Anti-Inflammatory Effect of Combined Sitagliptin and Vitamin D3 on Cytokines Profile in Patients with Type 2 Diabetes Mellitus

Studies indicated that imbalance of proinflammatory and anti-inflammatory cytokines may contribute to development of type 2 diabetes mellitus (T2DM). We hypothesized that sitagliptin and VitD3 may exert more anti-inflammatory effects on the regulation of cytokine balance in T2DM. Nonnephropathic and nephropathic T2DM patients were divided into the subgroups, based on treatments. The effect of 8 months sitagliptin, alone or together with 2 months of VitD3, on serum IFN-gamma, IL-4, IL-17, IL-6, IL-21, TGF-beta, and IL-37 levels was determined using enzyme-linked immunosorbent assay. Increased levels of interferon (IFN)-gamma and IL-17 in untreated (without sitagliptin and VitD3) nephropathic and nonnephropathic patients and decreased levels of IL-37 in untreated nephropathic patients were observed compared with healthy controls. Treatment with sitagliptin plus VitD3 reduced the levels of IFN-gamma and IL-17 in both nonnephropathic and nephropathic patients compared with untreated patients. The level of IL-37 was enhanced in patients treated with sitagliptin or sitagliptin plus VitD3, compared with untreated patients. Sitagliptin plus VitD3 treatment increased the levels of IL-4 in nonnephropathic patients. These findings indicated that the sitagliptin plus VitD3 was more effective to reduce the increased proinflammatory IFN-gamma and IL-17 cytokines in T2DM patients.