New Blood Test Predicts Alzheimer's Onset Years in Advance
Scientists at Washington University School of Medicine in St. Louis have developed a blood test capable of predicting the onset of Alzheimer's disease symptoms, estimating their appearance within a margin of approximately three to four years. The findings, which detail the test's ability to measure a specific protein that accumulates years before cognitive decline, were published in Nature Medicine on February 19. This development could potentially aid in the design of clinical trials and future early interventions for the neurodegenerative condition.
Research Findings
The new blood test is based on measuring levels of p-tau217, a specific form of the tau protein found in blood plasma. This protein is known to reflect the accumulation of amyloid and tau proteins in the brain, which are defining pathological features of Alzheimer's disease. These accumulations can occur years before symptoms such as memory loss manifest.
The new blood test measures p-tau217, a protein reflecting amyloid and tau accumulation in the brain, which can occur years before memory loss.
The study's model, developed by researchers including lead author Kellen K. Petersen, PhD, an instructor of neurology, and senior author Suzanne E. Schindler, MD, PhD, an associate professor in the Department of Neurology, utilized p-tau217 levels to estimate the age at which symptoms might begin. The model predicted symptom onset with an accuracy of approximately three to four years.
Researchers observed that the age at which p-tau217 levels become elevated influences the timeframe before symptom manifestation. For example, if p-tau217 levels increased at age 60, symptoms appeared approximately 20 years later. In contrast, an increase at age 80 resulted in symptoms approximately 11 years later.
Methodology
The study analyzed data from 603 older adults participating in the Knight Alzheimer Disease Research Center (Knight ADRC) and the Alzheimer's Disease Neuroimaging Initiative (ADNI). Plasma p-tau217 was measured using various diagnostic tests, including PrecivityAD2. The team has made their model development code and a web-based application publicly available for further research.
Brain-imaging tests that detect tangled tau are currently used in Alzheimer's diagnosis and can predict symptom appearance, but these methods are typically complex and costly. Blood-based methods, such as the one developed, offer a potentially simpler and more accessible alternative.
Offering a simpler and more accessible alternative to complex and costly brain-imaging tests, the new blood test marks a significant methodological advancement.
Implications and Future Outlook
The developers suggest that if validated through larger studies, this test could serve as a measurable biomarker to facilitate earlier interventions for Alzheimer’s disease, potentially enhancing treatment efficacy. It could also make clinical trials for Alzheimer’s treatments more efficient and less costly by identifying individuals most likely to develop symptoms. Howard Fink, a physician, noted that predicting when patients are likely to develop symptoms could benefit trial design for prevention or delay strategies.
Currently, p-tau217 testing aids in diagnosing Alzheimer's in patients already experiencing cognitive impairment. However, Suzanne Schindler cautions against individuals taking the test independently until further studies are concluded, and does not recommend any Alzheimer’s disease biomarker test for cognitively unimpaired individuals at this stage outside of research.
Suzanne Schindler cautions against individuals taking the test independently, emphasizing that it is not recommended for cognitively unimpaired individuals outside of research until further studies are concluded.
Future research may explore combining additional blood biomarkers to further improve prediction accuracy. Researchers anticipate that with further refinement, these methodologies could be accurate enough for use in individual clinical care, leading to advancements in treatment strategies.