Roux-en-Y gastric bypass with a long compared to a short biliopancreatic limb leads to better weight loss and glycemic control in obese mice

Objective

Roux-en-Y gastric bypass (RYGB) shows durable long-term weight loss and control of comorbidities in randomized controlled trials. However, the impact of the proportions of the biliopancreatic limb (BPL) and the total alimentary limb (TALL) on weight loss or glucose metabolism is still unclear.

Methods

Six weeks old C57BL/6J mice were fed high fat diet (HFD) to induce obesity and glucose intolerance. Mice underwent RYGB surgery with a very-long BPL (35% of total bowel length [TBL]), long BPL (25% of TBL), short BPL (15 % of TBL), or sham surgery. The alimentary limb (AL) was adjusted in dependency on the BPL to achieve a fixed CC length. Glycemia was assessment by intraperitoneal glucose tolerance tests.

Results

Mice undergoing RYGB with a very-long BPL showed excessive weight loss and mortality and were therefore excluded for further analyses. Total weight loss (TWL%) was significantly higher in the long BPL- compared to short BPL-group. Mice with a long BPL showed significantly improved glucose tolerance 14 days postoperatively, while 35 days postoperatively, the improvement in glucose tolerance with a long BPL was much less distinctive.

Conclusion

RYGB with a longer BPL leads to improved results including weight loss and glucose tolerance. However, the metabolic improvements seem to decrease over time. These findings could potentially be translated to humans by adjusting the BPL according to body weight and comorbidities. To avoid possible negative effects of a longer BPL total bowel length measurement is mandatory.