Regular physical activity is associated with improved immunity and reduced occurrence of many diseases such as hypertension, heart attacks and Alzheimer's. A new study has found how irisin, an exercise-induced muscle hormone, helps in the potential treatment of Alzheimer's.

Irisin is a hormone secreted from muscles during exercise, which may help in weight loss and thermoregulation. Studies have shown the hormone could be used in treating obesity and other conditions associated with it.

In the latest study, researchers evaluated the effect of irisin in reducing amyloid-beta associated with the loss of thought and memory in Alzheimer's disease. The team studied the brains of mice with Alzheimer's disease and found that with exercise, the levels of the enzyme Neprilysin elevate, which lowers amyloid-beta.

"Here, using a three-dimensional (3D) cell culture model of Alzheimer's disease, we show that irisin significantly reduces Aβ pathology by increasing astrocytic release of the Aβ-degrading enzyme neprilysin," the researchers wrote.

The findings were published in the journal Neuron.

"First, we found that irisin treatment led to a remarkable reduction of amyloid beta pathology. Second, we showed this effect of irisin was attributable to increased neprilysin activity owing to increased levels of neprilysin secreted from cells in the brain called astrocytes," said Se Hoon Choi, a co-author of the study.

Previous studies have shown that when irisin is introduced into the bloodstream of mice, it can travel to the brain, suggesting that the hormone could be used as a therapeutic agent.

"Our findings indicate that irisin is a major mediator of exercise-induced increases in neprilysin levels leading to reduced amyloid beta burden, suggesting a new target pathway for therapies aimed at the prevention and treatment of Alzheimer's disease," senior study author Rudolph Tanzi explained.

Researchers believe the findings will pave the way for two possibilities of using irisin in the treatment of Alzheimer's.

"One is to develop irisin into a drug where we mimic the effects of exercise by injecting irisin into the body and getting it to go into the brain and the amyloid beta that causes Alzheimer's. More than that, it emphasizes the need for exercise. Aside from all of the exciting drug possibilities, it shows how exercise itself dramatically reduces your risk for Alzheimer's disease," Tanzi said.