The new work by American scientists could also help in cases of Parkinson’s and dementia.
A new blood test can detect “toxic” proteins years before Alzheimer’s symptoms appear, according to a study published in the journal Proceedings of the National Academy of Sciences (PNAS).
Led by the washington university (United States), the work confirms that the test -still in trial- could help identify those individuals at risk or who are beginning to develop the disease, and open the door to the development of early treatments for Alzheimer’s.
Today, patients are generally diagnosed only after presenting with well-known signs of the disease, like memory loss describes a statement from the aforementioned university, which recalls that at that time the best treatment options are limited to slowing down the progression of symptoms.
But research has shown that the “seeds” of Alzheimer’s “planted” years before – even decades – long before the appearance of cognitive disorders that make diagnosis possible today.
These seeds are amyloid beta proteins They misfold and clump together to form small aggregates called oligomers. Over time, through a process scientists are still trying to understand, these “toxic” oligomers of beta amyloid are thought to develop into Alzheimer’s.
In the article published the day before yesterday, the team from the University of Washington describes a laboratory test which can measure the levels of amyloid beta oligomers in blood samples.
The researchers tested the test – known by the acronym SOBA– in blood samples from 310 subjects who had previously provided them, as well as some of their medical records for Alzheimer’s research.
At the time the samples were taken, the subjects were registered as no signs of cognitive declinemild cognitive impairment, Alzheimer’s disease, or another form of dementia.
SOBA detected oligomers in the blood of individuals with mild cognitive impairment and moderate to severe Alzheimer’s. In 53 cases, the diagnosis of the subjects was verified after of death by autopsy, and blood samples from 52 of them, which had been taken years before their deaths, contained toxic oligomers.
SOBA also detected oligomers in members of the control group who, according to the records, subsequently developed mild cognitive impairment.
“What doctors and researchers wanted was a reliable diagnostic test for Alzheimer’s, and not just one that would confirm the diagnosis, but one that could also detect signs of the disease before cognitive decline occurred,” says lead author Valerie Daggett. “What we show here is that SOBA can be the basis of such a test,” he added.
And how does the test work? When misfolded amyloid beta proteins begin to assemble into oligomers, they form a structure known as an alpha sheet; these sheets tend to stick together to other alpha sheets.
SOBA’s core is a synthetic alpha sheet that can bind to oligomers in cerebrospinal fluid or 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 novel platform is designed to selectively bind toxic oligomers, “which is like finding a needle in a haystack“, according to Daggett.
The team is now working with scientists from AltPep, a biotech company derived from the University of Washington, to convert SOBA into a diagnostic test for oligomers.
The study also showed that SOBA could be easily modified to detect toxic oligomers of other types of proteins associated with Parkinson’s and Lewy body dementia. EFE