The Insight Corner Hub: Exercise-Induced Hormone Protects Against Alzheimer's

Alzheimer's disease is a progressive brain disorder that causes memory loss, cognitive impairment, and behavioral changes. It is characterized by the accumulation of abnormal protein deposits called amyloid beta plaques and neurofibrillary tangles in the brain. There is no cure for Alzheimer's, but some treatments can slow down its progression and improve the quality of life of patients and caregivers.

One of the factors that may influence the risk and severity of Alzheimer's is physical exercise. Studies have shown that exercise can improve mental performance, reduce inflammation, and lower the levels of amyloid beta in the brain. However, the exact mechanism by which exercise exerts these beneficial effects is not fully understood.

A recent study by researchers from Massachusetts General Hospital has shed some light on this mystery. They have discovered that a hormone called irisin, which is produced by muscle tissue during exercise, may play a key role in protecting the brain from Alzheimer's. Irisin is carried by the bloodstream to various organs, including the brain, where it regulates glucose and lipid metabolism, energy expenditure, and inflammation.

The researchers found that irisin can reduce both the plaque and the tangle formation in the brain by increasing the activity of an enzyme called neprilysin. Neprilysin is responsible for degrading amyloid beta and preventing its accumulation. The researchers also showed that irisin can increase the levels of neprilysin by stimulating the secretion of this enzyme from astrocytes, which are star-shaped cells that support and nourish neurons.

The study used 3D human cell culture models of Alzheimer's disease, which were developed by the same team in previous research. These models allow the researchers to mimic the complex interactions between different cell types and molecular pathways in the brain. The study also used mouse models of Alzheimer's disease to test the effects of irisin injections on amyloid beta pathology.

The findings suggest that irisin is a major mediator of exercise-induced benefits on brain health and function. Irisin may also offer a new target for therapies aimed at preventing and treating Alzheimer's disease. The researchers hope to further explore the potential of irisin-based interventions in future studies.

The study was published in the journal Neuron on Sept. 8, 2023¹. It was led by Se Hoon Choi and Rudolph Tanzi from the Genetics and Aging Research Unit at Massachusetts General Hospital²³⁴⁵.

References

1. HealthDay. (2023, September 8). An Exercise-Induced hormone might help protect against Alzheimer’s. US News & World Report. https://www.usnews.com/news/health-news/articles/2023-09-08/an-exercise-induced-hormone-might-help-protect-against-alzheimers
2. An Exercise-Induced hormone might help protect against Alzheimer’s. (2023, September 11). MedicineNet. https://www.medicinenet.com/exercise_induced_hormone_fights_alzheimers/news.htm
3. Scientist, N. (2019, January 17). A hormone released during exercise might protect against Alzheimer's. New Scientist. https://www.newscientist.com/article/2189845-a-hormone-released-during-exercise-might-protect-against-alzheimers/
4. How exercise may protect against Alzheimer’s. (2019, February 19). ScienceDaily. https://www.sciencedaily.com/releases/2019/02/190208173511.htm
5. Hicks, T. (2023, September 8). Alzheimer’s: Exercise-induced hormone may help reduce plaque and tangles in the brain. Healthline Media UK. https://www.medicalnewstoday.com/articles/alzheimers-exercise-induced-hormone-may-help-reduce-plaque-and-tangles-in-the-brain