¹Research Institute, Toronto

¹⁰Department of Molecular and Medical Genetics, University of Toronto, Ontario

²The Lung Gene Therapy Program, The Hospital for Sick Children, Toronto

³National Heart and Lung Institute, Emmanuel Kaye Building, Manresa Road, London SW3 6LR, UK

⁴Inex Pharmaceuticals Corporation, Vancouver, BC, Canada

⁵Pathology, University of Toronto, Ontario

⁶MRC Group in Lung Development, Toronto

⁷Paediatrics, University of Toronto, Ontario

⁸Physiology, University of Toronto, Ontario

⁹Institut für Klinische Biochemie der Universität Bonn, Bonn, Germany

Intratracheal (i.t.) and intravenous (i.v.) delivery of DNA-vector formulations are two strategies to obtain gene transfer to the lung. It is still uncertain, however, which of these two modes of delivery will be more effective in the treatment of cystic fibrosis and other lung diseases. In this study, we attempted to optimize formulations of the cationic liposome DODAC:DOPE (dioleoyldimethylammonium- chloride:dioleoylphosphatidylethanolamine) complexed to plasmids encoding chloramphenicol acetyltransferase for i.t. and i.v. injection into CD-1 mice and compared the two methods. Our results showed that both methods conferred reporter gene expression in the lung that was significantly higher relative to injection of plasmid DNA alone. Expression using either mode of administration was maximal 24 h after injection and declined to around 10% of day 1 levels 2 weeks after injection. For i.v. delivery of DODAC: DOPE-DNA complexes multilamellar vesicles were more effective than large unilamellar vesicles in all organs investigated. Recombinant DNA could be detected in the distal lung region following either route of administration. However, i.t. administration predominantly led to DNA deposition in epithelial cells lining the bronchioles, eg in clara cells, whereas i.v. administration resulted in DNA deposition in the alveolar region of the lung including type II alveolar epithelial cells.

lung gene therapy; cystic fibrosis; cationic liposomes