Chitin-glucan improves important pathophysiological features of irritable bowel syndrome

BACKGROUND Irritable bowel syndrome(IBS)is one of the most frequent and debilitating conditions leading to gastroenterological referrals.However,recommended treatments remain limited,yielding only limited therapeutic gains.Chitin-glucan(CG)is a novel dietary prebiotic classically used in humans at a dosage of 1.5-3.0 g/d and is considered a safe food ingredient by the European Food Safety Authority.To provide an alternative approach to managing patients with IBS,we performed preclinical molecular,cellular,and animal studies to evaluate the role of chitin-glucan in the main pathophysiological mechanisms involved in IBS.AIM To evaluate the roles of CG in visceral analgesia,intestinal inflammation,barrier function,and to develop computational molecular models.METHODS Visceral pain was recorded through colorectal distension(CRD)in a model of long-lasting colon hypersensitivity induced by an intra-rectal administration of TNBS[15 milligrams(mg)/kilogram(kg)]in 33 Sprague-Dawley rats.Intracolonic pressure was regularly assessed during the 9 wk-experiment(weeks 0,3,5,and 7)in animals receiving CG(n=14)at a human equivalent dose(HED)of 1.5 g/d or 3.0 g/d and compared to negative control(tap water,n=11)and positive control(phloroglucinol at 1.5 g/d HED,n=8)groups.The anti-inflammatory effect of CG was evaluated using clinical and histological scores in 30 C57bl6 male mice with colitis induced by dextran sodium sulfate(DSS)administered in their drinking water during 14 d.HT-29 cells under basal conditions and after stimulation with lipopolysaccharide(LPS)were treated with CG to evaluate changes in pathways related to analgesia μ-opioid receptor(MOR),cannabinoid receptor 2(CB2),peroxisome proliferator-activated receptor alpha,inflammation[interleukin(IL)-10,IL-1b,and IL-8]and barrier function[mucin 2-5AC,claudin-2,zonula occludens(ZO)-1,ZO-2]using the real-time PCR method.Molecular modelling of CG,LPS,lipoteichoic acid(LTA),and phospholipomannan(PLM)was developed,and the ability of CG to chelate microbial pathogenic lipids was evaluated by docking and molecular dynamics simulations.Data were expressed as the mean±SEM.RESULTS Daily CG orally-administered to rats or mice was well tolerated without including diarrhea,visceral hypersensitivity,or inflammation,as evaluated at histological and molecular levels.In a model of CRD,CG at a dosage of 3 g/d HED significantly decreased visceral pain perception by 14%after 2 wk of administration(P<0.01)and reduced inflammation intensity by 50%,resulting in complete regeneration of the colonic mucosa in mice with DSS-induced colitis.To better reproduce the characteristics of visceral pain in patients with IBS,we then measured the therapeutic impact of CG in rats with TNBS-induced inflammation to long-lasting visceral hypersensitivity.CG at a dosage of 1.5 g/d HED decreased visceral pain perception by 20%five weeks after colitis induction(P<0.01).When the CG dosage was increased to 3.0 g/d HED,this analgesic effect surpassed that of the spasmolytic agent phloroglucinol,manifesting more rapidly within 3 wk and leading to a 50%inhibition of pain perception(P<0.0001).The underlying molecular mechanisms contributing to these analgesic and anti-inflammatory effects of CG involved,at least in part,a significant induction of MOR,CB2 receptor,and IL-10,as well as a significant decrease in pro-inflammatory cytokines IL-1b and IL-8.CG also significantly upregulated barrier-related genes including muc5AC,claudin-2,and ZO-2.Molecular modelling of CG revealed a new property of the molecule as a chelator of microbial pathogenic lipids,sequestering gram-negative LPS and gram-positive LTA bacterial toxins,as well as PLM in fungi at the lowesr energy conformations.CONCLUSION CG decreased visceral perception and intestinal inflammation through master gene regulation and direct binding of microbial products,suggesting that CG may constitute a new therapeutic strategy for patients with IBS or IBSlike symptoms.

Efficacy and tolerability of chitin-glucan combined with simethicone(GASTRAP^(■)DIRECT)in irritable bowel syndrome:A prospective,open-label,multicenter study

BACKGROUNDIrritable bowel syndrome(IBS),defined according to the Rome IV diagnostic criteria,is a chronic functional gastrointestinal disorder characterized by recurrent abdominal pain related to altered bowel habits.First-line recommended treatments are limited to combining drugs targeting predominant symptoms,particularly pain(antispasmodics),constipation(laxatives),and diarrhea(loperamide),yielding only a limited therapeutic gain.GASTRAP^(■)DIRECT is a class IIa medical formulation composed of a combination of chitin-glucan and simethicone indicated for the symptomatic treatment of gas-related gastrointestinal disorders by combining different mechanisms of action.AIM To evaluate the efficacy,tolerability,and safety of 4-week GASTRAP^(■)DIRECT treatment in patients with IBS.METHODS In this prospective,multicenter,open-label trial,120 patients with IBS received three sticks of GASTRAP^(■)DIRECT(1.5 g/d of chitin-glucan and 0.75 mg/d of simethicone)per day for 4 weeks.The primary endpoint was the responder rate,defined as the number of patients whose abdominal pain score decreased by≥30%from baseline to week(W)4.The analysis was performed using the per-protocol set.Cardinal symptoms,impact of global symptoms on daily life,change in stool consistency,and improvement in defecatory disorders were evaluated.RESULTS Overall,100 patients were evaluated.At W4,67%(95%CI:57-75)showed improvement in abdominal pain(score:5.8±2.4 vs 2.9±2.0,P<0.0001).Similar improvements were observed for bloating[8.0±1.7 vs 4.7±2.9,P<0.0001;60%(95%CI:50-70)responders],abdominal distension[7.2±2.1 vs 4.4±3.1,P<0.0001;53%(95%CI:43-63)responders],and impact of global symptoms on daily life[7.1±2.0 vs 4.6±2.9,P<0.0001;54%(95%CI:44-64)responders].Stool consistency improved in most patients(90%and 57%for patients with liquid and hard stools,respectively).Overall,42%of patients with defecatory disorders reported very much/considerable improvements by W2.No severe adverse event occurred,and tolerability was rated“good”or“very good”by 93%of patients.CONCLUSION GASTRAP^(■)DIRECT is safe and well tolerated,alleviating IBS symptoms rapidly in 2 weeks.This open-label study suggests that the combination of chitin-glucan and simethicone could be beneficial in patients with IBS.