Gene therapy in the neuroendocrine system: its implementation in experimental models using viral vectors

Gene therapy, the transfer of genetic material for therapeutic purposes, has undergone an explosive development in the last few years. Within this context, development of gene therapy approaches for the neuroendocrine system, while incipient, has already generated a core of results which emerge as a promising area of research in neuroendocrinology. The present review presents a brief description of the viral vector-based gene delivery systems being currently used in neuroendocrinology, namely the adenoviral and herpes simplex type-1 (HSV-1)-derived vector systems, as well as an updated account of neuroendocrine pathologies for which gene therapy approaches in animal models are being implemented is provided. Current research efforts include treatment of experimental pituitary tumors by adenoviral vector-mediated transfer of the suicide gene for the HSV-1 thymidine kinase, which converts the prodrug ganciclovir into a toxic metabolite. An adenoviral vector encoding the human retinoblastoma suppressor oncogene has also been successfully used to rescue the phenotype of spontaneous pituitary tumors of the pars intermedia in mice. At the hypothalamic level, an adenovirus harboring the cDNA for arginine vasopressin has been used in Brattleboro rats to correct diabetes insipidus for several weeks. The last part of the review outlines the potential of gene therapy to correct age-associated neurodegenerative processes at the neuroendocrine level. Although effective implementation of gene therapy strategies still faces significant technical obstacles, these are likely to be progressively overcome as gene delivery systems are being improved.