Fecal microbiota transplantation in patients with ulcerative colitis: fecal donor selection and interplay between intestinal microbiota, diet and host genetics

Ulcerative colitis (UC) is a relapsing and remitting inflammatory bowel disease, characterized by bloody diarrhea. It is widely accepted that UC results from an abnormal immune reaction against the gut microbiota in genetically predisposed subjects. Patients often need to be treated with expensive medication that can have significant side-effects. Still, more than 20% of patients does not respond to any medical therapy and needs colectomy. Fecal microbiota transplantation (FMT) is a successful therapy for refractory Clostridium difficile infection. As alterations in the gut microbiota have shown to play a key role in UC, manipulation of its composition by FMT is a promising treatment. However, treatment success still needs to be optimized by determining impact of donor selection, UC patient features, diet and host genetics on FMT success. Our aim is to perform a national multicenter trial with repeated FMT in a large cohort of UC patients. We will preselect donors based on their microbial richness. Patients will be randomized in two groups, one group of patients will receive a specific diet that increases the microbial richness 2 weeks prior to FMT and the other group will receive directly a FMT without priming. The primary endpoint is endoscopic healing after 3 months. The integration of assessing microbiota and diet together with host genetics, will enable to study the interplay between different triggers contributing to the multifactorial mechanisms underlying FMT success.