EFFECT OF TIME ON THE VIABILITY OF ISCHEMIC SKIN FLAPS TREATED WITH VASCULAR ENDOTHELIAL GROWTH-FACTOR (VEGF) CDNA

This study examined the efficacy of gene therapy on wound healing. The authors investigated whether delivery of the gene encoding a particul ar cytokine, known to be important in angiogenesis, could affect ische mic skin flaps. Anterior abdominal skin flaps, based solely on the epi gastric artery and vein, were created in the Sprague-Dawley rat model. At the time of elevation, the arterial pedicle supplying each flap wa s infused either with the gene for vascular endothelial growth factor (VEGF) or physiologic saline alone. The flaps were resutured into plac e and observed for a period of either 4 or 3 days, at which time the p edicle was ligated. Twenty minutes following ligation, blood flow in t he flaps was measured by dye fluorescence. Tissue viability of the fla ps was subsequently measured by planimetry after a period of 7 days. F laps that received the VEGF gene and were ligated at 4 days had an ave rage dye fluorescence index (DFI) of 31.1 following ligation, and 93.9 percent viable tissue after 7 days. Flaps that received saline alone, and were ligated following a similar interval, had an average DFI of 14.0 and 31.9 percent viable tissue. Among the subjects that were liga ted at 3 days, only a single, gene-infused flap had any noticeable via ble tissue after 7 days. The DFI of these groups was 11.0 for the gene -infused group and 22.1 for the saline-infused group. The results sugg est that delivery of the gene for VEGF can improve the survival of isc hemic skin flaps, but that the effect of gene therapy is not limitless .