-type natriuretic peptide, and C-reactive protein (all P < .05). CONCLUSIONS:Gut microbiome of patients with COVID-19 displayed impaired capacity for SCFA and L-isoleucine biosynthesis that persisted even after disease resolution. These 2 microbial functions correlated with host immune response underscoring the importance of gut microbial functions in SARS-CoV-2 infection pathogenesis and outcome. 10.1053/j.gastro.2021.10.013
    Pain regulation by gut microbiota: molecular mechanisms and therapeutic potential. Guo Ran,Chen Li-Hua,Xing Chungen,Liu Tong British journal of anaesthesia The relationship between gut microbiota and neurological diseases, including chronic pain, has received increasing attention. The gut microbiome is a crucial modulator of visceral pain, whereas recent evidence suggests that gut microbiota may also play a critical role in many other types of chronic pain, including inflammatory pain, headache, neuropathic pain, and opioid tolerance. We present a narrative review of the current understanding on the role of gut microbiota in pain regulation and discuss the possibility of targeting gut microbiota for the management of chronic pain. Numerous signalling molecules derived from gut microbiota, such as by-products of microbiota, metabolites, neurotransmitters, and neuromodulators, act on their receptors and remarkably regulate the peripheral and central sensitisation, which in turn mediate the development of chronic pain. Gut microbiota-derived mediators serve as critical modulators for the induction of peripheral sensitisation, directly or indirectly regulating the excitability of primary nociceptive neurones. In the central nervous system, gut microbiota-derived mediators may regulate neuroinflammation, which involves the activation of cells in the blood-brain barrier, microglia, and infiltrating immune cells, to modulate induction and maintenance of central sensitisation. Thus, we propose that gut microbiota regulates pain in the peripheral and central nervous system, and targeting gut microbiota by diet and pharmabiotic intervention may represent a new therapeutic strategy for the management of chronic pain. 10.1016/j.bja.2019.07.026
    Dysbiosis of the gut microbiome is a risk factor for osteoarthritis in older female adults: a case control study. Chen Juanjuan,Wang Anqi,Wang Qi BMC bioinformatics BACKGROUND:Osteoarthritis (OA) is a multifactorial joint degenerative disease with low-grade inflammation. The gut microbiome has recently emerged as an pathogenic factor of OA, and prebiotics supplementation could alleviate OA symptoms in animal models. However, the relationship between the gut microbiome and OA in the older female adults is hitherto not clear. RESULTS:Here we studied the gut microbiome of 57 OA patients and their healthy controls by metagenome-wide association study based on previously published data. A significant reduction in the richness and diversity of gut microbiome were observed in OA patients. Bifidobacterium longum and Faecalibacterium prausnitzii were decreased while Clostridium spp. was increased in the OA group. The functional modules, particularly the energetic metabolism and acetate production were also decreased in the OA patients. To evaluate the diagnostic value of identified species for elderly patients with OA, we constructed a set of random forest disease classifiers based on species differences between the two groups. Among them, 9 species reached the lowest classification error in the random forest cross validation, and the area under ROC of the model was 0.81. CONCLUSIONS:Significant alterations in the gut microbial composition and function were observed between the older patients with OA and their controls, and a random forest classifier model for OA were constructed based on the differences in our study. Our study have identified several potential gut microbial targets in the elderly females with OA, which will facilitate the treatment of OA based on gut microbiota, is of great value in alleviating pain and improving the quality of life for them. 10.1186/s12859-021-04199-0
    Gut microbiome: pertinence in fibromyalgia. Minerbi Amir,Fitzcharles Mary-Ann Clinical and experimental rheumatology The human gut microbiome constitutes a diverse and dynamic community of microorganisms that inhabit the digestive tract. In recent years, there is growing appreciation for the role of the gut microbiome in host health and disease. Gut bacteria are involved in the pathogenesis of numerous medical conditions in a variety of medical fields including gastroenterology, metabolic, rheumatologic, neurologic and psychiatric disorders. Recently, evidence is mounting that gut bacteria could also play a role in chronic pain and specifically fibromyalgia (FM). The composition of the gut bacterial community is altered in individuals with FM, with an altered abundance of a small subset of bacterial species. Some of these species, either with increased or decreased abundance in patients, have established metabolic activity which could have pertinence in the expression of FM symptoms. The putative mechanisms which could allow these bacterial species to affect pain, fatigue, mood and other symptoms include the entry of short-chain-fatty-acids, bile acids, neurotransmitters and bacterial antigens into the host circulation. While these are merely the first steps in understanding the role of the gut microbiome in chronic pain and specifically FM, one might envision exciting future perspectives for better mechanistic understanding of FM, for the development of objective diagnostic aids and potentially for new therapeutic modalities.
