Effect of Sitagliptin and Vitamin D3 on Secretion of IL-6 and TNF-α Inflammatory Factors in Patients with Type 2 Diabetes

  Diabetes mellitus is one of the most commonly reported diseases that is associated with insulin resistance and increased blood glucose levels. The aim of this study was to determine the probable anti-inflammatory effects of sitagliptin and vitamin D3 (VitD3) on pro-inflammatory IL-6 and TNF-α in patients with type 2 diabetes mellitus (T2DM). In this case-control study, 20 blood samples of patients with T2DM and healthy controls (HCs) were collected (n=20). Peripheral blood mononuclear cells (PBMCs) were isolated using the Ficoll-Paque method and cultured with Phytohemagglutinin (PHA) in the presence or absence of sitagliptin and VitD3 for 4 days. The enzyme-linked immunosorbent assay was used to analyze the levels of IL-6 and TNF-α produced by PBMCs. After PHA stimulation, the production of IL-6 was increased significantly in T2DM patients compared to HCs (P=0.03) . Compared to PHA cultures, sitagliptin and VitD3 resulted in the reduction of IL-6 production in patients (P≤0.001, P≤0.001), and HCs (P=0.03, P=0.02), respectively. Moreover, with regard to the cultures with sitagliptin or VitD3, sitagliptin with VitD3 reduced the level of IL-6 in both groups of patients (P=0.02, P=0.002) and HCs (P=0.002, P=0.03). There was a significant reduction in the level of TNF-α by sitagliptin with VitD3 in patients (P=0.04, P=0.002) and HCs (P=0.04, P=0.03) , compared to cultures with sitagliptin or VitD3. According to the results, it can be concluded that the combined use of sitagliptin and VitD3 is more influential regarding the anti-inflammatory effects on patients. In addition, the reduction of sitagliptin dose may result in decreasing its possible side effects