The possible origin of oxidized low-density lipoproteins in the circulation

Oxidized low-density lipoprotein (OxLDL) is thought to be involved in the early development of atherosclerosis through foam cell formation. However, the actual nature of OxLDL found in vivo remained obscure until recently. We have established a sensitive method of measuring OxLDL present in human plasma by utilizing an anti-OxLDL monoclonal antibody, DLH3, together with an anti-apoB antibody. OxLDL levels appeared to increase in patients with acute myocardial infarction, cerebral infarction and several other pathological conditions. Evidence is accumulating which supports the close relation between vascular diseases and plasma OxLDL levels. In this article, a major concern is the source of the OxLDL. Our recent studies on the OxLDL present in both atherosclerotic lesions and in plasma, together with observations of minimally modified LDL, provide some further clues to the understanding of some of the features and behavior of OxLDL in the circulation. A possible scenario detailing the origin and dynamics of OxLDL in vivo is discussed.