More research is needed, and such a test is likely to be available for years to come, but researchers say the results are promising.
“This study is an exciting step toward developing a blood test that could help detect Alzheimer’s disease by focusing on specific subtypes of tau, one of the key proteins that becomes abnormal as part of a change in Alzheimer’s disease in the brain,” said Clive Ballard, a professor of age. disease at the University of Exeter Medical School in the UK, who did not participate in the study.
“A reliable blood test for Alzheimer’s disease would be a huge stimulus for dementia research, allowing scientists to test treatments at a much earlier stage, which in turn could lead to a breakthrough for those living with dementia,” said Dr. Rosa. Sancho, head of research at Alzheimer’s Research UK, who also did not participate in the study.
Looking for a mutant protein
In a three-time study, researchers in the United States and Sweden measured an abnormal version of the tau protein called p-tau217 and found more of this modified tau in the blood of people with Alzheimer’s disease than in healthy participants.
How does tau get into the bloodstream? It appears to cross the blood-brain barrier.
“The Tau protein is modified and coalesced abnormally in the brains of people with Alzheimer’s disease and some fronto-temporal dementias. Some of this tau protein leaks from the brain into the blood,” said Tara Spears-Jones, deputy director of the Discovery Brain Science Center at the University of Edinburgh. did not participate in the study.
The researchers report that a blood test can distinguish Alzheimer’s disease from dementia and other Parkinson’s diseases with a high degree of accuracy – from 89% to 98%.
In addition, measuring the level of p-tau217 can also detect brain changes 20 years before the onset of dementia symptoms.
“Once tested and confirmed, this test opens the possibility of early diagnosis of Alzheimer’s disease before dementia, which is very important for clinical trials evaluating new therapies that can stop or slow the disease,” the researchers said. Written by Oscar Hanson of Lund University in Sweden.
“These two documents add growing evidence that modified tau proteins in the blood can accurately reflect Alzheimer’s disease in brain processes,” said Amanda Gesglegrave, a senior fellow at the British Dementia Research Institute at University College London, who was not involved in the study.
In the doctor’s office
The formation of brain proteins, amyloid and tau, in clusters of amyloid plaques and tau balls determine the physical characteristics of Alzheimer’s disease, but they are difficult to detect without expensive PET scans or invasive spinal taps, none of which are usually covered by insurance.
Physicians remain verbal and written memory tests and cognitive impairments combined with interviews with patients’ family members and caregivers. This approach complicates the accurate diagnosis of Alzheimer’s disease as different from other types of cognitive impairment.
In addition, brain scans and spinal outflows can only identify beta-amyloid plaques, not tau protein. Experts believe that the tau test is important – beta-amyloid alone is not enough to diagnose Alzheimer’s disease, because some people with high levels do not develop neurological disease.
The new blood test can detect both amyloid plaques and tau turbidity and is very specific for Alzheimer’s disease, experts say.
A third synopsis presented at the Alzheimer’s Conference showed that the test can distinguish between less common frontotemporal dementia, which affects young people and leads to changes in behavior and personality rather than memory loss, and Alzheimer’s disease, which illustrates the test’s diagnostic abilities. These include personality changes, behaviors, and language difficulties.
“These studies (and others) show that blood-based tau is a marker of amyloid pathology. Very interesting, but not what would have been predicted 5 years ago,” said John Hardy, head of molecular biology of neurological diseases at University College London.
These achievements mean that the day may come in the next few years when your doctor will be able to do a blood test for Alzheimer’s disease while you are in the hospital, experts say.
“It’s very exciting, because we all know that blood tests are really important and they are needed as the first pass in the clinic, in the general practice,” said Maria Carrillo, chief physician of the Alzheimer’s Association.
And unlike modern detection methods, blood tests could be more easily increased to test many people at a much lower cost.
Experts note that early detection and treatment before the brain is severely damaged by Alzheimer’s disease will be a change of game. The test can also help identify the right people for clinical drug trials.
“We know that brain changes in Alzheimer’s disease can occur decades before symptoms begin to appear, and the early stages of the disease are likely to be the time when future drugs will be most effective,” Sancho said.
Carrillo and other experts warn that, despite the prospects, blood tests should still be tested among asymptomatic people and the general population.
“We now need longer and more extensive research to confirm these results and see if this test can accelerate our ability to develop new treatments for Alzheimer’s disease in the future.” said Fiona Carragher, director of policy and research at the Alzheimer’s Society in the UK.
Ballard agrees: “Although this study looks extremely promising, further validation of people with more routine clinical conditions is still needed, and much work will be needed to achieve standardization of the test in laboratories.
“Thus, it may take at least another five years before we see an accurate analysis of blood biomarkers for dementia in the clinic.”