Hyaluronate-binding by proteoglycans. Comparison of mildly and severely osteoarthritic regions of human femoral cartilage.

The ability of proteoglycans from hip cartilage of a patient with osteoarthritis to bind hyaluronic acid was examined. Proteoglycans from areas showing severe morphologic changes of the disease showed no interaction with hyaluronic acid in vitro. Moreover, fractions which normally contain aggregated proteoglycans were no larger in hydrodynamic size than disaggregated proteoglycans, suggesting that the proteoglycans from these regions were not aggregated in vivo. Proteoglycans from less extensively diseased areas, in contrast, underwent aggregation in vitro and appeared to have been aggregated by tissue hyaluronic acid in vivo. The results suggest that the progressive morphologic changes of osteorthritis are associated with progressive defects in proteoglycan aggregation due, at least in part, to impaired ability of the proteoglycans to interact with hyaluronic acid.