Hoffmann et al. took six different microorganisms implicated in inflammatory bowel disease (IBD)-associated dysbiosis, and studied their effects on intestinal inflammation in a mono-associated mouse model. Bacteroides thetaiotaomicron had the greatest effect on the immune system through Treg pathways; Ruminococcus gnavus had major effects on tryptophan metabolism, while Roseburia intestinalis induced a high production of short-chain fatty acids. Interestingly, the probiotic Saccharomyces boulardii stimulated angiogenesis, and this was confirmed with morphological observation of the mucosa. None of the six tested microorganisms had an effect on bile acid metabolism.
Authors say deciphering the complex mechanisms of action of each microorganism could lead to insights that will help clinicians and patients better manage IBDs.