The therapeutic use of proteins or of genes of naturally occurring growth factors may be potentially beneficial for controlling the growth of collaterals or the remodeling of arteries. Whether the mother vessels will regress or evolve into welldifferentiated daughter vessels that continue to function indefinitely depends on the duration of therapy. A number of vector systems and sophisticated local drug delivery strategies may be of use in combination with protein or gene therapy to control the duration of therapy. Proteins and nonviral or viral gene transfer may induce transient new vessel formation. A number of antiangiogenic chemicals and proteins may be potentially used to stop angiogenesis. In terms of gene therapy, retroviral and adeno-associated vectors allow stable gene transfer, with the potential of long-lasting therapeutic effects that can be controlled by inducible promoters...