Adenovirus-Mediated Gene Transfer Is Augmented in Basilar and Carotid Arteries of Heritable Hyperlipidemic Rabbits

Background and Purpose —There are major differences in susceptibility of intracranial and extracranial arteries to atherosclerosis. The goal of this study was to examine adenovirus-mediated gene transfer to basilar and carotid arteries of Watanabe heritable hyperlipidemic (WHHL) rabbits, which have spontaneous hypercholesterolemia and atherosclerosis, and normal New Zealand White (NZW) rabbits. We used 2 different adenoviral vectors, driven by either cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoters. Methods —Basilar and carotid arteries were removed from WHHL and NZW rabbits and cut into rings. The arteries were incubated with an adenoviral vector that expresses β-galactosidase and is driven by either a cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoter (AdCMVβgal or AdRSVβgal). Arteries were incubated with virus for 2 hours, and then incubated in medium for 24 hours to allow expression of transgene. Transgene expression was assessed by enzyme activity (Galacto-Light assay) and by a histochemical method after X-Gal staining. Results —After gene transfer, β-galactosidase was expressed in endothelium and adventitia but not media. There were moderately severe atherosclerotic lesions in carotid arteries and early lesions in basilar arteries. Enzyme activity after gene transfer with AdCMVβgal (3×1011 particles/mL) was greater in the basilar artery of WHHL than NZW (137±40 versus 25±10 mU/mg protein, P <0.05) (mean±SE) and in the carotid artery (133±27 versus 34±11 mU/mg protein, P <0.05). After gene transfer with AdRSVβgal, transgene expression was similar in arteries from WHHL and normal NZW rabbits. Conclusions —This is the first study to examine gene transfer to intracranial and extracranial arteries from atherosclerotic animals. The findings suggest that an adenoviral vector with a CMV, but not RSV, promoter provides greater transgene expression in the basilar and carotid arteries from spontaneously atherosclerotic rabbits than from normal rabbits.