    Gastrointestinal problems, mechanisms and possible therapeutic directions in Gulf war illness: a mini review. Kimono Diana A Military Medical Research By its nature, Gulf war illness (GWI) is multisymptomatic and affects several organ systems in the body. Along with other symptoms, veterans who suffer from GWI commonly report chronic gastrointestinal issues such as constipation, pain, indigestion, etc. However, until recently, most attention has been focused on neurological disturbances such as cognitive impairments, chronic fatigue, and chronic pain among affected veterans. With such high prevalence of gastrointestinal problems among Gulf war (GW) veterans, it is surprising that there is little research to investigate the mechanisms behind these issues. This review summarizes all the available works on the mechanisms behind gastrointestinal problems in GWI that have been published to date in various databases. Generally, these studies, which were done in rodent models, in vitro and human cohorts propose that an altered microbiome, a reactive enteric nervous system or a leaky gut among other possible mechanisms are the major drivers of gastrointestinal problems reported in GWI. This review aims to draw attention to the gastrointestinal tract as an important player in GWI disease pathology and a potential therapeutic target. 10.1186/s40779-021-00341-4
    Dietary supplementation of gingerols- and shogaols-enriched ginger root extract attenuate pain-associated behaviors while modulating gut microbiota and metabolites in rats with spinal nerve ligation. Shen Chwan-Li,Wang Rui,Ji Guangchen,Elmassry Moamen M,Zabet-Moghaddam Masoud,Vellers Heather,Hamood Abdul N,Gong Xiaoxia,Mirzaei Parvin,Sang Shengmin,Neugebauer Volker The Journal of nutritional biochemistry Neuroinflammation is a central factor in neuropathic pain (NP). Ginger is a promising bioactive compound in NP management due to its anti-inflammatory property. Emerging evidence suggests that gut microbiome and gut-derived metabolites play a key role in NP. We evaluated the effects of two ginger root extracts rich in gingerols (GEG) and shogaols (SEG) on pain sensitivity, anxiety-like behaviors, circulating cell-free mitochondrial DNA (ccf-mtDNA), gut microbiome composition, and fecal metabolites in rats with NP. Sixteen male rats were divided into four groups: sham, spinal nerve ligation (SNL), SNL+0.75%GEG in diet, and SNL+0.75%SEG in diet groups for 30 days. Compared to SNL group, both SNL+GEG and SNL+SEG groups showed a significant reduction in pain- and anxiety-like behaviors, and ccf-mtDNA level. Relative to the SNL group, both SNL+GEG and SNL+SEG groups increased the relative abundance of Lactococcus, Sellimonas, Blautia, Erysipelatoclostridiaceae, and Anaerovoracaceae, but decreased that of Prevotellaceae UCG-001, Rikenellaceae RC9 gut group, Mucispirillum and Desulfovibrio, Desulfovibrio, Anaerofilum, Eubacterium siraeum group, RF39, UCG-005, Lachnospiraceae NK4A136 group, Acetatifactor, Eubacterium ruminantium group, Clostridia UCG-014, and an uncultured Anaerovoracaceae. GEG and SEG had differential effects on gut-derived metabolites. Compared to SNL group, SNL+GEG group had higher level of 1'-acetoxychavicol acetate, (4E)-1,7-Bis(4-hydroxyphenyl)-4-hepten-3-one, NP-000629, 7,8-Dimethoxy-3-(2-methyl-3-buten-2-yl)-2H-chromen-2-one, 3-{[4-(2-Pyrimidinyl)piperazino]carbonyl}-2-pyrazinecarboxylic acid, 920863, and (1R,3R,7R,13S)-13-Methyl-6-methylene-4,14,16-trioxatetracyclo[11.2.1.0∼1,10∼.0∼3,7∼]hexadec-9-en-5-one, while SNL+SEG group had higher level for (±)-5-[(tert-Butylamino)-2'-hydroxypropoxy]-1_2_3_4-tetrahydro-1-naphthol and dehydroepiandrosteronesulfate. In conclusion, ginger is a promising functional food in the management of NP, and further investigations are necessary to assess the role of ginger on gut-brain axis in pain management. 10.1016/j.jnutbio.2021.108904
    BMI, Alcohol Consumption and Gut Microbiome Species Richness Are Related to Structural and Functional Neurological Abnormalities. Geisler Corinna,Pankoke Jil,Schlicht Kristina,Knappe Carina,Rohmann Nathalie,Hartmann Katharina,Settgast Ute,Türk Kathrin,Seoudy Anna Katharina,Franke Andre,Schreiber Stefan,Schulte Dominik M,Laudes Matthias Nutrients The incidence of neurological diseases is increasing throughout the world. The aim of the present study was to identify nutrition and microbiome factors related to structural and functional neurological abnormalities to optimize future preventive strategies. Two hundred thirty-eight patients suffering from (1) structural (neurodegeneration) or (2) functional (epilepsy) neurological abnormalities or (3) chronic pain (migraine) and 612 healthy control subjects were analyzed by validated 12-month food frequency questionnaire (FFQ) and 16S rRNA microbiome sequencing (from stool samples). A binomial logistic regression model was applied for risk calculation and functional pathway analysis to show which functional pathway could discriminate cases and healthy controls. Detailed analysis of more than 60 macro- and micronutrients revealed no distinct significant difference between cases and controls, whereas BMI, insulin resistance and metabolic inflammation in addition to alcohol consumption were major drivers of an overall neurological disease risk. The gut microbiome analysis showed decreased alpha diversity (Shannon index: = 9.1× 10) and species richness ( = 1.2 × 10) in the case group as well as significant differences in beta diversity between cases and controls (Bray-Curtis: = 9.99 × 10; Jaccard: = 9.99 × 10). The Shannon index showed a beneficial effect (OR = 0.59 (95%-CI (0.40, 0.87); = 8 × 10). Cases were clearly discriminated from healthy controls by environmental information processing, signal transduction, two component system and membrane transport as significantly different functional pathways. In conclusion, our data indicate that an overall healthy lifestyle, in contrast to supplementation of single micro- or macronutrients, is most likely to reduce overall neurological abnormality risk and that the gut microbiome is an interesting target to develop novel preventive strategies. 10.3390/nu13113743
