Acid mucopolysaccharide patterns in aging human cartilage.

Abstract

Human cartilage, digested with papain, yielded a mixture of acid mucopolysaccharides (AMP). The AMP were fractionated on anion exchange resin to yield a mixture of a chondroitin sulfates-A and-C (CS-A and CS-C) and a highly sulfated skeletal keratosuifate (SKS) as a separate component. The relative amounts of CS-A and CS-C were determined. Embryonic and early growth patterns of AMP are roughly similar for man and higher vertebrates, although rates of change are variable SKS is absent, the degree of sulfation of CS-C or CS-A or both rises to equlmolar sulfate and galactosamine and the ratio CS-A/CS-C increases from less than 0.7 to more than 1.0. From the first tothe 4th decade, the proportion of SKS in the total AMP rises to a plateau near 55%, CS-C declines slightly and the ratio CS-A/CS-C falls to 0.25 or less. Little change, if any, occurs thereafter. The changes in proportion of CS-A and CS-C generally appear as the reverse of AMP patterns of embryonic development and early growth. Aging effects in cartilage may be related responses to alterations of physiological conditions associated with cessation of development and growth. Although age-related patterns are generally similar for human cartilages, rates of change which are lower in cricoid, thyroid and tracheal cartilages than in costal cartilage vary with the individual. These differences may be related in part to the local differences in the physical and nutritional environment of cartilage cells.