ALTERATION OF ARTERIAL VASOMOTOR FUNCTION IN-VITRO BY GENE-TRANSFER WITH A REPLICATION-DEFICIENT ADENOVIRUS

Gene transfer technologies offer great potential both to investigate a nd alter the course of vessel wall pathophysiology. Replication-defici ent 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 endothelial an d smooth muscle cells. The potential effects of transfection with a re plication-deficient adenovirus on vasomotor function have not, however , been described. This study reports gene transfer experiments with a replication-deficient adenovirus containing a cytomegalovirus promotor and a nuclear localizing variant of the bacterial beta-galactosidase gene. Excised carotid artery segments from 6 rabbits were divided into four segments and infected in pairs for thirty minutes with four vira l titers (control [0], 2.5x10(9), 5x10(9), and 1x10(10) pfu/ml) at 37 degrees C in serum-free culture media (M199). Expression of beta-galac tosidase and in vitro vasomotor function were determined after seventy -two hours' incubation. Isometric tension studies were performed to ex amine the response of the vessel segments to the contractile agonist n orepinephrine. beta-galactosidase was expressed in all vessel segments exposed to the adenovirus. There was a significant difference in the sensitivity to norepinephrine (P < 0.04) of the segments treated with the highest and lowest viral titers (mean +/- sem, -log(10) [EC(50)] o f 5.98 +/- 0.09, 5.77 +/- 0.11, 5.68 +/- 0.14, and 5.52 +/- 0.13 for t he control, 2.5x10(9), 5x10(9), and 1x10(10) plaque-forming units (pfu )/mL groups respectively). Replication-deficient adenovirus vectors ca n rapidly and efficiently infect rabbit carotid vessels, but there is, however, a dose-dependent alteration of in vitro vessel vasomotor fun ction that may be mediated by a cytotoxic effect of the viral vector. Although further in vivo work is required to verify these results, thi s effect needs to be taken into account in studies involving adenovira l gene transfer.