BACKGROUND

Changes in gut microbiota induced by bariatric surgery have been associated with metabolic benefits.

OBJECTIVES

Our aim was to identify specific gut microbiota that may contribute to the improvement of type 2 diabetes (T2D) after Roux-en-Y gastric bypass (RYGB).

SETTING

Laboratories of Shanghai Diabetes Institute and Shanghai Sixth People's Hospital.

METHODS

Diabetic rats induced via a high-fat diet and low-dose streptozotocin administration were randomized to RYGB or sham surgery, and stool samples were collected at baseline and at postoperative week 8. The fecal microbiota was profiled using 16S ribosomal RNA gene sequencing. Additionally, we performed a case-control study of the gut microbial community profiles of T2D patients compared with those of healthy individuals via 16S ribosomal RNA gene sequencing of mucosal-luminal interface samples collected from the ascending colon during colonoscopy.

RESULTS

RYGB significantly reduced the weight and improved glucose tolerance and insulin sensitivity in diabetic rats. Principal coordinate analysis showed that RYGB caused marked alterations in the gut microbiota. The RYGB group was postoperatively enriched for Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria, whereas the sham surgery group was enriched for Firmicutes and Verrucomicrobia. Based on the gut microbial patterns in the T2D patients, we found that the family Coriobacteriaceae within Actinobacteria might contribute to the beneficial effects of RYGB on T2D.

CONCLUSIONS

RYGB significantly improves glucose metabolism and alters the gut microbiota. Moreover, the family Coriobacteriaceae may partly mediate the beneficial effects of RYGB on T2D and thus possibly contribute to the development of novel bacteria-based therapeutic approaches.