Evidence for oxidised low density lipoprotein in synovial fluid from rheumatoid arthritis patients

The oxidative modification of human LDL has been implicated in atherosclero sis, but the mechanisms by which such modification occurs in vivo are not f ully understood. In the present study, we have isolated LDL from knee-joint synovial fluid of patients with rheumatoid arthritis. We demonstrate that such LDL is oxidatively modified as evidenced by an increased negative char ge, distorted particulate nature and more rapid degradation by cultured mac rophages. These results indicate that formation of oxidised LDL is associat ed with the local inflammatory response. Because the cellular interactions in rheumatoid arthritis have analogies with those in atherogenesis, we sugg est that the rheumatoid joint is a useful model of atherosclerosis in which the ii vivo process of LDL oxidation may be readily studied.