Application of HVJ-liposome mediated gene transfer in lung transplantation-distribution and transfection efficiency in the lung.

Objective: A novel hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer system has been shown to have benefits of a high efficiency of transfection and low immunogenicity. The aims of this study were to determine the effect of re-transfection of the HVJ-liposome system via the airway, and to quantify the distribution of gene expression between transtracheal and transplantation approaches.

Methods: Beta-galactosidase (beta-gal) plasmid DNA was introduced into lung tissues using the HVJ-liposome method. Two groups of Sprague-Dawley (SD) rats received intratracheal instillation of 10 microg of the beta-gal gene, once on Day 0 in 1 group (Group Tb-1, n=4) and 3 times on Days 0-2 in another (Group Tb-3, n=4). In a third group of SD rats (Group Tx, n=5), an orthotopic left lung transplantation was performed after the donor lung was flushed with an HVJ-liposome complex solution and preserved for 1h. Gene expression and distribution in lung tissue was then quantified by counting the X-gal stained cells.

Results: Both the transtracheal and transplantation approaches resulted in low levels of transfection in the vascular endothelial cells (0.2+/-0.1 and 4.0+/-1.8%), respectively, but a moderate degree of transfection to the airway (11.0+/-7.1 and 28.0+/-20.7%) and alveolar cells (3.0+/-1.8 and 6.0+/-3.6%). Three repetitive injections via the airway increased gene expression in airway epithelial cells of 41.0+/-12.0% compared with the single administration of 11.0+/-4.3%.

Conclusions: Our results suggest that the repeated transtracheal gene transfection using HVJ-liposome may have benefits for treatment of problems after lung transplantation. In addition, gene transfer using a flushing solution during harvest may provide an opportunity for gene manipulation in the setting of lung transplantation.