Adenoviral Catheter-Mediated Intramyocardial Gene Transfer Using the Mature Form of Vascular Endothelial Growth Factor-D Induces Transmural Angiogenesis in Porcine Heart

Abstract

Background— It is unclear what is the most efficient vector and growth factor for induction of therapeutic vascular growth in the heart. Furthermore, the histological nature of angiogenesis and potential side effects caused by different vascular endothelial growth factors (VEGFs) in myocardium have not been documented. Methods and Results— Adenoviruses (Ad) at 2 doses (2×10 11 and 2×10 12 viral particles) or naked plasmids (1 mg) encoding Lac Z control, VEGF-A 165 , or the mature, soluble form of VEGF-D (VEGF-D ΔNΔC ) were injected intramyocardially with the NOGA catheter system into domestic pigs. AdVEGF-D ΔNΔC gene transfer (GT) induced a dose-dependent myocardial protein production, as measured by ELISA, resulting in an efficient angiogenic effect 6 days after the injections. Also, AdVEGF-A 165 produced high gene transfer efficacy, as demonstrated with immunohistochemistry, leading to prominent angiogenesis effects. Despite the catheter-mediated approach, angiogenesis induced by both AdVEGFs was transmural, with maximal effects in the epicardium. Histologically, strongly enlarged α-smooth muscle actin–positive microvessels involving abundant cell proliferation were found in the transduced regions, whereas microvessel density did not change. Myocardial contrast echocardiography and microspheres showed marked increases in perfusion in the transduced areas. VEGF-D ΔNΔC but not matrix-bound VEGF-A 165 was detected in plasma after adenoviral GT. A modified Miles assay demonstrated myocardial edema resulting in pericardial effusion with the higher AdVEGF doses. All effects returned to baseline by 3 weeks. Naked plasmid–mediated GT did not induce detectable protein production or vascular effects. Conclusions— Like AdVEGF-A 165 , AdVEGF-D ΔNΔC GT using the NOGA system produces efficient transmural angiogenesis and increases myocardial perfusion. AdVEGF-D ΔNΔC could be useful for the induction of therapeutic vascular growth in the heart.