امیرحسین افتخاری

Diabetes has been the most common metabolic disorder in recent decades. Oxidative stress and its related factors play an important role in the onset and complications of diabetes. In this study, glutathione peroxidase activity and oxidative stress indices in serum of type 2 diabetes patients and their correlation with blood glucose and lipid parameters were evaluated.

This is a case-control study. 50 healthy people (24 men and 26 women) and 50 diabetic people (25 men and 25 women) were randomly selected. Following a 12-hour fasting condition, the blood samples were taken and the sera were isolated. Fasting blood sugar, lipid profiles, lipid peroxidation, total antioxidant status, and glutathione peroxidase activity were measured by relevant protocols. All information was analyzed using SPSS software version 16. A significance level of p ≤0.05 was considered.

Serum glutathione peroxidase activity and total antioxidant status in the patient group had a significant decrease in comparison with the control group. Serum levels of malondialdehyde, FBS, TG, VLDL-C, and HbA1c increased significantly in the patient group than in the control group. Statistical analysis showed a significant and direct correlation between glutathione peroxidase activity and TAC and HDL-C levels, and a significant and inverse correlation between glutathione peroxidase activity and serum MDA, HbA1C, and FBS levels. It was also shown that there was a significant and direct correlation between MDA serum concentration and levels of HbA1C, TG, FBS, and VLDL-C. However, there was a significant and inverse correlation between serum TAC concentration and HbA1C, TG, FBS, TC, and VLDL-C levels.

Oxidative stress is a major contributor in the development of diabetes and its complications, so that the decrease in the level of antioxidative factors and the increase in the level of oxidants are closely related to the metabolic disorder of carbohydrates and lipids.

Type 2 diabetes (T2DM) is a complex metabolic disorder characterized by insulin resistance and progressive failure of pancreatic beta-cell function. Selenoprotein P (SelP) ​​plays an important role in selenium homeostasis in the body and prevents oxidative stress. The aim of this study was to determine the SelP level and oxidative stress indices in serum type 2 diabetic patients and also to determine their correlation with glucose and lipid parameters.

One hundred subjects were recruited in current study, including 50 T2DM patients and 50 age, sex and BMI matched healthy controls. Blood samples were collected from all subjects. The serum SelP level was measured using ELISA kit. Serum levels of HbA1c, FBS, and lipid parameters were evaluated by autoanalyzer. In order to evaluate the serum samples for oxidative stress, total antioxidant capacity (TAC) was measured based on ferric ion reduction by Ferric Reducing Ability of Plasma (FRAP) method. Malondialdehyde was measured by fluorimetric method.

The results showed that serum SelP level in type 2 diabetes was significantly higher than control group (p <0.001). Also, serum levels of TAC in the patient group decreased while levels of MDA increased significantly (p <0.001). There was a significant and direct correlation between serum SelP concentration and HbA1C, FBS, TG, VLDL-C, and MDA levels and a significant and inverse relationship between the serum concentration of SelP and serum TAC levels. Also, the TAC serum levels have a reverse and significant correlation with HbA1C, FBS, TG, VLDL-C, and TC levels. Findings showed that the serum levels of MDA have a direct and significant correlation with HbA1C, FBS, TG, and VLDL-C levels.

Overall, the results of this study showed that the serum level of SelP in subjects with type 2 diabetes is higher than healthy subjects, and correlates with hyperglycemic indices such as HbA1c and FBS, as well as some lipid indices (such as TG and VLDL-C) which can indicate the probable role of SelP in the pathogenesis of type 2 diabetes. Also, for the first time, findings demonstrated that serum SelP correlates with oxidative stress markers (MDA and TAC) that can indicate the probable role of SelP in pathogenesis of type 2 diabetes through oxidative stress pathways.