German researchers from Ruhr-Universität Bochum (RUB) have developed a two-tier test which can help detect Alzheimer’s disease long before any plaques begin forming in the brain. Their report is published in the journal Alzheimer’s and Dementia: Diagnosis, Assessment and Disease Monitoring.
“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 RUB.
In Alzheimer’s disease, the amyloid beta protein folds incorrectly due to pathological changes long before the first symptoms occur. In the new study, a research team headed by Gerwert successfully diagnosed this misfolding with a simple blood test; as a result, the disease can be detected approximately eight years before the first clinical symptoms occur.
The test wasn’t suitable for clinical applications, however: While it did detect 71 percent of Alzheimer’s cases in symptomless stages, it also provided false positive diagnoses for nine percent of the study participants.
In order to increase the number of correctly identified Alzheimer’s cases and to reduce the number of false positive diagnoses, the team poured a lot of time and effort into optimizing the test.
As a result, they developed a two-tier diagnostic method. This involves the original blood test to identify high-risk individuals and a second biomarker test (to detect tau protein) for those who are deemed high-risk. If both biomarkers show a positive result, there is a high likelihood of Alzheimer’s disease.
“Through the combination of both analyses, 87 of 100 Alzheimer’s patients were correctly identified in our study,” Gerwert said. “And we reduced the number of false positive diagnoses in healthy subjects to 3 of 100. The second analysis is 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,” he said. Gerwert is hoping that existing therapeutic antibodies will still have an effect.
He added that the team is now conducting in-depth research to detect tau protein in the blood, so they can use a solely blood-based test in future.
“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. “If our attempts to arrest the progression of Alzheimer’s fail, it will put a lot of strain on our society.”
The blood test has been upgraded to a fully automated process at the RUB Department of Biophysics. “The sensor is easy to use, robust when it comes to fluctuation in concentration of biomarkers, and standardized,” Nabers said.
Source: Ruhr-Universität Bochum