Smoking Gun For Alzheimer's Disease

The research is significant because drugs that are in the advanceddevelopmental phase for other conditions might be able to be used onAlzheimer's patients, to halt the disease progressing. At present,there are only minimally effective treatments for the condition, whichis increasing with the ageing population.

"We found that all of the brains of dementia patients showedquinolinic acid neurotoxicity," said Professor Bruce Brew, Director ofNeurology at St Vincent's Hospital and Professor of Medicine at theUniversity of New South Wales (UNSW). "This acid kills nerve cells inthe brain, leading to brain dysfunction and ultimately death."

There are currently more than 200, 000 people with Alzheimer's disease in Australia. The number will exceed 730, 000 by 2050.

"Quinolinic acid is part of a biochemical pathway called thekynurenine pathway," said the lead author of the research, UNSW's DrGilles Guillemin, who is based at the Centre for Immunology at StVincent's Hospital. "The activation of that pathway is also found inother major brain diseases including Huntington's disease, stroke,dementia and schizophrenia."

The paper Indoleamine 2, 3 dioxygenase and quinolinic acidImmunoreactivity in Alzheimer's disease hippocampus has been publishedthis week in the leading international journal Neuropathology andApplied Neurobiology. It is the result of collaboration betweenresearchers from St Vincent's Hospital, UNSW, the University of Sydneyand Hokkaido University, Japan.

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

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

"Quinolinic acid may not be the cause of Alzheimer's disease,but it plays a key role in its progression," said Alzheimer'sresearcher, Dr Karen Cullen from the University of Sydney. "It's thesmoking gun, if you like.

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

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