To Age or Not to Age,
That is the Question
What Makes A SuperAger
Super
In a recent study done by Tamar Gefen and colleagues
at Northwestern University, they have found and characterized a group of people
who have aged remarkable well when it comes to memory cognition. These people
are what they call “SuperAgers.” This
cohort of 80-year-old individuals are cognitively functioning at the same level
as 50 and 60 year olds when it comes to memory. This study revealed that there
is a biological signature in the brains of SuperAgers. The structural features
present in their brain show that they have a thicker anterior cingulate cortex
in the right hemisphere. What makes the anterior cingulate so fascinating is
that it indirectly functions on the “emotional” limbic system and the
“cognitive” prefrontal cortex. Thus the
cingulate cortex is indirectly related to emotions such as motivation,
perseverance, and cognitive function, while also being indirectly related to
episodic memory. (Gefen et. Al.)
Why is a thicker cingulate
cortex better?
First of, the biggest risk factor in
causing thinning of the cingulate cortex is the neurodegenerative
characteristics seen in patients with Alzheimer’s. Alzheimer’s can be generally
described as drastic memory impairment in all aspects of life, as a result of an
accumulation of amyloid plaques and neurofibrillary tangles in the brain.
Usually before getting Alzheimer’s patients go through a phase where the
amyloid plaques and neurofibrillary fibers appear sparsely in memory regions of
the brain, but do not result in memory impairment. Throughout time cells
associated with plaques and tangles begin to die and these neurons do not
connect their action potential to other neurons involved in memory. Thus memory
impairment begins. For the SuperAgers, there was very little evidence of this cortical atrophy which is usually seen in most people their age.
As one gets older, it is assumed that with the normal accumulation of
plaques and cell death, the cingulate cortex would thin out a
bit. What is special about SuperAgers is that they do not have or have very
little of these plaques and tangles, and thus have retained their cortical thickness; which is speculated to be a contributing factor in their preserved cognitive
function.Gefen showed us that the thicker cingulate cortex lacked the characteristics of Alzheimer's, and thus that is why the cingulate cortex was thicker, but what about the people with Alzheimer's who have the thinner cingulate cortex?
Attack the Amyloid Plaque
On top of the study done by Gefen et
al. at Northwestern University, Dr. Frank Longo, chairman of the neurology and
neurological studies at Stanford University, has developed a knew drug known as
LM11A-31, in the hopes that it will alleviate some of the symptoms of Alzheimer’s. In the Time Magazine article, Alzheimer’s
From A New Angle, Alice Park explains to us Dr. Longo’s new approach. As
mentioned earlier, Alzheimer’s is characterized by an accumulation of amyloid plaques and neurofibrillary tangles in the brain.
A New Perspective
As
explained in the Time article, scientists have begun to think that the amyloid
plaques are the initial trigger, and that the tau protein is the silver bullet.
(Park) Tau is a protein that stabilized microtubules and when it begins to degrade
language and memory organization begin to fail. In the same article, Dr.
William Jagust, a professor of neuroscience and public health at the University
of California Berkley, explains to us that he believes Alzheimer’s occurs in
two stages: 1) Amyloid accumulation and 2) degradation of tau. If there could
be a treatment that attacks the plaque-- as many have already done--in combination with Dr. Longo’s new drug that keeps the cells healthy, and a
drug to keep tau from breaking down, then maybe scientists could be close to
curing Alzheimer’s.
Is the damage of Alzheimer’s
reversible?
Furthermore, in
a recent study by scientists at Rush University Alzheimer’s Center they have found
evidence that patients with high levels of the nerve growth factor BDNF retain
more of their cognitive brain function even when amyloid build up has already begun.
(Park) While there is no drug to boost BDNF levels yet, it seems that researchers
at Rush are very intrigued on finding out if higher levels of growth factors could
allow people to retain some of their cognitive function or even counteract the
effects of the plaque.
What would Gefen say?
In
the Northwestern study done by Gefen et al, they proclaimed that the cingulate
cortical thickness has been preserved because it lacked the amyloid plaques and
neurofibrillary tangles that lead to cingulate atrophy. Thus, the thicker
cingulate cortex was able to function more effectively for the memory cognition
of the SuperAgers. Gefen acknowledges that her SuperAgers seem to lack the
aging brain signature, but did not know why. What is clear is that research, such
as Dr. Longo’s, can shed some new light on preserving the cingulate cortex. It
can be inferred from both studies, that if the cingulate cortex is preserved
and strengthened then maybe one day we can all become SuperAgers.
Bibliography
Park, Alice.
"Alzheimer's from a New Angle." Time. Time, 11 Feb. 2016. Web.
04 May 2016.
Time Magazine
link:
Gefen, Tamar,
Melanie Peterson, Steven T. Papastefan, Adam Martersteck, Kristen Whitney,
Alfred Rademaker, Eileen H. Bigio, Sandra Weintrab, Emily Rogalski, Marsel
Mesulum, and Changuz Geula. "The Journal of Neuroscience." Morphometirc
and Histologic Substrates of Cingulate Integrity in Elders with Exceptional
Memory Capacity (2015): n. pag. Web. 3 May 2016.
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