CNN
—
Testing a person’s blood for a type of protein called phosphorylated tau (p-tau) may be able to screen for Alzheimer’s disease with “high accuracy” even before symptoms begin to appear, a new study suggests. research suggests.
The study involved testing blood for a key biomarker of Alzheimer’s disease called p-tau217, which is linked to other damaged proteins (beta-amyloid and tau) in the brains of Alzheimer’s patients. ) increases at the same time as it accumulates. Currently, to identify beta-amyloid and tau buildup in the brain, patients undergo brain scans or spinal taps, which are often inaccessible and can be expensive.
But this simple blood test was found to be up to 96% accurate at identifying elevated beta-amyloid levels and up to 97% accurate at identifying tau, according to a study published Monday in the journal did JAMA Neurology.
“What was impressive about these results was that blood tests were as accurate as advanced tests such as cerebrospinal fluid tests and brain scans in indicating Alzheimer’s disease pathology in the brain,” said Sweden. said Nicholas Ashton, professor of neurochemistry at the University of Gothenburg. said one of the study’s lead authors in an email.
Ashton said the study’s results are not surprising, as the scientific community has known for several years that using blood tests to measure tau and other biomarkers could potentially assess Alzheimer’s disease risk. he added.
“We are now nearing prime time for these tests, and this study shows that,” he said. Alzheimer’s disease, Brain disorders that affect memory and thinking skillsthe most common type of dementia, according to the National Institutes of Health.
Last year, the first blood test to assess beta-amyloid protein became available to consumers in the United States. AD detection, which can help people with mild cognitive impairment identify their risk of developing Alzheimer’s disease.Several Researchers are raising questions About the science behind the test. Quest Diagnostics, which operates the test, emphasizes that the test is not intended to diagnose Alzheimer’s disease, but that it can help assess a person’s risk of developing the disease. Says.
The test used in the new study was ALZpath pTau217 assayis a commercial tool developed by ALZpath, which provided the materials for research free of charge. The test is currently available for research use only, but Ashton said it is expected to be available for clinical use soon.
“This is a valuable discovery in blood-based biomarkers for Alzheimer’s disease and paves the way for the clinical use of the ALZpath pTau 217 assay,” said study co-author Kai Brenow of the University of Gothenburg. said Professor Henrik Zetterberg. press release. “This robust assay is already in use in multiple laboratories around the world.”
ALZpath estimates that the test could cost between $200 and $500.
“Robust and accurate blood-based biomarkers would enable a more comprehensive assessment of cognitive impairment in settings where advanced testing is limited,” the researchers wrote in the study. ing. “The use of blood biomarkers is therefore intended to enhance early and accurate Alzheimer’s disease diagnosis, leading to improved patient management and ultimately timely access to disease-modifying therapies.”
For example, the test showed “high accuracy” in identifying tau pathology in people who tested positive for beta amyloid, according to the study. It may help guide treatment decisions for patients considering beta-amyloid-targeted therapies, such as: Rekenbi and AduhelmBecause it may be less effective in patients with advanced tau disease, the researchers wrote.
“These results highlight the important role of plasma p-tau217 as an early screening tool in the management of cognitive impairment by highlighting those who may benefit from anti-amyloid immunotherapy.” the researchers wrote.
The study included data from 786 people, with an average age of 66 years, who completed brain scans and spinal taps, and also had blood samples taken. The data and those samples come from his Translational Biomarkers of Aging and Dementia, the Wisconsin Registry for Alzheimer’s Disease Prevention, and his Sant Pau Initiative on Neurodegeneration.
Some participants showed signs of cognitive decline during data collection, while others did not. Researchers from institutions in Sweden, the United States and other countries analyzed data from participants from February to June last year.
Researchers tested participants’ blood samples with the p-tau217 immunoassay and found that the blood test had similar results and accuracy in identifying abnormal beta-amyloid and tau as participants’ spinal taps and brain scans. I discovered what was shown.
Only about 20% of study participants had blood test results that were unclear in clinical practice and required further testing with imaging or spinal taps.
