Therapeutic cell and gene transfers into the central nervous system.

The current conception of progressive nerve cell loss associated with neurodegenerative diseases is no longer compatible with the completely irreversible process regularly accepted for so many years. This optimistic observation is based on the demonstration that the central nervous system in the adult is a very plastic entity. Data on neuroplasticity suggest that neurons could be replaced by integrating cells into adult nervous circuits and thus counteract neuron death although the initial cause of the disease would remain unknown. Intracerebral neuron transplantations, used as substitution material, and the transfer of genes encoding neuroprotective factors are among the latest therapeutic approaches which, it is hoped, will open a new era in neurology where the neurologist's main activity will no longer be simply diagnosis.