Circulating IL-6, clusterin and irisin in obese subjects with different grades of obesity: association with insulin resistance and sexual dimorphism.

Objective: There are discrepancies about the relationship of IL-6, clusterin and irisin with obesity and obesity associated insulin resistance and also about their sexual dimorphism. This study aimed at evaluating the circulating levels of IL-6, clusterin and irisin in obese subjects of both sexes who had different grades of obesity and examining their sexual dimorphism and their association with insulin resistance.

Methods: This study included 176 non-diabetic subjects of both sexes who were classified according to their sex into two groups; the male and the female groups. The male group (88 men) was classified according to BMI into; group 1 (22 lean men), group 2 (22 class I obese men), group 3 (22 class II obese men) and group 4 (22 class III obese men). The female group (88 women) was classified according to BMI exactly as the male group. Metabolic parameters, IL-6, clusterin, and irisin levels were measured. Data were analyzed by ANOVA test, post hoc Tukey's test and independent -test. Pearson correlation was used to assess the association between variables.

Results: In obese subjects of both sexes, circulating IL-6, clusterin and irisin levels were significantly elevated and positively correlated with HOMA-IR. Obese males showed significantly higher HOMA-IR, IL-6, clusterin and irisin levels than obese females.

Conclusion: Obesity in both sexes, especially in males was associated with high levels of IL-6, clusterin and irisin and worsened the metabolic pattern. Circulating IL-6, clusterin and irisin may represent possible therapeutic targets for insulin resistance in obese subjects.