In Vivo Adenoviral Vector-M4ediated Gene Transfer Into Balloon-Injured Rat Carotid Arteries

We studied the ability of adenoviral vectors to achieve gene transfer into injured arteries. A recombinant adenoviral vector expressing a nuclear-targeted f-galactosidase gene was constructed and infused into balloon-injured rat carotid arteries. Three days after gene transfer, recombinant gene expression was assessed quantitatively by (1) measuring 13-galactosidase antigen and activity in tissue extracts and (2) histochemical staining and counting of cells expressing,B-galactosidase. Exposure of injured carotid arteries to increasing concentrations of the vector (10 ' to 1010 plaque-forming units per milliliter) resulted in a dose-responsive increase in f-galactosidase expression, with peak expression of approximately 43 mU or 25 ng f-galactosidase per vessel. Microscopic examination of histochemically stained arteries demonstrated gene transfer limited to the vascular media; transduced cells were identified immunohis-tochemically as smooth muscle cells. Counting of both histochemically stained and total nuclei in the media revealed that approximately 30 % of the cells in the media of the injured vessels were transduced. Calculations based on both counting cells and on the level of f-galactosidase expression in tissue extracts suggested the presence of 5000 to 10 000 transduced cells per 10 mm of vessel. Arteries infused with either vehicle only, a control adenoviral vector, or liposomes combined with the vector plasmid contained little or no evidence of 13-galactosidase expression. High levels of in vivo 3-galactosidase expression persiste