Gut microbiota after gastric bypass in human obesity: increased richness and associations of bacterial genera with adipose tissue genes

Abstract

Background: Roux-en-Y gastric bypass (RYGB) surgery is one of the most efficient procedures for treating morbid obesity and results in weight-loss and improvements in metabolism and inflammation. Objective: We examined the impact of RYGB on modifications of gut microbiota and its potential associations with changes in gene expression in white adipose tissue (WAT). Design: Gut microbiota were profiled from fecal samples by using pyrosequencing in morbidly obese individuals, explored before (0 mo), 3 mo after, and 6 mo after RYGB. WAT gene expression was studied at 0 and 3 mo. We explored associations between microbial genera and differentially expressed genes in WAT and clinical markers. Results: The richness of gut microbiota increased after RYGB; 37% of increased bacteria belonged to Proteobacteria. The associations between gut microbiota composition and WAT gene expression increased after RYGB. Fourteen discriminant bacterial genera (7 were dominant and 7 were subdominant) and 202 WAT genes changed after RYGB. Variations in bacterial genera correlated with changes in both clinical phenotype and adipose tissue gene expression. Some genes encode metabolic and inflammatory genes. Almost half of the correlations were independent of the change in calorie intake. Conclusion: These results show an increase in gut microbiota richness and in the number of associations between gut microbiota and WAT genes after RYGB in obesity. Variations of gut microbiota were associated with changes in WAT gene expression. These findings stimulate deeper explorations of the mechanisms linking gut microbiome and WAT pathological alterations in human obesity and its changes after weight loss.Am J Clin Nutr 2013;98:16-24.

Obesity diabetes and the role of bile acids in metabolism

“…A recent review of bariatric surgery in adolescent patients found little difference in weight reduction when Roux en Y was compared with sleeve gastrectomy [25] . The patients who had the Roux en Y procedure were the heaviest at the start with a mean BMI of 54 (52)(53)(54)(55), whereas the sleeve gastrectomy subjects had a mean BMI of 50 (48)(49)(50)(51)(52). The percent change was 28 for the Roux en Y as compared to 26 for the sleeve gastrectomy operation.…”

“…The authors suggest that the changes are perhaps due to the differences in diet after the operation or very low calorie diet of the non-operated subjects. Kong et al [52] examined gut microbiota after Roux en Y surgery, and found increased microbiota, 37% due to proteobacteria. They also found an increase in Bacteroides.…”

The microbiota in inflammatory bowel disease

“…These ''Western'' diseases are increasing in prevalence, and manipulating the gut microbiota is an attractive therapeutic approach in their management. Strategies for combating obesity and related conditions that involve manipulating the gut microbiota include bariatric surgery [78,79], microbial transplantation [80,81] and probiotics [82].…”

Does gastric bypass surgery change body weight set point?

“…The gut microbiome changes after gastric bypass surgery in humans, [66][67][68] rats 69 and mice, 70 and a recent transplant study in mice suggests that the changes in gut microbiome are responsible for at least some effects on body weight. 70 The signaling pathways leading from the microbiota in the intestinal lumen to reduced body weight are not known (Figure 3).…”