Faecal microbiota transplantation—A clinical view

Faecal microbiota transplantation has gained increasing attention over the last decade as various phenotypes could be transferred from a donor to a recipient in different animal models. Clinically, however, the sole indication with evidence from a randomized placebo controlled trial is refractory Clostridium difficile infection. Despite revealing successful clinical outcomes, questions concerning regulatory affairs, the identification of the best donor, the optimal mixture of the transplant as well as the preferred route of administration remain to be clarified even for this indication. Initiated by the idea that alterations in the composition of the intestinal microbiota are associated with intestinal inflammation in inflammatory bowel disease, several studies investigated whether faecal microbiota transplantation would be an equally suitable approach for these devastating disorders. Indeed, the available data indicate changes in the microbiota composition following faecal microbial transplantation depending on the degree of intestinal inflammation. Furthermore, first data even provide evidence that the transplantation of an “optimized” microbiota induces clinical remission in ulcerative colitis. However, despite these intriguing results it needs to be considered that not only “a cure of inflammation”, but also risk factors and phenotypes including obesity can be transferred via faecal microbiota transplantation. Thus, a deeper understanding of the impact of a distinct microbiota composition is required before “designing” the optimal faecal microbiota transplant.