    Gut microbiome and circulating bacterial DNA ("blood microbiome") in a mouse model of total parenteral nutrition: Evidence of two distinct separate microbiotic compartments. Clinical nutrition ESPEN BACKGROUND & AIMS:Total parenteral nutrition (TPN) causes gut atrophy, dysbiosis and leakage of the gut barrier. This study aimed to characterize the gut microbiome in response to different TPNs and tested the hypothesis whether increased gut permeability in TPN would lead to changes in the circulating bacterial DNA ("blood microbiome"). METHODS:Male C57BL/6J mice were randomly allocated to the following groups for seven days (1) chow-fed control (C) without jugular vein catheter (JVC, n=6) (2) chow-fed with JVC and infusion of saline (S) (n = 6) (3) Intralipid-based TPN (n-6:n-3 ratio 7:1) (IL, n = 6) (4) Omegaven-based TPN (n-6:n-3 ratio 1:8) (OV, n = 6). Blood was collected by cardiac puncture and feces (stool pellet) were collected from the colon. Blood and stool samples were analyzed by 16S rRNA gene sequencing. RESULTS:TPN administration was associated with a compositional shift in the gut microbial community that involved the expansion of Bacteroidota along with a decrease in gut bacteria belonging to the Firmicutes phylum as compared to chow-fed mice. Gram-negative Verrucomicrobiota and Proteobacteria were also increased in the gut microbiome of mice receiving TPN. Gammaproteobacteria, namely Burkholderiales, were specifically increased in Intralipid-based TPN. On the other hand, Proteobacteria and Actinobacteriota were the dominant taxa in blood samples. The families Comamonadaceae and Burkholderiaceae (both from Burkholderiales order) were increased in the "blood microbiome" of mice with indwelling JVC when compared with chow-fed mice without JVC. The increase in Burkholderiaceae was more pronounced in Intralipid-based TPN. CONCLUSIONS:Profound changes in the gut microbiome of mice subjected to TPN occurred, which were not reflected in the "blood microbiome" suggesting that the gut and "blood microbiome" represent two rather distinct separate microbiotic compartments. The parenteral provision of n-3 fatty acids appears to protect against proinflammatory bacteria in the gut and against the increased presence of JVC-associated bacteria as measured by circulating bacterial DNA. 10.1016/j.clnesp.2022.03.038
    The effect of gut microbiome on tolerance to morphine mediated antinociception in mice. Kang Minho,Mischel Ryan A,Bhave Sukhada,Komla Essie,Cho Alvin,Huang Charity,Dewey William L,Akbarali Hamid I Scientific reports There is growing appreciation for the importance of gastrointestinal microbiota in many physiological and pathophysiological processes. While morphine and other narcotics are the most widely prescribed therapy for moderate to severe pain clinically, they have been noted to alter microbial composition and promote bacterial translocation to other tissues. Here we examined the pharmacodynamic properties of chronic morphine in mice following bacterial depletion with oral gavage of an antibiotic cocktail (ABX). ABX significantly reduced gut bacteria and prevented chronic morphine induced increases in gut permeability, colonic mucosal destruction, and colonic IL-1β expression. In addition, ABX prevented the development of antinociceptive tolerance to chronic morphine in both the tail-immersion and acetic acid stretch assays. Morphine tolerance was also reduced by oral vancomycin that has 0% bioavailability. These findings were recapitulated in primary afferent neurons isolated from dorsal root ganglia (DRG) innervating the lower gastrointestinal tract, wherein in-vivo administration of ABX prevented tolerance to morphine-induced hypoexcitability. Finally, though ABX repeatedly demonstrated an ability to prevent tolerance, we show that it did not alter susceptibility to precipitation of withdrawal by naloxone. Collectively, these finding indicate that the gastrointestinal microbiome is an important modulator of physiological responses induced by chronic morphine administration. 10.1038/srep42658
    Gut microbiome and serum metabolome analyses identify molecular biomarkers and altered glutamate metabolism in fibromyalgia. Clos-Garcia Marc,Andrés-Marin Naiara,Fernández-Eulate Gorka,Abecia Leticia,Lavín José L,van Liempd Sebastiaan,Cabrera Diana,Royo Félix,Valero Alejandro,Errazquin Nerea,Vega María Cristina Gómez,Govillard Leila,Tackett Michael R,Tejada Genesis,Gónzalez Esperanza,Anguita Juan,Bujanda Luis,Orcasitas Ana María Callejo,Aransay Ana M,Maíz Olga,López de Munain Adolfo,Falcón-Pérez Juan Manuel EBioMedicine BACKGROUND:Fibromyalgia is a complex, relatively unknown disease characterised by chronic, widespread musculoskeletal pain. The gut-brain axis connects the gut microbiome with the brain through the enteric nervous system (ENS); its disruption has been associated with psychiatric and gastrointestinal disorders. To gain an insight into the pathogenesis of fibromyalgia and identify diagnostic biomarkers, we combined different omics techniques to analyse microbiome and serum composition. METHODS:We collected faeces and blood samples to study the microbiome, the serum metabolome and circulating cytokines and miRNAs from a cohort of 105 fibromyalgia patients and 54 age- and environment-matched healthy individuals. We sequenced the V3 and V4 regions of the 16S rDNA gene from faeces samples. UPLC-MS metabolomics and custom multiplex cytokine and miRNA analysis (FirePlex™ technology) were used to examine sera samples. Finally, we combined the different data types to search for potential biomarkers. RESULTS:We found that the diversity of bacteria is reduced in fibromyalgia patients. The abundance of the Bifidobacterium and Eubacterium genera (bacteria participating in the metabolism of neurotransmitters in the host) in these patients was significantly reduced. The serum metabolome analysis revealed altered levels of glutamate and serine, suggesting changes in neurotransmitter metabolism. The combined serum metabolomics and gut microbiome datasets showed a certain degree of correlation, reflecting the effect of the microbiome on metabolic activity. We also examined the microbiome and serum metabolites, cytokines and miRNAs as potential sources of molecular biomarkers of fibromyalgia. CONCLUSIONS:Our results show that the microbiome analysis provides more significant biomarkers than the other techniques employed in the work. Gut microbiome analysis combined with serum metabolomics can shed new light onto the pathogenesis of fibromyalgia. We provide a list of bacteria whose abundance changes in this disease and propose several molecules as potential biomarkers that can be used to evaluate the current diagnostic criteria. 10.1016/j.ebiom.2019.07.031
