Adenoviral catheter-mediated intramyocardial gene transfer using the mature form of vascular endothelial growth factor-D induces transmural angiogenesis in porcine heart

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 x 10(11) and 2 x 10(12) viral particles) or naked plasmids ( 1 mg) encoding LacZ control, VEGF-A(165), or the mature, soluble form of VEGF- D ( VEGF-D-DeltaNDeltaC) were injected intramyocardially with the NOGA catheter system into domestic pigs. AdVEGF-D-DeltaNDeltaC 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 alpha- 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-DeltaNDeltaC 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-DeltaNDeltaC GT using the NOGA system produces efficient transmural angiogenesis and increases myocardial perfusion. AdVEGF- D-DeltaNDeltaC could be useful for the induction of therapeutic vascular growth in the heart.