Entero-endocrine changes after gastric bypass in diabetic and nondiabetic patients: a preliminary study

Alterations in entero-endocrine signaling may play a role in improvements in satiety and glucose tolerance after Roux-en-Y gastric bypass (RYGB). We report our findings of gut hormone secretion in a cohort of diabetic and nondiabetic morbidly obese patients.

Ten morbidly obese subjects who underwent uncomplicated RYGB were studied: 5 were diabetic and 9 were female. Nonfasting plasma levels of glucagon-like peptide-1 (GLP-1), insulin, desacyl ghrelin, active ghrelin, neuropeptide Y (NPY), and gastric inhibitory polypeptide (GIP) were determined preoperatively and 6 months postoperatively.

Mean patient age was 42 +/- 11 years, and the mean preoperative body mass index was 50 +/- 6 kg/m(2). At 6 months mean BMI fell to 33 +/- 5 kg/m(2) (P < 0.0001), and there were no differences between diabetics and nondiabetics with respect to amount of weight loss. In non-diabetics, compared to preoperative levels, there were significant increases in GLP-1 and desacyl-ghrelin in the nondiabetic patients (P = 0.046 and P = 0.016, respectively); no change in plasma insulin, active ghrelin, NPY, or GIP was demonstrated. In contrast, when compared to preoperative levels, there were no significant changes in entero-endocrine hormone levels in the diabetic cohort postoperatively.

At 6 months postoperation, RYGB significantly alters the hormone levels for GLP-1 and desacyl-ghrelin in morbidly obese nondiabetic patients. No significant change was noted in a matched cohort of diabetic patients. Weight loss was similar in diabetics and nondiabetics, suggesting that GLP-1 and ghrelin are not the only mechanisms producing weight loss after RYGB.