Gene delivery of plasmid DNA to rabbit aorta by genetic engineering of cationized gelatin hydrogel coated partially covered endovascular stent graft

Objective: To genetically engineer endovascular stent grafts that facilitate plasmid DNA delivery and offer the promise of sustained intravascular delivery system of therapeutic materials. Methods Partially covered polyester stent-grafts coated with cationized gelatin hydrogels (CGH) containing pCAGGS- LacZ or pEGFP were implanted in the descending aorta of 8 rabbits, which had neointima due to balloon injury four weeks ago. The aorta with stent-graft containing pCAGGS-LacZ and the one containing pEGFP was taken as negative control for each other. Expression of the plasmid-encoded marker genes, β-galactosidase and enhanced green fluorescence protein (EGFP) were evaluated at 3 days after implantations by X-Gal staining and RT-PCR or fluorescence microscopy. Results: Local plasmid DNA transfer was confined to the vessel wall at the site of stent-graft implantation, especially where the graft was compressed firmly to the vessel by metal struts. Plasmid DNA was not detected in vessel segments immediately proximal or distal to the stent graft and dissemination of plasmid DNA to brain, heart, lung, liver or kidney was not observed. The β-galactosidase-expressed cells were identified as endothelial cells, and smooth muscle cells by pathological analysis. Fluorescence microscopy identified the EGFP expression which demonstrated the transgene delivery of plasmid DNA and it was not related to the plasmid-encoded marker genes. No signal was detected in the aorta of the rabbits that received cationized gelatin hydrogels coated stent-grafts without plasmid DNA. Conclusions: Cationized gelatin hydrogels coated partially covered stent grafts provide a new access for transgene delivery to the cells of aortic wall. (authors)