Scientists find a big cause of cognitive decline in older people

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Dementia is a debilitating condition that affects millions of people worldwide, and it is characterized by a decline in cognitive function, including memory loss, confusion, and difficulty performing daily tasks.

The causes of dementia are still not fully understood, and there is no known cure for the condition.

However, recent research by a team of scientists at Weill Cornell Medicine has shed new light on the role of astrocytes in the development of dementia.

Astrocytes are non-neuronal cells that play a critical role in maintaining the health and function of neurons in the brain.

These cells have long been viewed as playing only supporting roles to neurons in brain health, and much less research has focused on them compared to neurons.

However, the new study suggests that astrocyte dysfunction alone can cause memory loss, even when neurons and other cells are otherwise healthy.

The study found that people with dementia have protein build-up in astrocytes that may trigger abnormal antiviral activity and memory loss.

The accumulation of a protein called TDP-43 in astrocytes within the hippocampus, a brain region crucial for memory, was observed in tissue samples from deceased individuals who were diagnosed with either Alzheimer’s disease or frontotemporal dementia.

The research team then conducted a series of experiments in mouse models and brain cells grown in the laboratory.

They found that the build-up of TDP-43 in astrocytes was sufficient to cause progressive memory loss in mice, but not other behavioral changes.

The team also analyzed gene expression and found high levels of antiviral gene activities, even though no virus was present in the brain.

Astrocytes produced excessive amounts of immune messengers called chemokines, which can activate CXCR3 chemokine receptors typically found on infiltrating immune cells.

To their surprise, the team discovered that CXCR3 receptor levels were elevated in hippocampal neurons, and that excessive CXCR3 receptor activity made neurons “hyperactive,” which led to cognitive deficits.

The findings suggest that abnormal immune activity in astrocytes is sufficient to cause cognitive deficits in dementia.

The discovery could lead to new treatments that reduce excess immune activity in astrocytes and their detrimental effects on other brain cells and cognition.

Drugs that target the identified immune pathways might help improve cognitive function in people with dementia.

Scientists are already testing CXCR3 blockers to treat arthritis and other inflammatory conditions in clinical trials. These drugs could be tested and potentially repurposed for dementia.

How to prevent cognitive decline

Cognitive decline is a normal part of aging, but there are ways to slow down or prevent its progression. Here are some strategies that can help prevent cognitive decline:

Physical exercise: Regular exercise has been shown to improve brain function and prevent cognitive decline.

Exercise increases blood flow to the brain, which can promote the growth of new brain cells and strengthen existing connections between neurons. It also reduces the risk of cardiovascular disease, which is a known risk factor for dementia.

Healthy diet: A healthy diet rich in fruits, vegetables, whole grains, lean protein, and healthy fats is associated with better cognitive function.

Eating a Mediterranean-style diet that includes foods such as fish, nuts, and olive oil has been linked to a reduced risk of cognitive decline.

Mental stimulation: Keeping the brain active and engaged can help maintain cognitive function. Engage in activities such as reading, puzzles, and learning new skills or hobbies.

Social engagement: Maintaining social connections can help prevent cognitive decline.

Activities such as volunteering, joining a club or organization, or spending time with friends and family can help keep the brain active and stimulated.

Adequate sleep: Getting enough sleep is important for brain health. Sleep helps the brain consolidate memories and recharge for the next day. Chronic sleep deprivation has been linked to cognitive decline.

Stress management: Chronic stress can have negative effects on the brain, including cognitive decline. Finding ways to manage stress, such as through meditation, exercise, or spending time in nature, can help prevent cognitive decline.

Manage chronic health conditions: Chronic health conditions such as diabetes, high blood pressure, and heart disease can increase the risk of cognitive decline.

Managing these conditions through lifestyle changes and medications can help prevent cognitive decline.

If you care about dementia, please read studies that your walking speed may tell your risk of dementia, and these high blood pressure drugs could prevent dementia.

For more information about brain health, please see recent studies that high-fiber diet could help lower the dementia risk, and these antioxidants could help reduce dementia risk.

The study was conducted by Avital Licht-Murava et al and published in Science Advances.

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