Protein Tau, Alzheimer's Linked in Study Using New Brain-Scanning Tech

The protein tau may be a better marker of Alzheimer's than amyloid beta, a new study suggests.

Researchers at the Washington University School of Medicine in St. Louis said in a Wednesday statement that amyloid beta had long been studied in connection with Alzheimer's disease but tau had not because scientists previously lacked a way of imaging it. Now, a new imaging agent, called positron emission tomography (PET) scanning, is allowing researchers to track tau.

"A buildup of plaque and dysfunctional proteins in the brain are hallmarks of Alzheimer's disease," the university statement said.

"While much Alzheimer's research has focused on accumulation of the protein amyloid beta, researchers have begun to pay closer attention to another protein, tau, long associated with this disease but not studied as thoroughly, in part, because scientists only recently have developed effective ways to image tau."

With PET scanning, university scientists were able to compare brain images of people who are cognitively healthy to patients with mild Alzheimer's disease. By doing so, they found that measures of tau better predicted symptoms of dementia than amyloid beta.

"Our work and that of others has shown that elevated levels of amyloid beta are the earliest markers of developing Alzheimer's disease," said Dr. Beau M. Ances, the senior author of the study.

"But in the earliest stages of Alzheimer's disease, even with amyloid buildup, many patients are cognitively normal, meaning their memory and thought processes are still intact. What we suspect is that amyloid changes first and then tau, and it's the combination of both that tips the patient from being asymptomatic to showing mild cognitive impairment," Ances continued.

The Associated Press wrote that the findings need to be confirmed with a larger study, but also said the initial study provides good reasons to develop drugs that can treat both amyloid and tau buildup.

"This is exactly the type of information we're going to need," said Alzheimer's Association chief science officer Maria Carrillo, who was not connected with the study. "It's cool to see the utility of this new imaging technology actually being deployed and used."

Details of the new study were published in the journal Science Translational Medicine this week.

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