Stem cells from a person's own bone marrow can be used to generate brain cells and other nervous system cells that, when put back into the body, may be a way to treat diseases like brain cancer or Alzheimer's.  
 "Neural stem cells have a lot of characteristics that make them an attractive means of treating neurological disorders but they come from precarious sources," said Dr. John Yu, co-director of the brain tumor program at Cedars-Sinai Medical Center in Los Angeles and the study's senior author.He was referring to the political and ethical issues surrounding the use of embryonic and fetal stem cells in medical research.Using renewable stem cells culled from bone marrow solves that dilemma , as well as potential problems with tissue rejection and uncontrolled growth of stem cells cultivated in a lab dish, Yu said.
Stem cell research is a broad but preliminary field based on the discovery of master cells that can give rise to various cells of the body. Most adult tissue and blood contain small numbers of stem cells but the more controversial source is from very early embryos, whose cells can become any kind of cell. Scientists consider both routes promising. Researchers who pursue embryonic stem cell work believe it would one day be possible to take a small plug of skin from a patient and grow new brain cells, new heart muscle or even a new organ such as a kidney. It would do away with the need for organ donations and be a way to treat now-incurable diseases. But the approach requires the use of a human egg and the production of a very early human embryo. Opponents say this involves taking a human life.Current U.S. policy strictly limits the amount of publicly funded research that can be done on embryonic stem cells. Private companies can do as they please, but some legislators are calling for an end to that too.
At Cedars-Sinai, researchers were able, for the first time, to generate neural progenitor cells from whole adult bone marrow.
In an experiment detailed in the latest issue of the journal Experimental Neurology, the team injected genetically engineered neural stem cells into the arteries of rats with stroke-related brain lesions. Forty-eight hours later, they found transplanted cells distributed throughout the damaged part of the brain. Similar results have been seen in human tissue, Yu said, noting that Cedars-Sinai hopes to begin testing the technique in stroke or brain tumor patients within a year. Several studies are already underway using stem cells to treat neurodegenerative diseases like Parkinson's, but these trials use so-called 'immortalized' stem cell lines originally derived from embryos or fetal stem cells. One trial of fetal stem cells as a treatment for Parkinson's disease. "worked too well," Yu said, explaining that the therapy created too much dopamine, the neurotransmitter that patients with the disease are short of."There is always the risk of going too far but in some cases it might be better to go too far, and then pull back, rather than wait several years without an effective treatment for an incurable disease," the researcher said.
       
