It’s a long-standing medical mystery that women are at higher risk of developing Alzheimer's disease compared to men. Now, a team of scientists believes they have found the answer: follicle-stimulating hormone (FSH). In a new study, reported in the journal Nature this week, researchers from Emory University School of Medicine and the Chinese Academy of Sciences show how female hormones can have a significant impact on the formation of amyloid plaques and tau in the brain, which is the core factor driving the development of neurodegenerative diseases. The team found that FSH, a prominent hormone in females that increases during menopause, acts directly on the brain’s neurons to accelerate the formation of amyloid plaques and tau through the so-called C/EBPβ/AEP pathway. "During menopause, the serum concentration of FSH strongly increases, binding to the cognate FSH receptor on neurons and activating the C/EBPβ/AEP pathway. This results in Aβ and Tau pathologies, leading to the development of [Alzheimer's disease]," Dr Zaidi Mone, co-corresponding study author and a tenured professor at the Mount Sinai School of Medicine in New York, said in a statement. The team reached these conclusions through a number of experiments in mice. In one arm of the study, they injected FSH into male mice and discovered that the hormone promoted the development of clear signs associated with Alzheimer's. As another part, they saw how female mice with their ovaries removed responded to anti-FSH antibody treatment and the deletion of their FSH receptors. This was found to alleviate the pathology of the disease and boost cognitive dysfunction. This isn’t the first study to implicate hormones in the development of Alzheimer’s disease. Another study published earlier this year found that low testosterone in older men has a link to dementia and Alzheimer's disease. Almost two-thirds of people living with Alzheimer's disease in the US are women, according to the Alzheimer's Association. Some have previously assumed this is just a reflection of women tending to live longer than men, but increasing evidence has suggested it's most likely underpinned by other biological factors. This new study provides some of the sturdiest evidence yet that hormones, especially FSH, play a key role. In a follow-up to this latest study, the researchers hope to understand how certain genes may also play a role in the relationship between FSH and Alzheimer's. In turn, this could help to identify people most at risk of neurodegenerative diseases and gain a deeper understanding of this dreadful disease. Source
