Published on: May 1, 2013
by Anna Salleh for ABC:
Blood tests could one day be used to tell who is at risk of developing Alzheimer’s disease, say researchers.
Dr Samantha Burnham, from SCIRO’s Preventative Health flagship in Perth, and colleagues, report their findings today in the journal Molecular Psychiatry. “We have a set of blood markers that estimate how much toxic protein people have in their brain,” says Burnham. “We’re hoping that this will develop into a population screening test.”
Alzheimer’s disease is the leading cause of dementia and affects 250,000 Australians – a number that is expected to grow to 1 million by 2050.
The disease is associated with the build up of a protein called amyloid beta in the brain, which Burnham and colleagues recently found occurs 17 years before dementia symptoms appear. Burnham and colleagues’ latest research focused on finding ways to predict who is at risk of amyloid build up.
Burnham says this will be important once a treatment is actually developed.
“To make a real difference to people suffering from Alzheimer’s disease we’re going to need to give them treatment quite early on,” says Burnham.
“We need to be able identify people before they have clinical symptoms, which is when Alzheimer’s disease is normally picked up.”
Blood samples and brain scans
The researchers used data from the Australian Imaging and Biomarkers Lifestyle Study (AIBL), which is following 11,000 people, aged 60 years and over.
The researchers looked at blood samples from 273 participants who also had brain scans to assess the levels of amyloid protein in the brain.
Burnham and colleagues found seven proteins in the blood samples that, together with a person’s age and cognitive test results, could be used to develop a mathematical formula to predict levels of amyloid in the brain with 80 per cent accuracy.
They validated their findings by showing the formula correctly predicted the level of amyloid protein in the brains of 82 people, from a separate brain scan study.
The researchers are also in the process of fully validating the formula on the other participants in the AIBL study.
At this stage Burnham and colleagues are not sure how the blood markers relate to Alzheimer’s disease.
A patent has been filed by Burnham and two other colleagues covering the blood marker formula and two of the research team members are consultants with Prana Biotechnology.
‘Verified by the data’
Neuroscientist Dr Bryce Vissel of the Garvan Institute of Medical Research welcomes the conclusions that blood markers could be used to predict people’s risk of Alzheimer’s.
“It looks to be verified by the data,” says Vissel.
He supports the findings despite his argument that inflammation rather than amyloid protein is more likely to cause Alzheimer’s disease.
“Regardless of whether the amyloid hypothesis is right or not we actually need to start treatment a lot earlier and we have to find better ways to diagnose the disease.”
Vissel says while there is some debate about whether amyloid is the best early marker of Alzheimer’s disease, he agrees amyloid plaque appears in the brain of the vast majority of people with the condition.
“No one debates amyloid load is a good indicator of Alzheimer’s. Whether it’s the cause of Alzheimer’s is another issue.”
Vissel says he is excited by the findings that blood markers found by Burnham include markers he associates with inflammation.
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