A simple blood test can detect Alzheimer’s disease a long time before the first clinical symptoms appear
A two-tier method developed by researchers can help detect Alzheimer’s disease at a much earlier stage. The findings were published in the journal Alzheimer’s and Dementia: Diagnosis, Assessment and Disease Monitoring.
Alzheimer’s disease, the most frequent cause of dementia, can only be detected once the typical plaques have formed in the brain and thereafter, therapy is limited. However, the first changes caused by Alzheimer’s take place on the protein level up to 20 years sooner.
“This has paved the way for early-stage therapy approaches, where the as yet inefficient drugs on which we had pinned our hopes may prove effective,” said Professor Klaus Gerwert from the Department of Biophysics at Ruhr-Universität Bochum (RUB).
“We are now conducting in-depth research to detect the second biomarker, namely tau protein, in the blood, in order to supply a solely blood-based test in future”
In Alzheimer’s patients, the amyloid beta protein folds incorrectly due to pathological changes long before the first symptoms occur. Researchers successfully diagnosed this misfolding using a simple blood test; as a result, the disease can be detected approximately eight years before the first clinical symptoms occur. The test detects 71 percent of Alzheimer’s cases in symptomless stages, but at the same time provided false positive diagnoses for 9 percent of the study participants.
As a result, they have now introduced the two-tier diagnostic method. To this end, they use the original blood test to identify high-risk individuals. Subsequently, they add a dementia-specific biomarker, namely tau protein, to run further tests with those test participants whose Alzheimer’s diagnosis was positive in the first step. If both biomarkers show a positive result, there is a high likelihood of Alzheimer’s disease. Through the combination of both analyses, 87 percent of Alzheimer’s patients were correctly identified in the study and the number of false positive diagnoses reduced to 3 percent. The second analysis was carried out in cerebrospinal fluid that is extracted from the spinal cord.
“Now, new clinical studies with test participants in very early stages of the disease can be launched,” said Gerwert. “Recently, two major promising studies have failed, especially Crenezumab and Aducanumab – not least because it had probably already been too late by the time therapy was taken up. The new test opens up a new therapy window.”
“Once amyloid plaques have formed, it seems that the disease can no longer be treated,” said Dr. Andreas Nabers, head of the research group and co-developer of the Alzheimer’s sensor.
The blood test has been upgraded to a fully automated process. “We are now conducting in-depth research to detect the second biomarker, namely tau protein, in the blood, in order to supply a solely blood-based test in future,” concluded Klaus Gerwert.
