Effects of miglitol, sitagliptin, and initial combination therapy with both on plasma incretin responses to a mixed meal and visceral fat in over-weight Japanese patients with type 2 diabetes. “The MASTER randomized, controlled trial”

•Miglitol, an alpha-glucosidase inhibitor, decreased GIP secretion and body weight, and increased GLP-1 secretion.•Sitagliptin, a DPP-4 inhibitor, increased circulating active forms GIP and GLP-1.•Combination of both attenuated increase in active GIP by DPP-4 inhibitor and brought further enhanced active GLP-1 with reduced body weight and increased adiponectin.

AbsrtactAimTo assess changes in circulating incretin levels and body fat compositions with initial combination therapy with α-glucosidase inhibitor and dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes (T2D).MethodsIn this multicenter open-label 24-week trial, Japanese over-weight (BMI ≥ 25 kg/m2) patients with T2D not taking medication or taking metformin and/or sulfonylurea were randomly assigned to receive either 50 mg of miglitol three times a day (M, n = 14), 50 mg of sitagliptin once a day (S, n = 14), or a combination of both (M + S, n = 13). Changes in plasma incretin levels during a meal tolerance test (MTT) and body fat composition with impedance method were evaluated.ResultsDuring MTT, postprandial plasma glucose levels decreased more after M + S than after M or S, and postprandial serum insulin levels decreased significantly after M and M + S whereas they increased after S. After M, active gastric inhibitory polypeptide (aGIP) decreased significantly at 30 min despite a significant increase at 120 min. After S, aGIP levels increased significantly throughout the MTT. After M + S, aGIP increased significantly at 0 and 120 min despite of significant decrease at 30 min. M + S further enhanced postprandial active glucagon-like peptide-1 levels during MTT than S did. Total body fat mass decreased significantly after M and M + S. Visceral fat mass decreased significantly only after M + S. Serum adiponectin increased significantly only after M + S.ConclusionsIn over-weight patients with T2D, M + S may have a beneficial effect on adiposity with relation to these different effects on two incretins.