Brain cells converted to blood vessels?

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Brain cells converted to blood vessels?

Report could broaden debate over stem-cell research

WASHINGTON - Primordial brain cells may be coaxed into changing their

character completely, U.S. and Japanese researchers reported Wednesday

in a report that could broaden the debate on stem cell research.

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They found that in mice, stem cells from the brain turned into blood

vessel cells when they were incubated together with blood vessel

cells.

The finding, published in this week's issue of the journal Nature,

contradicts other findings that suggested so-called adult stem cells

cannot truly change their character.

One big hope is to create tailor-made transplants of organs and tissue

to treat a range of diseases.

Fred Gage and colleagues at the Salk Institute in La Jolla, Calif.,

and Kumamoto University in Japan teased out the stem cells from the

brains of mice.

Those neural stem cells are primitive cells that give rise to various

brain cells, including neurons and glial cells.

Fused cells or stem cells?

Some studies had suggested they could also be coaxed into changing

into other types of cells, such as muscle cells, but later research

showed they were fusing with other tissues, not truly changing type.

" Resolving this issue is important, because fused cells may have a

different therapeutic potential than stem cells that differentiate

into new cells, " said Bradley Wise of the National Institute on Aging,

which funded the study.

" While this new finding doesn't fully answer this vital question, it

keeps open the possibility that adult stem cells from different organs

one day may be harnessed to help prevent and treat neurological

disorders. "

Gage's team grew mouse brain stem cells in the same culture dishes

with human endothelial cells, which form the lining of blood vessels.

About 6 percent of the mouse neural stem cells grew to look like

endothelial cells.

The cells kept their mouse characteristics and had only mouse

chromosomes, which suggested they had converted into a different type

of cell rather than merging with a human endothelial cell, Gage's team

reported.

When transplanted into the brains of mouse embryos, just under 2

percent of the brain stem cells turned into endothelial cells rather

than brain cell types, the researchers said.

The issue is more than just an esoteric debate among scientists.

Researchers around the world are racing to find the best way to

harness stem cells to use in medicine and biology.

Opponents of using human embryos as a source of those powerful cells

argue that adult stem cells may be just as useful.

Earlier Wednesday, Health and Human Services Secretary Tommy

wrote in a letter to lawmakers that the government stood firm on its

policy that taxpayers who oppose destroying human embryos should not

be forced to pay for it.

" The National Institutes of Health will create a National Embryonic

Stem Cell Bank that will provide a ready source of human embryonic

stem cells to scientists, ensure consistent quality of the lines and

provide other technical support that will make it easier for

scientists to use federally approved stem cells, " he wrote.

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