title: Biosafety in ex vivo gene therapy and conditional ablation of lentivirally transduced hepatocytes in nonhuman primates.
abstract: Ex vivo gene therapy is an interesting alternative to orthotopic liver transplantation (OLT) for treating metabolic liver diseases. In this study, we investigated its efficacy and biosafety in nonhuman primates. Hepatocytes isolated from liver lobectomy were transduced in suspension with a bicistronic liver-specific lentiviral vector and immediately autotransplanted (SLIT) into three cynomolgus monkeys. The vector encoded cynomolgus erythropoietin (EPO) and the conditional suicide gene herpes simplex virus-thymidine kinase (HSV-TK). Survival of transduced hepatocytes and vector dissemination were evaluated by detecting transgene expression and vector DNA. SLIT was safely performed within a day in all three subjects. Serum EPO and hematocrit rapidly increased post-SLIT and their values returned to baseline within about 1 month. Isoforms of EPO detected in monkeys' sera differed from the physiological renal EPO. In liver biopsies at months 8 and 15, we detected EPO protein, vector mRNA and DNA, demonstrating long-term survival and functionality of transplanted lentivirally transduced hepatocytes. Valganciclovir administration resulted in complete ablation of the transduced hepatocytes. We demonstrated the feasibility and biosafety of SLIT, and the long term (>1 year) functionality of lentivirally transduced hepatocytes in nonhuman primates. The HSV-TK/valganciclovir suicide strategy can increase the biosafety of liver gene therapy protocols by safely and completely ablating transduced hepatocytes on demand.
authors: Research Laboratory of Pediatric Surgery, Department of Microbiology and Molecular Medicine, University of Geneva Medical School, Geneva, Switzerland.
authors: Olivier
authors: O
authors: Menzel
authors: Jacques
authors: J
authors: Birraux
authors: Barbara E
authors: BE
authors: Wildhaber
authors: Caty
authors: C
authors: Jond
authors: Françoise
authors: F
authors: Lasne
authors: Walid
authors: W
authors: Habre
authors: Didier
authors: D
authors: Trono
authors: Tuan H
authors: TH
authors: Nguyen
authors: Christophe
authors: C
authors: Chardot
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D004921:Erythropoietin / Q000235:genetics / Q000502:physiology; D015774:Ganciclovir / Q000031:analogs & derivatives / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006367:HeLa Cells; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000821:virology*; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D008107:Liver Diseases / Q000628:therapy; D008252:Macaca fascicularis; D008297:Male; D016133:Polymerase Chain Reaction; D018139:Simplexvirus / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics / Q000502:physiology; D014161:Transduction, Genetic / Q000379:methods*; D000077562:Valganciclovir; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology
chemical_list: D000998:Antiviral Agents; D014764:Viral Proteins; D004921:Erythropoietin; D013937:Thymidine Kinase; D000077562:Valganciclovir; D015774:Ganciclovir