Gene transfer and expression in rat anastomotic artery in vivo using adenoviral vector

Objective To observe the efficiency and time course of gene expression and the safety of adenoviral vector mediated gene transfer in vivo. Methods After soaking soluble stents in a high concentration of glucose solution containing Adv(5)-CMV (cytornegalovirus) (control group) or Adv(5)-CMV/LacZ (treatment group) for 30 minutes, the stents were inserted into the lumina of cut rat carotid arteries and end-to-end anastomoses of the cut carotid were performed with standard microvascular surgical techniques. On days 2, 7, 14, 28, 60 and 90 after gene transfer, anastomotic arteries of the two groups were observed. On days 7 and 14, the ascending aortas, hearts, brains, livers, lungs, spleens and kidneys of the treatment group were observed. All samples were analyzed for the presence of P-galactosidase activity and histochemical staining. Results beta -galactosidase activity was not detected in the carotid arteries of the control group and organs not directly exposed to adenoviral vector of the treatment group. The amount of P-galactosidase activity ( x 10(-3) U/g tissue) in the treatment group on the 2nd, 7th, 14th, 28th, 60th and 90th day after gene transfer was 3.87, 11.38, 9.8, 6.43, 3.18 and 2.43, respectively. Microscopic examination of sections from vessels of the control group and from the aortas, hearts, brains, livers, lungs, spleens or kidneys of the treatment group revealed no X-gal staining. Microscopic examination of carotid arteries of the treatment group revealed blue-staining in all anastomotic arteries and in all layers of the arterial wall observed on days 7 and 14 after gene transfer. Conclusion Adenoviral vector can effectively infect blood vessels in vivo. After adenoviral vector mediated direct gene transfer into anastomotic rat carotid arteries, recombinant gene expression began on day 2, peaked between days 7 and 14, prominently declined after day 28, and persisted at low levels more than three months. A recombinant gene could be delivered to a specific site by direct gene transfer in vivo by adenoviral vector infection.