The regulation of serum resistin levels in metabolically healthy and unhealthy obese individuals.

Purpose: We have recently demonstrated that absolute counts of circulating proinflammatory monocytes were lower in obese patients without metabolic syndrome (MS) (metabolically healthy obese, MHO) compared with those with MS (metabolically unhealthy obese, MUO), but higher compared with healthy lean controls (MHL). We hypothesized that circulating resistin, a cytokine secreted by white blood cells (WBC), is involved in obesity-related low-grade inflammation. The aim of this study was to (a) determine serum resistin levels among MUO and MHO subjects and (b) investigate the role of circulating WBC subsets as potential determinants of resistin.

Methods: Study participants were 58 obese (33 MUO, 25 MHO) and 25 MHL individuals. Serum levels of resistin, high-sensitivity C-reactive protein (hsCRP), and absolute counts of circulating WBC subpopulations were determined. Comparisons were sex- and age-adjusted.

Results: Serum resistin levels in MHL were lower compared with those of obese (p = 0.041), but similar to those of MHO (p = 0.856) individuals. Both resistin (p = 0.005) and absolute neutrophil count (NeuA) (p = 0.025) were higher in MUO compared with MHO. The difference in resistin levels between obese and MHL individuals disappeared after adjustment for NeuA. Resistin correlated positively with absolute total monocyte count (p = 0.037) in MHL and with body mass index (BMI) (p = 0.023), hsCRP (p = 0.022), and NeuA (p = 0.044) in obese subjects. Resistin association with ΒΜΙ disappeared after adjustment for hsCRP, while association with hsCRP disappeared after further adjustment for NeuA.

Conclusion: Circulating resistin was higher in MUO compared with MHO. The increased secretion of resistin by the greater number of neutrophils in the former may have contributed to this regulation.