Fecal Microbiota Transplantation: a Future Therapeutic Option for Obesity/Diabetes?

The aim of this review is to summarize the current data available on the metabolic effects of fecal microbiota transplantation (FMT) including obesity and glucose metabolism in humans. Gut microbiota dysbiosis is a frequent characteristic observed in obesity and related metabolic diseases. Pieces of evidence mostly generated in mouse models suggest that rescuing this dysbiosis associates with improved metabolism. In humans, dietary or bariatric surgery interventions are often accompanied by complete or partial restoration of this dysbiosis together with weight reduction and metabolic amelioration. FMT is an interesting option to modify gut microbiota and has been associated with improved clinical outcomes, albeit only used in routine care for Clostridium difficile infection. However, there are only limited data on using FMT in the metabolic context. FMT from lean donors significantly improves insulin sensitivity in obese subjects with metabolic syndrome. However, there is a wide range of clinical responses. Interestingly in subjects with high microbial gene richness at baseline and when FMT donors that are metabolically compromised are used, no metabolic improvement is seen. Moreover, more studies evaluating the effect of FMT in patients with overt type 2 diabetes are warranted. Furthermore, interventions (in the receiver prior to FMT) aiming to enhance FMT response also need evaluation.