895. Ex Vivo Gene Therapy of Metabolic Liver Disorders Using Uncultured and Lentivirally Transduced Hepatocytes

• Published in: Molecular therapy Vol. 11; no. S1; pp. S346 - S347
• Main Authors: Nguyen, Tuan Huy, Birraux, Jacques, Wildhaber, Barbara, Fux, Catherine, Trivin, Francois, Myara, Anne, Lecoultre, Claude, Trono, Didier
• Format: Journal Article
• Language: English
• Published: Milwaukee Elsevier Inc 01.05.2005; Elsevier Limited
• Subjects: Adenoviruses; Automation; Diabetes; Efficiency; Gene expression; Gene therapy; Liver diseases; Metabolism; Proteins; Vectors (Biology); Istanbul Turkey; Turkey; France; Switzerland; Paris France
• ISSN: 1525-0016; 1525-0024
• DOI: 10.1016/j.ymthe.2005.07.438

Background: At the present time, orthotopic liver transplantation is the only effective therapy for several congenital and acquired hepatic disorders. Because of a chronic organ shortage, and of the necessity of heavy and lifelong immunosuppression after transplantation, gene therapy represents a promising alternative. We have previously described an ex vivo gene therapy protocol that allows very high rates of transduction of human hepatocytes (up to 98%), in which freshly isolated hepatocytes are transduced in suspension and immediately transplanted. This protocol is easily performed, rapid, does not required primary culture of hepatocytes, and preserves full cell engraftment potential and in vivo cell functionality. In this study, we used the Gunn rat, which is the model for Crigler-Najjar syndrome type I, a defect in bilirubin UDP-glucuronyltransferase (BGT), to evaluate our approach.Methods: We constructed vectors coding for human BGT under control of the E1a ubiquitous promoter. Freshly isolated hepatocytes were transduced in suspension at a multiplicity of infection of 30 for 4 hrs. After washing, twenty millions hepatocytes were immediately transplanted into jaundiced Gunn rats.Results: Transduction efficiency was limited to 30% in Gunn rat hepatocytes. Despite this low level of transduction efficiency, serum bilirubin levels decreased by 30% in rats receiving BGT-transduced hepatocytes. This decline was equivalent to that obtained with transplantation of wild-type hepatocytes. It was sustained for up to 150 days. Accordingly, conjugated bilirubin appeared in the bile. In contrast, in rats receiving untransduced or GFP-transduced hepatocytes, serum bilirubin didn't decline but rather increased. GFP-positive hepatocytes amounted at most to 1% of rat livers, which is in agreement with the gene transfer efficiency. Noteworthy, these results also suggested an absence of immune response against the transduced hepatocytes, as expected by selective targeting of the hepatocytes using an ex vivo approach, even though transgene expression was driven by a ubiquitous promoter.Conclusion: In contrast to human hepatocytes, adult rodent hepatocytes were lowly transducible by lentiviral vectors. Despite this limitation, we demonstrated the efficacy of ex vivo approach in Gunn rats. Recent clinical trials have shown that uncultured allogeneic hepatocyte transplantation has resulted in metabolic benefits in patients with metabolic liver disorders. Altogether, these data open new perspectives for the treatment of metabolic liver disorders using an ex vivo approach using lentiviral vectors.