Table 1.

Summary of Currently Used Vascular Growth/Signaling Factors

	Growth/signaling factor	Function	Critical issues	References
Time course of delivery	Vascular endothelial growth factor	Most important family of cytokines in neovascularization; initiator of endothelial capillary formation;	Rapidly degraded due to short half-life; excessive amounts cause vascular leakage	3, 6, 7, 14
	Basic fibroblast growth factor	Heparin-binding protein; induces proliferation of ECs, SMCs; initiator of endothelial capillary formation	Rapidly diffuses, requires controlled release; mitogen for wide variety of cell types	3, 18, 26
	Hepatocyte growth factor	Mitogen of hepatocytes and other various cell types; stimulates growth of ECs but not SMCs	Short half-life, rapid diffusion; large amounts of protein required for response	17
	Platelet-derived growth factor	Mitogen for connective tissue cells, released from platelets; recruits SMCs to endothelial linings; promotes vessel maturation	High levels result in vessel destabilization; increased activity linked with several diseases	9, 13, 25
	Angiopoietin-1	Plays key regulatory role in regulating vessel homeostasis; promotes EC migration, stabilization of newly formed capillaries	Overexpression induces endothelial hyperplasia and reduced vessel leakage	3, 8, 10, 11

SMCs, smooth muscle cells; ECs, endothelial cells.