Scientists find a new cause of dementia

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Dementia is a serious condition that affects millions of people worldwide, leading to significant declines in memory, thinking, and the ability to carry out everyday tasks.

Despite many years of research, the exact causes of dementia remain unclear, and there is currently no cure.

However, new research from scientists at Weill Cornell Medicine is offering fresh insights into how dementia might develop, particularly through the role of a type of brain cell called astrocytes.

Astrocytes are star-shaped cells in the brain that were traditionally thought to play only supportive roles for neurons, the primary cells responsible for communication within the brain.

For a long time, most research has focused on neurons themselves, with less attention given to these supporting cells. But this new study is changing that view, showing that astrocytes might play a much more significant role in dementia than previously thought.

The research team discovered that dysfunction in astrocytes alone can lead to memory loss, even if the neurons and other brain cells are still healthy.

This finding was based on the observation of a protein called TDP-43 building up in astrocytes located in the hippocampus, a region of the brain that is essential for memory.

This buildup was found in brain tissue samples from people who had been diagnosed with Alzheimer’s disease or frontotemporal dementia after they had passed away.

To understand more about how this protein buildup affects brain function, the researchers conducted experiments using mice and cultured brain cells. They found that even when TDP-43 accumulates only in astrocytes, it can cause progressive memory loss in mice.

Interestingly, this memory loss occurred without any impact on other behaviors, indicating that the problem was specifically related to memory function.

The study also uncovered that astrocytes with accumulated TDP-43 showed increased activity of antiviral genes, even though no viruses were present.

This abnormal immune response led to an overproduction of immune messengers called chemokines, which then activated specific receptors on neurons in the hippocampus. This activation made the neurons hyperactive, which is believed to be the cause of the memory problems observed in the mice.

These findings suggest that when astrocytes behave abnormally, they can trigger immune responses that disrupt the normal functioning of neurons, leading to cognitive impairments like those seen in dementia.

This new understanding opens up the possibility of developing treatments that specifically target the immune activity in astrocytes. By moderating this activity, it might be possible to prevent or reduce the cognitive decline experienced by people with dementia.

The discovery has also broadened the range of potential treatments for dementia. For example, CXCR3 blockers, which are already being tested in clinical trials for other inflammatory conditions like arthritis, could potentially be repurposed to treat dementia.

This could offer a new approach to managing the condition, focusing on the immune system rather than just the neurons.

While research continues to explore the complexities of dementia, there are steps that people can take to help reduce the risk of cognitive decline:

  • Physical Exercise: Regular physical activity can boost brain function and help prevent cognitive decline. It also improves heart health, which is closely linked to brain health.
  • Healthy Diet: A diet rich in fruits, vegetables, whole grains, and healthy fats, like the Mediterranean diet, has been associated with better brain health and a lower risk of dementia.
  • Mental Stimulation: Keeping the brain active with puzzles, reading, and learning new skills can help maintain cognitive abilities.
  • Social Engagement: Staying socially connected through community activities or personal relationships can support mental health and cognitive resilience.
  • Adequate Sleep: Good quality sleep is essential for memory and overall brain health. Chronic sleep deprivation can increase the risk of cognitive decline.
  • Stress Management: Chronic stress can harm the brain, so finding ways to manage stress is important for maintaining cognitive health.
  • Managing Chronic Conditions: Conditions like diabetes and high blood pressure can raise the risk of dementia, so it’s crucial to manage these with a healthy lifestyle and, if necessary, medication.

The study led by Avital Licht-Murava and her team, published in Science Advances, not only enhances our understanding of dementia but also underscores the importance of a holistic approach to maintaining cognitive health as we age.

By combining scientific research with proactive lifestyle choices, we can work towards reducing the impact of dementia on individuals and society.

If you care about dementia, please read studies about Vitamin B9 deficiency linked to higher dementia risk, and flavonoid-rich foods could help prevent dementia.

For more information about brain health, please see recent studies that cranberries could help boost memory, and how alcohol, coffee and tea intake influence cognitive decline.

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