ABSTRACT
This chapter summarizes information on age-related phenomena in cartilage. This will concern macroscopic changes in cartilage, changes in cartilage cellularity, and in the composition of extracellular matrix. Chondrocyte secretory and proliferative function in aging are then reviewed to examine the hypothesis that altered cartilage structure is the consequence of aging of chondrocyte functions and to create a background for the discussion of regulatory mechanisms in chondrocytes that are potentially responsible for these changes. Proteoglycans in aging cartilage are smaller in size. The total glucosaminoglycan content of human articular cartilage may not significantly change with aging. IL-8 is one of the most potent chemotactic factors for neutrophils. It also promotes enhanced production of oxidative and 5-lipoxygenase products, and increases surface expression of certain leukocyte adhesive proteins. FGF was purified as a heparin-binding growth factor, and binding to heparan sulfate protects it from proteolytic degradation.
