Harvard researchers specialized in Alzheimer’s disease are scanning the brains of healthy patients for the presence of the tau protein, which is involved in starting the process of intertwining the nerve fibers related with the fatal disease.
The scans are part of a large clinical trial called Anti-Amyloid Treatment in Asymptomatic Alzheimer’s or A4, initially designed to identify and treat patients with early stages of Alzheimer’s prior to beginning of memory loss.
Participants in the A4 study already had deposits of beta amyloid, the accompanying protein associated with Alzheimer’s. By adding the tau in the scan allows scientists to have a clear picture of events leading to Alzheimer’s, a disease affecting 5 million Americans, with 16 million projected to suffer by 2050.
Dr. Reisa Sperling of Massachusetts General Hospital in Boston, who is leading the 1,000-patient trial, said tau is commonly found in small amounts in healthy people over age 70, but it is generally confined to an area of the brain called the medial temporal lobe.
In the presence of amyloid, tau has an open path to spread to other parts of the brain, causing widespread cell death of cognitive decline.
“Tau is the actual bad actor on the front line that tears up the brain. Being able to see it in living humans is a breakthrough,” said Dr. Keith Johnson, director of molecular neuroimaging at Massachusetts General, who is leading the imaging portion of the A4 trial.
In the study, patients will be offered treatments to remove amyloid from the brain in the hopes of keeping tau in check.
Companies have developed drugs aiming to remove amyloid and alter the course of Alzheimer’s, but all failed to show a significant benefit. Sperling and other researchers believe that’s because the drugs were introduced too late after the onset of disease.