The increased T helper cells proliferation and inflammatory responses in patients with type 2 diabetes mellitus is suppressed by sitagliptin and vitamin D3 in vitro.

Objective: The probably effects of sitagliptin and vitamin D3 (VitD3) on proliferation capacity and cytokines production were investigated in type 2 diabetes mellitus (T2DM) in vitro.

Materials And Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with T2DM and 26 healthy controls (HCs). CFSE-labeled PBMCs stimulated with phytohamagglutinin (PHA, 5 μg/mL) in the presence/absence of sitagliptin (200 mg/mL) with/without VitD3 (10 M) for 4 days. The proliferation of CD4 T helper cells and non-CD4 cells was analyzed using flow cytometry. The supernatant levels of IFN-γ, IL-17, IL-4, TGB-β and IL-37 were detected using ELISA.

Results: The proliferation of CD4 T cells in response to PHA was higher in T2DM patients compared with HCs. The production of IFN-γ and IL-17 in PHA-stimulated cultures was higher, and the levels of IL-4 and IL-37 were lower in T2DM patients compared to HCs. The addition of sitagliptin or VitD3 to the cultures decreased the CD4 T cells and non-CD4 cells proliferation in patients and HCs. Sitagliptin with VitD3 was more effective in suppression of proliferation, decreasing of IL-17 and enhancing of IL-37 production.

Conclusion: Sitagliptin plus VitD3 effectively reduces the proliferative T cells response and modulates pro-inflammatory/anti-inflammatory cytokines production.