Blood Test Can Estimate Presence of Alzheimer’s Disease Changes and Blood Vessel Damage in the Brain

By LabMedica International staff writers
Posted on 11 Mar 2022

Image: Blood test could be possible diagnostic tool for Alzheimer’s (Photo courtesy of Unsplash)

The detection of disease-causing pathology associated with Alzheimer’s disease and Vascular Contributions to Cognitive Impairment and Dementia (VCID) is limited to cognitive evaluations and neuroimaging like MRI and PET scans. Now, a recent study shows promising results for a blood test that could be used to identify Alzheimer’s changes in the brain before the onset of any symptoms, which could result in preventative treatments being used before any memory loss.

Due to recent technological developments, blood-based biomarkers of disease are now available and researchers from the Sanders-Brown Center on Aging at the University of Kentucky (Lexington, KY, USA) believe they could be beneficial in the diagnosis of Alzheimer’s and other dementias. A biomarker – short for biological marker – is a measurable indicator that captures what is happening in a cell or an organism at a given moment.

Up until recent years, the only way to know if someone had Alzheimer’s or a related dementia was after death through an autopsy. Advances in research regarding biomarkers, like the recent study from Sanders-Brown, are allowing researchers to see changes in the brain while people are alive, monitor the disease’s progression, and test the effectiveness of potential treatments. For their study, the researchers identified samples from participants who had blood taken and banked within two years of their death. They then tested blood samples from 90 participants for a variety of proteins with the goal of identifying biomarkers in the blood that could predict changes in the brain that might have contributed to dementia.

The researchers found through autopsies that there are mixed causes of dementia and that proteins in the blood are associated with brain changes. They believe those discoveries provide additional evidence that blood biomarkers have a strong potential for the diagnosis of Alzheimer’s and other causes of dementia. The team believes their results support the continued study of blood-based biomarkers as a clinical screening tool for Alzheimer’s and VCID. The researchers agree that establishing biomarkers that allow doctors to diagnose and monitor patients is a crucial step towards identifying at-risk but not yet symptomatic patients, who could be more responsive to potential therapeutics.

“This study provides evidence that a blood test could be used to estimate the presence of Alzheimer’s disease changes and blood vessel damage in the brain. We identified proteins in blood that indicate protein changes and changes in the brain known to cause dementia. Higher pTau181 and lower beta-amyloid in the blood indicate amyloid plaques of Alzheimer’s in the brain,” said Donna Wilcock, Ph.D., the Robert P. and Mildred A. Moores Endowed Chair in Alzheimer’s Disease, who is associate director at Sanders-Brown. “Protein markers of inflammation in the blood were also associated with higher amyloid plaques in the brain. We also looked at proteins that might have a relationship with damage to the blood vessels of the brain. We found that inflammation proteins in blood were related to damage to blood vessels in the brain.”

“Blood samples can be easily obtained, even at primary care visits. The development of a blood test would eliminate the need for expensive, specialized PET scans or invasive, uncomfortable spinal taps,” added Wilcock.

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