Stem cell transplantation for neurodegenerative disease: A distant dream?

The massive surge of interest in stem cell biology over the last 20 years is reflected in the 100-fold increase in related publications over that time, and the emergence of the term 'stem cell' into the public consciousness. Much of the interest has been generated by the often promised health benefits that stem cell transplantation could bring to hitherto untreatable diseases, but to what extent are we really able to manipulate these cells for therapeutic use in neurodegenerative disease? Is stem cell therapy a reality or a distant dream? In addressing these questions, it is important to recognize that the answers depend on which stem cells are being considered for use as donor cells, what demands are placed on the cells and which target diseases are being considered for treatment.