Gene Transfer into the Carotid Artery Using an Adventitial Collar: Comparison of the Effectiveness of the Plasmid–Liposome Complexes, Retroviruses, Pseudotyped Retroviruses, and Adenoviruses

Abstract

We studied the efficiency of plasmid/liposome complexes, Moloney murine leukemia virus-derived (MMLV) retroviruses, pseudotyped vesicular stomatitis virus protein-G (VSV–G)-containing retroviruses, and adenoviruses in delivering genes into the rabbit carotid artery using a silastic collar applied to the adventitia. This method was used for gene transfer because (a) it provides a gene delivery reservoir; (b) no intraluminal manipulations are performed; (c) installation of the collar induces arterial smooth muscle cell (SMC) proliferation and enhances retroviral gene transfer efficiency where target cell proliferation is required. The transfer of the β-galactosidase (lacZ) marker gene to the adventitia and media occurred with all gene transfer systems. Adenoviruses also transferred the β-galactosidase gene to some endothelial cells. After 5 days, adenoviral vectors produced the highest gene transfer efficiency with up to 10% ± 6% of cells showing β-galactosidase activity. Pseudotyped VSV–G retroviruses were also effective in achieving gene transfer in 0.05% ± 0.03% of cells in the adventitia and media. Plasmid/liposome complexes and MMLV retroviruses infected 0.05% ± 0.03% and <0.01% ± 0.01% of cells, respectively. It is concluded that replication-deficient adenoviruses, VSV–G pseudotyped retroviruses, and plasmid/liposome complexes can be used for gene transfer to the arterial wall using the collar method. Because the endothelium remains anatomically present throughout the experiments, the model may be useful for the gene transfer studies involving diffusible or secreted gene products that primarily act on the endothelium. Effects on medial SMC and even endothelium can be achieved from the adventitial side, suggesting an alternative route for the delivery of therapeutically useful genes into the arterial wall. We have developed a model for arterial gene transfer via adventitia using a silastic collar wrapped around rabbit carotid arteries. The collar served as a reservoir for the delivery of β-galactosidase marker gene. No intraluminal manipulations were performed. It was found that all gene transfer systems tested in the model—plasmid/liposome complexes, MMLV retroviruses, VSV–G pseudotyped retroviruses, and adenoviruses—led to a detectable gene transfer to the artery wall. The model is useful for gene transfer studies involving diffusible or secreted gene products that primarily act on the endothelium and might be useful during vascular operations, such as prosthesis and anastomosis surgery and by-pass operations.