Stabilized HIF-1α is superior to VEGF for angiogenesis in skeletal muscle via adeno-associated virus gene transfer

Therapeutic angiogenesis provides a potential alternative for the treatment of cardiovascular ischemic diseases. Vascular endothelial growth factor ( VEGF) is an important component of the angiogenic response to ischemia. Here we used adeno-associated virus (AAV) gene delivery to skeletal muscle to examine the effects of VEGF vs. a stabilized form of hypoxia-inducible factor-1 alpha ( HIF-1 alpha). The recombinant AAVs were injected into mouse tibialis anterior muscle, and their effects were analyzed by immunohistochemistry and functional assays. These analyses showed that stabilized HIF-1 alpha markedly increase capillary sprouting and proliferation, whereas VEGF(164) or VEGF(120) induced only proliferation of endothelial cells without formation of proper capillary structures. The Evans Blue permeability assay indicated that, unlike VEGF, HIF-1 alpha overexpression did not increase vascular leakiness in the transduced muscle. Doppler ultrasound imaging showed that vascular perfusion in the HIF-1 alpha treated muscles was significantly enhanced when compared to the controls and not further improved by co-expression of the arteriogenic growth factors angiopoietin-1 or platelet-derived growth factor-B. Our results show that AAV-mediated transduction of a stabilized form of HIF-1 alpha can circumvent the problems associated with overexpression of individual angiogenic growth factors. HIF-1 alpha should thus offer a potent alternative for pro-angiogenic gene therapy.