Abstract
Background
Gene delivery to the pulmonary circulation has been studied in adult animals, but has not been extensively investigated in neonates.
Methods
We tested the ability of recombinant, replicationβdefective adenovirus to transduce the pulmonary circulation when delivered by percutaneous ventricular puncture. Fiveβdayβold rat pups were injected with 10^7^ to 10^10^ particles (approximately 10^5^ to 10^8^ pfu) in 30 Β΅l total volume.
Results
Using RTβPCR, we detected transgene expression in both lung and liver at all dosages. However, whereas only 1/6 pups injected with 10^7^ particles had detectable expression, 8/9 pups in the two highest dose groups had detectable expression. In the highest dose group expression was approximately 5βfold greater in lung than liver, though in the lower dose groups no difference between lung and liver was found. Expression decreased by only 25% from day 4 through the last time point at day 28 in lung, whereas liver expression was undetectable in 7 of 9 samples on day 28. Histopathological examination demonstrated expression both within the media of large arteries and in small, peripheral arteries and capillaries, with a concentration of expression in the most distal areas of both the lungs and liver. No evidence of inflammation was seen.
Conclusions
We conclude that the neonatal pulmonary circulation can be effectively transduced using systemic adenoviral vector injection, has more sustained expression than liver, and may be a target for therapeutic gene delivery. Copyright Β© 2004 John Wiley & Sons, Ltd.