Fecal and Mucosal Microbiota Profiling in Irritable Bowel Syndrome and Inflammatory Bowel Disease

Abstract

An imbalance in the bacterial species resulting in the loss of intestinal homeostasis has been described in inflammatory bowel diseases (IBD) and irritable bowel syndrome (IBS). In this prospective study, we investigated whether IBD and IBS patients exhibit specific changes in richness and distribution of fecal and mucosal-associated microbiota. Additionally, we assessed potential 16S rRNA gene amplicons biomarkers for IBD, IBS, and controls (CTRLs) by comparison of taxonomic composition. The relative abundance of bacteria, at phylum and genus/species levels, and the bacterial diversity were determined through 16S rRNA sequence-based fecal and mucosal microbiota analysis. Linear discriminant analysis effect size (LEfSe) was used for biomarker discovery associated to IBD and IBS as compared to CTRLs. In fecal and mucosal samples, the microbiota richness was characterized by a microbial diversity reduction, going from CTRLs to IBS to IBD. β-diversity analysis showed a clear separation between IBD and CTRLs and between IBD and IBS with no significant separation between IBS and CTRLs. β-diversity showed a clear separation between mucosa and stool samples in all the groups. In IBD, there was no difference between inflamed and not inflamed mucosa. Based upon the LEfSe data, the Anaerostipes and Ruminococcaceae were identified as the most differentially abundant bacterial taxa in CTRLs. Erysipelotrichi was identified as potential biomarker for IBS, while Gammaproteobacteria, Enterococcus , and Enterococcaceae for IBD. This study provides an overview of the alterations of microbiota and may aid in identifying potential 16S rRNA gene amplicons mucosal biomarkers for IBD and IBS.

Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults

“…To better explore the difference between dietary fibers and prebiotics, it is important to remark that human enzymes are not able to degrade several glyosidic linkages present in a subset of polysaccharides, such as cellulose, hemicelluloses, mucilage, pectin and lignin, and those not digested by human enzymes are often partly fermented in the gastrointestinal tract [20]. Some dietary fibers are also able to selectively stimulate the growth and/or activity of intestinal bacteria potentially associated with health and well-being, acting as prebiotics [10].…”

“…As gut microbiota have been involved in the pathogenesis of several GI disorders [20], there is an increasing interest in dietary strategies to modulate microbiota. For this reason, research has focused on the use of prebiotics, since many of these polysaccharides can be metabolized by intestinal microbiota, leading to the production of SCFAs (including acetate, butyrate, and propionate) [26].…”

Preventive Effects of Pyungwi-san against Dextran Sulfate Sodium- and Clostridium difficile-Induced Inflammatory Bowel Disease in Mice

“…In our study, the community structure of the gut microbiota was analyzed using T-RFLP, revealing that, at the phylum level, the population of Bacteroidetes was lower in the DSS + CD group than in both the DSS and normal groups. Although the differences were insignificant, a previous study showed that phylum distribution in IBD patients harbored significantly fewer Bacteroidetes than that in healthy subjects [70]. Furthermore, an inverse association has been reported between infection with C. difficile and abundance of Bacteroidetes [71].…”

Liver X Receptor regulates Th17 and RORγt+ Treg cells by distinct mechanisms

“…In these experiments, we observed significantly higher enrichment of bacteria belonging to the family Ruminococcaceae and Lachnospiraceae in LXRα −/− mice compared to WT littermates in steady state, suggesting that lack of LXRα allows preferential colonization of specific groups of bacteria. Both Ruminococcaceae and Lachnospiraceae belong to the order Clostridiales and phylum Firmicutes and have been associated with multiple human diseases including IBD 22-24 and atherosclerosis 25,26 . While the abundance of both Ruminococcaceae and Lachnospiraceae are decreased in IBD patients, suggesting a protective role, they have been shown to be associated with pro-atherogenic effects.…”