TNF-alpha in the development of insulin resistance and other disorders in metabolic syndrome

Insulin resistance and obesity are very frequent disorders and are described as the dominant risk factors for cardiovascular disease. The aim of this study was to analyze the interrelations between several metabolic variables (including TNF-alpha) and factors related to insulin resistance in groups of both normal and hyperlipidemic postmenopausal women and men of appropriate age, and to attempt to elucidate the gender differences. The study was carried out on 70 out-patients of the Metabolic Center. From these, 40 patients (20 men and 20 women) were selected with mild hyperlipidemia. Two other groups (10 men and 20 women) with approximately normal serum lipids parameters were taken as "controls". In hyperlipidemic women the mean serum concentration of the TNF-alpha was no different from that in the control group in spite of the fact that values of HOMA IR, insulin, proinsulin and lipid parameters increased significantly. In hyperlipidemic men we have found the decrease in TNF-alpha in comparison with the control group. In all four groups the statistical analysis showed correlations between metabolic parameters (including TNF-alpha) and parameters related to insulin resistance. Also differences in relation to the gender have been found. Multiple regression analysis demonstrated the important role of TNF-alpha in the regulation of both the insulin resistance and in the secretion of insulin in women. In men, BMI and HDL-cholesterol played a dominant role, while the role of TNF-alpha seemed to be minimal.