Pathophysiology Of Irritable Bowel Syndrome Research Articles

Tranilast alleviates visceral hypersensitivity and colonic hyperpermeability by suppressing NLRP3 inflammasome activation in irritable bowel syndrome rat models

Visceral hypersensitivity resulting from compromised gut barrier with activated immune system is a key feature of irritable bowel syndrome (IBS). Corticotropin-releasing factor (CRF) and Toll-like receptor 4 (TLR4) activate proinflammatory cytokine signaling to induce these changes, which is one of the mechanisms of IBS. As activation of the NLRP3 inflammasome by lipopolysaccharide (LPS) or TLR4 leads to release interleukin (IL)-1β, the NLRP3 inflammasome may be involved in the pathophysiology of IBS. Tranilast, an anti-allergic drug has been demonstrated to inhibit the NLRP3 inflammasome, and we evaluated the impact of tranilast on visceral hypersensitivity and colonic hyperpermeability induced by LPS or CRF (IBS rat model). Visceral pain threshold caused by colonic balloon distention was measured by monitoring abdominal muscle contractions electrophysiologically. Colonic permeability was determined by quantifying the absorbed Evans blue within the colonic tissue. Colonic protein levels of NLRP3 and IL-1β were assessed by immunoblot or ELISA. Intragastric administration of tranilast (20–200 mg/kg) for 3 days inhibited LPS (1 mg/kg)-induced visceral hypersensitivity and colonic hyperpermeability in a dose-dependent manner. Simultaneously, tranilast also abolished these alterations induced by CRF (50 µg/kg). LPS increased colonic protein levels of NLRP3 and IL-1β, and tranilast inhibited these changes. β-hydroxy butyrate, an NLRP3 inhibitor, also abolished visceral hypersensitivity and colonic hyperpermeability caused by LPS. In contrast, IL-1β induced similar GI alterations to LPS, which were not modified by tranilast. In conclusion, tranilast improved visceral pain and colonic barrier by suppression of the NLRP3 inflammasome in IBS rat models. Tranilast may be useful for IBS treating.

Management of irritable bowel syndrome: a narrative review.

As our understanding of the pathophysiology of irritable bowel syndrome (IBS) has advanced, so too has the therapeutic landscape, offering a myriad of approaches to alleviate symptoms and enhance the well-being of patients. This review paper is dedicated to a comprehensive exploration of the diverse therapeutic modalities available for managing IBS. By delving into the complexities of IBS therapeutics, our aim is to contribute to the enhancement of patient care and the overall quality of life for patients grappling with this complex condition. This review utilized information from PubMed/MEDLINE using the key search term "irritable bowel syndrome" as well as the 2020 American College of Gastroenterology (ACG) and 2022 American Gastroenterological Association (AGA) society guidelines on IBS. The search was restricted to articles in the English language only and included peer-reviewed observational studies and randomized controlled trials (RCTs) in adult patients from April 22, 2020 to October 16, 2023. This review will start with an overview of the current guidelines for pharmacologic therapies for IBS as recommended by the ACG and the AGA, with an emphasis on clinical trials published after the most recent guidelines. It will then delve into the literature on dietary modifications, probiotics, fecal microbiota transplant, behavioral therapy, and complementary and alternative medicine approaches to IBS. It is evident that the management of IBS has transcended a one-size-fits-all approach. As the field of IBS management continues to evolve, it is imperative for physicians to stay informed and receptive to the array of therapeutic options available, ultimately providing patients with the most effective and personalized care.

Role of autoantibodies in the pathophysiology of irritable bowel syndrome: a review.

