'While we won't be able to prevent people from getting Alzheimer's disease, we may eventually, with the use of drugs, be able to slow down the progression.'

Drugs that are already in the advanced developmental phase for other conditions also might be appropriate for use with Alzheimer's patients, the researchers suggest, based on their latest findings.

This possibility could offer new hope for those suffering from the condition -- a group that is increasing as the population ages. At present, the only treatments available are minimally effective.

Acid Kills Nerve Cells

"We found that all of the brains of dementia patients showed quinolinic acid neurotoxicity," said Professor Bruce Brew, Director of Neurology at St. Vincent's Hospital and Professor of Medicine at the University of New South Wales (UNSW).

"This acid kills nerve cells in the brain, leading to brain dysfunction and ultimately death," he explained.

"Quinolinic acid is part of a biochemical pathway called the kynurenine pathway," said the lead author of the research, UNSW's Dr. Gilles Guillemin, who is based at the Center for Immunology at St. Vincent's Hospital.

"The activation of that pathway is also found in other major brain diseases, including Huntington's disease, stroke, dementia and schizophrenia," he noted.

"There are several drugs which can block this pathway, which are already under investigation by our laboratory and others," said Dr. Guillemin.

The drugs, which would need to be tested for efficacy, could be used to complement other treatments.

Key Role in Progression

"Quinolinic acid may not be the cause of Alzheimer's disease, but it plays a key role in its progression," said Alzheimer's researcher Dr. Karen Cullen of the University of Sydney.

"It's the smoking gun, if you like," she remarked.

"While we won't be able to prevent people from getting Alzheimer's disease," Dr. Cullen explained, "we may eventually, with the use of drugs, be able to slow down the progression."

The other researchers are Claire Noonan from Sydney University and Osamu Takikawa from Hokkaido University, Japan.