Background: Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGBP) are associated with similar type 2 diabetes mellitus (T2DM) resolution rates for morbidly obese subjects. However, the mechanisms underlying the resolution of T2DM after SG have not been clarified to date. This study aimed to compare the early changes in gastrointestinal hormones involved in insulin and glucagon secretion in morbidly obese T2DM subjects undergoing SG or RYGBP.
Methods: This prospective study investigated 12 subjects with T2DM who had undergone SG (n = 6) or RYGBP (n = 6). Five body mass index (BMI)-matched obese non-diabetic subjects and five BMI-matched obese diabetic subjects served as control subjects. Glucose, insulin, glucagon, glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and GLP-2 were determined after a standardized mixed liquid meal before surgery and 6 weeks afterward.
Results: After 6 weeks, five of the six subjects in each surgical group presented with T2DM remission, although the area under the curve (AUC)0–120 of glucose was greater than that of the non-diabetic control subjects (P < 0.01). Postsurgically, the indices of insulin and glucagon secretion were comparable between the two surgical groups. The AUC0–120 of GLP-1 (P < 0.05) and GLP-2 (P < 0.05) was significantly and comparably enlarged after SG and RYGB. The postsurgical GIP response was significantly associated with the glucagon response throughout the meal test (ρ = 0.747; P < 0.01).
Conclusions: The data show that in a cohort of morbidly obese T2DM subjects, SG and RYGBP are associated with an early improvement in glucose tolerance, similar changes in insulin and glucagon secretion, and a similar GLP-1, GIP, and GLP-2 response to a standardized mixed liquid meal.