SYNOVIAL-FLUID LIPIDS AND APOLIPOPROTEINS - A CONTEMPORARY PERSPECTIVE

Normal human synovial fluid contains extremely low concentrations of l ipoproteins and apolipoproteins, in sharp contrast to those found in p lasma, Increased amounts of cholesterol and other lipids have been fou nd in the synovial fluid of a chronic inflammatory joint disorder, rhe umatoid arthritis (RA), More recently, apolipoproteins AI, B and E hav e also been found in increased amounts in RA synovial fluid, Theories have been proposed to account for this increase in the amount of apoli poproteins and for the source of lipids and lipoproteins in normal syn ovial fluid; however, the mechanisms have not yet been established. Li poproteins may play dual roles in synovial fluid: A functional one in normal synovial fluid and, as some suggest, a pathologic one in the ab normal synovial fluid of certain arthritic diseases, The recent data p rompt the need to define synovial fluid lipids, lipoprotein particle s ubfractions and their constituent apolipoproteins, as well as their re spective roles in synovial fluid.