996-8 In Vivo Adenovirus-Mediated Gene Transfer via the Pulmonary Artery of Rats

Abstract

Gene transfer into the pulmonary vasculature may be a powerful technique both for the investigation of pulmonary pathophysiology and for the development of genetic therapies for pulmonary vascular disease. To evaluate the potential for in vivo pulmonary arterial gene transfer, we infused adenoviral vectors into the left pulmonary artery of Sprague-Dawley and cotton rats. Access to the left pulmonary artery was obtained either by a percutaneous, transcatheter approach, or via a thoracotomy and pulmonary arteriotomy. When using the thoracotomy approach, both the pulmonary arterial inflow and the pulmonary venous outflow were occluded during vector infusion and throughout a subsequent 20 minute dwell period. The success of gene transfer was assessed by staining for evidence of recombinant gene expression in lungs excised at time points ranging from 48 to 72 hours after virus infusion. Using the surgical technique, pulmonary gene transfer was successful in 15% of surviving Sprague-Dawley and 30% of surviving cotton rats. Percutaneous pulmonary gene transfer was not successful. In those rats with pulmonary gene transfer. 1–8% of total pulmonary cells expressed the recombinant gene. Recombinant gene expression was found in endothelial cells (0.2–18% of total transduced cells). smooth muscle cells (0–3%). macrophages (1–7%). airway epithelial cells (2–50%). and alveolar epithelial cells (38–94%). Studies investigating the low rate of successful gene transfer in individual animals suggested that insufficient physical contact of the virions with pulmonary cells was the likely etiology. In vivo gene transfer into the rat pulmonary vasculature can be accomplished with adenovirus vectors. Pulmonary arterial infusion of the vectors results in low level endothelial cell transduction. with higher levels of gene transfer into nonvascular pulmonary cells.