Alzheimer’s: in women, stress would increase the risk of developing the disease

In women, the risk of developing Alzheimer’s disease is twice as high as for men. To learn more about this inequality, researchers at Washington University School of Medicine in St. Louis looked at the effects of stress on the brain.

Different genders react to stress

In order to carry out their research, the scientists used male and female mice. The objective: to demonstrate the effects of stress on the brain according to sex. According to the researchers, under stressful situations, levels of the beta-amyloid protein linked to Alzheimer’s disease increase sharply in the brains of female mice, but not in those of males.

“How women respond to stress compared to how men cope with it is an important area of ​​research that has implications not only for Alzheimer’s disease, but for other conditions as well.”said lead author Carla M. Yuede, PhD, associate professor of psychiatry.

More beta-amyloid produced under stress

Every 22 hours, the researchers therefore measured the level of the beta-amyloid protein in the brains of the mice, starting 8 hours before they suffered stress. The stressful experience for these rodents was similar for both males and females. However, the scientists discovered that the responses in their brains were different.

Indeed, in female mice, beta-amyloid levels increased significantly within the first two hours. Until the end of the monitoring period, these levels are elevated. In contrast, in male mice, levels of this protein on average did not change, although in about 20% of them delayed and weak argumentation of beta-amyloid was noted.

Stress, a risk factor for Alzheimer’s in women?

In addition, other experiments have also demonstrated that stress causes the release of a hormone known as “corticotropin releasing factor”. In female mice, the stress hormone is absorbed triggering a cascade of events that results in increased levels of beta-amyloid in the brain. Male mice do not have this absorptive capacity. It is not known, however, whether this distinction is also present in humans.

For John Cirrito, Phd, associate professor of neurology and co-author of the study, “We don’t believe that stress is the only factor driving the gender difference in Alzheimer’s disease. There are many other differences between men and women – relating to hormones, lifestyle, other illnesses – that undoubtedly contribute in one way or another. But that stress is driving an aspect of that sexual difference that I think is very likely.”