By SIMON COLLINS Science Reporter
New Zealand scientists have helped topple a long-held belief that our
brains start to decline from the teenage years.
A team at Auckland University's medical
school, led by Professor Richard Faull, has found that our bodies
actually create new brain cells when they are hit with brain disorders
such as Huntington's disease.
The discovery offers hope for eventual
treatment of previously incurable brain diseases such as Huntington's,
Parkinson's, Alzheimer's and epilepsy.
"Up till now the only thing we
have been able to tell patients with any certainty, once we have made a
diagnosis [of brain disease], is that they are going to get worse,"
Professor Faull said.
"To be able to turn that around
and say we've just found something which shows that the diseased brain
does make new brain cells, and if we can make that go faster, suddenly
you are holding a glimmer of hope."
The discovery is only a first step, and
Professor Faull said scientists faced "a pretty fundamental
challenge" to work out how to help brain cells multiply more
quickly.
But the discovery itself had
"turned around science by showing the brain can repair
itself".
"When I went to medical school I
was told that by the age of 15, whatever size of brain you had, that was
it for life, and you had to look after your brain because you were
gradually going to lose a few more brain cells each year."
That belief was first challenged five
years ago when United States researchers gave cancer patients a
"marker" that showed up on every new cell in their brains.
They were testing a drug and wanted to see whether it stopped tumours
growing.
The drug did not work and the patients
died. But when researchers opened the dead patients' brains, they found
the "new-cell" marker not only in the tumours but also in
other cells in a part of the brain called the hippocampus.
Professor Faull's team used a unique
"bank" of brains donated by the families of brain disease
victims to find that new cells are also generated in a region of the
brain called the basal ganglia, which co-ordinates movement.
Doctoral student Maurice Curtis and
other researchers used three stains as markers to test whether the new
cells were true brain cells, or neurons, rather than glia, the
connective cells which were thought to just help clean up the brain.
They found that the brains of patients
with Huntington's disease - a genetic disorder which makes victims
twitch - were generating both glia and neurons.
"The exciting thing is that the
human brain is creating increased numbers of new brain cells,"
Professor Faull said. "The problem, of course, is that for the
Huntington's patients, it's too little, too late. So we have to try and
see how we can enhance this process."
The discovery does not mean that
eventually we may live forever.
"We don't deny there is an ageing
process," Professor Faull said. "But it's not inevitable that
you are going to become dumber and dumber.
"Everyone thought senile dementia
was an inevitable process of ageing, that if you lived long enough you
would lose your marbles.
