Age-related changes and sex differences in chondroitin sulfate isomers and hyaluronic acid in normal synovial fluid

The effects of factors such as age and sex on the metabolism of chondroitin sulfate (CS) and hyaluronic acid (HA) in knee joint tissues are believed to be profoundly important in the onset of joint diseases including osteoarthritis. To test whether age and sex influence CS isomers and HA in normal synovial fluid, we determined concentrations of chondroitin 6-sulfate (C6S), chondroitin 4-sulfate (C4S), and HA in healthy subjects of different ages. Synovial fluids were obtained from 187 healthy volunteers, 14–89 years of age. Chondroitin 6-sulfate, C4S, HA concentrations, and C6S : C4S ratio showed a significant negative correlation with age. There were no sex-related differences in HA concentration, but the concentrations of C6S and C4S and the C6S : C4S ratio were significantly lower in women than in men in most age groups.