Objective: Vascular gene transfer is a powerful tool for investigating and treating vascular diseases; however, its utility is limited by brevity of transgene expression and vector-associated inflammation. Helper-dependent adenovirus (HDAd), an advanced-generation adenovirus that lacks all viral genes, is superior to first-generation adenovirus (FGAd) in normal rabbit arteries. We compared HDAd to FGAd in arteries of cholesterol-fed rabbits, a model of early atherogenesis in which transgene expression might be decreased, and inflammation increased.
Methods and results: Carotid arteries of chow- and cholesterol-fed rabbits were infused with FGAd, HDAd, or medium. HDAd expressed a transgene at least as well in arteries of cholesterol-fed rabbits as in arteries of chow-fed rabbits and expressed more durably than FGAd. In arteries of cholesterol-fed rabbits, HDAd stimulated less intimal growth, lipid deposition, and inflammation than FGAd. Neither vector affected phenylephrine-induced contraction or nitroprusside-mediated relaxation; however, both vectors decreased maximal acetylcholine-stimulated vasorelaxation. The relative absence of intimal growth in HDAd arteries could interfere with the utility of this model for testing atheroprotective genes; however, both coinfusion of FGAd and extension of cholesterol feeding yielded larger intimal lesions, on which atheroprotective genes could be tested.
Conclusion: HDAd is superior to FGAd for expression of transgenes in atherosclerosis-prone arteries.