10 July 2024
How come some people's brains seem to be able to resist Alzheimer's disease? Researchers have found that some people have biomarkers of Alzheimer's disease in their brains without showing symptoms. This phenomenon is called 'resilience'.
Luuk de Vries, a researcher at the VU, has been investigating this question. He works at the Verhaagen research group of the Netherlands Brain Institute. His research has been published in the scientific journal Acta Neuropathologica Communications.
The study used data from the Dutch Brain Bank. This bank contains tissue samples, medical history and symptoms of donors. The researchers found 11 resistant donors in the brain bank, fewer than expected.
This research could be important for the development of more effective drugs against Alzheimer's. Currently, there are drugs that reduce amyloid, a harmful protein. But these drugs do not yet have the desired effects. De Vries and his team hope that if they can find out why some people do not develop symptoms, this could lead to better treatments.
To understand what causes this resilience, the researchers studied gene expression in the frontal cortex, a part of the brain. They compared three groups: people with Alzheimer's, resilient brains and a control group. The total study included 35 individuals.
The researchers found that resilient brains produced more of an antioxidant called metallothionein. Astrocytes, cells that protect the brain, produced more of this antioxidant in the resilient group. This may help reduce tau protein, which, along with amyloid accumulations, is a key feature of Alzheimer's disease.
In addition, they saw that the 'unfolded protein response', a process that removes harmful proteins, functioned better in the resilient group. These brain cells also had more mitochondria, which improved energy production. These mechanisms may contribute to the maintenance of cognitive functions in the resilient group.
It is still unclear how and if you can stimulate this resilience. However, previous research does show that a healthy lifestyle, such as exercising, socialising and staying cognitively active, can delay symptoms of Alzheimer's.
Interestingly, the data suggested possible gender-dependent resilience mechanisms. Indeed, women are twice as likely to be diagnosed with Alzheimer's. Although the study group was too small to draw definitive conclusions about this, it is an important focus for future research.
The research on symptomless Alzheimer's offers new insights into how some people are able to resist the disease. By better understanding how this resilience works, we can hopefully find new ways to prevent or treat Alzheimer's. A healthy lifestyle remains an important factor in reducing the risk of this disease.