Gene therapy in a new model of delayed wound healing

Abstract: Diabetes wounds result in significant morbidity, prolonged hospitalization and huge health care expenses. As of yet, no optimal animal models of diabetic wound healing exist to study potential beneficial therapies. Porcine wound healing is very similar to human wound healing. We stipulated that by inducing diabetes in yorkshire pigs, wound healing would be delayed and exhibit abnormalities similar to those seen in human diabetic wound healing. Furthermore we hypothesized that cell therapy and gene therapy may enhance epidermal healing in this model of delayed wound healing. In study one, we establish a delayed wound healing model in yorkshire pigs, mimicking diabetic wound healing, by injecting streptozotocin intravenously. High serum glucose was established and wound healing was considerably delayed and showed alterations in the intrinsic pathways. In study two, transplantation of suspensions of fibroblasts or keratinocytes enhanced re-epithelialization in this new model of delayed wound healing. In study three, the beneficial effect of transplanting keratinocytes seen in study two was enhanced by transfecting keratinocytes with a plasmid coding for IGF-1. Results showed a substantial over expression of IGF-1 in the wound as well as improved epidermal healing in the treated group. In study four, the beneficial effect of allogenic cells transfected with EGF was shown in healthy non-diabetic pigs. In study five, the beneficial effect of EGF seen in study four, was taken into account and autologous keratinocytes transfected with EGF were transplanted into cutaneous wounds in our model of delayed wound healing. Clear beneficial effects were demonstrated. Collectively, we demonstrate a new model of delayed wound healing in the pig which mimicks deficiencies seen in diabetic wounds. We were able to accelerate wound healing in this model by using cell therapy and further improved it using gene therapy.