Relationships between human serum resistin, inflammatory markers and insulin resistance

OBJECTIVE: Data on the association of resistin levels with markers of insulin resistance are highly contrasting in humans and very few studies about its role in inflammation are available. This study investigates associations between serum resistin levels and markers of insulin resistance, inflammation (C-reactive protein (CRP)) and of oxidative stress (nytrotirosine (NT)). SUBJECTS: A randomly collected sample of 300 men from a population-based cohort was analysed, separated into two groups according to body mass index (BMI) and waist values. RESULTS: Correlations between resistin and BMI, waist, triglyceride, uric acid, fasting glucose, insulin and Homeostasis Model Assessment (HOMA) values were significant in subjects with normal BMI, but not in overweight/obese subjects. In a multiple regression model, after multiple adjustments and exclusion of diabetic patients, only fasting glucose remained significantly associated with resistin levels. Otherwise, resistin is associated to CRP levels in all individuals, after multiple adjustments and exclusion of diabetic patients (in normal BMI beta = 0.82; 95% CI 0.21, 1.42; in overweight/obese beta = 0.43; 95% CI 0.10, 0.76). In the same model, resistin values are negatively related to NT levels in normal weight individuals (beta = -1.61; 95% CI - 0.77-2.45). CONCLUSIONS: Serum resistin is weakly associated with metabolic abnormalities in subjects with normal BMI, while in overweight/obese patients this correlation is not significant, perhaps due to the higher fat content in these subjects. Serum resistin is directly correlated with CRP and inversely to NT. An intriguing hypothesis, which needs to be tested, is that resistin is secreted in response to a chronic low-grade inflammation, and has antioxidant properties.