For the current study, Gefen’s team analyzed brain tissue from seven super agers — all women — who had died in their 80s or 90s. The results were compared with brain studies from six elderly adults who’d had normal thinking skills before their deaths.
The super agers had all taken standard memory tests, and scored at or above the norm for people 20 to 30 years younger.
The researchers found that both super agers and their peers harbored similar amounts of amyloid plaque in the brain.
They differed, however, when it came to tangles: People with average memory and thinking skills had three times the amount of tau tangles in a memory-related brain region called the entorhinal cortex.
Sexton agreed the findings align with other evidence on the importance of tau.
“It’s been understood for a while that tau tracks better with cognitive performance than amyloid does,” she said.
These findings, Sexton said, suggest a role for tau in the “secrets” to super-aging.
That does not mean plaques are unimportant, however. Abnormal amyloid and tau may interact with each other, and with other factors, to fuel Alzheimer’s brain changes, Sexton said.
According to the Alzheimer’s Association, it’s thought that as amyloid increases in the brain, it hits a tipping point that triggers abnormal tau to spread throughout the brain. And that’s when memory and thinking skills head downhill.
Gefen agreed that it’s probably a complex mix of factors — nature and nurture — that allows super agers to resist typical age-related declines in brain power.
It’s unlikely to be a magic something that can be turned into a pill, she said.
More broadly, Gefen said far more work is needed to understand tau tangles, including why they zero in on memory cells.
That’s not to say tau has been completely ignored: Tau-targeting therapies for Alzheimer’s are under development, Sexton said.
For now, it seems clear that few people will become super agers. But, Sexton said, there are ways for everyone to support their brain health, including controlling heart disease risk factors like high blood pressure and diabetes, getting regular exercise, eating healthfully and staying mentally and socially engaged.
The findings were published Feb. 17 in the journal Cerebral Cortex.
More information
The U.S. National Institute on Aging has more on super agers.
