Synergistische therapeutische Effekte von bFGF und VEGF165 nach Transplantation isogener adenoviral transfizierter Fibroblasten im ischämischen Lappenmodell der Ratte

Introduction: Previous studies have demonstrated that bFGF and VEGF165 can improve the formation of new blood vessels by stabilizing blood vessel walls. Recently we have shown that a) there is a cessation of the transferred genetic information within 7-10 days after adenoviral modification of rat fibroblasts and b) the transient production of VEGF165 in the target area alone cannot induce effective formation of new blood vessels when implanted 14 days prior to ischemia. We now present a rat ischemic-flap model investigating the synergistic therapeutic effects of bFGF and VEGF165. Methods: 10 million rat-fibroblasts per animal were genetically modified (50% bFGF, 50% VEGF165) and implanted into the whole flap and the area of the wound margin of a McFarlane flap (2×8 cm). We had 12 groups each containing 10 animals. Setting I: implantation of bFGF/ VEGF165 modified cells during flap surgery (group 1); implantation of GFP-modified cells during flap surgery (group 2); implantation of non-modified cells during flap surgery (group 3); implantation of control medium during flap surgery (group 4); Setting II: same procedure but 1 week prior to flap surgery (group 5-8); Setting III: same procedure but 2 weeks prior to flap surgery (group 9 - 12). After 7 days post-operationem all animals were sacrificed, the flaps were evaluated clinically by performing a planimetric analysis of vital flap tissue, histology, microangiography and proteoanalysis. Results: In Setting I there was no therapeutically significant improvement in flap survival after ischemic insult. Whereas in group 5 we found significant improvement (p < 0.05 versus controls) of flap survival, both clinically and increased vessel density in the target area by microangiography. Group 9 showed an even further improvement and was again highly significant (p<0.01 versus controls). Proteoganalysis 7 days after flap surgery revealed maximum expression for bFGF and VEGF165 in Settings I and II only. Conclusion: Using the combined expression of bFGF and VEGF165, we were able to achieve an optimisation of therapeutic angiogenic effects in the target area. These effects outlined the maximum expression of growth factors and can be interpreted as a synergistic effect of bFGF and VEGF165 causing a lasting angiogenesis in vivo in this model.