Role of intestinal microbiota and metabolites in inflammatory bowel disease

OBJECTIVE: The metabolites produced by the gut microbiota are of interest to scientists. The objective of this review was to provide an updated summary of progress regarding the microbiota and their metabolites and influences on the pathogenesis of inflammatory bowel disease (IBD). DATA SOURCES: The author retrieved information from the PubMed database up to January 2018, using various combinations of search terms, including IBD, microbiota, and metabolite. STUDY SELECTION: Both clinical studies and animal studies of intestinal microbiota and metabolites in IBD were selected. The information explaining the possible pathogenesis of microbiota in IBD was organized. RESULTS: In IBD patients, the biodiversity of feces/mucosa-associated microbiota is decreased, and the probiotic microbiota is also decreased, whereas the pathogenic microbiota are increased. The gut microbiota may be a target for diagnosis and treatment of IBD. Substantial amounts of data support the view that the microbiota and their metabolites play pivotal roles in IBD by affecting intestinal permeability and the immune response. CONCLUSIONS: This review highlights the advances in recent gut microbiota research and clarifies the importance of the gut microbiota in IBD pathogenesis. Future research is needed to study the function of altered bacterial community compositions and the roles of metabolites.