Around fifty million people worldwide are affected by dementia, and this figure could well triple by 2050. According to a Spanish study, stress is a risk factor for Alzheimer’s disease, particularly if several stressful events have occurred. experienced in midlife and during childhood.
People who experience stressful experiences during their lives may have a higher risk of developing Alzheimer’s disease at a later age. To reach this conclusion, the authors of this study published in Annals of Neurology relied on 1,290 participants, volunteers without cognitive disorders at the time of the study, but who had cases of Alzheimer’s in their family. They were questioned about the presence of stressful events during their life (death of a loved one, period of unemployment, illness, etc.), their frequency and their age at the time they experienced them. Researchers from the Barcelona Institute for Global health (ISGlobal) also carried out clinical tests (lumbar punctures and MRIMRI) to detect biomarkers of Alzheimer’s disease.
These periods when we are more sensitive to stress
Analyzing all this data, the researchers found that the accumulation of stressful experiences during midlife was associated with higher levels of proteinprotein β-amyloid (Aβ), which plays a key role in the development of Alzheimer’s disease. “ We know that midlife is a time when pathologiespathologies of Alzheimer’s disease begin to accumulate. It is possible that these years represent a vulnerable time where psychological stress can have a lasting impact on brain health “, says Eleni Palpatzis, researcher at ISGlobal and first author of the study in a press release.
The childhood period should also be monitored. Experiencing stressful events at a young age may be associated with a higher risk of developing neuroinflammation later in life. “ L’inflammationinflammation is recognized as a key molecular response in neurodegenerative diseasesneurodegenerative diseases and these findings are consistent with emerging evidence suggesting that childhood trauma is linked to increased inflammation in adulthood “.
Differences between men and women
Researchers have also found that the effects of stressful experiences may differ by gender. In men, a greater number of stressful events was linked to increased protein betabeta-amyloid (Aβ), the accumulation of which marks the starting pointstarting point of the disease. In women, they noted a reduction in volumevolume of mattermatter gray in the brainbrain. Gray matter is made up of nerve cells and plays a crucial role in our cognitive functions such as reading, calculation, attention and memory.
Individuals with a history of psychiatric disorders appeared to be more susceptible to the effects of stressful life events. These people have a higher level of stress linked to increased levels of beta-amyloid proteins and tau, a protein abundant when one is affected by Alzheimer’s disease, thus promoting its development. Additionally, these participants had lower gray matter volumes.
Limitations of the study
This study, however, has certain limitations. Research has found that relying on participants’ memory to remember stressful events can bias results. Furthermore, measuring stress does not necessarily take into account the personal impact it has or the gravitygravity events.
“ Our study reinforces the idea that stress may play an important role in the development of Alzheimer’s disease and provides initial evidence regarding the mechanisms behind this effect, but additional research is needed to replicate and validate our findings. initial results “, says Eider Arenaza-Urquijo.
Article Extract from BE China No. 35 – Embassy of France in China, published on December 15, 2006
A team from the Institute of Biology of the Chinese Academy of Sciences (CAS) in Shanghai, led by Pei Gang of the Institute of BiochemistryBiochemistry and of Cellular biologyCellular biologyhas just discovered that activation of the receptor adrenergicadrenergic beta-2 (beta2-AR) would lead to the formation of amyloid plaquesamyloid plaquesthe main cause of Alzheimer’s disease.
Currently affecting several million people in China with an aging population and therefore at risk, it is the most common form of senile degenerative dementia.
Previous studies have shown that substances called amyloid beta (A-beta) can build up and form brain lesions characteristic of Alzheimer’s. The CAS team discovered that beta2-ARs could cause the formation of A-beta through stimulationstimulation gamma-secretase. Experiments on mice showed that the formation of amyloid plaques was favored by treatment based on moleculemolecule agonistagonist beta2-AR (interacting with this membrane receptor and activating it) and reduced by a treatment based on an antagonist molecule (interacting but blocking its activity) which could thus enter into the composition of possible treatments.
Finally, since beta2-ARs are responsible for communication between cells, their activation by external factors such as stress can also lead to the formation of amyloid plaques and then to Alzheimer’s.
