Identification and concentration of the glycosaminoglycans of human articular cartilage in relation to age and osteoarthritis.

Abstract

The glycosaminoglycans in articular cartilage from the femoral condyles of 119 human autopsy cases have been isolated and subsequently characterized using cetylpyridinium chloride. Using the same column method in microscale the glycosaminoglycans were estimated quantitatively in normal articular cartilage from birth to 95 years of age and in osteoarthritic cartilage. In normal cartilage chondroitinsulphate occurred as chondroitin-4-sulphate and chondroitin-6-sulphate, decreasing in ratio with age. The chondroitinsulphate had a sulphate/hexuronic acid ratio below unity, below 20 years, above unity in the higher age groups. Two types of keratansulphate and hyaluronic acid were isolated. The glycosaminoglycans isolated from osteoarthritic cartilage showed no differences from normal cartilage as to the amount of their moities of chondroitin sulphate isomers. In normal cartilage there was a significant decrease of total hexosamines from birth to 11–20 years, due to a reduction of chondroitinsulphate. In adults, an increasing ratio of the keratansulphate plus glycoprotein fraction to chondroitinsulphate was observed. Osteoarthritic cartilage showed a significant reduction of all glycosaminoglycan fractions without change of distribution. Normal cartilage taken from osteoarthritic joints was unaltered. Solubility profiles indicated decreases in molecular weight of chondroitin sulphate in normal cartilage from birth to 21–30 years, and a trend towards lower molecular weight in osteoarthritic cartilage.