The chylomicron and atherosclerosis. The atherosclerotic plaque is composed of a lipid-rich core containing cholesterol and necrotic tissue and is covered by a fibrous smooth muscle cell cap. Low density lipoprotein (LDL) is the major contributor to plaque cholesterol, but chylomicron remnants are also taken up into the subendothelial space, and because of the rapid turnover of chylomicrons the amount of cholesterol they can deliver to the plaque is not reflected in serum chylomicron cholesterol. Chylomicrons are delipidated by lipoprotein lipase on the artery wall. They are attached to the endothelium by high-density lipoprotein-binding protein 1 (GPIHBP1) and heparin sulphate proteoglycans (HPSG) which facilitate their uptake into the subendothelial space. Chylomicron remnants become trapped in the artery wall and disintegrate to contribute cholesterol to the lipid-rich core.
