Association of serum tumour necrosis factor-α and interleukin-6 with insulin secretion and insulin resistance in subjects with type 2 diabetes in a Bangladeshi population : research article

Objective : Epidemiological evidence suggests that levels of inflammatory markers, such as tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), can predict the development of diabetes but the association of these inflammatory markers with the basic pathology of type 2 diabetes is unclear. In the present study we investigated the association of TNF-α and IL-6 with insulin secretion and insulin sensitivity in subjects with type 2 diabetes. Methods : Thirty-seven subjects with type 2 diabetes were studied along with 56 age- and body mass index (BMI)-matched controls. Insulin was measured by ELISA analysis and TNF-α and IL-6 chemiluminescence-based EIA. Results : Fasting serum TNF-α and IL-6 levels were significantly higher in subjects with type 2 diabetes (p = 0.032) than in controls. In binary logistic regression analysis, TNF-α was significantly (p = 0.026) associated with diabetes when age, gender and BMI were matched. In linear multiple regression analysis, it was found that levels of HOMA S (p = 0.010), HOMA B (p = 0.003) and fasting glucose (p = 0.004), and WHR (p = 0.017) were negatively associated with TNF-α in diabetic subjects. In the same analysis, HOMA S (p = 0.013), HOMA B (p = 0.002) and fasting glucose levels (p = 0.001), and WHR (p = 0.038) were positively associated with IL-6 in diabetic subjects. The association of TNF-α was positive with IL-6 (p = 0.001). Conclusion : TNF-α and IL-6 levels were both associated with insulin resistance and insulin secretory defects in patients with type 2 diabetes, and hyperglycaemia seemed to be a major trigger for pro-inflammatory changes in diabetes.