FMT in Obesity: RYGB vs. LEAN vs. Autologous FMT

This double-blinded proof-of-concept study is proposed to explore the effects of fecal microbiota transfer (FMT) in human subjects. Here we perform FMTs into obese recipients using stool from lean unoperated donors and from previously obese patients after successfull treatment with bariatric Roux-en-Y Gastric Bypass (RYGB) surgery. Obese patients treated with their own material (autologous FMT) serve as controls. After FMT treatment the functional impact of post-surgery microbiome changes on host energy consumption and regulation of blood glucose levels will be analysed. Additionally the variations on the microbiota and metabolite composition will be profiled using extensive sequencing analyses. The major aim of the study is to explore the scientific rationale for targeted gut microbiota modulation in management of obesity and related metabolic diseases.We estimate the transfer of microbiota from RYGB donors is superior to the transfer of lean microbiota at inducing reduced adiposity and improving high blood glucose levels in obese recipients. Each is better than a sham procedure (autologous FMT), which itself can also induce considerable short-term effects.

Patients and stool donors (for RYGB-/Lean-FMT-intervention groups) will be recruited at the Endocrinology outpatient clinic at the University Hospital of Graz. Patients will be randomized in a 1:1:1 manner. In all three study groups, patients will be treated with FMT totaling three times every 7 days after an antibiotic pretreatment. Patients randomized to the RYGB- FMT-intervention group will be treated with donor stool from previously obese patients successfully treated with RYGB surgery in terms of maintained weight reduction and improved glucose homeostasis. Patients randomized to Lean-FMT-intervention group will be treated with donor stool from un-operated, metabolically healthy and lean individuals, while patients randomized to the FMT-placebo group will be treated with autologous FMT. For both allogenic FMT interventions, the donor stool from five different patients successfully treated with RYGB surgery (for RYGB-FMT intervention) and from five un-operated, lean and healthy individuals (for Lean-FMT intervention), respectively, will be anaerobically processed before active study period and stored at - 20° C for analysis and subsequent FMT. In addition, stool from all 30 obese FMT recipients (FMT-intervention groups and FMT-placebo group) will be collected before the active study period, processed anaerobically and frozen at -80° C. Only stool samples from patients randomized to the FMT-placebo group (n=10) will be used as allogenic transplants.