Although Alzheimer’s disease is present decades before the first symptoms appear, the vast majority of patients are diagnosed after showing the first signs, such as memory loss. The problem is that the treatments, in this phase, only delay the progression of the symptoms.
It is known that in Alzheimer’s disease it occurs, among other reasons, because amyloid beta proteins misfold and clump together, forming small aggregates called oligomers. Over time, through a process scientists are still trying to understand, these ‘toxic’ oligomers of beta amyloid are thought to cause Alzheimer’s.
For years, researchers have been trying to identify the disease long before symptoms appear, and it appears that a team led by researchers from the University of Washington (USA) and the biotech company AltPep Corporation has taken a very important step. for early detection of Alzheimer’s.
As explained in a study published in The Proceedings of the National Academy of Sciences (PNAS), scientists have designed a laboratory test that can measure the levels of amyloid beta oligomers in blood samples.
The test, known by the acronym SOBA (soluble oligomer binding assay), could detect oligomers in the blood of patients with Alzheimer’s disease, but not in the majority of study participants, a control group, who had no symptoms of cognitive decline. at the time the blood samples were obtained.
But the SOBA test was able to detect oligomers in the blood of 11 individuals in the control group. Ten of these individuals were diagnosed years later with mild cognitive impairment or brain pathology consistent with Alzheimer’s disease.. That is, for these 10 individuals, SOBA had detected the toxic oligomers before symptoms arose.
The search for a reliable diagnostic test for Alzheimer’s disease that can detect signs of the disease before cognitive decline occurs has been sought for years. “What we show here is that SOBA may be the basis for such a test,” notes lead author Valerie Daggett.
SOBA exploits a unique property of toxic oligomers. When misfolded amyloid beta proteins begin to clump together into oligomers, they form a structure known as alpha sheet. Alpha sheets do not exist in normal situations, and Daggett’s team’s previous research showed that alpha sheets tend to attach to other alpha sheets.
The test contains a synthetic alpha sheet designed by this team that can bind to oligomers in cerebrospinal fluid or blood samples. The test uses standard methods to confirm that the oligomers attached to the test surface are made up of amyloid beta proteins.
The test detected oligomers in the blood of people with mild cognitive impairment and moderate to severe Alzheimer’s
The team tested their test on blood samples from 310 people donated years before.. At the time the blood samples were taken, the volunteers had no signs of cognitive impairment, mild cognitive impairment, Alzheimer’s disease or any other form of dementia.
SOBA detected oligomers in the blood of people with mild cognitive impairment and moderate to severe Alzheimer’s. In 53 cases, the investigational Alzheimer’s diagnosis was verified by autopsy after death, and blood samples from 52 of them, which had been taken years before death, contained toxic oligomers.
But in addition, the test discovered oligomers in those members of the control group who, according to available medical records, subsequently developed mild cognitive impairment. Blood samples from other individuals in the control group that remained intact lacked toxic oligomers.
The researchers say the test can be modified to detect toxic oligomers of another type of protein associated with Parkinson’s disease and Lewy body dementia.
Test could help identify people at risk of developing the disease
“We are discovering that many human diseases are associated with the accumulation of toxic oligomers that form these alpha sheet structures; not only Alzheimer’s, but also Parkinson’s, type diabetes, etc. Daggett says. ANDWe hope that this method can help diagnose and study many other diseases caused by protein misfolding.».
“The research highlights the unique and broad potential of the AltPep platform to address multiple amyloid diseases,” said Chad Robins, AltPep Board Member and Co-Founder and CEO of Adaptive Biotechnologies.
“We believe that SOBA could help identify people at risk of developing the disease, as well as serve to monitor therapeutic efficacy to aid in the development of treatments for Alzheimer’s,” adds Daggett.