Potential for germ line transmission after intramyocardial gene delivery by adeno-associated virus.
Intramyocardial injection of adeno-associated virus (AAV) has been shown to be an effective strategy for cardiac gene delivery. This approach leads to long-term gene expression in the heart, offering the possibility of chronic gene therapy. However, the long-term safety of this approach with regard to vector bio-distribution and extracardiac transgene expression has not been evaluated. To examine these issues, 8-week-old male Sprague-Dawley rats were injected intramyocardially with either 4x10(11) particles of AAV-2-lacZ or saline at five locations in the anterioposterior apical region of the left ventricle. Animals were sacrificed at 3 and 6 months after gene transfer, tissues were harvested and analyzed for lacZ expression by semi-quantitative RT-PCR and beta-galactosidase activity using X-gal staining. We observed high level of transgene expression in the myocardium at 3 months after gene transfer, which persisted up to 6 months of follow-up. Also, significantly we detected lacZ expression and beta-galactosidase activity in extracardiac tissues such as liver, kidney, and testes at 6 months. More significantly, late transgene expression was detected in cellular elements of the seminiferous tubule, including Sertoli cells and spermatogonia like cells. These data demonstrate the efficacy of AAV-2 delivery for long-term myocardial gene therapy, but raise concerns about the possibility of ectopic transgene expression and germ cell line infection.
Pachori
Alok S
AS
Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
Melo
Luis G
LG
Zhang
Lunan
L
Loda
Massimo
M
Pratt
Richard E
RE
Dzau
Victor J
VJ
D000818:Animals; D015139:Blotting, Southern; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics*; D018014:Gene Transfer Techniques; D007150:Immunohistochemistry; D007763:Lac Operon; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D019076:Transgenes; D001616:beta-Galactosidase / Q000378:metabolism
D018076:DNA, Complementary; D012333:RNA, Messenger; D004247:DNA; D001616:beta-Galactosidase