Peripheral Monocytes of Obese Women Display Increased Chemokine Receptor Expression and Migration Capacity

Context: The activation of peripheral immune cells and the infiltration of immune cells into adipose tissue in obesity are implicated in the development of type 2 diabetes mellitus. Objective: The aim of the study was to compare peripheral immune cells from obese and normal-weight women with regard to composition of immune cell subpopulations, surface expression of the chemokine receptors (CCRs) CCR2, CCR3, CCR5, and CXCR3 (chemokine (C-X-C motif) receptor 3) and cell-intrinsic migration capacity. Design: This was a case-control study. Setting: The study was conducted at a university clinical study center. Patients: Obese females and normal-weight females were included for fluorescence-activated cell sorting analysis and migration assays. Main Outcome Measures: Peripheral blood mononuclear cells were prepared from fasting blood samples and used for fluorescence-activated cell sorting analysis and migration assays. Results: An increase in the percentages of CD14(+)CD16(+) monocytes was observed in obese subjects compared with controls. The CCR profile of monocytes differed significantly in the obese state; in particular, CCR2 levels were increased. In addition, a higher chemotactic activity of monocytes from obese subjects was observed in a migration assay, which was associated with both insulin resistance and CCR2 expression. Conclusion: Our results suggest that the enhanced intrinsic migratory capacity of peripheral monocytes in obese women may be due to the increased CCR expression, further supporting a link between peripheral immune cell dysfunction and obesity.