High levels of aggrecan aggregate components are present in synovial fluids from human knee joints with chronic injury or osteoarthrosis

Abstract

One new approach which has considerable potential for use in the diagnosis and prognosis of osteoarthrosis (OA) is the determination of biochemical markers in body fluids, and aggrecan, the major proteoglycan of articular cartilage, has been identified as a candidate marker (Israel et al. 1991, Lohmander et al. 1989, 1993. Ratcliffe et al. 1992, Saxne et al. 1985, 1986). In the matrix the aggrecan molecules form large aggregates by binding to hyaluronan, and this interaction is stabilized by a separate link protein. Catabolism of the aggrecan aggregates results in cleavage of the aggrecan protein core and link protein at specific sites, and the fragments are released from the cartilage into the synovial fluid. In normal tissue these are events of maintenance, but in degenerative cartilage proteoglycan catabolism occurs at accelerated rates. Previous studies have shown that the levels of specific components of the aggrecan aggregate, including the sulfated glycosaminoglycan (S-GAG). keratan sulfate (KS) an...