New Blood Test May Forecast Alzheimer’s Symptoms Years in Advance
A simple blood test could soon help answer one of the most difficult questions in Alzheimer’s disease: When will symptoms start? In a study published in Natural medicineResearchers report that levels of a specific protein in the blood can help estimate when a person is likely to begin experiencing cognitive symptoms of Alzheimer’s disease. Using long-term data from hundreds of older adults, the team built models that predicted the onset of symptoms within about three to four years.
The findings suggest that a relatively accessible blood test could help identify people who are still cognitively healthy but biologically on the path to Alzheimer’s disease, potentially reshaping the way prevention trials are designed.
“Our work shows the feasibility of using blood tests, which are significantly cheaper and more accessible than brain imaging or cerebrospinal fluid tests, to predict the onset of Alzheimer’s disease symptoms,” lead author Suzanne E. Schindler said in a press release.
Learn more: Blood test for Alzheimer’s disease could lead to earlier, more effective treatment
The protein that tracks the progression of Alzheimer’s disease
The study focuses on a protein called p-tau217, which circulates in blood plasma. Previous research has shown that levels of p-tau217 increase as two hallmark proteins of Alzheimer’s disease – amyloid and tau – accumulate in the brain.
Amyloid plaques and tau tangles begin to form years or even decades before memory problems appear. Like rings forming in a tree trunk, these proteins accumulate in a fairly predictable pattern over time. The more they accumulate, the more advanced the disease process tends to be.
Until recently, detecting these changes required expensive brain scans or invasive spinal taps. Blood tests for p-tau217 offer an easier way to track these changes.
To understand the link between blood levels and the timing of symptoms, researchers analyzed data from 603 adults enrolled in two long-term Alzheimer’s disease research programs.
By tracking p-tau217 levels over time and comparing them to when cognitive symptoms appeared, the team developed models linking high levels of the protein to the likely age of symptom onset.
When p-tau217 increased earlier in life, symptoms tended to appear decades later. When protein increased at older ages, the window between biological change and cognitive decline was shorter.
For example, people with high levels at age 60 developed symptoms about 20 years later. Those whose levels increased at age 80 developed symptoms closer to 11 years later.
Why timing matters
Alzheimer’s disease affects more than seven million Americans, and although treatments can relieve some patients’ symptoms, no treatment currently prevents the disease. One of the biggest challenges in developing preventive treatments is identifying people who are biologically at risk but who are not yet showing signs of memory loss. Clinical trials often last several years, in part because researchers must wait for symptoms to appear.
If researchers can more accurately estimate when symptoms are likely to begin, they may be able to enroll participants at the right stage, making trials shorter and more efficient.
The researchers also tested their model on different p-tau217 blood tests and found similar results, suggesting that the approach could work beyond a single proprietary platform.
A future based on previous knowledge
The team has made its modeling tools publicly available so that other researchers can refine and expand them. Additional blood biomarkers could further improve the accuracy of future studies.
Although the idea of predicting the onset of symptoms may seem daunting, experts say the goal is not to alarm patients, but to prepare them.
“In the short term, these models will accelerate our research and clinical trials,” Schindler said. “Ultimately, the goal is to be able to tell each patient when they are likely to develop symptoms, which will help them and their doctors develop a plan to prevent or slow symptoms.” »
This article does not offer medical advice and should be used for informational purposes only.
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