Efficacy of intestinal microbiota transplantation in ulcerative colitis: A review of current literature and knowledge

Inflammatory bowel disease (IBD) results in chronic inflammation in the intestine and is thought to arise from an abnormal immune response to host commensal bacteria. The current treatment paradigm for IBD is focused on suppression of the immune system. However, intestinal microbiota transplant (IMT) may present an avenue to treat IBD by altering the target of inflammation without necessitating immune suppression. Presently, reports of the greatest success with IMT in IBD have been with ulcerative colitis (UC). Four randomized controlled trials have evaluated the efficacy of IMT in UC and reported a pooled rate of combined clinical and endoscopic remission of 28% (95% CI: 4-10). For clinical remission alone, the pooled rate was as high as 42% with a number needed to treat of 5 (95% CI: 3-17). While promising, many questions remain which include elucidating the optimal microbiota enrichment, exacting donor profiling, and identifying the optimal IMT route and frequency. Longer follow-up is needed to determine the ability to achieve stable engraftment for maintenance of remission as well as safety of IMT therapeutics. This review will critically appraise the current literature for IMT in UC and identify key knowledge gaps.