The Sydney Morning Herald
Thursday, August 16th. 2001
Human brain cells offer hope on diseases
By Deborah Smith, Science writer

Australian researchers have made a significant discovery which
could lead to self-repair of damaged brains or spinal cords,
avoiding the need to use ethically controversial human
embryonic stem cells.

The Melbourne team has succeeded in extracting stem cells
from the brains of  mice - master cells that can produce new
nerve cells in the adult brain.

The neural stem cells also changed into muscle cells under
the right laboratory conditions.

The Australian research, says team leader Dr Perry Bartlett,
offers  the first "unequivocal" evidence that adult stem cells
could develop into different tissue types, just like embryonic
cells.

Stimulating the body's own adult stem cells to repair organs
was a preferable approach to transplanting human embryonic
stem cells, which could require immunosuppressive drugs
to prevent rejection, said Dr Bartlett, of the Walter and
Eliza Hall Institute of Medical Research.

"This appears an easier way forward," he said.

The development comes less than a week after United States
President George Bush approved federal funding for research
into embryonic stem cells, which scientists believe can grow
into any type of human tissue.

They offer enormous potential to cure conditions such as
Alzheimer's disease, spinal cord injuries and diabetes.
But they are controversial because their extraction involves
the destruction of days-old human embryos.

While different kinds of adult stem cells are found in different
organs, they do not appear to be as versatile as embryonic
cells.

Dr Bartlett said one adult neural stem cell could generate
tens of thousands of new nerve cells. The challenge was to
find drugs that could stimulate this natural process, so the
brain could repair  damage caused by illnesses such as
Alzheimer's, stroke and Parkinson's.

"Now we have the cells in our hot little hands we can ask,
'What are the factors that regulate their change into normal
nerve cells?"'

The research is published today in the journal Nature.

Ten years ago it was scientific heresy to suggest the adult brain
could grow new nerve cells.

Then, in 1992, two teams, including Dr Bartlett's, showed that
mice had neural stem cells in their brains. They have since been
found in human brains.

Several studies have also shown that mammals are constantly
growing new brain cells, particularly in the olfactory lobes,
associated with smell, and in the hippocampus, where memories
are formed.

Team member Mr Rodney Rietze spent several years perfecting
the method for identifying and isolating the neural stem cells
from mice brains.

Three years ago, Mr Rietze discovered that neural stem cells
from mice could change into blood cells. Other studies have
shown different types of adult stem cells, such as blood and
skin stem cells, are also versatile, and can be transformed
into fat, muscle and nerve cells. But there had been debate
whether this was due to contamination.

The  experiment was convincing, Dr Bartlett said, because
they were able to observe a single purified neural stem cell
differentiate into a muscle cell. More than 50 per cent of the
neural stem cells were quickly converted into muscle cells.

In the US,  government funding will be confined to work on
previously harvested embryos - and prohibits any new ones
being used. Mr Bush even stopped short of approving stem
cell research using excess IVF embryos, which are routinely
discarded.

His decision was derided by scientists as excessively
conservative but he had faced intense lobbying from
right-to-life activists who believe the destruction of embryos
for stem cells is equivalent to abortion.

SOURCE: The Sydney Morning Herald
http://www.smh.com.au/news/0108/16/national/national102.html

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