A patient presents with a large wound to his right forearm that is the result of a chain saw accident. You treat his wound appropriately and follow him in your surgery clinic at routine intervals. Initially his wound is filled with granulation tissue, which is composed of proliferating fibroblasts and proliferating new blood vessels (angiogenesis). A growth factor that is capable of inducing all the steps necessary for angiogenesis is

fibroblast growth factor (FGF) can induce the growth and proliferation of fibroblasts. Additionally, one type of FGF, basic FGF, is capable of inducing all of the stages of angiogenesis (basement membrane and extracellular matrix degradation, endothelial migration, endothelial proliferation, and endothelial differentiation). The epidermal growth factor family includes epidermal growth factor (EGF) and transforming growth factor a (TGF-a). These substances can cause proliferation of many types of epithelial cells and fibroblasts. TGF-b, produced by platelets, endothelial cells, T cells, and macrophages, is associated with fibrosis. In low concentrations it causes the synthesis and secretion of PDGF, but in high concentrations it inhibits growth due to inhibition of the expression of PDGF receptors. Reference: Robbins & Cotran Pathologic Basis of Disease, 9edition.