Inflammation or dysbiosis: what comes first?

The complex ecosystem formed by the interaction between resident microbiota and the mucosal epithelium is essential for the maintenance of the intestinal homeostasis.Aim: investigate if Dysbiosis occurs in the gut of mice submitted to a gut, antigen specific chronic inflammation. Methods: C57Bl/6 mice received 100μg Peanut Protein Extract (PPE) or saline twice subcutaneously. 21 days after the booster inoculation half of the animals of each group received a raw-peanut, 30 day, challenge diet, while the other half continued eating mouse chow. After a macroscopic inspection of the peritoneal cavity, gut samples were retrieved for histological and microbiological analysis (DcodeTM Universal Mutation Detection System - BioRad). Results: PPE inoculated groups presented significantly higher anti-peanut antibodies compared to saline groups, irrespective of their diet. PPE inoculated animals that ate peanuts showed significant reduction of the villi number, shortening of the villi and increase in the mononuclear cell infiltrate in the epithelial layer and lamina propria altering the mucosal architecture.  A significant qualitative shift of the bacterial profile was only observed in PPE inoculated animals challenged with the peanut diet.  We are currently undertaking the quantitative analysis to determine which components of the microbiota altered most. Conclusion: the antigen specific chronic inflammatory bowel disease, developed by our group, is a good model to study the microbial shift of the gut microbiota during food allergies.