Direct injection of AAV1 into pig myocardium mediated more efficient gene transduction than AAV2, while plasmid was inefficient, and AAV-mediated VEGF transfer induced neovascular formation.
Does AAV1 mediate more efficient gene transfer to pig myocardium compared to AAV2 and plasmid?
AAV serotype 1 is more efficient than AAV serotype 2 and plasmid for direct gene transfer into pig myocardium, successfully inducing neovascularization with VEGF without causing inflammation.
Adeno-associated virus (AAV) has many properties of an ideal vector for delivery of therapeutic genes into the myocardium. Previous studies in a mouse model of myocardial infarction showed that AAV serotype 1 (AAV1) is superior to AAV serotypes 2-5 to transfer genes into the myocardium by direct injection. Since vectors may behave differently in humans and because the human and the pig hearts resemble each other closely, we tested whether AAV1 is also superior to AAV2 in transferring genes into the pig myocardium. We also compared gene transduction efficiency between AAV vectors and plasmid. We injected CMVLacZ and CMVVEGF (vectors with the cytomegalovirus (CMV) promoter driving LacZ and VEGF gene expression) unpackaged or packaged in AAV serotypes 1 or 2 capsids into pig myocardium. Hearts were collected 3, 14 and 28 days after the injection. Gene expression was analyzed by real-time reverse-transcription polymerase chain reaction (RT-PCR) and histological staining. Capillaries and smooth muscle alpha-actin (SMA)-positive vessels were quantified. Potential lymphocyte infiltration at the injection sites was analyzed by immunostaining using specific antibodies. As in the mouse, AAV1 mediated better gene transduction than AAV2. Plasmid mediated minimal gene expression only. More capillaries and SMA-positive vessels were detected at AAV1CMVVEGF- and AAV2CMVVEGF-injected than AAV1CMVLacZ-injected sites. We did not detect inflammatory cell infiltration at the injection sites. In conclusion, by direct injection, AAV1 is more efficient than AAV2, and plasmid is inefficient in mediating gene transfer into the pig myocardium. AAV-mediated VEGF gene transfer can also induce neovascular formation in the pig myocardium.
Su et al. (Thu,) conducted a other in Myocardial gene transfer. AAV serotype 1 (AAV1) vs. AAV serotype 2 (AAV2) and plasmid was evaluated on Gene transduction efficiency. Direct injection of AAV1 into pig myocardium mediated more efficient gene transduction than AAV2, while plasmid was inefficient, and AAV-mediated VEGF transfer induced neovascular formation.
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