Alzheimer’s dementia mainly occurs from the age of 65 and leads to an increasing loss of neurons and cognitive abilities. Years before the first clinical symptoms appear, beta-amyloid plaques and tau fibrils, which consist of harmful proteins, form in the brain of the patient. One of the great mysteries surrounding the previously incurable disease is why 70 percent of those affected are female. The course is also more serious for them on average. Now, a study led by Keqiang Ye of Emory University School of Medicine, Atlanta, provides an answer to this question that has plagued science for decades.
Shortly before the onset of menopause (the last menstrual period in a woman’s life), the follicle-stimulating hormone (FSH) is increasingly released from the pituitary gland. At the same time, the first symptoms of Alzheimer’s often set in. Estrogen from the ovaries, on the other hand, which has long been traded as a possible trigger for dementia, remains constant at the time. Keqiang Ye and his colleagues suspect that FSH interacts with the so-called C/EBPβ/AEP signaling pathway, which is central to the development of Alzheimer’s pathology. To test their thesis, they removed the ovaries from demented laboratory mice and then blocked FSH with the help of antibodies. As the team was able to demonstrate, this inactivated the signaling pathway in the nerve cells.
But that’s not all: the plaques in the brains of the Alzheimer’s mice receded, and the cognitive symptoms also disappeared. In another series of experiments, the team injected FSH into both female and male rodents. This in turn made the disease worse and plaques formed in the hippocampus and other regions. The results indicate that the FSH hormone plays an important role in the development of Alzheimer’s via the C/EBPβ/AEP signaling pathway. Since men also secrete more FSH with increasing age, the researchers hope to be able to test a treatment for both sexes in the future that uses this hormone.