Embryonic stem cells as a cell source for treating Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease characterised by a loss of midbrain dopaminergic (DA) neurons. Transplantation of DA neurons represents a promising treatment for PD, and embryonic stem (ES) cells are a good candidate source for DA neurons. However, although recent reports have demonstrated that DA neurons can be efficiently induced from ES cells and function therapeutically in an animal model of PD, many problems remain to be solved in order for ES cells to be used for clinical applications. This review will describe the current status of this field and the obstacles yet to be overcome, and will outline future research approaches from the clinical perspective.