1012-102 Alteration of Rabbit Carotid Artery Vasomotor Function by Gene Transfer with a Replication Deficient Adenovirus

Gene transfer technologies offer great potential both to investigate and alter the course of vessel wall pathophysiology. Replication-deficient adenovirus vectors appear particularly useful for the transfection of blood vessels, because, of their ability to accommodate large cDNA inserts and to rapidly and efficiently infect mammalian cells. However, the potential effects of transfection with a replication-deficient adenovirus on vasomotor function have not been previously described. We performed gene transfer experiments with a replication-deficient adenovirus which contained a cytomegalovirus promoter and a nuclear-localizing variant of the bacterial β-galactosidase gene. Excised carotid artery segments from 6 rabbits were divided into multiple segments and infected in pairs, for 30minutes with four different viral titers (0, 2.5×109.5×109, 1×1010 pfu/ml) at 37°C in serum free media. These segments were tested for β-galactosidase staining and vasomotor function 2 days later. Isometric tension studies were performed to examine the response of the vessel segments to the contractile agonist, norepinephrine (NE). The results are shown below as mean±standard error, -log10 [EC50] with * p≤0.04 between the lowest and the highest group.Viral Titer (pfu/ml)02.5×1095×1091×1010NE Dose5.98±0095.77±115.68±0,145,5.52±0.13**p≤0.04In cell culture, rabbit vascular smooth muscle cells were infected in a similar manner. β-Galactosidase staining was present at all 3 viral concentrations but when a viral concentration of 1×1010 pfu/ml was used there were areas of cellular necrosis not seen at the lower viral concentrations.ConclusionReplication-deficient adenovirus vectors can rapidly and efficiently infect rabbit carotid vessels. However at doses often employed for gene transfer experiments in-vivo, there is a dose dependent alteration of vessel vasomotor function which may be mediated by a cytotoxic affect of the viral vector. This effect needs to be taken into account in studies involving adenoviral gene transfer