PDGF is involved in a number of biological processes, including hyperplasia, embryonic neuron development, chemotaxis, and respiratory tubule epithelial cell development. The A-chain homodimers of the platelet-derived growth factor (PDGF AA) are widely expressed in normal and transformed cells. The mitogenic properties of PDGF AA are well established. FGF-2 and platelet-derived growth factor-A (PDGF-AA) are potent modulators of oligodendrocytes, the main responsible cells for myelin regeneration.