Irritable bowel syndrome (IBS) is a chronic, recurrent disorder that is characterized by abdominal pain associated with defecation. IBS was previously considered to manifest without any structural alterations until the discovery of post-infection IBS. An increasing body of published evidence indicates that immune activation plays an important role in the development of IBS. Nevertheless, the pathophysiology of IBS, including mainly visceral hypersensitivity and gastrointestinal dysmotility, has not yet been explicitly elucidated. The observation of potential inflammatory degenerative neuropathy, including neuronal degeneration, spearheaded research on autoimmune responses targeting the enteric nervous system. Subsequently, several autoantibodies were detected in the sera of IBS patients, among which some were presumed to exert a pathogenic influence or be associated with the etiology of gastrointestinal dysmotility in IBS. Moreover, certain specific autoantibodies evidently served as biomarkers to facilitate the differentiation between IBS and other related diseases. Therefore, we aimed to present an overview of autoantibodies reported in the sera of IBS patients and highlight their significance in diagnosing and comprehending the pathophysiology of IBS. Consequently, we propose a therapeutic strategy from an autoimmune perspective.

Reminder of Important Clinical Lesson: Irritable Bowel Syndrome in Primary Care Physicians

Irritable bowel syndrome (IBS) is one of the most commonly diagnosed gastrointestinal diseases. IBS, in the absence of any other causative disease, is defined as the presence of abdominal pain or discomfort with altered bowel habits. The etiology of IBS is broad and not clearly understood. Nearly 12 percent of patients seek medical care in primary care practices for IBS related complaints. The pathophysiology of IBS is broad and includes abnormalities involving motility, visceral sensation, brain-gut interaction, and psychosocial distress. The clinical case presented has the textual characteristics that represent treating a patient with diagnostic criteria for this pathology. Presenting prevalent cases helps the physician in training and specialists not to overlook what is common in clinical practice.

The Role of Diet in the Management of Irritable Bowel Syndrome: A Comprehensive Review.

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder that has a significant impact on the general population. The suboptimal medical treatments available for IBS contribute to its large economic burden. The pathophysiology of IBS is complex, and treatments often focus on managing specific symptoms. Many individuals with IBS associate their symptoms with specific food intake, leading to increased scientific research on the role of diet in managing IBS. Dietary management has become a crucial aspect of IBS treatment, with initial recommendations focusing on adopting a healthy eating pattern and lifestyle. This comprehensive review aims to synthesise the current literature on the impact of diet on IBS, exploringvarious dietary approaches to managing IBS, including the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, gluten-free diet, Mediterranean diet, and tritordeum-based diet. It presents evidence from both experimental and observational studies and summarises the underlying dietary triggers in IBS, including gut microbiota dysbiosis, visceral hypersensitivity, and immune activation. In addition, it explores the efficacy and limitations of the key diet and lifestyle recommendations provided by dietary guidelines and scientific literature, highlighting the importance of individualised dietary strategies tailored to the unique needs of different types of IBS patients. By elucidating the complex interplay between diet and IBS pathophysiology, this review provides valuable insights into optimising dietary management approaches for improving symptom control and enhancing the quality of life for individuals with IBS.

Contextualization of the concept of nociplastic pain in irritable bowel syndrome.

The objective of this letter to the editor is to contextualize the concept of "nociplastic pain" in functional digestive disorders, especially in irritable bowel syndrome (IBS); and try to differentiate it from the term central sensitization, increasingly used in the literature, and with notable relevance in the pathophysiology of IBS.

Variety of Serotonin Levels in Pediatric Gastrointestinal Disorders.

(1) Serotonin primarily regulates our emotions. A complex process, which includes dysfunctions in gastrointestinal motility and deregulation of the gene responsible for serotonin reuptake (SERT), is implicated in the pathophysiology of irritable bowel syndrome (IBS). This also encompasses changes in intestinal microbiota, the response to stress, the intricate interplay between the brain and the digestive tract, heightened sensitivity to visceral stimuli, and low-grade inflammation. This paper aims to investigate the effectiveness of probiotic therapy in managing gastrointestinal and neuropsychiatric symptoms related to serotonin levels, with a focus on individuals with serotonin deficiency and those with normal serotonin levels experiencing gastrointestinal disorders. (2) The study involved 135 pediatric patients aged 5-18 years with gastrointestinal disturbances, including constipation, diarrhea, and other symptoms, such as nausea, flatulence, feeling full, or gastrointestinal pain. (3) Serotonin testing was performed, and administering probiotics appeared to be effective in addressing serotonin deficiency and other gastrointestinal disorders. (4) Serotonin's pivotal role in regulating neurotransmitter secretion and its impact on neuropsychiatric health, coupled with gender differences and age-related declines, underscore the complexity of their influence on gastrointestinal and neuropsychiatric conditions.

