Why some older people less likely to have Alzheimer’s disease

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Many people develop Alzheimer’s or other forms of dementia as they get older. However, others remain sharp well into old age, even if their brains show underlying signs of neurodegeneration.

Among these cognitively resilient people, researchers have identified education level and amount of time spent on intellectually stimulating activities as factors that help prevent dementia.

In a new study from MIT, researchers found that this kind of enrichment appears to activate a gene family called MEF2, which controls a genetic program in the brain that promotes resistance to cognitive decline.

The researchers found this link between MEF2 and cognitive resilience in both humans and mice. The findings suggest that enhancing the activity of MEF2 or its targets might protect against age-related dementia.

In the study, the team used data from two human datasets comprising slightly more than 1,000 people altogether.

They found that cognitive resilience was highly correlated with the expression of MEF2 and many of the genes that it regulates.

The researchers also found that MEF2 appears to be most active in a subpopulation of excitatory neurons in the prefrontal cortex of resilient individuals.

The team also showed MEF2 was more active in the brains of the mice exposed to the enriched environment. These mice also performed better in learning and memory tasks.

The researchers then explored whether MEF2 could reverse some of the symptoms of cognitive impairment.

They found if mice were engineered to overexpress MEF2 at a young age, they did not show the usual cognitive impairments produced by the tau protein later in life.

The findings suggest that enhancing MEF2 activity could help to protect against dementia; however, because MEF2 also affects other types of cells and cellular processes, more study is needed to make sure that activating it wouldn’t have adverse side effects.

The study is published in Science Translational Medicine. One author of the study is Li-Huei Tsai.

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