    Visceral sensitivity modulation by faecal microbiota transplantation: the active role of gut bacteria in pain persistence. Pain ABSTRACT:Recent findings linked gastrointestinal disorders characterized by abdominal pain to gut microbiota composition. The present work aimed to evaluate the power of gut microbiota as a visceral pain modulator and, consequently, the relevance of its manipulation as a therapeutic option in reversing postinflammatory visceral pain persistence. Colitis was induced in mice by intrarectally injecting 2,4-dinitrobenzenesulfonic acid (DNBS). The effect of faecal microbiota transplantation from viscerally hypersensitive DNBS-treated and naive donors was evaluated in control rats after an antibiotic-mediated microbiota depletion. Faecal microbiota transplantation from DNBS donors induced a long-lasting visceral hypersensitivity in control rats. Pain threshold trend correlated with major modifications in the composition of gut microbiota and short chain fatty acids. By contrast, no significant alterations of colon histology, permeability, and monoamines levels were detected. Finally, by manipulating the gut microbiota of DNBS-treated animals, a counteraction of persistent visceral pain was achieved. The present results provide novel insights into the relationship between intestinal microbiota and visceral hypersensitivity, highlighting the therapeutic potential of microbiota-targeted interventions. 10.1097/j.pain.0000000000002438
    Vitamin D deficiency changes the intestinal microbiome reducing B vitamin production in the gut. The resulting lack of pantothenic acid adversely affects the immune system, producing a "pro-inflammatory" state associated with atherosclerosis and autoimmunity. Gominak S C Medical hypotheses STUDY OBJECTIVES:Vitamin D blood levels of 60-80ng/ml promote normal sleep. The present study was undertaken to explore why this beneficial effect waned after 2years as arthritic pain increased. Pantothenic acid becomes coenzyme A, a cofactor necessary for cortisol and acetylcholine production. 1950s experiments suggested a connection between pantothenic acid deficiency, autoimmune arthritis and insomnia. The B vitamins have been shown to have an intestinal bacterial source and a food source, suggesting that the normal intestinal microbiome may have always been the primary source of B vitamins. Review of the scientific literature shows that pantothenic acid does not have a natural food source, it is supplied by the normal intestinal bacteria. In order to test the hypothesis that vitamin D replacement slowly induced a secondary pantothenic acid deficiency, B100 (100mg of all B vitamins except 100mcg of B12 and biotin and 400mcg of folate) was added to vitamin D supplementation. METHODS:Vitamin D and B100 were recommended to over 1000 neurology patients. Sleep characteristics, pain levels, neurologic symptoms, and bowel complaints were recorded by the author at routine appointments. RESULTS:Three months of vitamin D plus B100 resulted in improved sleep, reduced pain and unexpected resolution of bowel symptoms. These results suggest that the combination of vitamin D plus B100 creates an intestinal environment that favors the return of the four specific species, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria that make up the normal human microbiome. HYPOTHESES:1) Seasonal fluctuations in vitamin D levels have normally produced changes in the intestinal microbiome that promoted weight gain in winter. Years of vitamin D deficiency, however, results in a permanently altered intestinal environment that no longer favors the "healthy foursome". 2) Humans have always had a commensal relationship with their intestinal microbiome. We supplied them vitamin D, they supplied us B vitamins. 3) The four species that make up the normal microbiome are also commensal, each excretes at least one B vitamin that the other three need but cannot make. 4) Improved sleep and more cellular repairs eventually depletes body stores of pantothenic acid, causing reduced cortisol production, increased arthritic pain and widespread "pro-inflammatory" effects on the immune system. 5) Pantothenic acid deficiency also decreases available acetylcholine, the neurotransmitter used by the parasympathetic nervous system. Unopposed, increased sympathetic tone then produces hypertension, tachycardia, atrial arrhythmias and a "hyper-adrenergic" state known to predispose to heart disease and stroke. 10.1016/j.mehy.2016.07.007
    Psychoneuroimmunological approach to gastrointestinal related pain. Toljan Karlo,Vrooman Bruce Scandinavian journal of pain BACKGROUND AND PURPOSE (AIMS):Psychoneuroimmunology is both a theoretical and practical field of medicine in which human biology and psychology are considered an interconnected unity. Through such a framework it is possible to elucidate complex syndromes in gastrointestinal related pain, particularly chronic non-malignant. The aim is to provide insight into pathophysiological mechanisms and suggest treatment modalities according to a comprehensive paradigm. The article also presents novel findings that may guide clinicians to recognize new targets or scientists to find new research topics. METHODS:A literature search of 'PubMed' and 'Google Scholar' databases was performed. Search terms included: 'Visceral pain', 'Psychoneuroimmunology', 'Psychoneuroimmunology and pain', 'Pain in GI system', 'GI related pain', 'Pain and microbiota', 'Enteric nervous system', 'Enteric nervous system and inflammation', 'CNS and pain', 'Inflammation and pain in GI tract', 'Neurogastroenterology', 'Neuroendocrinology', 'Immune system in GI pain'. After searching and reading sources deemed recent and relevant, a narrative review was written with a tendency to discriminate the peripheral, intermediate, and central pathophysiological mechanisms or treatment targets. RESULTS:Recent evidence point out the importance of considering the brain-gut axis as the main connector of the central and peripheral phenomena encountered in patients suffering from chronic non-malignant gastrointestinal related pain. This axis is also a prime clinical target with multiple components to be addressed in order for therapy to be more effective. Patients suffering from inflammatory bowel disease or functional gastrointestinal disorders represent groups that could benefit most from the proposed approach. CONCLUSIONS (BASED ON OUR FINDINGS):Rather than proceeding with established allopathic single-target central or peripheral treatments, by non-invasively modulating the brain-gut axis components such as the psychological and neuroendocrinological status, microbiota, enteric nervous system, or immune cells (e.g. glial or mast cells), a favourable clinical outcome in various chronic gastrointestinal related pain syndromes may be achieved. Clinical tools are readily available in forms of psychotherapy, prebiotics, probiotics, nutritional advice, and off-label drugs. An example of the latter is low-dose naltrexone, a compound which opens the perspective of targeting glial cells to reduce neuroinflammation and ultimately pain. IMPLICATIONS (OUR OPINION ON WHAT OUR FINDINGS MEAN):Current findings from basic science provide sound mechanistic evidence and once entering clinical practice should yield more effective outcomes for patients. In addition to well-established pharmacotherapy comprised notably of anti-inflammatories, antibiotics, and proton-pump inhibitors, valid treatment strategies may contain other options. These disease modulating add-ons include probiotics, prebiotics, food supplements with anti-inflammatory properties, various forms of psychotherapy, and low-dose naltrexone as a glial modulator that attenuates neuroinflammation. Clearly, a broader and still under exploited set of evidence-based tools is available for clinical use. 10.1016/j.sjpain.2017.10.010