Probotics: A Promising Solution for Irritable Bowel Syndrome (Ibs)

Irritable Bowel Syndrome (IBS) is a distressing functional gastrointestinal disorder that is increasingly recognized as a condition involving both the gut and the brain. In today's healthcare landscape, probiotics have become a common component of many people's wellness routines, independent of prescribed medications. There is substantial evidence supporting the potential of probiotics to provide therapeutic benefits for individuals dealing with irritable bowel syndrome. Recent studies emphasize the pivotal role of the microbial factor in the pathophysiology of IBS, as some research has identified significant alterations in the gut microbiome of individuals with IBS. Consequently, the impact of probiotics on IBS patients is under intense investigation in the current era of probiotic research. The precise mechanisms of action are not yet fully understood, but presently, probiotic products tailored for IBS relief are readily available in the market and have shown the potential to alleviate symptoms effectively. Evidence suggested that strains of Lactobacillus species, strains of Pediococcus species and Bifidibacterium species may show effective results in some patients of IBS. The aim of this study is to uncover potential causative factors contributing to IBS and to explore the use of probiotics as an efficacious treatment approach for IBS.

Modulation of Intestinal Motility in an Adolescent Rat Model of Irritable Bowel Syndrome

Introduction: The pathophysiology of irritable bowel syndrome (IBS) remains unknown. This study aimed to evaluate colonic motility and serotonin system response to restraint stress (RS) among adolescent rats who underwent neonatal maternal separation (NMS) to clarify the features of pathogenesis in adolescents with IBS. Methods: Male rats were exposed to NMS as chronic stress, and a normally handled (NH) group was used as control. Four groups were created by adding RS as acute stress treatment to the NMS and NH groups. To realize the RS treatment, the subjects were restrained for 1 h at the age of 5 weeks, and hourly fecal pellet discharge was determined. After euthanization and proximal colon intestinal tissue collection, 5-hydroxytryptamine (5-HT) and 5-hydroxytryptamine receptor 3 (5-HT3R) concentrations, enterochromaffin (EC) cell density, and the expression of mRNA-encoding slc6a4 were examined. Results: The amount of fecal pellet discharge during RS increased significantly in the RS and NMS+RS groups compared with that in the NH and NMS groups, respectively. The 5-HT concentration in the intestinal tissue of rats in the RS and NMS groups increased significantly compared with that of rats in the NH group. EC cell density also increased significantly in the NMS and NMS+RS groups compared with that in the NH and RS groups. However, combined stress did not result in any significant differences in the expression of 5-HT3R and mRNA-encoding slc6a4. Conclusions: The combination of juvenile and acute stress effectively induced increased 5-HT concentration or EC cell density via the 5-HT pathway in the proximal colon of adolescent rats.

A systematic review and meta-analysis of diet and nutrient intake in adults with irritable bowel syndrome.

Numerous individual and environmental factors including diet may play an important role in the pathophysiology of irritable bowel syndrome (IBS). It is unclear to what degree dietary intake is affected in individuals with IBS. We aimed to perform a systematic review and meta-analysis to summarize dietary intake of adults with IBS and to compare dietary intake between adults with IBS and non-IBS controls. Ovid MEDLINE, Embase, Cochrane, CINAHL, and Scopus were searched through February 2023 for clinical trials and observational studies measuring usual diet in adults with IBS. Pooled weighted averages were estimated for total energy, macronutrient, and micronutrient data. Mean differences (MD) in nutrient intake were estimated for adults with IBS versus non-IBS controls using a random effects model. Heterogeneity was assessed by the inconsistency index (I2). Sixty-three full-text articles were included in the review of which 29 studies included both IBS and control subjects. Nutrients not meeting the recommended intake level for any dietary reference values in the IBS population were fiber and vitamin D. Meta-regression by female proportion was positively correlated with total fat intake and negatively correlated with carbohydrate intake. Comparisons between participants with IBS and controls showed significantly lower fiber intake in participants with IBS with high heterogeneity (MD: -1.8; 95% CI: -3.0, -0.6; I2 = 85%). This review suggests that fiber and vitamin D intake is suboptimal in IBS; however, overall dietary intake does not appear to be comprised. Causes and consequences of reduced fiber in IBS deserve further study. Results of this systematic review and meta-analysis suggest that fiber and vitamin D intake is suboptimal in IBS. However, overall intake of other macro- and micronutrients does not appear to be compromised. Causes and consequences of reduced fiber and Vitamin D intake in IBS deserve further study.

