Can we slow down brain aging and prevent dementia?

A series of articles in the journal Neuron report progress in understanding how aging affects the brain. However, many questions remain unanswered.

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Illustration, Photo: Shutterstock
Illustration, Photo: Shutterstock
Disclaimer: The translations are mostly done through AI translator and might not be 100% accurate.

Life takes its toll on our brains. Brain cells wear out over the years, making our brains slower, forgetful, and less mobile.

It is still unclear whether this brain decline is due to aging or genetic predisposition.

A series of scientific articles, published in the journal Neuron, attempts to answer these questions, as well as whether, taking into account current knowledge about brain aging, it can reduce cognitive decline due to aging and neurodegenerative diseases such as Alzheimer's. It was discovered that many physical and biological changes are responsible for brain deterioration, which in the long term has a negative impact on cognitive decline.

Finding solutions is increasingly important, as it is predicted that by 2050, 152 million people will be living with some form of reduced cognitive function.

What causes brain aging?

"We know the basic mechanisms of aging, and through molecular research over the last 25 years we have discovered what drives them," says Costantino Jadecola, a neurologist at the American Weill Cornell Medical College, who led research on the influence of the brain's circulatory system on the aging of that organ.

Research has shown that the causes of brain aging are both physical and biological.

Aging physically changes the brain, which loses mass, and visible changes in its structure are visible - our brain literally shrinks.

Biological factors that contribute to cognitive decline include DNA damage, what Jadekola calls “baseline inflammation” throughout the brain, and the brain’s ability to eliminate harmful substances.

Another scientific article emphasized that with age, the brain's immune system is no longer "in shape", which leads to disruption of normal brain functioning.

In one of the articles, neuroscientist David Rubinstein from the University of Cambridge, UK, proved that the inability to eliminate harmful proteins significantly contributes to aging, as well as the decline in cognitive function.

As we age, our brain cells become less efficient at eliminating harmful proteins, which damage cells and interfere with brain function.

Tau protein is one of these harmful proteins linked to several neurodegenerative diseases, including Alzheimer's disease, dementia, and diseases associated with head injuries, such as chronic traumatic encephalopathy (CTE).

"Tau protein accumulation causes a neurodegenerative condition called Alzheimer's disease, so there are clear links between protein breakdown mechanisms and neurodegenerative diseases. But we know less about how they affect the normal decline in cognitive function during aging," Rubinstein explains to DW.

Scientists still don't understand the basics of aging.

Recent research has revealed that aging scientists cannot agree on some basic questions: What is aging? What causes it? When does it start?

"These are questions that have not been answered throughout history. They were even discussed in the Bible," Jadekola tells DW.

That's one of the reasons why the journal "Neuron" published the articles - to highlight what scientists still don't know.

Rubinstein says that one of the problems facing the field is an overemphasis on studying cognitive decline caused by pathologies such as stroke, Alzheimer's or Parkinson's disease, instead of studying how healthy brains develop these problems.

"We need to understand what causes cognitive decline that are related to aging alone, without the influence of disease. We don't have answers about what is normal cognitive decline that is not affected by dementia," Rubinstein explains.

Will we ever be able to slow down brain aging?

Scientists have begun to understand how to strengthen the brain as we age.

It has long been known that healthy lifestyle habits reduce the risk of dementia and cognitive decline associated with aging. Some of these habits include: exercise and proper nutrition, avoiding exposure to air pollution and smoking, encouraging social interaction - avoiding social isolation and loneliness, and treating vision and hearing problems.

Scientists like Jadekola believe that, from the moment we are conceived, genes influence the way our brain ages.

"Diet, exercise, avoiding harmful substances, and quitting smoking have a big impact on how we age. However, it is genetics that fundamentally determines how we age," says Jadekola.

"Risk behaviors, like smoking, can accelerate aging. But avoiding these risks can slow it down quite a bit."

This essentially means that a healthy lifestyle cannot change the genetic predisposition to brain aging, but bad lifestyle habits can speed up the entire process.

Jadekola is not optimistic that scientists will find a cure for aging or discover how to artificially extend life.

"Aging is a part of human life and there is a limit to how much we age. That limit is our genes. There are too many factors that cause aging for us to be able to extend our life beyond 120 years," the scientist concludes.

Sources:

Disagreement on foundational principles of biological aging

Autophagy, aging, and age-related neurodegeneration.

DNA damage and its links to neuronal aging and degeneration.

Pathobiology of neurovascular aging: Advances and implications for cognitive health

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