Faecal virome transplantation decrease symptoms of type-2-diabetes and obesity in a murine model

Objective: Development of obesity and type-2-diabetes (T2D) are associated with gut microbiota (GM) changes. The gut viral community is predominated by bacteriophages (phages), which are viruses that attack bacteria in a host-specific manner. As a proof-of-concept we demonstrate the efficacy of faecal virome transplantation (FVT) from lean donors for shifting the phenotype of obese mice into closer resemblance of lean mice. Design: The FVT consisted of viromes extracted from the caecal content of mice fed a low-fat (LF) diet for fourteen weeks. Male C57BL/6NTac mice were divided into five groups: LF (as control), high-fat diet (HF), HF+Ampicillin (Amp), HF+Amp+FVT and HF+FVT. At week six and seven of the study the HF+FVT and HF+Amp+FVT mice were treated with FVT by oral gavage. The Amp groups were treated with ampicillin 24 h prior to first FVT treatment. Results: Six weeks after first FVT the HF+FVT mice showed a significant decrease in weight gain compared to the HF group. Further, glucose tolerance was comparable between the lean LF and HF+FVT mice, while the other HF groups all had impaired glucose tolerance. These observations were supported by significant shifts in GM composition, blood plasma metabolome, and expression levels of genes involved in obesity and T2D development. Conclusions: Transfer of gut viral communities from mice with a lean phenotype into those with an obese phenotype reduce weight gain and normalise blood glucose parameters relative to lean mice. We hypothesise that this effect is mediated via FVT-induced GM changes.