The Use of Fibers, Herbal Medicines and Spices in Children with Irritable Bowel Syndrome: A Narrative Review.

The pathophysiology of irritable bowel syndrome in children involves multiple factors. Thus, treatment options are variable, targeting both diet and the child's and parents' behavior via pharmacological and psychological interventions or neuromodulation. Parents are increasingly interested in complementary and alternative therapies for children with irritable bowel syndrome, especially when other treatments have been tried without relieving the child's symptoms. This paper examines current evidence for the benefits and side effects of herbal remedies and spices in pediatric patients with IBS. The benefits of peppermint oil, STW5, psyllium fiber, Curcuma, ginger, and other herbal medicines are discussed based on findings in the current literature.

Gut Microbiome and Lipidome Signatures in Irritable Bowel Syndrome Patients from a Low-Income, Food-Desert Area: A Pilot Study.

Irritable bowel syndrome (IBS) is a common gastroenterological disorder with triggers such as fructose. We showed that our IBS patients suffering from socioeconomic challenges have a significantly high consumption of high-fructose corn syrup (HFCS). Here, we characterize gut microbial dysbiosis and fatty acid changes, with respect to IBS, HFCS consumption, and socioeconomic factors. Fecal samples from IBS patients and healthy controls were subjected to microbiome and lipidome analyses. We assessed phylogenetic diversity and community composition of the microbiomes, and used linear discriminant analysis effect size (LEfSe), analysis of compositions of microbiomes (ANCOM) on highly co-occurring subcommunities (modules), least absolute shrinkage and selection operator (LASSO) on phylogenetic isometric log-ratio transformed (PhILR) taxon abundances to identify differentially abundant taxa. Based on a Procrustes randomization test, the microbiome and lipidome datasets correlated significantly (p = 0.002). Alpha diversity correlated with economic factors (p < 0.001). Multiple subsets of the phylogenetic tree were associated with HFCS consumption (p < 0.001). In IBS patients, relative abundances of potentially beneficial bacteria such as Monoglobaceae, Lachnospiraceae, and Ruminococcaceae were lower (p = 0.007), and Eisenbergiella, associated with inflammatory disorders, was higher. In IBS patients, certain saturated fatty acids were higher and unsaturated fatty acids were lower (p < 0.05). Our study aims first to underscore the influence of HFCS consumption and socioeconomic factors on IBS pathophysiology, and provides new insights that inform patient care.

Antibiotic use as a risk factor for irritable bowel syndrome: Results from a nationwide, case-control study.

