The Effect Of Sitagliptin On β-Cell Function And Regulatory T Cells Of Patients With Type 2 Diabetes

Background:Type 2 diabetes mellitus (T2DM) is a typically complex and polygenic disease. The pathogenesis is complex, and the disease has become one of the main death factors in the world. Now inflammation is believed to be an important factor in the development of T2DM and its complications. Regulatory T cells (Treg) play a key role in the immune and inflammatory regulation. There are studies have shown that patients with T2DM have an imbalance of peripheral Treg cells. That may be associated with diabetes and its development of inflammation.Sitagliptin is a kind of high selective inhibitor of DPP-4, which can reduce glucagon like peptide 1 (GLP-1) and glucose dependence polypeptide (GIP) inactivation in the body to promote insulin secretion in a kind of glucose dependent manner. Moreover, sitagliptin have a significant influence on autoimmune diabetes. Therefore, the aim of this study is to analyses the change of peripheral Treg cells in patients with T2DM, and reveal the effect of sitagliptin on β-cell function and regulatory T cells.Objective:The main aim of this study is to reveal the effect of sitagliptin on β-cell function and regulatory T cells of type 2 diabetic patients.Methods:Our study adopted self-contrast method. And eight patients with type 2 diabetes and 8 healthy volunteers were included in this study according to the inclusion criteria. The included patients were treated by sitagliptin phosphate tablets for 4 weeks. Then, the change of fasting plasma glucose (FPG), glucagon, proinsulin/insulin ratio, insulin resistance and islet beta cell function index were detected. Moreover, the proportion of peripheral Treg cells to PBMC cells (Treg/PBMC) in diabetes patients and healthy volunteers were assayed by flow cytometry.Results:The results indicated that the FPG, glucagon, proinsulin/insulin ratio and insulin resistance were dramatically increased and β-cell function was decreased in T2DM patients compared to healthy volunteers. The peripheral Treg/PBMC was significantly decreased in patients with T2DM (P< 0.05). The treatment of Sitagliptin could significantly decreased the FPG, glucagon and proinsulin/insulin while could improved islet β-cell function(P<0.05). However, Sitagliptin had no significant effect on peripheral Treg/PBMC ratio.Conclusion:Sitagliptin can improve (3-cell function of T2DM patients and effectively control type 2 diabetes patients’ glucose by promoting the insulin secretion and reducing the glucagon levels. Furthermore, Sitagliptin had no effects to the number of Treg cells, and it had no improvements on the inflammation statement of T2DM.