In utero AAV-mediated gene transfer to rabbit pulmonary epithelium

Area of Science:

• Gene therapy
• Fetal medicine
• Pulmonology

Background:

• Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs.
• Targeting fetal pulmonary epithelium for CF treatment is a potential strategy.
• In utero gene delivery methods require further investigation for safety and efficacy.

Purpose of the Study:

• To investigate the feasibility and safety of in utero intra-amniotic administration of adeno-associated virus (AAV) for potential cystic fibrosis (CF) gene therapy.
• To assess transgene expression patterns and levels in fetal tissues following intra-amniotic AAV delivery.

Main Methods:

• Intra-amniotic administration of AAV-luciferase vector (1x10^12 particles) to 110 fetal rabbits at 24-25 days gestation.
• Analysis of transgene expression in various fetal and maternal tissues at different time points post-delivery.
• Immunohistochemical analysis to identify transduced cell types in the lungs.

Main Results:

• Transgene expression was detected in amniotic membranes, trachea, and fetal pulmonary epithelium.
• Amniotic membranes showed the highest transgene expression; lung expression peaked at 10 days and declined by 24 days.
• Approximately 1 in 500 pulmonary cells were transduced, including alveolar cells. No significant inflammation or fetal loss was observed.

Conclusions:

• Intra-amniotic AAV administration is a potentially safe and effective method for fetal gene delivery to the lungs.
• This approach warrants further investigation for its therapeutic potential in treating congenital lung diseases like cystic fibrosis.
• High expression in amniotic membranes suggests a role in immune modulation or as a reservoir for sustained gene expression.