The microbiome plays an important role in the pathophysiology of irritable bowel syndrome (IBS). Antibiotic use can fundamentally alter gut microbial ecology. We examined the association of antibiotic use with IBS in a large population-based investigation. A case-control study with prospectively collected data on 29,111 adult patients diagnosed with IBS in Sweden between 2007 and 2016 matched with 135,172 controls. Using a comprehensive histopathology cohort, the Swedish Patient Register, and the Prescribed Drug Register, we identified all consecutive cases of IBS in addition to cumulative antibiotic dispensations accrued until 1 year prior to IBS (exclusionary period) for cases and time of matching for up to five general population controls matched on the basis of age, sex, country and calendar year. Conditional logistic regression estimated multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of IBS. Patients with IBS (n = 29,111) were more likely than controls (n = 135,172) to have used antibiotics up to 1 year prior to diagnosis (74.9% vs. 57.8%). After multivariable adjustment, this translated to a more than twofold increased odds of IBS (OR 2.21, 95% CI 2.14-2.28) that did not differ according to age, sex, year of IBS diagnosis or IBS subtype. Compared to none, 1-2 (OR 1.67, 95% CI 1.61-1.73) and ≥3 antibiotics dispensations (OR 3.36, 95% CI 3.24-3.49) were associated with increased odds of IBS (p for trend <0.001) regardless of the antibiotic class. Prior antibiotics use was associated with an increased odds of IBS with the highest risk among people with multiple antibiotics dispensations.

Sera anti-neuronal antibodies in patients with irritable bowel syndrome and their correlations with clinical profiles.

Immune factors were involved in the pathophysiology of irritable bowel syndrome (IBS). The aim of the study was to test anti-neuronal antibodies in sera of IBS patients and demonstrate their correlations with IBS profiles and psychological disorders. Patients with IBS met Rome III criteria and excluded organic diseases were enrolled. Controls included healthy subjects (HS), slow transit functional constipation, autoimmune diseases, and so on. Indirect immunofluorescence with monkey cerebellum and small intestine as substrates was used to detect anti-neuronal antibodies including anti-cerebral neuronal antibodies (ACNA) and anti-enteric neuronal antibodies (AENA). A total of 293 IBS patients, 100 HS and 153 disease controls were included in this study. The ACNA positive rate of IBS patients was significantly higher than HS (14% vs. 6%, p = 0.033). The positive rate of ACNA was significantly lower than AENA (14.0% vs. 76.8%, p = 0.028) in IBS patients. The prevalence of headache and sleeping disorder were higher in ACNA-positive IBS patients than ACNA-negative IBS patients (61% vs. 42.9%, p = 0.03; 75.6% vs. 57.1%, p = 0.03, respectively). Among IBS patients, ACNA and AENA were both negative in 21.8% patients, ACNA negative and AENA positive in 64.2% patients, and ACNA and AENA were both positive in 12.6% patients. There were no significant differences of intestinal symptoms among the three groups, while the prevalence of headache (64.9% vs. 37.5% and 44.7%, p = 0.03) and sleeping disorder (78.4% vs. 50.0% and 59.6%, p = 0.02) were higher in patients with both ACNA and AENA positive than patients with both ACNA and AENA negative, patients with ACNA negative and AENA positive. There were no significant differences of the prevalence of depression and anxiety, HAMD, and HAMA scores among the three groups. Anti-neuronal antibodies in sera of IBS patients were mainly targeted to enteric neurons and in a small part to cerebral neurons. ACNA were closely related to headache and sleeping disorder but unrelated to intestinal symptoms, depression, or anxiety of IBS patients.

Prevalence of Irritable Bowel Syndrome in Saudi Arabia: A Systematic Review and Meta-Analysis.

Irritable bowel syndrome (IBS) is a commonly found global functional pathology with no detectable structural changes. It affects the quality of life and often coexists with psychiatric and somatic issues. We reviewed all articles published between 1990 and April 2023. The databases used for the data search were Google Scholar, Web of Science, Cochrane Library, and PubMed/MEDLINE. Ovid search engine was also used to broaden the search strategy. Predefined keywords, including "Irritable bowel syndrome" (MeSH) OR "IBS" (all fields), along with "Saudi Arabia" and "Middle East," were used to avoid data loss and ambiguity. Any cross-sectional study that reported the prevalence of IBS in any gender, age, and group of the Saudi population was included. Data extraction was independently performed in duplicate to mitigate bias and data loss. Statistical analysis of proportion was conducted by using Miller (Freeman-Tukey double arcsine - exact inverse). Out of 350 records identified, only 38 studies were included in the quantitative synthesis. The total number of study participants was 26,567, on the basis of the predefined inclusion criteria of the study. StatsDirect software was used for the statistical analysis of the study parameters. Based on all 38 identified studies, the calculated pooled prevalence was 20.7% (95% confidence interval (CI) = 17.8% to 23.7% by applying random effects (DerSimonian-Laird method). IBS was identified in 21% (95% CI = 16.7% to 25.7%) of the general population, 22% (95% CI = 17.6% to 26.7%) of students, and 18.3% (95% CI = 13.3% to 23.9%) of healthcare workers. The pooled prevalence of IBS among the Saudi population was 20.7%. The pathophysiology of IBS is complexed and significantly affected by genetics, diet, cultural characteristics, age, anxiety, depression, stress, and sleep disorders. This study fills a gap in understanding IBS prevalence in Saudi Arabia, contributing valuable data to this region.

