ABSTRACT
The oxidation of low density lipoprotein (LDL) by cells also may depend on the presence of trace metal ions because media that support oxidation often contain either ferric iron or copper. Oxidatively modified LDL, like acetyl LDL, when injected intravenously into animals disappears within minutes. However, oxidized LDL is not a single, homogeneous entity, and LDL oxidized to a lesser degree may be present in the plasma. The modification of LDL by smooth muscle cells and monocyte is readily inhibited by superoxide dismutase. In addition to cell culture studies that suggested the involvement of lipoxygenases in the initiation of lipid peroxidation, earlier studies also showed that lipoxygenases can induce lipid peroxidation and oxidative modification of LDL. In summary, the oxidation hypothesis that centers around the oxidative modification of LDL is an attractive candidate for defining the initiating mechanisms in atherogenesis.
