Inhaled Stem Cells Might Replace Lost Neurons

Many diseases of the central nervous system involve the death of neurons - so, theoretically, the replacement of dead cells should improve symptoms of degenerative disorders such as Parkinson's, Huntington's, amyotrophic lateral sclerosis and Alzheimer's, as well as stroke and brain tumors.

http://www.scientificamerican.com/article.cfm?id=inhaled-stem-cells-might-replace-lost-neurons