Artículo de publicación ISIDeposition of low-density lipoproteins (LDLs) in the vessel wall and their oxidative modification seem to initiate, or at least accelerate, the atherosclerotic process by several mechanisms, including promotion of foam cell formation, chemotactic effects on monocytes, and mitogenic effects on smooth muscle cells. Recent studies have demonstrated that oxidized LDLs (oxLDLs) increase the expression of matrix metalloproteinases (MMPs) in endothelial cells, monocyte-derived macrophages, and smooth muscle cells1–3 and that MMP expression is enhanced in atherosclerotic plaque tissue.4 MMPs increase smooth muscle cell migration and proliferation5,6 and also seem to promote plaque instability by inducing extracellular matrix degradation.7 Expression of extracellular MMP inducer (EMMPRIN) in human atheroma has been described recently.8,9 EMMPRIN, also called CD147 or basigin, is a highly glycosylated plasma membrane protein ( 58 kDa) belonging to the immunoglobulin superfamily. EMMPRIN is expressed on several cell types like leukocytes and different tumor cells10 and stimulates MMP production in fibroblasts and various tumor cells.11,12 Several studies have shown that cancer cells express significantly higher EMMPRIN levels than normal cells, and it has been proposed that elevated EMMPRIN expression in tumor cells may promote tumor progression by inducing MMP expression in peritumoral stromal cells. In this study, we have demonstrated that EMMPRIN is expressed in cultured human coronary artery smooth muscle cells (HCA-SMCs) and that oxLDL significantly enhanced the release of soluble EMMPRIN as well as MMP-1 and MMP-2 release. In addition, we have shown that MMP-1 and MMP-2 seem to promote the cleavage of soluble EMMPRIN from the cell surface and that soluble EMMPRIN stimulates MMP synthesis in HCA-SMC. Thus our data suggest that oxLDL might induce a circular upregulation of matrix degradation.