Neural stem cells as delivery vehicles.

The discovery of neural stem cells (NSCs) has changed our long-held view that the adult mammalian central nervous system (CNS) is postmitotic and lacks the capability for self-repair. The role of NSCs in physiological and pathological processes in the brain is slowly emerging. We are now able to isolate, expand, genetically engineer and transplant NSCs. An important characteristic of NSCs, not fully understood so far, is their migratory ability and their tropism to brain pathology. The migratory ability of NSCs and their capacity to differentiate into all neural phenotypes gives us a potentially powerful tool for the treatment of both diffuse and localised neurologic disorders. The delivery of gene products by NSCs to specific sites in the CNS can maximise the efficiency of delivery and minimise the unwanted exposure of surrounding intact tissue. Here, the recent preclinical advances in the use of NSCs for the delivery of therapeutic products are reviewed, in particular the employment of their migratory potential and the homing ability to pathology in the nervous system.