Roux-en Y Gastric Bypass Is Superior to Duodeno-Jejunal Bypass in Improving Glycaemic Control in Zucker Diabetic Fatty Rats

Background: Whilst weight loss results in many beneficial metabolic consequences, the immediate improvement in glycaemia after Roux-en-Y Gastric bypass (RYGB) remains intriguing. Duodenal jejunal bypass (DJB) induces similar glycaemic effects, while not affecting calorie intake or weight loss. We studied diabetic ZDFfa/farats to compare the effects of DJB and RYGB operations on glycaemia. Methods: Male ZDFfa/farats, aged 12 weeks underwent RYGB, DJB or sham operations. Unoperated ZDFfa/faand ZDFfa/+were used as controls. Body weight, food intake, fasting glucose, insulin and gut hormones were measured at baseline and on postoperative days 2, 10 and 35. An oral glucose tolerance test (OGTT) was performed on days 12 and 26. Results: DJB had similar food intake and body weight to sham-operated and unoperated control ZDFfa/farats (p = NS), but had lower fasting glucose (p < 0.05). RYGB had lower food intake, body weight and fasting glucose compared to all groups (p < 0.001). DJB prevented the progressive decline in fasting insulin observed in the sham-operated or unoperated ZDFfa/farats, while RYGB with normalized glycaemia reduced the physiological requirement for raised fasting insulin. Conclusions: Bypassing the proximal small bowel with the DJB has mild to moderate body weight independent effects on glucose homeostasis and preservation of fasting insulin levels in the medium term. These effects might be further amplified by the additional anatomical and physiological changes after RYGB.