Digesting the Impact of Diet on Irritable Bowel Syndrome (IBS): Exploring Solutions for Controlling IBS.

Irritable bowel syndrome (IBS) plagues nearly a fifth of the general population. It is a chronic illness that can significantly lower quality of life (QoL) and work productivity. The relationship between diet and the functional gastrointestinal (GI) symptoms present in IBS is gaining more and more attention. In addition to being a factor in the pathophysiology of IBS, diet also has a significant impact on symptoms and overall well-being. Recent research has also shown that short-chain fermentable carbohydrates increase colonic gas production and small intestine water volume, which in turn causes functional GI symptoms in those with visceral hypersensitivity.This review article has consolidated various studies highlighting the association between certain foods and the pathophysiology of IBS. It has also talked about how restricting certain food items from the diet of affected individuals can relieve symptoms and in some cases can be more effective than pharmacotherapy. Although the low reduced fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet (LFD) is a well-known method of treating IBS symptoms, over a third of individuals do not benefit from it. This article has also discussed the effectiveness and applicability of the LFD compared to other dietary therapies for the long-term management of IBS.

Dysbiosis in Irritable Bowel Syndrome.

The human gut microbiota fosters the development of a dynamic group of microorganisms impacted by diverse variables that include genetics, diet, infection, stress, ingested drugs, such as antibiotics and small intestine bacterial overgrowth (SIBO) as well as the gut microbiota itself. These factors may influence the change in microbial composition, which results in dysbiosis (microbial imbalance) and exposes the gut to pathogenic insults. Dysbiosis is incidental to the etiology of inflammatory diseases such as irritable bowel syndrome (IBS) and metabolic diseases, including type 2 diabetes and obesity. IBS exhibits different symptoms like abdominal pain or discomfort, distention/bloating, and flatulence. To treat IBS, modification of dysregulated gut microbiota can be done using treatment strategies like a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, antibiotics that cannot be absorbed like rifaximin and neomycin, probiotics and prebiotics, and fecal microbiota transplantation (FMT). The remedial modalities in the existing literature have been demonstrated to be efficacious in the prevention and mitigation of IBS. Additionally, newer curative approaches with serum-derived bovine immunoglobulin (SBI) are an effective option. The focal point of the review paper is the pathophysiology of IBS, mainly due to dysbiosis and the various factors that advance dysbiosis. Here, we have also discussed the different treatment strategies targeting dysbiosis that effectively treat IBS. How to cite this article: Abraham P, Pratap N. Dysbiosis in Irritable Bowel Syndrome. J Assoc Physicians India 2023;71(9):75-81.

Can the change of vasomotor activity in irritable bowel syndrome patients be detected via color Doppler ultrasound?