    Gut Mucosal Microbiome Is Perturbed in Rheumatoid Arthritis Mice and Partly Restored after TDAG8 Deficiency or Suppression by Salicylanilide Derivative. International journal of molecular sciences Rheumatoid arthritis (RA), an autoimmune disease, is characterized by chronic joint inflammation and pain. We previously found that the deletion of T-cell death-associated gene 8 (TDAG8) significantly reduces disease severity and pain in RA mice. Whether it is by modulating gut microbiota remains unclear. In this study, 64 intestinal samples of feces, cecal content, and cecal mucus from the complete Freund's adjuvant-induced arthritis mouse models were compared. The - and -diversity indices of the microbiome were significantly lower in RA mice. Cecal mucus showed a higher ratio of to in RA than healthy mice, suggesting the ratio could serve as an RA indicator. Four core genera, , , , and , were reduced in content in both feces and mucus RA samples, and could serve microbial markers representing RA progression. TDAG8 deficiency decreased the abundance of proinflammation-related , , , , and , which reduced local mucosal inflammation to relieve RA disease severity and pain. The pharmacological block of the TDAG8 function by a salicylanilide derivative partly restored the RA microbiome to a healthy composition. These findings provide a further understanding of specific bacteria interactions with host gut mucus in the RA model. The modulation by TDAG8 on particular bacteria can facilitate microbiota-based therapy. 10.3390/ijms23073527
    The Human Gut Microbiome and Its Relationship with Osteoarthritis Pain. Turroni Silvia,Pedersini Paolo,Villafañe Jorge Hugo Pain medicine (Malden, Mass.) 10.1093/pm/pnaa422
    Pain, Motivation, Migraine, and the Microbiome: New Frontiers for Opioid Systems and Disease. Parker Kyle E,Sugiarto Elizabeth,Taylor Anna M W,Pradhan Amynah A,Al-Hasani Ream Molecular pharmacology For decades the broad role of opioids in addiction, neuropsychiatric disorders, and pain states has been somewhat well established. However, in recent years, with the rise of technological advances, not only is the existing dogma being challenged, but we are identifying new disease areas in which opioids play a critical role. This review highlights four new areas of exploration in the opioid field. The most recent addition to the opioid family, the nociceptin receptor system, shows promise as the missing link in understanding the neurocircuitry of motivation. It is well known that activation of the kappa opioid receptor system modulates negative affect and dysphoria, but recent studies now implicate the kappa opioid system in the modulation of negative affect associated with pain. Opioids are critical in pain management; however, the often-forgotten delta opioid receptor system has been identified as a novel therapeutic target for headache disorders and migraine. Lastly, changes to the gut microbiome have been shown to directly contribute to many of the symptoms of chronic opioid use and opioid related behaviors. This review summarizes the findings from each of these areas with an emphasis on identifying new therapeutic targets. SIGNIFICANCE STATEMENT: The focus of this minireview is to highlight new disease areas or new aspects of disease in which opioids have been implicated; this includes pain, motivation, migraine, and the microbiome. In some cases, this has resulted in the pursuit of a novel therapeutic target and resultant clinical trial. We believe this is very timely and will be a refreshing take on reading about opioids and disease. 10.1124/mol.120.119438
    Analysis of Gut Microbiome Reveals Significant Differences between Men with Chronic Prostatitis/Chronic Pelvic Pain Syndrome and Controls. Shoskes Daniel A,Wang Hannah,Polackwich Alan S,Tucky Barbara,Altemus Jessica,Eng Charis The Journal of urology PURPOSE:Chronic prostatitis/chronic pelvic pain syndrome is a common disorder with heterogeneous etiologies and clinical features. The gut microbiome is a metabolically active ecosystem linked to systemic conditions (gut-brain axis). We hypothesize that the gut microbiome will show alterations between patients with chronic pelvic pain syndrome and controls. MATERIALS AND METHODS:We identified patients with chronic pelvic pain syndrome and controls who were asymptomatic or only had urinary tract symptoms. After rectal examination the soiled glove tip was immersed in sterile saline and stored on ice. Symptom severity was measured with the NIH-Chronic Prostatitis Symptom Index and clinical phenotype with UPOINT. Total DNA was extracted from the pellet of samples. MiSeq sequencing of bacterial specific 16S rRNA capture was performed. Taxonomic and bioinformatic analyses were performed using principal coordinate analysis, QIIME and LEfSe algorithms. RESULTS:There were 25 patients and 25 controls with complete data. Mean age was similar (chronic pelvic pain syndrome 52.3 vs control 57.0 years, p=0.27). For patients with chronic pelvic pain syndrome median symptom duration was 48 months, mean Chronic Prostatitis Symptom Index was 26.0 and mean UPOINT domain was 3.6. Three-dimensional UniFrac principal coordinate analysis revealed tighter clustering of controls in a space distinct from the wider clustering of cases (p=0.001) with cases having decreased alpha diversity (p=0.001). Compared to controls, 3 taxa were overrepresented in cases and 12 were underrepresented, eg Prevotella. CONCLUSIONS:Patients with chronic pelvic pain syndrome have significantly less gut microbiome diversity which clusters differently from controls, and robustly lower counts of Prevotella, with separation sufficient to serve as a potential biomarker. The gut microbiome may serve as disease biomarker and potential therapeutic target in chronic pelvic pain syndrome. 10.1016/j.juro.2016.02.2959
