Endocrine Abstracts

Background: Obesity is associated with chronic low-grade inflammation that contributes to the development of metabolic syndrome (MS). Resistin, produced by neutrophils and monocytes, displays potent proinflammatory properties and has been associated with cardiometabolic disease. The aim of this study was to (a) determine serum resistin levels among obese patients with or without MS and (b) explore the role of the subsets of circulating white blood cells as potential determinants of serum resistin levels in these subjects.

Methods: 58 obese (33 metabolically unhealthy obese (MUO) and 25 metabolically healthy obese (MHO)) and 25 metabolically healthy lean (MHL) individuals participated in the study. Absolute and relative counts of circulating white blood cell subpopulations were determined and serum levels of high sensitivity C-reactive protein (hsCRP) were measured. Absolute blood counts of classical (Mon1A), intermediate (Mon2A) and nonclassical (Mon3A) monocyte subsets were measured by flow cytometry and serum resistin by enzyme-linked immunosorbent assay (ELISA). Comparisons were adjusted for gender and age.

Results: Log serum resistin levels in MHL controls were similar to those in the obese (P=0.131) and MHO (P=0.612) groups but lower compared to the MUO group (P=0.037). Moreover, in the MUO obese group, both log circulating resistin (P=0.032), Mon2A (P=0.036) and NeuA were higher compared to MHO (P=0.033). The difference in resistin levels disappeared after adjustment for NeuA. Obese patients were characterized by increased absolute neutrophil count (NeuA) (P=0.026), Mon2A (P=0.001) and Mon3A (P=0.017) compared to MHL individuals. Log resistin correlated positively with absolute count of total monocytes (r=0.560, P=0.037) in MHL, and with BMI (r=0.309, P=0.023), hs CRP (r=0.311, P=0.022) and NeuA (r=0.278, P=0.044) in obese patients. The resistin association with BMI disappeared after adjustment for hsCRP, while the association with hsCRP disappeared after adjustment for NeuA.

Conclusions: Serum resistin levels, absolute counts of circulating neutrophils and proinflammatory monocytes were higher in metabolically unhealthy obese compared to metabolically healthy obese individuals. In obese subjects, serum resistin levels correlated with the number of circulating neutrophils.