New blood tests could revolutionize the diagnosis and treatment of Alzheimer’s disease. In addition to confirming the presence of the disease, this test also helps determine the stage of its progression. This could fundamentally change the way doctors manage their care for Alzheimer’s.
This test was developed by experts in Washington University School of Medicine, St. Louis Lund University, Sweden. Their research shows that a specific blood protein, MTBR-TAU243, can be used to monitor the extent of dangerous tau accumulation in the brain.
Tau protein tangles are part of the characteristics of Alzheimer’s disease and are directly proportional to the intensity of the symptoms.
This new technique is much more convenient than brain scans as it is non-invasive and does not require expensive procedures that are difficult to access.
Blood tests track Alzheimer’s disease
Currently, doctors can use several blood tests to detect Alzheimer’s disease. Some of the tests already in use are based on previous findings at the University of Washington.
These tests look for early warning signs, but do not reveal how far the disease has progressed. That’s an important gap. Treatment of Alzheimer’s disease is most useful in the early stages before too much damage occurs.
Having a way to know if someone is in the early or late stages of the illness helps doctors decide which treatments are most effective. It can also clarify whether a person’s memory or thought problems are actually caused by Alzheimer’s disease or something.
“This blood test clearly identifies Tau Tangle in Alzheimer’s, which is our best biomarker measure of Alzheimer’s symptoms and dementia,” said co-author Dr. Randall J. Bateman.
“There are no easy or accessible measurements of Alzheimer’s or dementia in current clinical practice. Therefore, if symptoms are caused by Alzheimer’s and the physician can help determine which treatment is best for the patient, such intertwined blood tests may provide better indications.”
A reliable way to monitor illness
Alzheimer’s disease usually starts with the accumulation of amyloid proteins in the brain. It marks when tau tangles develop later and symptoms begin to appear.
The best way to see these changes was through PET scans that could track amyloid and tau deposits. However, these scans are expensive, time-consuming and are often only available in large hospitals and research centers. That’s why scientists have been working on blood-based alternatives.
The team was already developing blood tests to measure amyloid plaque accumulation. Previous studies have shown that levels of MTBR-TAU243 in spinal fluid may be consistent with brain tau levels.
In this new study, researchers demonstrated that blood samples could be used to obtain the same results. Blood draws are much easier and more accessible than spinal snakes.
Testing a new approach
To validate the test, researchers used data from two groups of people. One group came from the University of Washington Research Center and included 108 volunteers. Other groups included 55 people from a Swedish study known as Biofinder-2.
Experts then checked the findings with data from 739 additional people in the Biofinder-2 group.
These participants represent stages of Alzheimer’s disease, from those without symptoms but with brain amyloid, to those with mild cognitive problems, to those with dementia.
This study also included individuals with memory and thought problems due to other conditions, as well as cognitively healthy individuals.
The progression of Alzheimer’s disease has been revealed in blood
The results were promising. MTBR-TAU243 levels in the blood coincided with the amount of tangles in the brain with a 92% accuracy.
Levels were normal in healthy people and in the earliest stages of illness. However, protein levels are clearly elevated in people with symptoms, and much higher in people with progressive disease.
This difference made it easy to see who was in the early or late stages of Alzheimer’s disease. It also helped to distinguish dementia in Alzheimer’s disease from other types of cognitive problems.
Such clarity can make a significant difference in choosing the right treatment path.
The new test uses technology licensed by the University of Washington for C2N diagnostics. This previously developed a similar blood test for amyloid plaque. Previous tests were designed to detect another tau protein called P-TAU217.
“We believe that using blood-based P-TAU217 will determine whether an individual has Alzheimer’s disease, but we believe that MTBR-TAU243 will be a very valuable complement in both clinical settings and research trials,” said Oskar Hansson, professor of neurology at Lund University.
“If both of these biomarkers are positive, the likelihood that Alzheimer’s disease is the underlying cause of a person’s cognitive symptoms is significantly increased compared to cases where P-TAU217 is abnormal. This distinction is important in order to select the most appropriate treatment for each patient.”
I look forward to better treatment
Currently, there are two FDA-approved drugs that target brain amyloids to slow down Alzheimer’s disease. However, more treatments are being tested, including those aimed at tau proteins and other disease mechanisms.
Once these treatments become available, doctors will need reliable methods to match the appropriate treatment to each stage of the illness. Blood tests could be key to this shift towards personalized Alzheimer’s disease.
“We are about to enter the age of personalised medicine for Alzheimer’s,” says Kanta Holly, Associate Professor of Neurology at Wash Medicine.
“In the early stages where tau tangles are less, anti-amyloid therapy may be more effective than later stages. However, it may be more effective after the onset of dementia with high tau tangles, anti-tau therapy, or one of many other experimental approaches.”
“In addition to clinically available blood tests for staging, treatments working at different stages of the disease allow physicians to optimize treatment plans to suit each patient’s specific needs.”
The complete study was published in the journal Natural Medicine.
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