The Dipeptidyl Peptidase-4 Inhibitor Sitagliptin Improves Vascular Endothelial Function in Type 2 Diabetes

The vascular endothelial function is impaired in the very early stage of atherosclerosis in diabetic patients. The goal of this study was to identify the mechanism underlying the improvement in vascular endothelial function by sitagliptin in type 2 diabetes mellitus patients. This study was an open-labeled prospective observational single arm trial. Forty patients were treated with 50 mg of sitagliptin once daily for 12-weeks. The flow-mediated dilation (FMD) and plasma adiponectin were measured at baseline and 12 weeks after initiating treatment. The %FMD was significantly increased after treatment (4.13 ± 1.59 vs 5.12 ± 1.55, P < 0.001), whereas the nitroglycerin-mediated dilation (NMD) did not change. The plasma adiponectin levels significantly increased (13.0 ± 11.3 vs 14.3 ± 12.8, P < 0.001). The changes in the FMD were significantly correlated with those of the plasma adiponectin (r = 0.322, P < 0.05). A multivariate linear regression analysis demonstrated that the improvement in the FMD is associated with the plasma adiponectin (P < 0.05). The treatment of type 2 diabetes mellitus patients with sitagliptin reverses vascular endothelial dysfunction, as evidenced by increase in the FMD, and improvement of the adiponectin levels.