Researchers have developed a blood-based model that estimates when Alzheimer’s symptoms are likely to begin within a margin of about 3 to 4 years.
The findings suggest a single blood test could act as a biological ‘clock’ helping identify individuals who are likely to develop cognitive symptoms within a specific time frame.
If validated in broader populations, this approach could improve the design of prevention trials and support earlier, more personalized planning for people at risk of Alzheimer’s disease.
How the blood ‘clock’ works
The research team, led by experts at Washington University School of Medicine in St. Louis, focused on a protein called p-tau217.
This protein, found in the plasma component of blood, is already known to reflectTrusted Source the abnormal accumulation of amyloid and tau proteins in the brain, which are hallmarks of Alzheimer’s disease
The study’s findings show that p-tau217 levels rise in the bloodstream in a consistent pattern as Alzheimer’s pathology develops.
By measuring p-tau217 and integrating those results into a statistical model, the research team could estimate the likely age when cognitive symptoms would begin, with a margin of error of 3 to 4 years.
Amyloid and tau proteins build up predictably in the brain over time. The researchers say this consistent pattern resembles tree rings.
In the same way that it is possible to determine how old a tree is from its rings, the researchers can use plasma p-tau217 levels to act like a ‘clock’ to strongly predict when someone is going to develop Alzheimer’s symptoms.
Speaking to Medical News Today, Kellen Petersen, PhD, study author and an instructor in neurology at WashU Medicine, explained how the ‘biological clock’ model improve upon existing methods for predicting disease progression.
“Most existing approaches can tell you if someone has changes in the brain related to Alzheimer’s disease or whether they are at higher or lower risk for developing symptoms, but they do not provide a clear estimate of when symptoms are likely to appear,” Petersen told us.