Human embryonic stem cells could provide a valuable source or replacement neurons to ameliorate the effects of neural disorders such as Parkinson's disease, but the majority of such cells do not differentiate into specific neuron subtypes when grafted into the adult central nervous system. In November 11 advanced online Nature Neuroscience, Ping Wu and colleagues at the University of Texas Medical Branch, Galveston, Texas, USA, show that a novel priming procedure for fetal human neural stem cells (hNSCs) can transform them into cholinergic neurons in adult rat CNS (Nature Neuroscience, DOI:10.1038/nn974, November 11, 2002).

Wu et al. treated primary fetal human neural stem cells (hNSCs) with tropic factors or other chemicals important in the development of cholinergic neurons. They observed that after this procedure, mitogen-expanded hNSCs were transformed almost exclusively into neurons when grafted into adult rat CNS. In addition, they showed that a large number of these transplanted cells acquired a cholinergic phenotype when grafted into cholinergic areas of CNS.

"Other critical issues, such as whether these fetal hNSC-derived neurons could project to correct targets or functionally replace dead neurons, need to be addressed before using the stem cell technology to treat the various neurological disorders that arise from loss of neurons," conclude the authors.