By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - Scientists said Friday they had
developed a new way to grow human brain cells for use in
transplants, and said cells grown this way had fixed brain
defects in mice.
They hope their new technology can lead to better ways to
treat a range of brain damage, from Parkinson's disease to
paralysis caused by stroke.
Evan Snyder of Harvard Medical School in Boston and
colleagues got human fetal brain cells to grow in a laboratory
dish, transplanted them into the brains of newborn mice -- where
they grew and seemed to work. The mice seemed normal.
There are two achievements here -- the development of the
perpetual line of human brain cells, and getting them to spread
around, grow and operate correctly in the brains of mice.
``This kind of thing can put fetal tissue out of business,''
Snyder, who reported his findings in the journal Nature
Biotechnology, said in a telephone interview.
Researchers have made headlines by injecting brain cells
from aborted fetuses into the brains of Parkinson's patients,
and finding these cells seem to help the patients.
But the use of fetal tissue is controversial, and getting a
good supply of clean cells at the right time is hard.
Snyder's team used brain cells from a single aborted or
miscarried fetus -- he does not know which -- and got them to
grow in the laboratory. The cells grow and die perpetually.
``We got this tissue and we've never had to go back to a
fetus again,'' Snyder said. ``It's a pure culture, abundant, and
the cells can be manipulated. We can do genetic manipulation on
them. Perhaps we can engineer them to be the right cells (for a
specific treatment).''
And the cells are useful, Snyder's team found.
``We wanted to show that they do engraft, they behave
normally, the mice are normal,'' he said. ``These cells should
be useful for human therapies.''
Tests in humans are a long way off, but Snyder ran a battery
of trials in mice to see what the cells can do.
They used mice that had a genetic mutation that leads to the
equivalent of Tay-Sachs disease, an untreatable genetic disease
that causes the brain to deteriorate. Victims die by age 3 or 4.
Human brains cells put into a dish with brain cells from
such genetically engineered mice -- but separated by a membrane
-- produced enzymes that corrected the defects in the mouse
brain cells.
They them injected their human cells into the brains of
mutant mice known as ``meander tail'' mice. They have a genetic
defect that causes many of their brain cells to be missing.
The human cells grew into their brains and replaced the
missing cells.
Although they worked with newborn mice, whose brains are
still developing, Snyder thinks the technique will work in
adults or children with damaged or diseased brains.
``We believe that in adults, certain injuries actually do
recapitulate certain developmental processes,'' Snyder said.
``It's sort of like re-seeding the lawn. It's using the
initial cells the brain was started with to fill in the gaps.''
In a second study in the same journal, Ronald McKay of the
National Institute of Neurological Disorders and Stroke in
Bethesda, Maryland, and colleagues in Germany and France did a
similar experiment with cells from aborted fetuses.
They placed them into the rat brains. The human neural cells
spread throughout the rats' brains and differentiated into
different kinds of cells.
Snyder said the experiments show that everything scientists
have been doing with rats and mice for years should work in
humans, too. ``It brings us closer to clonical (human) trials,''
he said.
^REUTERS(AT)