Inflammatory molecules affect the interaction between human dendritic cells and vascular smooth muscle cells

Despite inflammatory and immune mechanisms participating to vascular remodeling, and dendritic cells (DCs) driving immune and non-immune tissue injury response, the interactions between DCs and vascular smooth muscle cells (SMCs) possibly relevant to vascular pathology are still unclear. This study has investigated the interaction of human coronary SMCs and human DCs in vitro, with regard to influence exerted by obesity, insulin-resistance and inflammation. Monocyte-derived DCs (MoDCs) obtained from obese (BMI>30) and type 2 diabetic patients were studied by electron microscopy, immunohistochemistry and CFSE dilution assay. Mo-DCs from patients displayed higher ability than those of healthy controls to adhere to coronary SMCs, possibly due to an increase in cell adhesion molecules including integrins. When Mo-DC, isolated from healthy subjects, were let to adhere to inflammatory cytokine-stimulated coronary SMCs, an increased cell adhesion was measured. This effect was counteracted by pre-treating SMCs with either a statin or a PPAR-gamma agonist. These findings suggest that an inflammatory environment in the vascular wall may stimulate the interaction between DCs and VSMCs and give rise to a vicious circle perpetuating and even worsening local inflammation and causing or complicating atherosclerosis.