New blood test may help diagnose, show how far Alzheimer’s has progressed

For this new blood test, researchers focused on a protein called MTBR-tau243, which researchers of this study identified as a potential biomarkerTrusted Source for tau tanglesTrusted Source in Alzheimer’s disease in previous research published in August 2023.

“MTBR-tau243 is a chipped (off) piece of the protein in Alzheimer’s tau tangles,” Randall J. Bateman, MD, the Charles F. and Joanne Knight Distinguished Professor of Neurology at WashU Medicine in St. Louis, MO, and co-senior author of this study explained to Medical News Today. “The blood test measures this piece of tau tangles in the blood as a measure of how many tangles are in the brain.”

“New biomarkers are tools that allow us to track the disease in different ways,” Bateman continued. “Just like doctors use a stethoscope, x-ray, and CAT scan to measure different aspects of the disease, these biomarkers enable us to measure different aspects of Alzheimer’s disease. By tracking different processes of Alzheimer’s disease, we can better diagnose, predict and even develop new and better treatments for Alzheimer’s disease.”

“The new biomarker — plasma eMTBR-tau243 — reflects changes in tau pathology occurring in the clinical symptomatic phase of Alzheimer’s disease and can be used to stage Alzheimer’s disease tauopathy, and to determine if cognitive symptoms are likely due to Alzheimer’s disease tau pathology,” added Kanta Horie, PhD, voluntary research associate professor of neurology at WashU Medicine in St. Louis, MO, and both co-first and co-corresponding author of this study.

“Also, many therapeutic developments are ongoing including anti-amyloid and anti-tau drugs. We believe that this new biomarker becomes the key to establish the plasma biomarkers panel to stage Alzheimer’s disease, which would open the new window of precision medicine era for Alzheimer’s disease.”

During the study, researchers tested study participants from three main stages of Alzheimer’s disease: presymptomatic, early-stage with mild cognitive impairmentsTrusted Source, and late symptomatic disease where participants have been diagnosed with dementia.

The scientists found that blood MTBR-tau243 levels reflected the amount of tau tangles in the brain with 92% accuracy.

Among participants showing cognitive symptoms of Alzheimer’s disease, researchers discovered that MTBR-tau243 levels were significantly higher for participants at the mild cognitive stage, and up to 200 times higher for those in the late symptomatic disease stage.

A new protein biomarker for Alzheimer’s

“The cognitive decline in Alzheimer’s disease is highly associated with (tau) neurofibrillary tangles (NFTs) pathology in (the) brain, not amyloid plaques pathology. Since we know that NFTs are more generated in the dementia stage in Alzheimer’s disease, it is reasonable for us to see the drastic increase of MTBR-tau243 in the dementia stage compared to the preclinical Alzheimer’s disease stage, which suggests the validation to characterize the plasma MTBR-tau243 biomarker as the tau NFTs-specific biomarker.”
— Kanta Horie, PhD

“The significance of finding increasing amounts of MTBR-243 related to Alzheimer’s symptoms — memory loss and thinking impairment — is (that) this discovery now allows us to track the clinical symptoms of Alzheimer’s disease with a blood test,” Bateman explained.

“This new blood test can confirm the amount of tau tangles in the brain that helps determine the stage of Alzheimer’s disease and if cognitive decline is likely due to Alzheimer’s disease. This test can be used to accelerate new treatments, and with further validation, improve diagnosis and stage of Alzheimer’s disease.”
— Randall J. Bateman, MD

MNT spoke with Manisha Parulekar, MD, FACP, AGSF, CMD, director of the Division of Geriatrics at Hackensack University Medical Center and co-director of the Center for Memory Loss and Brain Health at Hackensack University Medical Center in New Jersey, about this study.

Parulekar commented that this blood test represents a logical next step in Alzheimer’s diagnosis and treatment, building upon previous research and addressing significant unmet needs.

“Scientists have identified key biomarkers associated with Alzheimer’s, such as amyloid-beta plaques and tau tangles in the brain,” she explained. “Earlier diagnostic methods, like PET scans and cerebrospinal fluid analysis, could detect these biomarkers, but they are expensive, invasive, and not readily accessible.”

“A blood test offers a much simpler and less costly alternative. There’s a growing understanding that early diagnosis of Alzheimer’s, which is a complex process, is crucial for effective intervention. Current treatments, while limited, may be more beneficial in the early stages of the disease. A readily available blood test could enable much earlier detection than current methods, allowing for earlier intervention and potentially slowing disease progression.”
— Manisha Parulekar, MD, FACP, AGSF, CMD

“The initial study needs to be replicated in larger and more diverse populations to confirm its accuracy and reliability across different demographics, ethnicities, and stages of the disease,” Parulekar added. “This includes testing individuals with other neurological conditions to ensure specificity. Clear and standardized protocols for blood collection, processing, and analysis must be established to ensure consistent and reproducible results across different laboratories and healthcare settings.”