Growth factors and articular cartilage

Studies of articular cartilage over the decades have demonstrated a surprisingly brisk rate of synthesis of the matrix proteins which appears to vary considerably with metabolic, physicochemical and pathological state of the tissue. It has become evident that much of this activity is directed by low molecular weight protein mediators which act at specific receptor sites. Platelet derived growth factor (PDGF) is of limited action in normal cartilage, but insulin and its analogues, insulin growth factor-I and II are powerful stimulants of DNA synthesis. Basic fibroblast growth factor stimulates both DNA and protein synthesis and works synergistically with other factors. Transforming growth factor beta potentiates the action of the mitogens and enhances and regulates proteoglycan synthesis. These actions may be of special importance in osteoarthritis and lacerative injury to cartilage.