Low Density Lipoproteins in the Aorta: Relation to Atherosclerosis

Abstract

A link between plasma low density lipoproteins (LDL) and the atherosclerotic process has been suggested from both clinical-correlative studies in man (Kannel et al. 1964) and diet-fed experimental animal models (St. Clair 1976). LDL is the major carrier of cholesterol into the arterial wall and the deposition of cholesterol is the hallmark of the atherosclerotic process (St. Clair 1976). However the details surrounding the transport and deposition of cholesterol are not completely understood. LDL could transit the entire vessel wall and enter the lymphatics. It could be metabolized following uptake by arterial smooth muscle cells as was shown in cultured fibroblasts (Goldstein and Brown 1977). In a non-human primate model as much as 25% of total LDL entering the aorta became TCA-soluble, suggesting breakdown of the protein moiety (Hollander et al. 1977). Finally some LDL could be selectively retained in the arterial intima. A retention of this lipoprotein in the intimai lining of major arteries has been demonstrated by numerous immuno- fluorescence studies from our laboratory (Hoff et al. 1974, 1975a,b).

Supported in part by USPH Grants HL 17269 and NS 09287, and a Grant-in-Aid from the American Heart Association. Henry F. Hoff is an Established Invest- gator of the American Heart Association.