Stem cell transplantation as an approach to brain repair

Disease of the nervous system causes considerable suffering, places a large economic burden on society and, to date, remains relatively untapped by pharmaceutical and biotechnology companies. The burgeoning field of stem cell biology promises to revolutionise and expand the use of cell therapy in the treatment of nervous system disease. By virtue of their multipotentiality stem cells are ideally suited to replace diverse neural and glial populations lost to disease or injury, and thereby functionally reconstruct neural circuits. The ease with which they can be genetically modified also makes them appealing vectors for ex vivo gene therapy in a multitude of conditions. This article reviews the approaches used to obtain large numbers of stem cells for such applications, including stem cells derived from neural tissue and propagated using either genetic or epigenetic means, totipotential embryonic stem cells and stem cells isolated from other tissues. The evidence for the efficacy of neural stem cell therapy in prototypical animal models of disease is then reviewed.