Local Angiogenic Gene Therapy/VEGF/Treat Diabetic Ulcers

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DESCRIPTION (provided by applicant) The goal of this proposal is to determine if local angiogenic gene therapy with ADV-VEGF accelerates healing in experimental diabetic mouse ulcers. Yearly, over 90,000 limb and digit amputations are performed on diabetic patients in the United States, 84 percent of these are proceeded by a foot ulcer. The 5-year mortality associated with these amputations is between 39 percent and 68 percent. The estimated annual cost of $9 billion doesn't include the pam, suffering, and morbidity of diabetic foot ulcers. Decreased angiogenesis in the wound, in addition to neuropathy and pressure, is a major causative factor for the delayed healing of these wounds. Currently, there is no directly angiogenic therapy available to treat diabetic foot ulcers. VEGF's ability to stimulate angiogenesis is well established. Since angiogenesis maintains a critical role in wound healing and VEGF is experimentally decreased in diabetic wounds, locally administered VEGF may provide an effective treatment, either alone or as part of combination therapy, for patients with diabetic wounds. Local adenoviral mediated gene therapy provides the theoretical advantage of sustained delivery of the target molecule with minimal toxicity. Although VEGF165 gene therapy has been effective in reversing peripheral ischemia of the limbs, cardiac ischemia, and diabetic neuropathy, it has not been thoroughly tested in neuropathic diabetic ulcers, which are known to have decreased angiogenesis. We hypothesize that local wound injection of ADV-VEGF will result in a sustained release of VEGF, thereby stimulating angiogenesis and accelerating healing in experimental diabetic mouse wounds, while demonstrating minimal systemic side effects. We will use ADV-VEGF in the female diabetic mouse model with 6-week mice, which have acceptable metabolic controls, to determine the minimal dose of ADV-VEGF that will result in a statistically significant decrease in time to 100 percent closure m experimental diabetic ulcers. We will measure potential systemic side effects (e.g., retinopathy and liver toxicity) and determine if increased levels of VEGF occur in the serum. End organ toxicity will be assayed by serum chemistries, complete blood count, and histologic analysis of the intestine, retina, lungs, kidney, spleen, thymus, brain, liver and heart. We will also check for signs of local wound toxicity. PCR will be used to assess the potential systemic distribution of the adenoviral vector. Specific quantification of the angiogenic response as compared to the changes in collagen deposition and wound healing epithelialization will be evaluated. In addition, we will analyze the wound fluid in order to determine the temporal expression of VEGF in a diabetic ulcer.