Resistin and High Glucose Concentrations-Activation of Human Smooth Muscle Cells Induces Enhanced Monocyte Chemotaxis

Objectives. Recent data indicate that upon activation by resistin and high glucose concentrations (HG) vascular smooth muscle cells (SMC) acquire pro-inflammatory properties. We questioned whether resistin and HG-activated SMC generate an enhanced monocytes chemotaxis and if the chemokine fractalkine (Fk) is involved in the process. Material and Methods: SMC were incubated with resistin or/and HG and the conditioned medium was used for monocytes chemotaxis assays. The role of Fk was assessed by blocking the Fk receptor, CX3CR1, on monocytes (U937 cell lines) prior to the chemotaxis assay. The quantification of migrated monocytes was assayed under an inverted microscope and statistically analyzed. Results: (i) conditioned medium (CM) collected from SMC incubated with resistin in the presence or absence of HG triggered a significant increase (25 - 100 %) of monocytes chemotaxis as compared to controls; (ii) blocking the CX3CR1 receptor significantly decreased the monocyte chemotaxis towards resistin-treated SMC. Conclusions: Resistin±HG increases the expression of chemotaxis inductors in human SMC and the ensuing monocytes chemotaxis by a mechanism in which Fk plays a major role.