Stem cells and neurodegenerative diseases: where is it all going?

Over the last few years there have been a number of major breakthroughs in the development of stem cells for diseases of the CNS. One of these has been in the ability to reprogram adult somatic cells to a more pluripotent state as well as directly to neurons and, by so doing, use patient-derived cells to study disease. In addition, the capacity to engineer embryonic stem cells to defined neuronal fates in the absence of proliferative contaminant cells is now feasible, which opens up the possibility of using these cells for cell transplantation. In this review, we will discuss how these developments have come about, particularly in the context of Parkinson's disease, and what this means for the future of this whole field over the next few years.