Restoration of blood flow by using continuous perimuscular infiltration of plasmid DNA encoding subterranean mole rat Spalax ehrenbergi VEGF.

The optimal vector, regulatory sequences, and method of delivery of angiogenic gene therapy are of considerable interest. The Spalax ehrenbergi superspecies live in subterranean burrows at low oxygen tensions and its tissues are highly vascularized. We tested whether continuous perimuscular administration of Spalax vascular endothelial growth factor (VEGF) DNA could increase tissue perfusion in a murine hindlimb ischemia model. Placebo or VEGF +/- internal ribosome entry site (IRES) was continuously administrated perimuscularly in the ischemic zone by using an infusion pump. None of the mice in the VEGF-treated group (>50 microg) developed visible necrosis vs. 33% of the placebo group. Microscopic necrosis was observed only in the placebo group. Spalax VEGF muscular infiltration resulted in a faster and more complete restoration of blood flow. The restoration of blood flow by VEGF was dose-dependent and more robust and rapid when using the VEGF-IRES elements. The flow restoration using continuous perimuscular infiltration was faster than single i.m. injections. Vessel density was higher in the VEGF and VEGF-IRES (-) groups compared with the placebo. Continuous perimuscular administration of angiogenic gene therapy offers a new approach to restore blood flow to an ischemic limb. Incorporation of an IRES element may assist in the expression of transgenes delivered to ischemic tissues. Further studies are needed to determine whether VEGF from the subterranean mole rat Spalax VEGF is superior to VEGF from other species. If so, 40 million years of Spalax evolution underground, including adaptive hypoxia tolerance, may prove important to human angiogenic gene therapy.