Adenovirus Biodistribution is Modified in Sensitive Animals Compared to Naïve Animals.

Abstract

Pre-existing immune response against adenovirus could diminish transgene expression efficiency when Ad is employed in humans as gene therapy vector. We previously used Ad-hΔuPA (Recombinant adenovirus expressing human urokinase-type plasminogen activator) as antifibrotic gene therapy in cirrhosis models and demonstrated its effectiveness. As a further clinical approach, transient Cyclosporine A (CsA) immunosuppression was induced in cirrhotic animals to determine whether Ad-hΔuPA administration retained efficacy. Adenovirus sensitization was achieved by systemic administration of non-therapeutic Ad-βGal (Recombinant adenovirus expressing beta-galactosidase) after 4weeks of intraperitoneal carbon tetrachloride (CCl4) regimen. Cirrhosis induction continued up to 8weeks. At the end of CCl4 intoxication, immunosuppression was achieved with three CsA doses (40mg/kg) as follows: 24h before administration of Ad-hΔuPA, at the moment of Ad-hΔuPA injection and finally, 24h after Ad-hΔuPA inoculation. At 2 and 72h after Ad-hΔuPA injection, animals were sacrificed. Liver, spleen, lung, kidney, heart, brain, and testis were analyzed for Ad-biodistribution and transgene expression. In naïve animals, Ad-hΔuPA genomes prevailed in liver and spleen, while Ad-sensitized rats showed Ad genomes also in their kidney and heart. Cirrhosis and Ad preimmunization status notably diminished transgene liver expression compared to healthy livers. CsA immunosuppression in cirrhotic animals has no effect on Ad-hΔuPA biodistribution, but increments survival.