Distinct cartilage proteoglycan chromatographic elution patterns in advanced human hip osteoarthritis: correlations with histologic analysis

Abstract

Articular cartilage explants were derived from 14 human osteoarthritic (OA) femoral heads. Newly synthesized, 35SO4 radiolabeled proteoglycans and endogenous uronic acid containing proteoglycans present in the extracellular matrix fell into one of 4 distinct patterns of elution on Sepharose CL-2B chromatography under associative conditions. There was a strong correlation between the elution patterns for newly synthesized and endogenous proteoglycans within a given hip specimen (p = 0.005). The proteoglycan elution pattern also strongly correlated when Day 1 and Day 20 explants were compared. The presence of a distinct subpopulation of hydrodynamically small proteoglycan (Kav, 0.6-0.9) correlated with a loss of both pericellular and extracellular matrix metachromasy in histologic sections of cartilage (p = 0.018). Our findings support the contention that different biochemical-histological subsets exist in "end-stage" hip OA.