Antibiotics,gut microbiota,and irritable bowel syndrome:What are the relations?

Irritable bowel syndrome(IBS)is a functional gastrointestinal disorder in which recurrent abdominal pain is associated with defecation or a change in bowel habits(constipation,diarrhea,or both),and it is often accompanied by symptoms of abdominal bloating and distension.IBS is an important health care issue because it negatively affects the quality of life of patients and places a considerable financial burden on health care systems.Despite extensive research,the etiology and underlying pathophysiology of IBS remain incompletely understood.Proposed mechanisms involved in its pathogenesis include increased intestinal permeability,changes in the immune system,visceral hypersensitivity,impaired gut motility,and emotional disorders.Recently,accumulating evidence has highlighted the important role of the gut microbiota in the development of IBS.Microbial dysbiosis within the gut is thought to contribute to all aspects of its multifactorial pathogenesis.The last few decades have also seen an increasing interest in the impact of antibiotics on the gut microbiota.Moreover,antibiotics have been suggested to play a role in the development of IBS.Extensive research has established that antibacterial therapy induces remarkable shifts in the bacterial community composition that are quite similar to those observed in IBS.This suggestion is further supported by data from cohort and case-control studies,indicating that antibiotic treatment is associated with an increased risk of IBS.This paper summarizes the main findings on this issue and contributes to a deeper understanding of the link between antibiotic use and the development of IBS.

Evaluation of the gastrointestinal anti-motility effect of Anacardium occidentale stem bark extract:A mechanistic study of antidiarrheal activity

Diarrhea is a prevalent gastrointestinal problem associated with fatal implications.It is a huge public health concern that requires better alternatives to current drugs.This study investigated the mechanisms involved in the antidiarrheal activity of Anacardium occidentale(Ao) stem bark extract,a plant commonly used in the management of diarrhea in Nigeria.Methanolic stem bark extract of the plant was partitioned into three fractions:hexane fraction,ethyl acetate fraction(Ao EF) and methanol fraction.In vitro studies on the effect of these fractions on guinea pig ileum(GPI) strips,as well as the modulatory effect of Ao EF on standard agonists-and antagonists-induced GPI contraction and relaxation,revealed Ao EF as the most active fraction.In vivo studies to assess the effect of Ao EF on the dopaminergic,muscarinic,and serotonergic pathways were carried out using gastric emptying(GE) and gastrointestinal transit(GT) as experimental end points.Ao EF was subjected to GC-MS analysis,while the identified compounds were docked with the muscarinic acetylcholine receptor M3(CHRM3) using Autodock Vina.Results indicated that Ao EF inhibited GE and GT via inhibition of CHRM3.In addition,GC-MS analysis revealed the presence of 24 compounds in Ao EF,while docking indicated that octadecanoic acid 2-(2-hydroxylethoxy)ethyl ester exhibited the highest binding affinity to CHRM3.This study indicated that the antidiarrheal activity of Ao is through its antimotility effect via the inhibition of the muscarinic pathway.And since none of the identified compounds exhibited higher binding affinity to CHRM3 relative to loperamide,the antimotility activity of these phytoconstituents may be via synergism.

Quantitative analysis of intestinal gas in patients with acute pancreatitis

BACKGROUND: Disturbance of gastrointestinal function is a common complication in the early phase of acute pancreatitis (AP). Intestinal gas may reflect the function of the gut. Using plain abdominal radiographs, we investigated whether intestinal gas volume is related to AP. METHODS: Plain abdominal radiographs of 68 patients with AP within 24 hours after admission and 21 normal controls were digitized and transmitted to a computer. The region of intestinal gas was identified by an image manipulation software and the gas volume score (GVS) was calculated. The relationships between the GVS values and various clinical factors of AP were analyzed. RESULTS: The GVS in the AP group was 0.084±0.016, in the mild AP (MAP) group 0.070±0.005, and in the severe AP (SAP) group 0.094±0.013; all values were higher than that in the control group (P<0.01). The GVS in the SAP group was higher than that in the MAP group. The GVSs were correlated to the Ranson’s scores (r=0.762, P<0.01) and the acute physiology and chronic health evaluation II (APACHE II) scores (r=0.801, P<0.01). In addition, the GVS in patients with secondary pancreatic and/or peripancreatic infection was 0.107±0.014, higher than that in patients without secondary infection (P<0.01). GVS was not related to gender, age, etiology or clinical outcome of AP. CONCLUSIONS: Intestinal gas volume is significantly elevated in patients with AP. It is closely related to Ranson’s and APACHE II score and secondary pancreatic and/or peripancreatic infection. GVS may be a new prognostic tool for assessing the severity of AP in the early course of the disease.