As the prevalence of Alzheimer’s Disease and dementia in our society continues to increase, scientists have been eager to better understand the physiology and biochemical pathways involved in these disease processes. Current research has honed in on a specific hormone, Irisin, that was found to be produced by muscles during exercise. This hormone, originally identified in 2012, is understood to affect multiple biochemical reactions in the body and be a key player in how energy is metabolized by our cells. It is accepted that altered energy metabolism in the brain has been associated with Alzheimer’s disease.
Therefore, scientists sought out to determine whether, or not, this hormone was present in the brain, and if so, what its’ impact was on memory and function. What they found was quite remarkable. With gathered tissue from brain banks they were able to confirm the presence of Irisin in the brain. They found that levels were particularly high in those who were free of dementia when they died and hardly detectable in those who had died with Alzheimer’s. In animals bred to have dementia, a concentrated dose of Irisin was demonstrated to improve performance on memory testing and ultimately improve synaptic health.
In other experiments, scientists blocked the production of this hormone and introduced beta amyloid, a component of plaques found in the brain of those with Alzheimer’s. By doing this, they were able to create dementia in those animals. This testing demonstrated that without the ability to produce this hormone, the mice showed evidence of declining memory and function in the neurons in their hippocampus, the memory center of the brain.
The final challenge was finding a connection between exercise and Irisin effects in the brain. Scientists found that in healthy mice, after five weeks of daily exercise, brain Irisin levels increased significantly and demonstrated profound resilience when subsequently exposed to beta amyloid. Although it is unclear if the effect of this hormone will be as remarkable in people, the results of these studies have proven to be exciting and promising. In addition to encouraging continued daily exercise as dementia prevention, scientists are working on a pharmaceutical form of Irisin that may be able to simulate the positive effects of this natural hormone.