SUCCESSFUL IN-VIVO AND EX-VIVO TRANSFECTION OF PULMONARY-ARTERY SEGMENTS IN LUNG ISOGRAFTS

Objective: Gene transfer to lung grafts may be useful in ameliorating ischemia-reperfusion injury and rejection, Efficient gene transfection to the whole organ may prove problematic, Proximal pulmonary artery e ndothelial transfection might provide beneficial downstream effects on the whole graft, The aim of this study was to determine the feasibili ty of transfecting proximal pulmonary artery segments in lung isograft s, Methods: Male Fischer rats were divided into six groups, In vivo tr ansfection: In group I (n = 7), a proximal segment of the left pulmona ry artery was isolated and injected,vith saline solution by means of a catheter inserted through the right ventricle, After an exposure peri od of 20 minutes, clamps were removed and blood flow was restored, In group II (n = 7), the isolated arterial segments were injected with ad enovirus carrying the Escherichia coli LacZ gene encoding for beta-gal actosidase. Ex vivo transfection: In group III (n = 5), arterial segme nts were injected ex vivo with saline solution and in group TV (n = 5) with the adenovirus construct, In group V (n = 6), arteries were inje cted with saline solution and in group VI (n = 11) with liposome chlor amphenicol acetyl transferase cDNA, In groups I to IV, animals were ki lled on postoperative day 3 and transgene expression was assessed by B lue-Gal staining, In groups V and VI, animals were killed on postopera tive day 2 and transgene expression was assessed by chloramphenicol ac etyl transferase activity assay, Results: Transgene expression was det ected grossly and microscopically in endothelial and smooth muscle cel ls of pulmonary artery segments from all surviving animals of groups I I and IV, In group VI, chloramphenicol acetyl transferase activity was significant in all assessed arterial segments, Conclusion: Significan t transgene expression is observed in proximal pulmonary artery segmen ts after both in vivo and ex vivo exposure.