Secrets of the brain revealed

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.

"But Alzheimer's disease is a form of dementia that we now know is caused by a disease. Once you say it's a disease, it's not an inevitable process of growing old.

"If it's caused by a disease, therefore there must be a cause, and therefore there must be a cure."

Studies showed that putting animals in more challenging environments boosted the number of new brain cells they generated.

"Rats that have running wheels or bits of paper to tear up make more brain cells," Professor Faull said.

"So 'use it or lose it' is an important message. The more supportive the environment, the more active you keep your brain, the longer you are going to keep your brain."

He said the discovery was only possible because families of brain disease patients provided the brains of loved ones within hours of death.