Neural transplantation for treatment of Parkinson's disease

Neural transplantation has emerged as an efficacious experimental treatment for CNS disorders, especially Parkinson's disease. However, logistical and ethical issues impede large-scale clinical trials. To this end, alternatives to human fetal cells as donor cell grafts have been examined, including xenografts, stem cells, genetically engineered cells, immortalized cell lines, or paraneural cells that secrete specific neurotrophic or growth factors. Accumulating evidence also suggests that exogenous treatment with neurotrophic or growth factors, immunosuppressants, free radical scavengers, and anti-apoptotic agents can enhance survival and functional effects of the grafts. This article will review recent studies demonstrating the potential of these alternative cell graft sources and novel drugs for treating Parkinson's disease.