What is the role of Low Density Lipoproteins (LDL) in Atherosclerosis?
LDL is considered to be the major atherogenic lipoprotein in the blood; serum concentration of LDL has been shown to be directly related to risk for CHD (serum concentration of HDL, on the other hand, has been shown to be inversely related to risk for CHD). Chronic high cholesterol, in the form of LDL, could be considered a form of metabolic stress; however, much evidence suggests that it is oxidized LDL and not unmodified LDL that plays a key role in the formation of at least the initial atherosclerotic plaque. Oxidation seems to be the most likely modification of LDL in vivo, because endothelial cells, smooth muscle cells, and macrophages in vitro are able to oxidize LDL. In addition to being a legend for the scavenger receptor, oxidized LDL also seems to have other biological effects: cytotoxicity, stimulation of endothelial-leukocyte adhesion, chemoattraction of monocytes, inhibition of macrophage migration, inhibition of NO (endothelium derived relaxation factor), and increased ti
