Scientists said Thursday they reprogrammed stem cells -- cells that act as building blocks for other cells in the body -- making it more likely that such cells can be cultivated to treat disease.
Working with mice, the Italian and Canadian scientists said they grew stem cells from the brain, which theoretically should only give rise to other nerve cells, and got them to produce blood stem cells.
"They have been reprogrammed and they have been shown to produce hematopoietic (blood-producing) cells," Angelo Vescovi of the National Neurological Institute in Milan, Italy, who led the research, said in a telephone interview.
If the research can be replicated in humans, Vescovi wrote in his report -- published in the journal Science -- it could make it easier to grow large batches of stem cells to treat diseases such as leukemia.
They might also offer an alternative to embryonic stem cells, which have been making headlines of late. Two teams of scientists reported late last year that they had cultivated cells known as pluripotent stem cells from embryos.
These pluripotent stem cells can give rise to any kind of cell in the body, and researchers hope to grow and program them to use for basic research, for drug screening, and for tissue transplants to treat a variety of diseases from Parkinson's, which results from the destruction of certain brain cells, to juvenile diabetes, caused when pancreatic cells are killed.
Because they are derived from human embryos, such cells are the subject of debate both in the United States, where President Clinton and lawmakers are studying the ethical issues involved, and in other countries such as Britain, where government advisers suggest it might be acceptable to grow them for medical and scientific research.
Vescovi's stem cells are found, in very small numbers, in the bodies of adult animals and humans. They are a source for replacing supplies of cells as they die out.