title: High-level secretion of growth hormone by retrovirally transduced primary human keratinocytes: prospects for an animal model of cutaneous gene therapy.
abstract: A gene therapy clinical trial for treatment of growth hormone (GH) deficiency has not been reached yet, but several strategies using different gene transfer methodologies and animal models have been developed and showed successful results. We have set up an ex vivo gene therapy protocol using primary human keratinocytes transduced with an efficient retroviral vector (LXSN) encoding the human (hGH) or mouse GH (mGH) genes. These stably modified cells presented high in vitro expression levels of hGH (7 microg/106 cells/d) and mGH (11 microg/106 cells/d) after selection with geneticin. When the hGH-secreting keratinocytes were grafted onto immunodeficient dwarf mice (lit/scid), hGH levels in the circulation were about 0.2-0.3 ng/mL during a 12-d assay and these animals presented a significant body weight increase (p < 0.01) compared to the control. Substitution of conventional grafting methodologies with organotypic raft cultures revealed a peak value of up to 20 ng mGH/mL in the circulation of grafted lit/scid mice at 1 h postimplantation, followed by a rapid decline to baseline (approximately 2 ng/mL) within 24 h. One week after grafting, however, the cultured excised implants still presented approx 45% of their original in vitro secretion efficiency. Further studies are being carried out to identify the main factor(s) that still constitute one of the major impediments to the success of this promising model of cutaneous gene therapy.
authors.affiliation: Biotechnology Department, IPEN-CNEN, Av. Lineu Prestes, 2242, Cidade Universitária, 05508-900 São Paulo, Brazil.
authors.forename: Cibele Nunes
authors.initials: CN
authors.lastname: Peroni
authors.forename: Cláudia Regina
authors.initials: CR
authors.lastname: Cecchi
authors.forename: Renata
authors.initials: R
authors.lastname: Damiani
authors.forename: Carlos R J
authors.initials: CR
authors.lastname: Soares
authors.forename: Maria Teresa C P
authors.initials: MT
authors.lastname: Ribela
authors.forename: Rosângela
authors.initials: R
authors.lastname: do Rocio Arkaten
authors.forename: Paolo
authors.initials: P
authors.lastname: Bartolini
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004393:Dwarfism, Pituitary / Q000628:therapy*; D015316:Genetic Therapy / Q000379:methods*; D013006:Growth Hormone / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000637:transplantation*; D051379:Mice; D012190:Retroviridae / Q000235:genetics; D012867:Skin / Q000166:cytology; D014161:Transduction, Genetic
chemical_list: D013006:Growth Hormone