A recent study published on January 1st, 2020 reveals that brain images of tau-protein “tangles” can reliably predict the locations of brain atrophy in Alzheimer’s patients more than a year in advance. Prediction of alzheimer’s in the brain can profoundly assist scientists and health practitioners in battling this crippling disease.
The study was performed by scientists at the UC San Francisco Memory and Aging Center, who determined that tau drives brain degeneration in Alzheimer’s patients more directly than amyloid protein. For decades, the location of amyloid plaques has been the focus of research and drug development for Alzheimer’s, but this told little about how damages would progress in the disease.
The researchers were also able to demonstrate the potential of new brain imaging technology, tau-based Positron Emission Tomography (PET), to accelerate Alzheimer’s clinical trials and improve individual patient care.
Neurologist Gil Rabinovinci, M.D. is the leader of the PET imaging program at UCSF Memory and Aging Center and the Edward Fein and Pearl Landrith Distinguished Professor in memory and aging. Here he talks about the teams work:
The match between the spread of tau and what happened to the brain in the following year was really striking. Tau PET imaging predicted not only how much atrophy we would see, but also where it would happen. These predictions were much more powerful than anything we’ve been able to do with other imaging tools, and add to evidence that tau is a major driver of the disease.
Lead author of the study, Renaud La Joie, Ph.D., speaks further about the discovery:
No one doubts that amyloid plays a role in Alzheimer’s disease, but more and more tau findings are beginning to shift how people think about what is actually driving the disease. Still, just looking at postmortem brain tissue, it has been hard to prove that tau tangles cause brain degeneration and not the other way around. One of our group’s key goals has been to develop non-invasive brain imaging tools that would let us see whether the location of tau buildup early in the disease predicts later brain degeneration.
The researchers found that overall tau levels in the participants’ brains at the beginning of the study predicted how much degeneration would occur until their next visit, which was 15 months later. The testings showed local patterns of tau buildup had predicted subsequent atrophy with more than a 40% accuracy, versus the baseline amyloid-PET, scans predicted future brain degeneration only 3% of the time.
“Seeing that tau buildup predicts where degeneration will occur supports our hypothesis that tau is a key driver of neurodegeneration in Alzheimer’s disease,” La Joie said.
This discovery will give researchers and doctors the ability to use tau PET imaging for prediction of Alzheimer’s brain degeneration, speed up clinical trials, and give the patients more personalized care. It will also provide a clearer picture to the doctors about how far along and how quickly they expect the disease to spread.
Rabinovici explains the further benefits here:
One of the first things people want to know when they hear a diagnosis of Alzheimer’s disease is simply what the future holds for themselves or their loved ones. Will it be a long fading of memory or a quick decline into dementia? How long will the patient be able to live independently? Will they lose the ability to speak or get around on their own? These are questions we can’t currently answer, except in the most general terms. Now, for the first time, this tool could let us give patients a sense of what to expect by revealing the biological process underlying their disease.
He goes on to say that this is not only valuable in the prediction of Alzheimer’s but can be an “extremely valuable precision medicine tool” for slowing down or even preventing a specific pattern of brain atrophy for individual patients.
