Effect of Sitagliptin Monotherapy on Beta-Cell and Endothelial Functions in Patients with Newly Diagnosed Type 2 Diabetes

Background/Aim: Recent research has focused on identifying new therapeutic targets and novel pathways for correcting impaired glucose homeostasis in type 2 diabetes (T2DM). The dipeptidyl peptidase-4 (DPP-4) inhibitor, sitagliptin contributes to suppression of postprandial hyperglycemia and diminishes risk of hypoglycemia through increasing the level of glucagon-like polypeptide. This study was conducted to assess the effect of sitagliptin on β-cell and endothelial functions in Egyptian patients with newly diagnosed T2DM. Methods: The study enrolled 40 patients with newly diagnosed T2DM and 40 controls matched for age and sex. Anthropometric measurements, plasma glucose, lipid profile, LFTs, HOMA-IR, HOMA-β, amylase, lipase and flow mediated dilatation (FMD) were assessed. Patients with T2DM were evaluated before and after treatment with 100 mg daily sitagliptin for 24 weeks. Results: Sitagliptin significantly reduced blood pressure, FPG, 2 h PPG, HbA1c, ALT, TGs, TC, LDL and HOMA-IR, whereas insulin, HOMA-β and FMD were significantly increased. Δ FMD was negatively correlated with Δ SBP, Δ FBG, Δ 2 h PPG, Δ HbA1c, Δ insulin, Δ TC, Δ TGs, Δ LDL, Δ HOMA-IR and positively correlated with Δ HOMA-β. With multivariate linear regression analysis, ΔTGs (B = – 0.140, P = 0.03), Δ LDL (B = – 0.158, P = 0.02), Δ HOMA-IR (B = – 0.904, P = 0.02) were independent predictors of Δ FMD after adjustment of Δ SBP, ΔTC. Conclusion: Sitagliptin monotherapy is effective not only on glycaemic control and insulin sensitivity but, also it ameliorates endothelial dysfunction, blood pressure and dyslipidemia in newly diagnosed T2DM.