WOUND-HEALING - THE ROLE OF PLATELET-DERIVED GROWTH-FACTOR AND TRANSFORMING GROWTH-FACTOR-BETA

Recent investigation into the mechanisms of wound healing has indicate d the interaction of many substances, including several growth factors . The activity of platelet-derived growth factor (PDGF) and transformi ng growth factor beta (TGF-beta), are best defined. Both factors are s ecreted primarily from the alpha granules of platelets, but also from activated macrophages and fibroblasts. Investigation implicates the pl atelet as the initiator of wound healing, secreting PDGF, TGF-beta, an d other factors that are chemotactic for monocytes, macrophages, and f ibroblasts. Although their mode of action and degree of effect are dif ferent, both PDGF and TGF-beta increase the collagen content and early rate of gain of strength in wounds in normal and compromised tissue. In normal tissue, however, there is no long-term effect on wound outco me. The use of exogenous growth factors offers potential for chemical manipulation of the healing wound, particularly in tissues that are co mpromised, or where healing is abnormal.