Much of the research into Alzheimer’s disease has focused on neurons – the nerve cells in the brain that transmit the electrochemical impulses that are associated with thinking and memory.
But what if the answer to treating Alzheimer’s actually resides in a different kind of brain cell?
A growing number of researchers now believe that these other brain cells – cells which actually outnumber neurons in the brain – could hold the answer to neurodegenerative problems like Alzheimer’s.
Here’s the scoop…
The cells I’m talking about are astrocytes – star-shaped immune cells in the brain that have usually been considered supporting players in maintaining brain health, mere assistants to neurons in their daily communications with each other.
But now research is starting to uncover the central role astrocytes play in thinking and memory.
And one unmistakable fact: In your brain, astrocytes massively outnumber neurons. The ratio? Fifty to one!
Astrocytes – from the Latin and Greek words for “star” — are constantly busy in the brain. They play a central part in:
- Producing the brain’s energy.
- Keeping the brain’s pH (acidity) in proper balance.
- Controlling the formation of synapses where neurons connect with each other.
Interestingly, scientists have discovered that one of the chief differences between human brains and the brains of animals is the development of our very advanced, larger and complex astrocytes. Our brains also contain many more astrocytes than animal brains possess.
“The role of the astrocyte is to provide the perfect environment for neural transmission,” says researcher Maiken Nedergaard, M.D., D. M. Sc., who studied these cells at the University of Rochester Medical Center and is now a full Professor at the University of Copenhagen.Â “At the same time,” she says, Â “we’ve observed that as these cells have evolved in complexity, size, and diversity – as they have in humans – brain function becomes more and more complex.”
I feel obliged to add that Prof. Nedergaard is one of the world’s most distinguished neuroscientists. She is credited with discovering an entirely new brain system, the glymphatic system, a waste-clearance function.
In our brains, astrocytes can put out large numbers of fibers that link to a multitude of neurons. They also connect with synapses – the area where neurons meet. The current understanding is that the astrocytes orchestrate the activities of thousands of neurons.
Don’t Oversimplify. . .
Prof. Nedergaard believes that by just studying neurons and neglecting astrocytes researchers are oversimplifying how our brains function.
“I have always found the concept that the human brain is more capable because we have more complex neural networks to be a little too simple, because if you put the entire neural network and all of its activity together all you just end up with is a super computer,” says Prof. Nedergaard. “But human cognition is far more than just processing data, it is also comprised of the coordination of emotion with memory that informs our higher abilities to abstract and learn.”
How to Make a Mouse into a Genius
In an experiment, Prof. Nedergaard and her research team placed human astrocytes into young mouse brains by transplanting what are called “human glial progenitors.”Â These progenitor cells are the stem cells that develop into astrocytes.1
As the young mice began to grow, the human astrocytes took over for the mouse astrocytes â€“ eliminating many of them â€“ and developed and behaved as if they were in a human brain.
Having human astrocytes in their brains turned the mice into rodent near-geniuses. Their brains could send signals across its neural networks faster, retain signals more effectively and enjoy enhanced plasticity â€“ the ability to shape new neural networks faster in order to form memories and learn new tasks.
All of these improved activities caused the brains of the mice to function in a way that more closely resembled those of humans.Â And their learning capacity was bumped up sharply.
Other studies have shown that malfunctioning astrocytes are undoubtedly linked to Alzheimer’s disease:
- A lab test in Finland shows that astrocytes from people with Alzheimer’s can damage healthy neurons in ways that reflect what occurs during Alzheimer’s disease.2
- Research in Germany demonstrates that changing the behavior of astrocytes during Alzheimer’s disease may normalize the brain’s network activity and improve learning and memory.3
Help your Astrocytes!
So far, researchers seem to have come up with three main tools for improving your astrocytes and your intellectual capacity.
The first consists of exercise. Scientists at Stanford have discovered that aerobic exercise “leads to a significant alteration in (beneficial) structure and function of astrocytes.”4
Avoiding or controlling stress also protects astrocytes. Tests in Australia demonstrate that chronic stress causes astrocytes to release substances that initiate damaging inflammation.5
The third tip is to keep your blood sugar under control. Researchers in South America have evidence that when your blood sugar is high, your astrocytes can spread harmful inflammation and release chemicals that poison neurons.6
Readers of this newsletter won’t be surprised by these recommendations.Â Exercise, de-stressing and healthy blood sugar are well known, first-line “treatments” for preventing or reversing dementia. What’s new is that their effect on astrocytes may be as important as their effect on neurons.