Decorin links low-density lipoproteins (LDL) to collagen: a novel mechanism for retention of LDL in the atherosclerotic plaque

A process central to the initiation of atherosclerosis is retention of plasma-derived low-density lipoprotein (LDL) particles in the extracellular matrix of the arterial intima. In this process, the apolipoprotein B-100 component of LDL binds to various components of the extracellular matrix, notably the negatively charged proteoglycans. In addition to proteoglycans, the intimal matrix contains large amounts of collagen. LDL also accumulates in collagen-rich areas of the arterial intima. The mechanism of this accumulation has remained obscure, because experiments in vitro have shown that LDL binds poorly to collagen. Our recent data provide evidence that the ability of collagen to bind LDL in vitro is greatly enhanced by decorin, a collagen-binding small proteoglycan that also is present in atherosclerotic lesions. This result provides a novel mechanism for retention of LDL in collagen-rich regions of the arterial intima.