November 18, 2008
Some Old Brains Stay Sharp With Fewer Tangles

Some people experience slower brain aging. Are you one of the lucky ones?

Now they have a preliminary answer. Scientists examined the brains of five deceased people considered super aged because of their high performance on memory tests when they were more than 80 years old and compared them to the brains of elderly, non-demented individuals. Researchers found the super aged brains had many fewer fiber-like tangles than the brains of those who had aged normally. The tangles consist of a protein called tau that accumulates inside brain cells and is thought to eventually kill the cells. Tangles are found in moderate numbers in the brains of elderly and increase substantially in the brains of Alzheimer's disease patients.

These results suggest that treatments for Alzheimer's disease that aim to prevent tangle formation will provide benefit to all people as their brains age. That's good news. A lot of effort is going into Alzheimer's treatment and the treatment development efforts aimed at tangles strike me as having a good chance of succeeding.

"This new finding in super aged brains is very exciting," said Changiz Geula, principal investigator of the study and a research professor of neurology at the Cognitive Neurology and Alzheimer's Disease Center at Northwestern's Feinberg School. "It was always assumed that the accumulation of these tangles is a progressive phenomenon through the aging process. But we are seeing that some individuals are immune to tangle formation and that the presence of these tangles seems to influence cognitive performance." Individuals who have few tangles perform at superior levels, while those who have more tangles appear to be normal for their age, Geula noted.

This begs the question: why are some people immune to tangle formation? Do they have immune systems that attack the tangles? Or do they have some genetic variant that lowers oxidative stress in the brain?

Geula will present his findings Sunday, November 16, at the Society for Neuroscience annual meeting in Washington, D.C.

The number of plaques in the brains of the super aged was similar to that in the brains of the normally aging group. The plaque is an aggregation of protein called amyloid that becomes deposited outside the brain cell and disrupts communication between neurons. Like tangles, plaques also are found in modest numbers in the brains of aged individuals and show a dramatic increase in number in Alzheimer's disease.

Geula said the lower number of tangles in the super aged appears to be the critical difference in maintaining memory skills.

Some of the super aged in the study performed memory tasks at the level of people who were about 50 years old. For example, after being told a story, they were able to remember it immediately after and still accurately recall its details 30 minutes later. They also remembered a list of 15 words and recalled these words equally well when tested after 30 minutes.

Stopping brain aging at age 50 wouldn't be ideal. But I'd take it as a good starter. Prevention of tangles won't stop all brain aging though. For example, demyelination (loss of insulation on neurons) would still proceed. We probably need some sort of cell therapy to reverse that process.

Share |      Randall Parker, 2008 November 18 08:03 AM  Brain Aging

Mama73 said at November 19, 2008 5:12 AM:

I had read some years ago that 75 yo men who exercised vigorously 5 days a week (an hour or more) maintained the brain function of 50 yo's.

Its great to have drugs to prevent Alzheimer/tangles, but it would be really great to find behaviors that could enable us to stay drug free as long as possible.


grace said at November 19, 2008 6:16 AM:

It can be very difficult to maintain vigorous exercise as one ages. there are so many problems, arthritis, hip and knee replacements, herniated discs, and on and on. If you are a healthy 75 year old physicaly, then you can do vigorous exercise. For the rest of us, and probably most of us try to do the best we can. For women, vigorous exercise can be cleaning the house.

Jim Ringo said at November 19, 2008 10:58 AM:

Interesting: "that 75 yo men who exercised vigorously 5 days a week (an hour or more) maintained the brain function of 50 yo's."

Would be lovely if there was something we could do to maintain brain function (seems harder even than maintaining cardiovascular function). A big caveat, however, regarding a study showing a result like the above quoted text is that the members of the comparison groups (exercise group vs. others) are self selected rather than randomly assigned. So, the exercise group is probably more energetic and more determined, both mental properties that in the 75 year old are probably a strong indicator of healthy brain function. In other words the exercisers were able/willing/interested-in exercise BECAUSE of their maintained brain function and perhaps a lot of correlation comes from that association (exercise, then, might or might not have additional protective value).

Horace said at November 19, 2008 12:32 PM:

They didn't mention diet as being part of the test. I think it would be interesting to determine if there is a correlation between diet and tangle formation. For example, do the super-aged eat more protein or less than average, more fat or less than average, etc.

ricpic said at November 19, 2008 4:08 PM:

A glass of red wine every day couldn't hurt. ;^)

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