Scientists from the University of Washington have discovered that maintaining a healthy brain as you age depends on keeping a key defense system strong—the blood-brain barrier. This barrier is made up of tiny blood vessels that control what goes in and out of the brain.
It helps protect the brain from harmful substances while still allowing important nutrients and signals to pass through.
The researchers reviewed over 150 studies to understand how this barrier changes with age. They found that even in healthy aging, the blood-brain barrier develops small leaks. These leaks may be linked to mild memory problems that many people experience as they grow older.
However, in some cases, a weakened blood-brain barrier could lead to more serious brain diseases, including Alzheimer’s.
The blood-brain barrier plays an important role in brain health. It acts as a filter, preventing toxins, bacteria, and other harmful substances from entering the brain while allowing essential nutrients to pass through. It also helps remove waste products from the brain.
When the barrier is damaged or becomes too leaky, unwanted substances can enter the brain, leading to inflammation and other issues that can contribute to memory loss and cognitive decline.
One important factor that affects brain health is genetics. The study found that people who carry a gene variation called ApoE4, which increases the risk of Alzheimer’s disease, experience more rapid changes in the blood-brain barrier as they age.
In these individuals, the barrier becomes less effective at clearing out a protein called amyloid beta, which can build up and form plaques in the brain. These plaques are a major feature of Alzheimer’s disease and are linked to memory loss and other cognitive problems.
The researchers also identified two types of cells in the blood-brain barrier that change with age—pericytes and astrocytes. Pericytes help maintain the structure of the barrier and keep it functioning properly.
As people age, they lose pericytes, which may be one reason the barrier starts to leak. On the other hand, astrocytes, which support brain cells, become overactive with age. This imbalance may contribute to brain aging and diseases like Alzheimer’s.
Some research suggests that keeping pericytes healthy may help slow down the aging process of the blood-brain barrier. Certain lifestyle habits, such as regular exercise and eating a balanced diet, have been linked to better pericyte health.
Other interventions, such as caloric restriction (eating fewer calories while still getting enough nutrients) and a drug called rapamycin, have shown potential benefits in slowing down aging in general.
This study highlights the importance of protecting the blood-brain barrier as we age. While mild memory problems are a normal part of aging, keeping the brain’s protective barrier strong may help reduce the risk of more serious conditions like Alzheimer’s.
Scientists continue to study ways to support brain health, including the role of diet, medications, and lifestyle choices.
The research was published in Nature Aging and conducted by William Banks and his team.
If you care about brain health, please read studies about vitamin D deficiency linked to Alzheimer’s and vascular dementia, and blood pressure problem at night may increase Alzheimer’s risk.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and epilepsy drug may help treat Alzheimer’s disease.
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