Expression of vascular endothelial growth factor from a defective herpes simplex virus type 1 amplicon vector induces angiogenesis in mice.

Vascular endothelial growth factor (VEGF) is a secreted endothelial cell-specific angiogenic growth factor. VEGF gene transfer strategies to stimulate focal angiogenesis could be used to ameliorate myocardial ischemia. To induce angiogenesis in vivo, we have constructed a replication-defective herpes simplex virus type 1 (HSV-1) amplicon vector that places the human VEGF-165 cDNA under the transcriptional control of the HSV immediate-early 4/5 promoter (HSVhvegf). Transduction of NIH 3T3 fibroblasts with HSVhvegf resulted in the secretion of high levels of biologically active VEGF, as assayed by microvascular endothelial mitogenesis. By use of an ex vivo protocol, BLK-CL4 fibroblasts were transduced with HSVhvegf or control HSVlac virus (expressing Escherichia coli beta-galactosidase), resuspended in basement membrane extract (matrigel), and coinjected subcutaneously into syngeneic C57BL/6 mice. One week later, the matrigel plugs with HSVhvegf showed a strong angiogenic response, in contrast to the plugs with HSVlac-transduced fibroblasts. These data indicate that transduction with HSVhvegf virus can induce an angiogenic response in vivo and suggest that this is a viable gene therapy approach for tissue ischemia.