Stem cell therapy for Parkinson's disease

Transplantation of fetal dopaminergic (DA) neurons can produce symptomatic relief for patients with Parkinson's disease, but the technical and ethical difficulties have limited the application of this therapy. Neural precursor cells and embryonic stem cells (ESCs) are expected to be candidates of potential donor cells for transplantation. Human neural precursor cells obtained from the midbrain give rise to TH-positive neurons. The growth of the cells, however, is slow and the differentiation rate of DA neurons is still low for clinical application. Monkey ESCs give rise to midbrain DA neurons, and the transplanted ESC-derived neurospheres function as DA neurons, attenuating the neurological symptoms of the monkey Parkinson's disease model. These results suggest the possibility of using stem cells for the treatment of Parkinson's disease, but problems such as the low survival rate in vivo and tumor formation must be solved.