Cytokines profile of T helper lymphocytes in Diabetic Patients: Correlation with Markers of Inflammation, Obesity, and Hormonal Status

Abstract

Diabetes mellitus; defined as a heterogeneous disease in which there is a defect in carbohydrate, fat and protein metabolism; involves several systems and is associated with the occurrence of various complications. Both the occurrence of complications and the prognosis of the disease might be affected by differential immune response, inflammatory state, obesity and hormonal levels prevalent in different individuals. Understanding these factors and their relation to the incidence and/or prognosis of diabetic complications in the Saudi population might help in designing methods to prevent and/or treat diabetes and associated complications. Therefore, the main aims of this study are to determine the T helper cell cytokines profile in diabetics both in the absence and presence of complications, to measure markers of inflammation and obesity, to determine sex hormonal status in female subjects, and to detect any statistical relation between the previous markers and the presence of complications. Material and methods: Three groups of subjects were recruited to the study: the control group, the group of diabetic male, and the group of diabetic female. Biochemical measurements (fasting plasma glucose, fasting insulin, lipid profile, liver function tests and renal function tests); complete and differential blood count; peripheral blood mononuclear cell (PBMC) separation, culture, activation and immunostaining in preparation for flow cytometric analysis were preformed. Then quantification of secreted cytokines, circulating levels of immunoinflammatory and obesity markers and hormone measurements were assessed in the studied subjects. Microsoft Excel and SPSS software were used to statistically analyze the obtained results. Results and discussion: The PBMC-released Th2 cytokine; interleukin 4 was elevated in diabetic male (as well as in the subgroups of diabetic male based on the absence or presence of complications). The PBMC-released Th1 cytokine; IFN-g was found to be positively associated with insulin resistance, and negatively associated with adiponectin and its high molecular weight (HMW) form. Higher levels of IL-6 and CRP were detected with increasing obesity markers. Moreover, CRP was positively correlated to insulin resistance in diabetic male patients. Resistin was found to have a positive association with the proinflammatory IL-6, CRP and WBC count; and with the obesity index, BMI in diabetic female. Leptin had a positive correlation with obesity indices. Adiponectin and HMW adiponectin on the other hand, had a negative correlation with the inflammatory markers and with the atherogenic triacylglycerol. Fasting insulin was found to be positively associated with both adiposity and inflammatory markers; and negatively associated with the anti- inflammatory adiponectin, its HMW form, and ratios of each of the adiponectin and HMW form to leptin. Serum levels of estradiol and progesterone were compared in both the follicular and the luteal phases of the menstrual cycle in control and diabetic female. It was found that during the follicular phase, the female diabetics showed lower progesterone level and somewhat higher estradiol levels relative to control. No further interpretation was able to be performed regarding the sex hormone association with other measured parameters. Conclusions and further studies: the present study confirms the key roles played by chronic inflammation and obesity in the pathophysiology of diabetes in Saudi population. Some limitations due to the small number of samples existed. Therefore, it is essential to conduct further studies on a larger sample size. This is expected to help in assessing patients with diabetes as far as the occurrence of diabetic complications, and might help in the future to design certain therapeutic measures specific for each diabetic patient.