Roux-en-Y Gastric Bypass and Vertical Banded Gastroplasty Induce Long-Term Changes on the Human Gut Microbiome Contributing to Fat Mass Regulation

Abstract

SummaryBariatric surgery is currently the most effective procedure for the treatment of obesity. Given the role of the gut microbiota in regulating host metabolism and adiposity, we investigated the long-term effects of bariatric surgery on the microbiome of patients randomized to Roux-en-Y gastric bypass or vertical banded gastroplasty and matched for weight and fat mass loss. The two surgical procedures induced similar and durable changes on the gut microbiome that were not dependent on body mass index and resulted in altered levels of fecal and circulating metabolites compared with obese controls. By colonizing germ-free mice with stools from the patients, we demonstrated that the surgically altered microbiota promoted reduced fat deposition in recipient mice. These mice also had a lower respiratory quotient, indicating decreased utilization of carbohydrates as fuel. Our results suggest that the gut microbiota may play a direct role in the reduction of adiposity observed after bariatric surgery.

Modulation of Gut Microbiota of Overweight Mice by Agavins and Their Association with Body Weight Loss

“…Taxa associated with greater body weight loss included Klebsiella and Citrobacter (Enterobacteriaceae; Figure 4B). Enterobacteriaceae have also been reported to increase during weight loss in obese mice [38] and human [39,40]. Other bacteria enriched by supplementation with oligofructose included Prevotella, Allobaculum and Faecalibacterium genera ( Figure 4C).…”

Roles of the Gut in Glucose Homeostasis

“…In germ-free mice colonized with stools from the patients, reduced fat deposition was found. The results suggest that the gut microbiota play a direct role in the reduction of adiposity observed after bariatric surgery (81) and that the changes were mainly due to weight loss. On the other hand, elimination of colonic microbiota has little or no effect on glucose metabolism in humans (82,83).…”

“…However, few studies have validated causality in humans, and the underlying mechanisms largely remain to be elucidated. In studies of the microbiome of patients randomly assigned to Roux-en-Y gastric bypass or vertical banded gastroplasty, similar and durable changes on the gut microbiome resulted in altered levels of fecal and circulating metabolites (81). In germ-free mice colonized with stools from the patients, reduced fat deposition was found.…”

Microbiotes et maladies métaboliques

“…À la suite de cette chirurgie, le duodénum et le jéjunum proximal ne reçoivent plus de nutriments. Ces derniers entrent donc directement au contact des microbiotes présents dans le jéjunum distal et l'iléon avec pour conséquence une modification drastique du métabolisme des bactéries qui y sont présentes [32,33]. Ces changements infligés au microbiote, révélés par l'analyse du microbiote fécal, pourraient, au moins en partie, expliquer l'efficacité thérapeutique exceptionnelle de cette procédure chirurgicale sur l'obésité et sur les perturbations trouvant leur origine dans les maladies métaboliques qui lui sont associées.…”

“…Un lien causal a pu être démontré dans le modèle murin. En colonisant des souris axéniques (dépourvues de bactéries et vivant en isolateur) avec un microbiote provenant de patients diabétiques et obèses et ayant subi ou non une chirurgie bariatrique, il a pu être montré que la prise de poids des souris, colonisées par le microbiote de patients opérés, était en effet inférieure à celle que l'on observe chez les souris traitées avec un microbiote provenant de patients non opé-rés [33]. Mais d'autres fonctions de l'intestin, telles que la sécrétion d'incrétines [34,67] (➜), la production intestinale de glucose [35] et la production d'acides biliaires [36,37], pourraient aussi expliquer l'impact majeur de la chirurgie bariatrique sur le contrôle des maladies métaboliques.…”