This was the 4th symposium held in Mexico on the role of the intestinal microbiota in health and disease. The topics explored during the meeting were diverse; in general, they discussed the current evidence for microbiota modulation in health and disease, with special focus on nutrition, including probiotics, and intestinal and metabolic disorders.
I presented specifically on the role of the microbiota in the maintenance of a balanced immune system and its importance in the development of chronic inflammatory disorders of the GI tract, such as celiac disease and inflammatory bowel disease.
Other lectures [by local and international speakers] discussed the evidence supporting the mutualistic relationship between host and intestinal microbes, which shapes host physiology and maintains gut homeostasis. There was a discussion of the concept that this relationship exists on a ‘continuum’ between mutualism and pathogenicity, and that this has relevance to microbiota modulation and the onset of inflammatory disorders.
Although alteration in intestinal microbiota composition has been associated with chronic GI diseases such as IBD, IBS and celiac disease, the relationship remains based on association. Evidence from basic research and animal models support the concept that certain bacteria can encourage inflammation while others protect against it. In particular, results from a study recently published in Inflammatory Bowel Diseases (Natividad, et al., 2015) showed that colonization of germ-free mice with microbiota low in Firmicutes (notably, Lachnospiraceae and Ruminococcaceae) derived from subjects with active ulcerative colitis, promoted expression of TH17-related genes, encouraging pathogenic characteristics. Although these specific patient-derived ecosystems were insufficient to induce spontaneous inflammation, they affected the immune response such that the molecular, low-grade inflammation led to more severe experimental colitis in mice. The results suggest that the efficacy of fecal transplantation strategies in ulcerative colitis may benefit from the inclusion of Lachnospiraceae and Ruminococcaceae families or the selection of healthy donors that have good representation of these families in the transplantation material.