Irritable Bowel Syndrome

Irritable bowel syndrome is a chronic disorder affecting the gastrointestinal tract, negatively impacting patients' quality of life. Here, we aimed to evaluate the effects of Lacticaseibacillus rhamnosus IDCC 3201 (RH 3201) on irritable bowel syndrome with constipation (IBS-C). In this randomised, double-blind, placebo-controlled trial, a total of 30 subjects with IBS-C were randomly assigned (1:1) to receive 8 weeks of probiotics administration or placebo. Concerning bowel activities, both irritant bowel movements and discomfort caused by constipation showed significant improvement with RH 3201 at 8 weeks. Symptoms including severity of abdominal bloating, frequency of abdominal bloating, and satisfaction of bowel habits based on the irritable bowel syndrome-severity scoring system also ameliorated in the probiotic group. Analysis of the fecal microbiome revealed that the abundance of Bacteroides cellulosilyticus and Akkermansia muciniphila was higher during the period of RH 3201 administration compared to the placebo. Untargeted metabolome analysis further suggested a correlation between specific metabolites, such as N-acetylornithine, xanthine, and 3-phenylpropionic acid, and the improvement of clinical symptoms. These results indicate that RH 3201 was effective in ameliorating IBS-C, potentially by enriching beneficial microbes and associated metabolites in the gut environment.

The gut microbiota plays a crucial role in the manifestation of intestinal dysfunction associated with irritable bowel syndrome (IBS). The mechanosensory Piezo2 has been implicated in the regulation of intestinal function. However, it remains unclear whether Piezo2 is modulated by the gut microbiota, thus contributing to the development of visceral hypersensitivity and gut dysmotility. The study enrolled patients with diarrhea-predominant IBS (IBS-D) alongside healthy controls (HC). Questionnaires, rectal barostat test, and colonoscopy with mucosal biopsy were conducted. Fecal microbiota transplantation (FMT) was performed using samples from HC or IBS-D patients, and interventions with Akkermansia muciniphila or Fusobacterium varium were carried out on colon- or dorsal root ganglion (DRG)- Piezo2 knockdown pseudo-germ-free mice. Visceral sensitivity and intestinal motility were assessed. Piezo2 levels were detected using western blot and immunofluorescence. Fecal 16S rRNA sequencing and cecum untargeted metabolomics analysis, followed by molecular docking predictions of Piezo2, were also performed. The ratio of Piezo2+/5-HT+ cells was lower in IBS-D patients, positively correlated with visceral sensation and intestinal dysbiosis. The mice that received FMT from IBS-D patients exhibited colonic dysmotility and visceral hypersensitivity, along with elevated Piezo2 protein levels in the colon and DRG. Knockdown of Piezo2 in the colon or DRG ameliorated the FMT-induced colonic dysmotility and visceral hypersensitivity. Fecal 16S rRNA sequencing revealed distinct microbiota composition. Notably, Fusobacterium varium, but not Akkermansia muciniphila, induced gut dysmotility and visceral hypersensitivity, effects that could be alleviated by colon or DRG Piezo2 knockdown. Additionally, Fusobacterium varium lead to increased Piezo2 protein levels, as well as elevated levels of indole-3-acetic acid and indole-3-acrylic acid, which were predicted to bind to Piezo2, causing disturbances. Piezo2 can be regulated by gut microbiota and involved in visceral hypersensitivity and colonic dysmotility, with Fusobacterium varium playing a crucial role.

Background: Approximately 20% of patients with irritable bowel syndrome (IBS) link symptoms to food intake; a low-FODMAP diet is effective in managing these symptoms. Aims: To evaluate the effectiveness of the Mediterranean version of the low-FODMAP Diet (MED-LFD) compared to NICE guidelines for IBS and to assess changes in stool volatile compound levels. Methods: 108 patients with Rome IV IBS without constipation were randomized into the MED-LFD or NICE group. Primary endpoints included changes in symptom severity and responder rate (reduction of >50 IBS-SSS points) after intervention and at 6 months. Secondary endpoints assessed quality of life, symptom burden, adequate relief, anxiety/depression levels, and adherence. Volatile compound levels were measured using Gas Chromatography/Mass Spectrometry. Results: At both time points, the MED-LFD group showed a significantly greater improvement in symptom severity (159 ± 80 vs. 253 ± 94 and 168 ± 117 vs. 245 ± 98), responder rates (84.6% vs. 60.8% and 79.1% vs. 52.3%), and adherence (75% vs. 41% and 45% vs. 7%). Similar results were observed for all secondary endpoints, with no serious adverse events reported. The MED-LFD intervention was the strongest independent predictor of being a responder at the first (OR = 6.66; 95%CI = 1.46, 30.4) and second follow-up (OR = 4.85; 95%CI = 1.31, 17.96). Short and branched-chain fatty acids were significantly reduced at both follow-ups. Conclusions: The MED-LFD is superior to NICE recommendations in managing non-constipated IBS symptoms and quality of life. It remains to be proven that reduced volatile compound levels might be an objective marker of response to dietary interventions. ClinicalTrials.gov ID: NCT03997708.

BackgroundExposure to COVID-19 has been shown previously to be associated with a higher risk for irritable bowel syndrome (IBS). This study aimed to better explain this relationship using mediation analysis.MethodsThis post hoc analysis of a multicenter cohort study includes 623 patients with and without COVID-19 infection. All participants completed the ROME IV criteria, gastrointestinal symptom rating scale (GSRS), and hospital anxiety and depression scale (HADS) over 1 year. Mediation analysis utilized the PROCESS macro and Baron and Kenny's method for parametric and nonparametric mediating variables, respectively.Key resultsThe impact of COVID-19 on the development of post-COVID-19 IBS is completely mediated by dyspnea at baseline (adjusted OR = 3.561, p = 0.012), severity of acid regurgitation at 1 month [indirect effect, log-odds metric = 0.090, 95% CI (0.006-0.180)], hunger pains at 1 [indirect effect, log-odds metric = 0.094, 95% CI (0.024-0.178)], and 6 months [indirect effect, log-odds metric = 0.074, 95% CI (0.003-0.150)], depression at 6 [indirect effect, log-odds metric = 0.106, 95% CI (0.009-0.225)] and 12 months [indirect effect, log-odds metric = 0.146, 95% CI (0.016-0.311)] as well as borborygmus [indirect effect, log-odds metric = 0.095, 95% CI (0.009-0.203)], abdominal distention [indirect effect, log-odds metric = 0.162, 95% CI (0.047-0.303)], and increased flatus [indirect effect, log-odds metric = 0.110, 95% CI (0.005-0.234)] at 12 months.Conclusions and inferencesOur findings provide evidence for psychological and clinical mediators between COVID-19 and post-COVID-19 IBS, which may be promising targets for interventions tailored for treating or preventing depression. The presence of specific GI symptoms at COVID-19 onset and their persistence should increase awareness of a potential new onset of IBS diagnosis.