Cartilage derived proteoglycans in body fluids of children. Inverse correlation with age.

We have previously shown synovial fluid (SF) proteoglycan concentrations to be sensitive markers of altered cartilage metabolism in arthritis. We determined the proteoglycan concentrations in sera and SF from 23 patients with juvenile chronic arthritis and in sera from 30 healthy children by a specific enzyme linked immunosorbent assay. In both groups of children, decreasing concentrations of proteoglycans were seen during growth. Changes were most marked at the age of 12-13. The serum levels were higher in the healthy children. Our results suggest an age related metabolic change of articular cartilage, resulting in diminished release of proteoglycans to SF and blood with growing age up to 20 years. Measurement of proteoglycans could be a useful tool for studying this process.