Irritable bowel syndrome (IBS) is one of the most frequently referred conditions to the gastrointestinal outpatient clinic. The pathophysiology of IBS has not been determined with certainty. Visceral hypersensitivity is indicated as one of the pathophysiologies. The sympathetic nervous system is primarily in charge of controlling the arteries, and its effect is vasospasm in the medium and large arteries, resulting in decreased blood flow. To demonstrate, using Doppler evaluation of the brachial artery, that sympathetic activity impairs vasomotor performance due to autonomic neuropathy, which we believe is associated with IBS. There were 58 participants in the study. The control group consisted of 29 healthy patients, while the remaining 29 patients had been diagnosed with IBS. Patients who met the Rome IV criteria and had IBS were included in the study. People with known polyneuropathy or non-IBS chronic conditions that can progress were excluded from the trial, as were those with essential hypertension, diabetes mellitus, cardiovascular disease, or peripheral arterial disease, and patients diagnosed with anxiety or depression. Those with moderate to severe carpal tunnel syndrome or a median nerve lesion due to trauma were also excluded from the trial. A Doppler probe was used to measure the baseline diameter and flow rates of the brachial artery from 2 cm superior to the antecubital fossa. The Doppler probe remained stationary throughout the experiment, allowing for continuous measurements. Then, to activate the sympathetic fibers, an electrical stimulus for 5 s with an intensity of 10 mA and a frequency of 1 Hz was applied to the median nerve at the wrist level via the bipolar stimulus electrode. The artery diameter and flow rates were measured again immediately following the fifth stimulus. In healthy persons with no history of chronic illness, there was a statistically significant decrease in flow rate after stimulation (P < 0.001). In addition, stimulation resulted in a statistically significant reduction in the diameter of the brachial artery (P < 0.001). Patients diagnosed with IBS had statistically significant vasodilation and an increase in flow rate. Sympathetic stimulation causes a reduction in vascular diameter and blood flow, whereas it has the reverse effect on IBS patients. In investigating the involvement of autonomic neuropathy in the development of IBS, significant changes in brachial artery Doppler parameters were observed before and after stimulation of the median nerve with low-current sensory stimulation. This method is thought to be more user-friendly and comfortable than other methods described in the literature.

Imeglimin prevents visceral hypersensitivity and colonic hyperpermeability in irritable bowel syndrome rat model

Visceral hypersensitivity and leaky gut, which are mediated via corticotropin-releasing factor (CRF) and Toll-like receptor 4 are key pathophysiology of irritable bowel syndrome (IBS). Metformin was reported to improve these gastrointestinal (GI) changes. In this study, we attempted to determine the effects of imeglimin, which was synthesized from metformin on GI function in IBS rat models. Imeglimin blocked lipopolysaccharide- or CRF-induced visceral hypersensitivity and colonic hyperpermeability. These effects were prevented by compound C or naloxone. These results suggest that imeglimin may be effective for the treatment of IBS by improved visceral sensation and colonic barrier via AMPK and opioid receptor.

Intestinal bacteria associated with irritable bowel syndrome and chronic fatigue.

The etiology of irritable bowel syndrome (IBS) is unknown. Abnormal intestinal bacterial profiles and low bacterial diversity appear to play important roles in the pathophysiology of IBS. This narrative review was designed to present recent observations made relating to fecal microbiota transplantation (FMT), which implicate possible roles of 11 intestinal bacteria in the pathophysiology of IBS. The intestinal abundances of nine of these bacteria increased after FMT in patients with IBS, and these increases were inversely correlated with IBS symptoms and fatigue severity. These bacteria were Alistipes spp., Faecalibacterium prausnitzii, Eubacterium biforme, Holdemanella biformis, Prevotella spp., Bacteroides stercoris, Parabacteroides johnsonii, Bacteroides zoogleoformans, and Lactobacillus spp. The intestinal abundances of two bacteria were decreased in patients with IBS after FMT and were correlated with the severity of IBS symptoms and fatigue (Streptococcus thermophilus and Coprobacillus cateniformis). Ten of these bacteria are anaerobic and one (Streptococcus thermophilus) is facultative anaerobic. Several of these bacteria produce short-chain fatty acids, especially butyrate, which is used as an energy source by large intestine epithelial cells. Moreover, it modulates the immune response and hypersensitivity of the large intestine and decreases intestinal cell permeability and intestinal motility. These bacteria could be used as probiotics to improve these conditions. Protein-rich diets could increase the intestinal abundance of Alistipes, and plant-rich diet could increase the intestinal abundance of Prevotella spp., and consequently improve IBS and fatigue.