In female mice, stress was associated with an increased risk of Alzheimer’s disease. Reported by the University of Washington.
It is known that women are approximately twice as likely to develop Alzheimer’s disease than men. This is largely due to age: women live longer on average, and old age is the most reliable indicator of this disease. But scientists are looking for ways to explain the observed gender inequality.
Carla Juede and her research team set out to find out if the reason for this lay in the different responses to stress in men and women. To do this, scientists conducted an experiment on laboratory mice. Starting 8 hours before the mice’s stressful event, they measured the levels of beta-amyloid, a protein important in Alzheimer’s disease, in the mice’s brains every hour for 22 hours. Judging by the level of hormones in their blood, the event was equally stressful for male and female mice, but the brain’s response to these hormones was significantly different.
Brain amyloid-beta levels in female mice increased significantly during the first two hours and remained elevated until the end of the observation period. In male mice, brain levels of this substance were generally unchanged, although approximately 20% of these had a delayed and mild increase in amyloid levels.
Further experiments showed that the difference was due to different cellular responses to stress. Stress triggers the release of a hormone known as corticotropin-releasing factor. Females’ neurons take up the stress hormone and initiate a series of events that lead to increased levels of beta-amyloid in the brain. In contrast, male rodent neurons cannot absorb the stress hormone.
The authors hope that if the data from model animals are correct for humans, their findings will reduce the number of women suffering from Alzheimer’s disease.
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