Somatic gene therapy for nervous system disease.

Neurotrophic factors are target-derived molecules that prevent neuronal degeneration during development and, in some cases, during adulthood. They offer substantial promise as therapeutic agents in neurological disease by preventing cell loss and promoting axonal regeneration. However, the optimal means of delivering neurotrophic factors to the nervous system, and the CNS in particular, is an unresolved issue. Neurotrophic factors rarely influence only a single target neuronal population, hence broad delivery of neurotrophic factors to the nervous system may results in effects on multiple non-targeted neuronal populations. Ideally, neurotrophin delivery to the nervous system should be target-specific, regionally restricted, chronic, safe, well-tolerated and of sufficient concentration to elicit responses from target neurons. In this paper we discuss the use of somatic gene transfer methods to deliver neurotrophic factors to the CNS in a manner that seeks to meet the above criteria.