    Visceral pain and gastrointestinal microbiome. Chichlowski Maciej,Rudolph Colin Journal of neurogastroenterology and motility A complex set of interactions between the microbiome, gut and brain modulate responses to visceral pain. These interactions occur at the level of the gastrointestinal mucosa, and via local neural, endocrine or immune activity; as well as by the pro-duction of factors transported through the circulatory system, like bacterial metabolites or hormones. Various psychological, in-fectious and other stressors can disrupt this harmonious relationship and alter both the microbiome and visceral pain responses. There are critical sensitive periods that can impact visceral pain responses in adulthood. In this review we provide a brief background of the intestinal microbiome and emerging concepts of the bidirectional interactions between the micro-biome, gut and brain. We also discuss recent work in animal models, and human clinical trials using prebiotics and probiotics that alter the microbiome with resultant alterations in visceral pain responses. 10.5056/jnm15025
    Correlation Between Gut Microbiome Composition and Acute Pain Perception in Young Healthy Male Subjects. Shiro Yukiko,Arai Young-Chang,Ikemoto Tatsunori,Ueda Wasa,Ushida Takahiro Pain medicine (Malden, Mass.) OBJECTIVE:Recently, there has been growing interest in the gut-brain axis because it is emerging as a player influencing the health status of the host human. It is a known fact that the gut microbiome (GM) through the gut-brain axis has been implicated in numerous diseases. We previously reported that stool condition was associated with pain perception. Stool consistency and constipation are known to be associated with GM composition. Thus, we imagine that GM composition could influence pain perception. The aim of this study was to investigate the correlations between GM composition and pain perception and psychological states in young healthy male subjects. SUBJECTS:A total of 42 healthy young male volunteers completed the present study. METHODS:The volunteers' pain perceptions were assessed by pressure pain threshold, current perception threshold, temporal summation of pain, and conditioned pain modulation, and a questionnaire on psychological state was obtained. During the current perception threshold examination, we used 5, 250, and 2,000 Hz to stimulate C, Aδ, and Aβ fibers. In addition, GM composition was evaluated by using 16S rRNA analysis. RESULTS:Pressure pain threshold showed a significant and negative correlation with Bacteroidetes phylum, in contrast to a significant and positive correlation with Firmicutes phylum. Current perception threshold of Aδ and Firmicutes phylum showed a significant correlation. There was a negative correlation between anxiety state and Bifidobacterium genus. In contrast, there was no significant correlation between psychological states and pain perceptions. CONCLUSION:The present study showed that acute pain perception was associated with GM composition in young healthy males. 10.1093/pm/pnaa401
    The bidirectional interaction of the gut microbiome and the innate immune system: Implications for chemotherapy-induced gastrointestinal toxicity. Secombe Kate R,Coller Janet K,Gibson Rachel J,Wardill Hannah R,Bowen Joanne M International journal of cancer Chemotherapy-induced gastrointestinal toxicity (CIGT) occurs in up to 80% of all patients undergoing cancer treatment, and leads to symptoms such as diarrhoea, abdominal bleeding and pain. There is currently limited understanding of how to predict an individual patient's risk of CIGT. It is believed the gut microbiome and its interactions with the host's innate immune system plays a key role in the development of this toxicity and potentially other toxicities, however comprehensive bioinformatics modelling has not been rigorously performed. The innate immune system is strongly influenced by the microbial environment and vice-versa. Ways this may occur include the immune system controlling composition and compartmentalisation of the microbiome, the microbiome affecting development of antigen-presenting cells, and finally, the NLRP6 inflammasome orchestrating the colonic host-microbiome interface. This evidence calls into question the role of pre-treatment risk factors in the development of gastrointestinal toxicity after chemotherapy. This review aims to examine evidence of a bidirectional interaction between the gut microbiome and innate immunity, and how these interactions occur in CIGT. In the future, knowledge of these interactions may lead to improved personalised cancer medicine, predictive risk stratification methods and the development of targeted interventions to reduce, or even prevent, CIGT severity. 10.1002/ijc.31836
    Intestinal microbiome composition and its relation to joint pain and inflammation. Boer Cindy G,Radjabzadeh Djawad,Medina-Gomez Carolina,Garmaeva Sanzhima,Schiphof Dieuwke,Arp Pascal,Koet Thomas,Kurilshikov Alexander,Fu Jingyuan,Ikram M Arfan,Bierma-Zeinstra Sita,Uitterlinden André G,Kraaij Robert,Zhernakova Alexandra,van Meurs Joyce B J Nature communications Macrophage-mediated inflammation is thought to have a causal role in osteoarthritis-related pain and severity, and has been suggested to be triggered by endotoxins produced by the gastrointestinal microbiome. Here we investigate the relationship between joint pain and the gastrointestinal microbiome composition, and osteoarthritis-related knee pain in the Rotterdam Study; a large population based cohort study. We show that abundance of Streptococcus species is associated with increased knee pain, which we validate by absolute quantification of Streptococcus species. In addition, we replicate these results in 867 Caucasian adults of the Lifelines-DEEP study. Finally we show evidence that this association is driven by local inflammation in the knee joint. Our results indicate the microbiome is a possible therapeutic target for osteoarthritis-related knee pain. 10.1038/s41467-019-12873-4
