Further research is needed and such a test is probably still available, but scientists say the results are promising.
“This research is an exciting step towards the development of blood tests that could help identify Alzheimer’s disease by targeting specific subtypes of tau, one of the key proteins that will become abnormal as a result of changes in Alzheimer’s disease in the brain,”; Clive said. Ballard, a professor of age-related diseases at Exeter Medical School in the UK who did not take part in the study.
“A reliable blood test for Alzheimer’s disease would be a huge stimulus for dementia research, allowing scientists to test treatment at a much earlier stage, which could lead to a breakthrough for people living with dementia,” she said. Rosa Sancho, Head of Research at Alzheimer Research Research UK, who also did not participate in the study.
You’re looking for a mutant protein
In a three-part study, researchers from the United States and Sweden measured an abnormal version of the tau protein called p-tau217 and found more 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.
“Tau protein is modified and aggregated in the brains of people with Alzheimer’s disease and some frontotemporal dementias, and some of this tau protein leaks from the brain into the bloodstream,” said Tara Spiers-Jones, deputy director of the Center for Discovery Brain Sciences at the University of Edinburgh. did not participate in the study.
Researchers claim that blood tests can distinguish Alzheimer’s disease from other types of dementia and Parkinson’s disease with a high degree of accuracy – 89% to 98%.
In addition, measuring p-tau217 levels may also be able to detect brain changes 20 years before the onset of dementia symptoms.
“This test, after validation and confirmation, opens up the possibility of early diagnosis of Alzheimer’s disease before the dementia stage, which is very important for clinical trials that evaluate new therapies that could stop or slow the disease process,” Oskar Hansson from Lund University in Sweden, wrote.
“These two documents contribute to the growing evidence that modified tau proteins in the blood can accurately reflect Alzheimer’s disease in the processes that occur in the brain,” said Amanda Heslegrave, chief researcher at the Dementia Research Institute in the UK in London. was not involved in the study.
In the doctor’s office
The formation of brain proteins, amyloid and tau, into clusters of amyloid plaques and tau tangles, are determinative of the physical properties of Alzheimer’s disease, but are difficult to detect without expensive PET or invasive spinal cock examinations, none of which are commonly insured.
Verbal and written tests of memory and cognitive impairment, combined with interviews with patients’ family members and carers about their behavior, remain with the physician. This approach makes it difficult to accurately diagnose Alzheimer’s disease unlike other types of cognitive impairment.
In addition, brain scans and spinal cords can only identify beta amyloid plaques, not tau protein. Experts say 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 is able to detect amyloid plaques and tau tangles and is very specific for Alzheimer’s disease.
A third abstract presented at the Alzheimer’s Disease Conference found that the test could distinguish between less common frontotemporal dementia, which affects younger people and leads to behavioral and personality changes rather than memory loss, and Alzheimer’s disease, illustrating the diagnostic capabilities of the test. These include changes in personality, behavior and language difficulties.
“These studies (and others) show that blood-based tau is a marker of amyloid pathology. Very interesting and not what could be predicted 5 years ago, “said John Hardy, President of Molecular Biology of Neurological Diseases at University College London.
This progress means that in the coming years, the day may come when your healthcare provider can do a blood test for Alzheimer’s disease while you are in the doctor’s office.
“It’s very exciting because we all know that blood tests are really important and that they are needed as a first pass at the clinic in your GP office,” said Maria Carrillo, chief physician of the Alzheimer’s Association.
And unlike current detection methods, blood tests could be more easily scaled to test a lot of people at a much lower cost.
Early detection and treatment before severe Alzheimer’s disease in the brain occurs would be a change in the game for individuals, experts said. The test could also help identify suitable people for clinical trials of drugs.
“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 while promising, a blood test should also be tested in asymptomatic people and larger populations.
“We now need longer and larger studies to confirm these results and see if this test could 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 research looks extremely promising, further validation is still needed in people from more routine clinical settings, and a lot of work will be needed to achieve standardization of the test in laboratories.
“It may take at least another five years before we see an accurate test of blood biomarkers for dementia at the clinic.”