Fecal transplantation for ulcerative colitis from diet conditioned donors followed by dietary intervention results in favorable gut microbial profile compared to fecal transplantation alone.

BACKGROUND AND AIMS: Several fecal microbial transplantation (FMT) approaches for ulcerative colitis (UC) have been investigated with conflicting results. We have recently published the clinical outcomes from the CRAFT-UC Trial using FMT with the UC Exclusion Diet (UCED), compared with FMT alone. Here we aimed to compare the two FMT strategies in terms of microbial profile and function.

METHODS: Subjects recruited to the CRAFT-UC study with available pre- and post-intervention fecal samples were included. Donors received diet conditioning for 14 days based on the UCED principles. Group-1 received single FMT by colonoscopy (Day 1) and enemas (Days 2 and 14) without donors' dietary conditioning (N=11). Group-2 received FMT but with donors' dietary pre-conditioning and UCED for the patients (N=10). Fecal samples were assessed by DNA shotgun metagenomic sequencing.

RESULTS: Following diet conditioning, donors had depletion in metabolic pathways involved in sulfur-containing amino acids biosynthesis. Only Group-2 showed significant shifts towards the donors' microbial composition (ADONIS: R2=0.15, p=0.008) and significant increased Eubacterium_sp_AF228LB post-intervention (β-coefficient 2.66, 95%CI 2.1-3.3, q<0.05) which was inversely correlated with fecal calprotectin (rho=-0.52, p=0.035). Moreover, pathways involved in gut inflammation and barrier function including branched chain amino acids were enriched post intervention in Group-2 and were significantly inversely correlated with fecal calprotectin.

CONCLUSION: FMT from diet conditioned donors followed by the UCED led to microbial alterations associated with favorable microbial profile which correlated with decreased fecal calprotectin. Our findings support further exploration of additive benefit of dietary intervention for both donors and patients undergoing FMT as a potential treatment of UC.