    Reduced Gut Microbiome Diversity in People With HIV Who Have Distal Neuropathic Pain. Ellis Ronald J,Heaton Robert K,Gianella Sara,Rahman Gibraan,Knight Rob The journal of pain Gut dysbiosis, defined as pathogenic alterations in the distribution and abundance of different microbial species, is associated with neuropathic pain in a variety of clinical conditions, but this has not been explored in the context of neuropathy in people with HIV (PWH). We assessed gut microbial diversity and dysbiosis in PWH and people without HIV (PWoH), some of whom reported distal neuropathic pain (DNP). DNP was graded on a standardized, validated severity scale. The gut microbiome was characterized using 16S rRNA sequencing and diversity was assessed using phylogenetic tree construction. Songbird analysis (https://github.com/mortonjt/songbird) was used to produce a multinomial regression model predicting counts of specific microbial taxa through metadata covariate columns. Participants were 226 PWH and 101 PWoH, mean (SD) age 52.0 (13.5), 21.1% female, 54.7% men who have sex with men, 44.7% non-white. Among PWH, median (interquartile range, IQR) nadir and current CD4 were 174 (21, 302) and 618 (448, 822), respectively; 90% were virally suppressed on antiretroviral therapy. PWH and PWoH did not differ with respect to microbiome diversity as indexed by Faith's phylogenetic diversity (PD). More severe DNP was associated with lower alpha diversity as indexed by Faith's phylogenetic diversity in PWH (Spearman's ρ = .224, P = 0.0007), but not in PWoH (Spearman's ρ = .032, P = .748). These relationships were not confounded by demographics or disease factors. In addition, the log-ratio of features identified at the genus level as Blautia to Lachnospira was statistically significantly higher in PWH with DNP than in PWH without DNP (t-test, P = 1.01e-3). Furthermore, the log-ratio of Clostridium features to Lachnospira features also was higher in PWH with DNP than in those without (t-test, P = 6.24e-5). Our results, in combination with previous findings in other neuropathic pain conditions, suggest that gut dysbiosis, particularly reductions in diversity and relative increases in the ratios of Blautia and Clostridium to Lachnospira, may contribute to prevalent DNP in PWH. Two candidate pathways for these associations, involving microbial pro-inflammatory components and microbially-produced anti-inflammatory short chain fatty acids, are discussed. Future studies might test interventions to re-establish a healthy gut microbiota and determine if this prevents or improves DNP. PERSPECTIVE: The association of neuropathic pain in people with HIV with reduced gut microbial diversity and dysbiosis raises the possibility that re-establishing a healthy gut microbiota might ameliorate neuropathic pain in HIV by reducing proinflammatory and increasing anti-inflammatory microbial products. 10.1016/j.jpain.2021.08.006
    An association between chronic widespread pain and the gut microbiome. Freidin Maxim B,Stalteri Maria A,Wells Philippa M,Lachance Genevieve,Baleanu Andrei-Florin,Bowyer Ruth C E,Kurilshikov Alexander,Zhernakova Alexandra,Steves Claire J,Williams Frances M K Rheumatology (Oxford, England) OBJECTIVES:Chronic widespread musculoskeletal pain (CWP) is a characteristic symptom of fibromyalgia, which has been shown to be associated with an altered gut microbiome. Microbiome studies to date have not examined the milder CWP phenotype specifically nor have they explored the role of raised BMI. The aim of this study was to investigate whether the microbiome is abnormal in CWP. METHODS:CWP was assessed using a standardized screening questionnaire in female volunteers from the TwinsUK cohort including 113 CWP cases and 1623 controls. The stool microbiome was characterized using 16S rRNA amplicon sequencing and amplicon sequence variants, and associations with CWP examined using linear mixed-effects models adjusting for BMI, age, diet, family relatedness and technical factors. RESULTS:Alpha diversity was significantly lower in CWP cases than controls (Mann-Whitney test, P-values 2.3e-04 and 1.2e-02, for Shannon and Simpson indices respectively). The species Coprococcus comes was significantly depleted in CWP cases (Padj = 3.04e-03). A genome-wide association study (GWAS) performed for C. comes in TwinsUK followed by meta-analysis with three Dutch cohorts (total n = 3521) resulted in nine suggestive regions, with the most convincing on chromosome 4 near the TRAM1L1 gene (rs76957229, P = 7.4e-8). A Mendelian randomization study based on the results of the GWAS did not support a causal role for C. comes on the development of CWP. CONCLUSIONS:We have demonstrated reduced diversity in the microbiome in CWP, indicating an involvement of the gut microbiota in CWP; prospectively the microbiome may offer therapeutic opportunities for this condition. 10.1093/rheumatology/keaa847
    Acyloxyacyl hydrolase is a host determinant of gut microbiome-mediated pelvic pain. Rahman-Enyart Afrida,Yang Wenbin,Yaggie Ryan E,White Bryan A,Welge Michael,Auvil Loretta,Berry Matthew,Bushell Colleen,Rosen John M,Rudick Charles N,Schaeffer Anthony J,Klumpp David J American journal of physiology. Regulatory, integrative and comparative physiology Dysbiosis of gut microbiota is associated with many pathologies, yet host factors modulating microbiota remain unclear. Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating condition of chronic pelvic pain often with comorbid urinary dysfunction and anxiety/depression, and recent studies find fecal dysbiosis in patients with IC/BPS. We identified the locus encoding acyloxyacyl hydrolase, , as a modulator of pelvic pain severity in a murine IC/BPS model. AOAH-deficient mice spontaneously develop rodent correlates of pelvic pain, increased responses to induced pelvic pain models, voiding dysfunction, and anxious/depressive behaviors. Here, we report that AOAH-deficient mice exhibit dysbiosis of gastrointestinal (GI) microbiota. AOAH-deficient mice exhibit an enlarged cecum, a phenotype long associated with germ-free rodents, and a "leaky gut" phenotype. AOAH-deficient ceca showed altered gene expression consistent with inflammation, Wnt signaling, and urologic disease. 16S sequencing of stool revealed altered microbiota in AOAH-deficient mice, and GC-MS identified altered metabolomes. Cohousing AOAH-deficient mice with wild-type mice resulted in converged microbiota and altered predicted metagenomes. Cohousing also abrogated the pelvic pain phenotype of AOAH-deficient mice, which was corroborated by oral gavage of AOAH-deficient mice with stool slurry of wild-type mice. Converged microbiota also alleviated comorbid anxiety-like behavior in AOAH-deficient mice. Oral gavage of AOAH-deficient mice with anaerobes cultured from IC/BPS stool resulted in exacerbation of pelvic allodynia. Together, these data indicate that AOAH is a host determinant of normal gut microbiota, and dysbiosis associated with AOAH deficiency contributes to pelvic pain. These findings suggest that the gut microbiome is a potential therapeutic target for IC/BPS. 10.1152/ajpregu.00106.2021
