The key role of the cystein protease catK in atherosclerosis [5] and proteolysis of ECM and in particular collagen [2, 18] led us to investigate the contribution of this protease in flow cessation-induced remodeling of the carotid artery in both macrophage-poor and macrophage-rich lesions of C57Bl6 wt and apoE-/- mice, respectively. This evidence concerns the gene APOE and atherosclerosis.