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2020 Alzheimer's Association Clinician Scientist Fellowship (AACSF)

High-Performance Plasma Phosphor-Tau Predicts Dementia, Tau and Amyloid PET

Can a potential blood test be accurate and cost-effective in diagnosing Alzheimer’s?

Tharick Ali Pascoal, M.D.
University of Pittsburgh
Pittsburgh, PA - United States



Background

An increasing number of studies reveal certain changes in blood may identify changes associated with Alzheimer’s long before symptoms appear. Such disease-related changes, called biological markers, or “biomarkers,” include abnormal levels of tau and beta-amyloid proteins, the two main hallmarks of Alzheimer’s.

Dr. Tharick Ali Pascoal, and colleagues have developed a test to measure levels of modified tau called p-tau181 (or phosphorylated tau) in the blood. Tau is normally modified by the addition of a molecule known as phosphate to specific parts of the tau protein. In Alzheimer’s and other brain diseases, tau becomes excessively phosphorylated and then clumps together to form the tangles. These tangles have been shown to cause brain cell damage and death. In preliminary studies, in collaboration with University of Gothenburg, the researchers found that a blood test may be able to distinguish people with Alzheimer’s from those without Alzheimer’s with improved accuracy. This study included participants from Canada and Sweden. Their findings may also be associated with results from standard testing methods, for example, positron emission tomography (PET) brain scans that measure levels of tau and beta-amyloid.
 

Research Plan

Building on their preliminary findings, Dr. Pascoal and colleagues now plan to validate their results by expanding to a large-scale project that includes 3,000 participants enrolled in several dementia studies and included participants from Canada, Sweden, England and other countries. The researchers will leverage the data collected in these studies, including the PET brain scans, and will collect additional blood samples from the participants. 

The researchers will use these samples to explore how their test may be applied in a clinical setting. To do so, they will use the results of the blood test when shared with the participants to understand the impact on Alzheimer’s care, including changes in treatment, counseling, cost-effectiveness. They will also study the clinical situations where this is the most beneficial for the participants. Dr. Pascoal’s work will build on the IDEAS (Imaging Dementia-Evidence for Amyloid Scanning) study which is evaluating the criteria for PET scan usage to measure beta-amyloid levels, developed by the Alzheimer’s Association and Society for Nuclear Medicine and Molecular Imaging (SNMMI) and how it would impact care for individuals with Alzheimer’s.

Impact

If successful, the study results could give rise an effective diagnostic tool for Alzheimer’s that may prove to be cost-effective in clinical practices.
 

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