Structural changes in the proteoglycans of human articular cartilage during aging

The structure of the aggregating proteoglycans from human articular cartilage changes continuously from the early fetus to the mature adult, due to variation in both synthetic and degradative processes. The changes due to synthesis are most prominent prior to the end of growth, and are responsible for variations in the structure and abundance of the glycosaminoglycan chains. In contrast, the changes due to degradation occur throughout life, but predominate during aging of the adult. They result in proteolytic fragmentation of both the proteoglycan subunits and the link proteins, with those products possessing hyaluronic acid-binding capability accumulating in the tissue.