    Relationship between the Gut Microbiome and Osteoarthritis Pain: Review of the Literature. Sánchez Romero Eleuterio A,Meléndez Oliva Erika,Alonso Pérez José Luis,Martín Pérez Sebastián,Turroni Silvia,Marchese Lorenzo,Villafañe Jorge Hugo Nutrients BACKGROUND:Osteoarthritis (OA) is the most common form of chronic pain in Europe (34%), representing a great economic and social cost to society. There are studies that suggest an intestine-brain-articulation axis and hint at the existence of low-grade intestinal inflammation in OA, which would be related to an alteration of the microbiota and to the impairment of the epithelial barrier, with leakage of the microbial components. PURPOSE:The purpose of this study was to review the association between gut microbiome and pain in the OA population through a review of the literature. METHODS:A literature search was conducted to identify all available studies on the association between the gut microbiome and pain in the OA population, with no publication date limit until September 2020 and no language limit, in the MEDLINE, CINAHL, Web of Science and Cochrane Central Register of Controlled Trials databases. RESULTS:Only three of 2084 studies detected and analyzed by performing the proposed searches in the detailed databases, were finally selected for this review, of which one was with and two were without intervention. These studies only weakly support a relationship between the gut microbiome and OA, specifically a correlation between certain taxa or microbial products and the inflammatory landscape and severity of OA symptoms, including knee pain. Conclusions Despite encouraging results, this review highlights the paucity of high-quality studies addressing the potential role of the gut microbiome in OA-related pain, along with the disparity of the techniques used so far, making it impossible to draw firm conclusions on the topic. 10.3390/nu13030716
    Gut Microbiome in Anesthesiology and Pain Medicine. Anesthesiology The gut microbiome plays critical roles in human health and disease. Recent studies suggest it may also be associated with chronic pain and postoperative pain outcomes. In animal models, the composition of the gut microbiome changes after general anesthesia and affects the host response to medications, including anesthetics and opioids. In humans, the gut microbiome is associated with the development of postoperative pain and neurocognitive disorders. Additionally, the composition of the gut microbiome has been associated with pain conditions including visceral pain, nociplastic pain, complex regional pain syndrome, and headaches, partly through altered concentration of circulating bacterial-derived metabolites. Furthermore, animal studies demonstrate the critical role of the gut microbiome in neuropathic pain via immunomodulatory mechanisms. This article reviews basic concepts of the human gut microbiome and its interactions with the host and provide a comprehensive overview of the evidence linking the gut microbiome to anesthesiology, critical care, and pain medicine. 10.1097/ALN.0000000000004204
    Rifaximin Improves Visceral Hyperalgesia via TRPV1 by Modulating Intestinal Flora in the Water Avoidance Stressed Rat. Gastroenterology research and practice BACKGROUND:Rifaximin is effective in relieving pain symptoms with IBS patients, although the mechanisms were not clear. The aims of the research were to investigate whether the visceral hyperalgesia was alleviated by rifaximin via TRPV1 channel in rats. METHODS:Rats were subjected to water avoidance stress (WAS) and were pretreated with rifaximin by oral gavage. The visceromotor response to colorectal distension was measured. The changes of TRPV1 in peripheral and central neurons of rats were detected by immunofluorescence, western blot method, and RT-PCR. Bacterial 16S ribosomal DNA in ileal contents was assessed using the Illumina MiSeq platform. The effect of intestinal flora on TRPV1 channel was observed by fecal microbiota transplantation (FMT) methods. RESULTS:Rifaximin could relieve the visceral hyperalgesia and reduce the TRPV1 expression of neurons and ileum mucosa in rats induced by WAS. The reduced relative abundance of intestinal flora induced by WAS could be partly prevented by rifaximin. The electromyographical activities and immunoreactivity of TRPV1 in rats could be changed after FMT. CONCLUSIONS:Rifaximin could improve visceral hyperalgesia via TRPV1 channels of peripheral and central neurons by modulating intestinal flora in rats. 10.1155/2020/4078681
    Gut flora-targeted photobiomodulation therapy improves senile dementia in an Aß-induced Alzheimer's disease animal model. Chen Qianqian,Wu Jinpeng,Dong Xiaoxi,Yin Huijuan,Shi Xiafei,Su Siying,Che Bochen,Li Yingxin,Yang Jichun Journal of photochemistry and photobiology. B, Biology BACKGROUND:Emerging evidence suggests that the gut microbiota plays an important role in the pathological progression of Alzheimer's disease (AD). Photobiomodulation (PBM) therapy is believed to have a positive regulatory effect on the imbalance of certain body functions, including inflammation, immunity, wound healing, nerve repair, and pain. Previous studies have found that the intestinal flora of patients with AD is in an unbalanced state. Therefore, we have proposed the use of gut flora-targeted PBM (gf-targeted PBM) as a method to improve AD in an Aß-induced AD mouse model. METHODS:PBM was performed on the abdomen of the mice at the wavelengths of 630 nm, 730 nm, and 850 nm at 100 J/cm for 8 weeks. Morris water maze test, immunofluorescence and proteomic of hippocampus, and intestinal flora detection of fecal were used to evaluate the treatment effects of gf-targeted PBM on AD rats. RESULTS:PBM at all three wavelengths (especially 630 nm and 730 nm) significantly improved learning retention as measured by the Morris water maze. In addition, we found reduced amyloidosis and tau phosphorylation in the hippocampus by immunofluorescence in AD mice. By using a quantitative proteomic analysis of the hippocampus, we found that gf-targeted PBM significantly altered the expression levels of 509 proteins (the same differentially expressed proteins in all three wavelengths of PBM), which involved the pathways of hormone synthesis, phagocytosis, and metabolism. The 16 s rRNA gene sequencing of fecal contents showed that PBM significantly altered the diversity and abundance of intestinal flora. Specifically, PBM treatment reversed the typical increase of Helicobacter and uncultured Bacteroidales and the decrease of Rikenella seen in AD mice. CONCLUSIONS:Our data indicate that gf-targeted PBM regulates the diversity of intestinal flora, which may improve damage caused by AD. Gf-targeted PBM has the potential to be a noninvasive microflora regulation method for AD patients. 10.1016/j.jphotobiol.2021.112152