GENE-TRANSFER INTO VASCULAR CELLS USING ADENOASSOCIATED VIRUS (AAV) VECTORS

Objectives: Recombinant viral vectors based on the nonpathogenic parvo virus, adeno-associated virus (AAV), have a number of attractive featu res for gene therapy, including the ability to transduce non-dividing cells and its long-term transgene expression. In this study, an AAV ve ctor containing bacterial beta-galactosidase gene (lacZ) was used to t ransduce cultured rat vascular smooth muscle cells (VSMC) in vitro and rat thoracic aortas ex vivo. Methods: VSMC were transduced with AAV-l acZ at multiplicities of infection (MOI) ranging from 5.0 x 10(5) to 1 .0 x 10(7). Expression of beta-galactosidase (beta-gal) in VSMC was ev aluated by X-gal staining and a beta-gal ELISA method. Excised rat aor tas were incubated with medium containing AAV-lacZ. Expression of beta -gal in the aortic segments was evaluated by X-gal staining. Results: With increasing MOI, up to 50% of cultured VSMC were positive by X-gal staining and the beta-gal expression increased up-to 15 ng/mg protein . The expression gradually decreased during the culture but was detect able for at least 1 month. In the ex vivo study, AAV vectors transduce d endothelial and adventitial cells in rat aortic segments, while no e xpression was seen in medial VSMC. Conclusions: AAV vectors can effici ently transduce rat VSMC in vitro. AAV-mediated ex vivo gene transfer into the normal aorta resulted in efficient gene transfer into endothe lial and adventitial cells but not into medial VSMC. These findings su ggest that AAV-based vectors are promising for use in cardiovascular g ene therapy. (C) 1997 Elsevier Science B.V.