Effect of sitagliptin on glucose control in type 2 diabetes mellitus after Roux-en-Y gastric bypass surgery.

The present study was a 4-week randomized trial to assess the efficacy and safety of sitagliptin, a dipeptidyl-peptidase-4 inhibitor, in persistent or recurring type 2 diabetes after Roux-en-Y gastric bypass surgery (RYGB). Participants (n = 32) completed a mixed meal test (MMT) and self-monitoring of plasma glucose (SMPG) before and 4 weeks after randomization to either sitagliptin 100 mg daily or placebo daily. Questionnaires were administered to assess gastrointestinal discomfort. Outcome variables were glucose, active glucagon-like peptide-1 and ß-cell function during the MMT, and glucose levels during SMPG. Age (56.3 ± 8.2 years), body mass index (34.4 ± 6.7 kg/m2 ), glycated haemoglobin (7.21 ± 0.77%), diabetes duration (12.9 ± 10.0 years), years since RYGB (5.6 ± 3.3 years) and ß-cell function did not differ between the placebo and sitagliptin groups at pre-intervention. Sitagliptin was well tolerated, decreased postprandial glucose levels during the MMT (from 8.31 ± 1.92 mmol/L to 7.67 ± 1.59 mmol/L, P = 0.03) and mean SMPG levels, but had no effect on ß-cell function. In patients with diabetes and mild hyperglycemia after RYGB, a short course of sitagliptin provided a small but significant glucose-lowering effect, with no identified improvement in ß-cell function.

Effect of meal size and texture on gastric pouch emptying and glucagon-like peptide 1 after gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) accelerates gastric pouch emptying, enhances postprandial glucagon-like peptide 1 (GLP-1) and insulin, and lowers glucose concentrations. To prevent discomfort and reactive hypoglycemia, it is recommended that post-RYGB patients eat small, frequent meals and avoid caloric drinks. However, the effect of meal size and texture on GLP-1 and metabolic response has not been studied. OBJECTIVES: To demonstrate that frequent minimeals and solid meals (S) elicit less GLP-1 and insulin release and less reactive hypoglycemia and are better tolerated compared with a single isocaloric liquid meal (L). SETTING: A university hospital. METHODS: In this prospective study, 32 RYGB candidates were enrolled and randomized to L or S groups before gastric bypass. Each subject received an L or S 600-kcal single meal (SM) administered at hour 0 or three 200-kcal minimeals administered at hours 0, 2, and 4 on 2 separate days. Twenty-one patients were retested 1 year after RYGB. Blood and visual analogue scale measurements were collected up to 6 hours postprandially. Outcome measures included gastric pouch emptying, glucose, insulin, and GLP-1; hunger, fullness, and stomach discomfort were measured by visual analogue scale. RESULTS: Twenty-one were patients retested after RYGB (L: n = 12; S: n = 9). Meal texture had a significant effect on peak GLP-1 (L-SM: 106.1 ± 67.2 versus S-SM: 45.3 ± 25.2 pM, P = .004), peak insulin, and postprandial glucose. Hypoglycemia was more frequent after the L-SM meal compared with the S-SM. Gastric pouch emptying was 2.4 times faster after RYGB but was not affected by texture. CONCLUSIONS: Meal texture and size have significant impact on tolerance and metabolic response after RYGB.

Glucose Metabolism After Gastric Banding and Gastric Bypass in Individuals With Type 2 Diabetes: Weight Loss Effect.

OBJECTIVE: The superior effect of Roux-en-Y gastric bypass (RYGB) on glucose control compared with laparoscopic adjustable gastric banding (LAGB) is confounded by the greater weight loss after RYGB. We therefore examined the effect of these two surgeries on metabolic parameters matched on small and large amounts of weight loss. RESEARCH DESIGN AND METHODS: Severely obese individuals with type 2 diabetes were tested for glucose metabolism, ß-cell function, and insulin sensitivity after oral and intravenous glucose stimuli, before and 1 year after RYGB and LAGB, and at 10% and 20% weight loss after each surgery. RESULTS: RYGB resulted in greater glucagon-like peptide 1 release and incretin effect, compared with LAGB, at any level of weight loss. RYGB decreased glucose levels (120 min and area under the curve for glucose) more than LAGB at 10% weight loss. However, the improvement in glucose metabolism, the rate of diabetes remission and use of diabetes medications, insulin sensitivity, and ß-cell function were similar after the two types of surgery after 20% equivalent weight loss. CONCLUSIONS: Although RYGB retained its unique effect on incretins, the superiority of the effect of RYGB over that of LAGB on glucose metabolism, which is apparent after 10% weight loss, was attenuated after larger weight loss.