Test Could Detect Alzheimer’s A Decade Before
Scientists say that identifying Alzheimer’s disease in its early stages is quite challenging. By the time Alzheimer’s is diagnosed, memory loss, behavioral changes, and other symptoms of this neurodegenerative disorder may have occurred. Nevertheless, researchers are working hard to overcome this challenge.
Researchers at the University of Pittsburgh School of Medicine say their new biomarker task could identify signs of Alzheimer’s disease up to 10 years early, which could improve diagnosis and treatment options.
“Our test identifies very early stages of tau tangle formation—up to a decade before any tau clumps can show up on a brain scan,” senior study author Thomas Karikari, an assistant professor of psychiatry at Pitt School of Medicine, said in a statement about the test.
The new Pitt biomarker test can detect small amounts of the clumping-prone tau protein and its misfolded pathological forms, which litter the brain, cerebrospinal fluid, and potentially blood, according to the study, published in February in the journal Nature Medicine.
Tau is a protein found in neurons in the brain that helps stabilize nerve cells. Tau can clump into tangles and cause cell damage. These irregular tau clumps are known as neurofibrillary tangles, a hallmark of Alzheimer’s disease. The abnormal buildup of tau and another protein, amyloid beta, in the brain can disturb cell function and cause cognitive decline.
According to the Alzheimer’s Association, nearly seven million Americans age 65 and older are living with Alzheimer’s disease, a progressive neurodegenerative disease that affects memory, thinking, and behavior. Alzheimer’s is the most common form of dementia and can severely disrupt an individual’s daily living activities as the disease’s symptoms worsen. While there is no known cure for Alzheimer’s, certain medications can help slow cognitive decline.
An Alzheimer’s diagnosis usually involves cognitive assessments, brain scans, and blood tests since no single test can provide a conclusive result. Tau PET imaging, a procedure involving a radioactive tracer that visualizes tau protein deposits in the brain, is also used to diagnose Alzheimer’s disease. According to the University of Pittsburgh research team, tau-PET scans can pick up the signal from neurofibrillary tangles only when a large number are present in the brain, at which point the degree of brain pathology has become pronounced and is not easily reversible. Additionally, the tau PET scan is not used too often in routine clinical practice due to high cost, unreliable detection of early stages of tau pathology, and the need for specialized imaging centers.
The new Pitt test involves a spinal tap, a procedure that involves inserting a needle into the lower back to extract cerebrospinal fluid and examining it for clumping-prone tau. The research team identified the core region of the tau protein where tau molecules can abnormally bind together and form tangles. According to the study, identifying the clumping-prone tau proteins can help initiate further diagnostics and early treatment.
“Early detection of tangle-prone tau could identify the individuals who are likely to develop Alzheimer ‘s-associated cognitive decline and could be helped with new generation therapies,” Karikari said.
While other tests measure amyloid-beta plaque levels in the brain, Karikari highlighted tau aggregation as a more significant indicator of Alzheimer’s disease.
“Amyloid beta is a kindling, and tau is a matchstick,” Karikari explained. “A large percentage of people who have brain amyloid-beta deposits will never develop dementia. But once the tau tangles light up on a brain scan, it may be too late to put out the fire, and their cognitive health can quickly deteriorate.”
SOBA Method Could Lead To Early Detection Of Alzheimer’s Disease
A team of researchers at the University of Washington (UW) developed a laboratory test to measure amyloid beta oligomer levels in blood samples. Oligomers are amyloid beta proteins that misfold (adopt an abnormal shape), clump together, and form small aggregates. These “toxic” amyloid beta oligomers are thought to develop into Alzheimer’s disease.
As part of the study, the UW research team tested whether the Soluble Oligomer Binding Assay (SOBA), could detect amyloid beta oligomers in blood samples of more than 300 people who were diagnosed as having no cognitive impairment, mild cognitive impairment, Alzheimer’s disease, or other forms of cognitive impairment. The individuals without cognitive impairment served as the control group. SOBA detected toxic oligomers in 52 out of 53 people with mild cognitive impairment and moderate to severe Alzheimer’s disease.
While SOBA did not detect oligomers in most of the control group, it did detect oligomers in 11 individuals. Follow-up examination records were available for 10 of these individuals, and all were diagnosed years later with mild cognitive impairment or brain pathology consistent with Alzheimer’s disease. Basically, for these 10 individuals, SOBA detected the toxic oligomers before any symptoms appeared.
“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,” senior author Valerie Daggett, a professor of bioengineering and faculty member in the UW Molecular Engineering & Sciences Institute, said in a statement about the study. “What we show here is that SOBA may be the basis of such a test.”
The team also measured conventional Alzheimer’s disease biomarkers in cerebrospinal fluid samples from the same people. None of these correlated with the state of the disease as well as the SOBA method did.
According to the research team, SOBA distinguished Alzheimer’s disease from other forms of cognitive impairment. The researchers also stated that SOBA could be modified to detect Parkinson’s disease and Lewy body dementia, both of which involve toxic protein oligomers.
According to the study, SOBA could lead to earlier diagnosis of Alzheimer’s and related diseases by detecting toxic proteins in the blood before cognitive impairment occurs.
“We believe that SOBA could aid in identifying individuals at risk or incubating the disease,” Daggett said, “as well as serve as a readout of therapeutic efficacy to aid in the development of early treatments for Alzheimer’s disease.”
Source Links:
https://nypost.com/2025/02/20/health/new-test-could-detect-alzheimers-sign-a-decade-before-brain-scans/
https://www.medschool.pitt.edu/news/biomarker-test-can-detect-alzheimers-pathology-earlier-pitt-study-shows
https://www.alz.org/news/2020/more-women-get-alzheimer-s-than-men-why
https://www.nih.gov/news-events/nih-research-matters/blood-test-early-alzheimer-s-detection
https://www.washington.edu/news/2022/12/05/alzheimers-blood-test/
