A simple blood test may be able to detect a "toxic" protein many years before a person starts to display symptoms of Alzheimer's.
Researchers at the University of Washington (UW) have developed a test that can spot the dangerous clumps of protein, called amyloid beta, long before symptoms such as memory loss show up.
At the moment, people tend to get diagnosed with Alzheimer's after they start to develop symptoms. But by that point, the best treatment option is only to slow down the progression of the disease, rather than prevent it.
Scientists believe that the 'seeds' of Alzheimer's are planted years before any well-known signs of the illness start to happen.
These amyloid beta proteins can clump together, forming something called oligomers, which are though to develop into Alzheimer's over time.
In a new study, researchers at UW say that their new blood test could detect oligomers in the blood of patients with Alzheimer’s, but not in most members of a healthy trial group who showed no signs of cognitive impairment at the time the blood samples were taken.
And the test was even able to detect the toxic proteins in the blood of 11 people from the non-Alzheimer’s group - all of which were later diagnosed with mild cognitive impairment or brain pathology consistent with the disease.
Essentially, for these 10 people, the test - known as SOBA - had detected the toxic oligomers before symptoms surfaced, the scientists say.
Senior author Valerie Daggett, a UW professor of bioengineering and faculty member in the UW Molecular Engineering & Sciences Institute, said: "We believe that SOBA could aid in identifying individuals at risk or incubating the disease, as well as serve as a readout of therapeutic efficacy to aid in development of early treatments for Alzheimer’s disease."
She added: "What clinicians and researchers have wanted is a reliable diagnostic test for Alzheimer’s disease – and not just an assay that confirms a diagnosis of Alzheimer’s, but one that can also detect signs of the disease before cognitive impairment happens.
"That’s important for individuals’ health and for all the research into how toxic oligomers of amyloid beta go on and cause the damage that they do.
"What we show here is that SOBA may be the basis of such a test."
SOBA, which stands for soluble oligomer binding assay, exploits a unique property of the toxic oligomers, researchers say.
When the oligomers are formed, they form a structure known as an alpha sheet – which tends to stick to other alpha sheets. The test features a synthetic alpha sheet that can bind to those detected in blood samples.
The test then uses standard methods to confirm that the oligomers attached to the test surface are made up of amyloid beta proteins.
The team tested SOBA on blood samples from 310 research subjects who had previously made their blood samples and some of their medical records available for Alzheimer’s research.
They detected oligomers in the blood of people with mild cognitive impairment and moderate to severe Alzheimer’s.
The findings are published in the Proceedings of the National Academy of Sciences.
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