AUGMENTED ADENOVIRUS-MEDIATED GENE-TRANSFER TO ATHEROSCLEROTIC VESSELS

Vascular endothelium is an important target for gene transfer in ather osclerosis. In this study, we examined gene transfer to normal and ath erosclerotic blood vessels from two species, using an organ culture me thod. Using normal aorta, we determined optimal dose, duration of expo sure to adenovirus, and duration of incubation of vessels in tissue cu lture. Aortas from normal and atherosclerotic monkeys were cut into ri ngs and incubated for 2 hours with a recombinant adenovirus, carrying the reporter gene for beta-galactosidase driven by a cytomegalovirus ( CMV) promoter. After 20 hours of incubation, transgene expression vas assessed with a morphometric method after histochemical staining and a chemiluminescent assay of enzyme activity. Expression of beta-galacto sidase after histochemical staining, expressed as percentage of total cells, was similar in adventitial cells of normal monkeys (21+/-4%, me an+/-SE%) and atherosclerotic monkeys (25+/-12%). Transgene expression in endothelium was higher in atherosclerotic than in normal vessel (5 3+/-3% versus 27+/-7%, P<.05). Chemiluminescent assay indicated greate r beta-galactosidase activity (2.5+/-0.6 mU/mg of protein) in the inti ma and media of atherosclerotic than normal vessels (0.6+/-0.2 mU/mg o f protein, P<.05). Aortas from normal (n=6) and atherosclerotic (n=5) rabbits also were examined. Transgene expression (after histochemical staining) in endothelium was much greater in atherosclerotic than norm al rabbits (39+/-3% versus 9+/-2%, P<.05) and expression in adventitia l cells was similar (normal 23+/-2%, atherosclerotic 24+/-4%). Chemilu minescent assay indicated greater beta-galactosidase activity (1.2+/-0 .4 mU/mg of protein) in the intima and media of atherosclerotic than n ormal vessels (0.2+/-0.1 mU/mg protein, P<.05). These findings suggest that an adenoviral vector with a CMV promoter provides similar transg ene expression in adventitia of both normal and atherosclerotic vessel s. Gene transfer to the endothelium was much more effective in atheros clerotic than in normal vessels. Thus it may be possible to achieve gr eater transgene expression in atherosclerotic than in normal arteries.