Fig. (1).

The atherogenic role of LDL vs. the atheroprotective properties of HDL. The deposition of the oxidized LDL in the intima media is the first crucial step that leads to the formation of a nascent atheroma. Oxidized LDL particles promote the inflammatory process, as they enhance the expression of adhesion molecules. Monocytes accumulate into the vessel wall, where they mature into tissue macrophages and subsequently into lipid-laden foam cells. These processes cause endothelial dysfunction and exacerbate the thrombotic status. By contrast, HDL mitigates the atherosclerotic process as it presents anti-inflammatory, anti-oxidative and anti-thrombotic properties, which enhance endothelial integrity. HDL also promotes cholesterol efflux from the artery wall and prevents the increase of the necrotic core volume. LDL: low-density lipoprotein; HDL: high-density lipoprotein; ox-LDL: oxidized LDL; NO: nitric oxide; PGI2: prostacyclin; SMCs: smooth muscle cells; RBCs: red blood cells.