ORIGINAL RESEARCH ARTICLE Dipeptidyl Peptidase-4 Inhibitor (Vildagliptin) Improves Glycemic Control After Meal Tolerance Test by Suppressing Glucagon Release

The Author(s) 2014. This article is published with open access at Springerlink.com Aim We aimed to evaluate changes in insulin and glu-cagon secretion, as well as glucose levels, with a meal tolerance test (MTT) before and after 6 months of treat-ment with vildagliptin in a clinical setting. Materials and Methods Participants were 15 patients with uncontrolled type 2 diabetes mellitus (glycated hemoglobin [HbA1c] over 6.9 % for more than 3 months). MTTs were conducted before and 6 months after addition of vildag-liptin (50 mg twice daily [bid]). Blood samples were col-lected immediately before, and 1 and 2 h after the test meal for measurement of blood glucose concentration, immune-reactive insulin (IRI), and glucagon. HbA1c was measured at 6 months. Results Mean age of participants was 55.5 ± 2.8 years, and ten (66.7 %) were male. Mean HbA1c significantly improved from 7.6 to 6.8 % at 6 months after addition of vildagliptin. Blood glucose at 1 and 2 h after the test meal was significantly reduced after addition of vildagliptin, while the reduction in glucagon showed borderline signif-icance and IRI showed no difference. In a comparison of blood glucose-related parameters between subgroups based on median glucose change in area under the curve during MTT (DAUC0–2h), glucagon DAUC0–2h was significantly lower in the group with more improved glucose levels (DAUC0–2h C65 mg/dL), but that of IRI did not differ. Conclusion Suppression of glucagon release by vildag-liptin may improve glycemic control without increasing insulin levels in patients with type 2 diabetes.