No abstract

In this study, the frequency and function of CD4+CD25+CD45RA+ regulatory T cells (Treg) and intracellular IL‐2 signalling molecules in patients with type 2 diabetes mellitus (T2DM) were investigated. Tregs and responder T cells (Tresp, CD4+CD25− T cells) were sorted and suppression assays were performed using flow cytometry. Phosphorylation of signal transducer and activator of transcription‐5 (pSTAT5) were assessed using flow cytometry. Gene expression of FOXP3 was performed with the SYBR green Real Time PCR method. Production of IL‐2 from cultured cells was assessed using ELISA. We observed a functional defect of CD4+CD25+CD45RA+ Tregs in T2DM patients with higher proliferation of Tresp cells, in response to anti‐CD3 and anti CD28 stimulation in the presence of Tregs in vitro. The results showed that the proliferation of Tresps in the absence of Treg cells was higher in T2DM patients than in healthy controls. Decreased FOXP3 mRNA expression and pSTAT5 were observed within the Tregs of the patients, whereas the level of secreted IL‐2 from PBMCs culture was not statically different between T2DM patients and healthy individuals. Changes in intracellular IL‐2 pathways and FOXP3 gene expression may contribute to the defect of Tregs in T2DM patients. These findings indicating that the purified CD4+CD25+CD45RA+ Treg cells have reduced functional capacity together with impaired IL‐2 pathway in T2DM, and the Tregs could be used for a potential novel therapeutic target.

Background and Objective: 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 proinflammatory IL-6 and TNF-α in patients with type 2 diabetes mellitus (T2DM). Materials and Methods: 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 enzymelinked immunosorbent assay was used to analyze the levels of IL-6 and TNF-α produced by PBMCs. Results: 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. Conclusion: According to the results, it can be concluded that the combined use of sitagliptin and VitD3 is more influential regarding the antiinflammatory effects on patients. In addition, the reduction of sitagliptin dose may result in decreasing its possible side effects.