“This will significantly reduce costly and high-demand testing,” Ashton said in an email. Therefore, based on the study results, “we believe that blood tests and laboratory tests can make a final decision in 80%” of people being investigated for early signs of dementia.
But even though this study’s blood tests were found to be highly accurate at predicting whether someone has the key hallmarks of Alzheimer’s disease in their brain, that doesn’t mean everyone with the hallmarks will develop Alzheimer’s disease. .
Additionally, the p-tau test is specific to Alzheimer’s disease, so even if the test result is negative, if there are signs of cognitive impairment, this test may be used to diagnose vascular dementia, Lewy body dementia, etc. We cannot identify other possible causes of your symptoms.
“A negative blood test speeds up investigation of other causes of symptoms, which is equally important,” Ashton says.
Overall, blood tests for Alzheimer’s disease, such as the one described in the new study, can help diagnose both those experiencing early memory loss and before patients show signs or symptoms of the disease. . Brain changes can occur in about 20 years Before any obvious symptoms appear, said Dr. Richard Isaacson, principal investigator at the Florida Institute for Neurodegenerative Diseases and a preventive neurologist who was not involved in the study.
“In fact, this test is one of the best pieces of evidence available to date for a single test for Alzheimer’s disease,” Isaacson said of the study results. “This study brings us a very powerful step closer to implementing that test. And the great thing about this study is that it also looks at people before they develop symptoms.”
with signs symptoms of alzheimer’s disease Although it varies from person to person, memory problems are often the first sign of the disease, such as forgetting dates, getting lost, misplacing things, or having difficulty completing tasks such as bathing, reading, or writing. there is.
Isaacson has been studying blood biomarkers in people with no or minimal cognitive complaints, and says that testing blood samples for signs of Alzheimer’s disease is not recommended for people with regular high cholesterol. I liken it to how to take a blood test.
“People get cholesterol tested before they have a heart attack. People get cholesterol tested before they have a stroke. To me, this kind of testing is ultimately going to be given to people before they have cognitive symptoms.” “We believe it is best for the government to do so,” Isaacson said. And, “Similar to cholesterol testing, by tracking pTau217 levels over time, we can better understand how different treatments and lifestyle changes are working to better control Alzheimer’s disease.” You will be able to do it.”
Isaacson said getting tested for Alzheimer’s disease before symptoms appear can help people make “brain-healthy choices” and talk to their doctors about their individual risk factors. It takes time,” he said, adding that blood-based tests can be expensive. -More effective than performing brain scans or other testing methods.
“PET scans involve radiation and can cost upwards of $5,000. Spinal taps are great because they give more detailed information, but not everyone wants it and they are expensive and can cost more than $5,000. These blood tests are generally more affordable,” Isaacson said.
“Providing blood tests like this will also help democratize access for people, making it easier for health systems to more proactively manage the tsunami of dementia risk facing our society.” Just do it,” he said. “This is the key that opens the door to the field of Alzheimer’s disease prevention and preventive neurology.”
More than 6 million people in the United States have dementia caused by Alzheimer’s disease, According to the Alzheimer’s AssociationThe number of people affected is expected to double over the next 20 years, rising to approximately 13 million by 2050.
Get CNN Health’s weekly newsletter
In the future, adults over 50 may be recommended to have regular blood tests for Alzheimer’s disease. David Curtis, emeritus professor at University College London, was not involved in the new study.
“When effective treatments to prevent the progression of Alzheimer’s disease become available, it will be essential to be able to identify people at high risk before they begin to deteriorate.” We show that it may be possible to do this with a simple blood test, by measuring the levels of tau protein in the blood. This could potentially have a huge impact.” Curtis said. This was said in a statement distributed by the UK-based Science Media Centre.
“Everyone over the age of 50 could be tested regularly every few years in much the same way that we are currently tested for high cholesterol. Currently available Alzheimer’s disease treatments may be more effective in patients diagnosed this early,” he said. “But I think the real hope is that better treatments will also be developed. Combining a simple screening test with effective treatments for Alzheimer’s disease could have a dramatic impact on individuals and society.” I guess.”