Enhanced Expression of the Homeostatic Chemokines CCL19 and CCL21 in Clinical and Experimental Atherosclerosis

Abstract

Objective— Based on their role in T-cell homing into nonlymphoid tissue, we examined the role of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in coronary artery disease (CAD). Methods and Results— We performed studies in patients with stable (n=40) and unstable (n=40) angina and healthy controls (n=20), in vitro studies in T-cells and macrophages, and studies in apolipoprotein-E–deficient (ApoE −/− ) mice and human atherosclerotic carotid plaques. We found increased levels of CCL19 and CCL21 within the atherosclerotic lesions of the ApoE −/− mice, in human atherosclerotic carotid plaques, and in plasma of CAD patients. Whereas strong CCR7 expression was seen in T-cells from murine and human atherosclerotic plaques, circulating T-cells from angina patients showed decreased CCR7 expression. CCL19 and CCL21 promoted an inflammatory phenotype in T-cells and macrophages and increased matrix metalloproteinase (MMP) and tissue factor levels in the latter cell type. Although aggressive statin therapy increased CCR7 and decreased CCL19/CCL21 levels in peripheral blood from CAD patients, conventional therapy did not. Conclusions— The abnormal regulation of CCL19 and CCL21 and their common receptor in atherosclerosis could contribute to disease progression by recruiting T-cells and macrophages to the atherosclerotic lesions and by promoting inflammatory responses in these cells. We show increased plasma levels of the homeostatic chemokines in CCL19 and CCL21 in clinical and experimental atherosclerosis. By promoting inflammatory responses in T-cells and by inducing a matrix degrading, prothrombotic, and inflammatory phenotype in macrophages, we suggest that these chemokines could contribute to atherogenesis and plaque destabilization.