Hormone released during exercise protects against Alzheimer’s disease, study finds
The relationship between regular exercise and a decreased risk of Alzheimer’s disease, a staggering 45% reduction, has been well-documented
[Sept. 13, 2023: Staff Writer, The Brighter Side of News]
Researchers have revealed a critical link between exercise and the prevention of Alzheimer’s disease. (CREDIT: Creative Commons)
In a breakthrough discovery at Massachusetts General Hospital (MGH), researchers have revealed a critical link between exercise and the prevention of Alzheimer’s disease. Central to this revelation is the hormone irisin, released during physical activity.
Historically, the relationship between regular exercise and a decreased risk of Alzheimer's disease – a staggering 45% reduction – has been well-documented. Yet, the underpinning mechanism remained an enigma. This new study illuminates how irisin plays a crucial role in this protective effect.
Irisin: The Protective Hormone
The primary function of irisin, which muscles produce during exercise, is to regulate glucose and fat metabolism. But the MGH team's research demonstrated another pivotal role: irisin combats the accumulation of sticky amyloid plaques known to impede brain cell communication – a hallmark of Alzheimer's.
Dr. Se Hoon Choi, from the Genetics and Aging Research Unit at MGH, noted, "First, we found that irisin treatment led to a remarkable reduction of amyloid beta pathology."
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He went on to say, "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 (immune cells)."
In simpler terms, irisin commands the brain's immune cells to produce more neprilysin, an enzyme responsible for breaking down the problematic amyloid.
Hope in the Lab
Further cementing the importance of irisin, when the team applied this hormone to cellular models of Alzheimer’s disease in a controlled lab environment, they witnessed a substantial reduction in amyloid.
Irisin reduces Aβ, dystrophic neurites, and hyperexcitability. Diagrams of lentiviral internal ribosome entry sites (IRESs) constructs. CMV, cytomegalovirus. (CREDIT: Neuron)
The implications of these findings are twofold: they not only elucidate how exercise functions as a potent preventative measure against dementia but also spotlight potential avenues for innovative treatments. Two promising drugs, which counteract Alzheimer’s by eliminating amyloid plaques, are currently undergoing trial phases, awaiting UK approval.
A National Health Crisis
The current dementia statistics for Britain are sobering. Predictions estimate the number of dementia patients will surge past one million by the end of this decade. Alarmingly, one-third of the UK's newborns this year face the likelihood of developing dementia during their lifetimes.
secNEP activity levels (A) and western blots of secNEP and secIDE (B) in the media of 5-week 3D-AD cultures treated with irisin or PBS. Graphs represent densitometric quantifications. (CREDIT: Neuron)
Alzheimer’s is not only a health menace but also an economic one. The nation grapples with an annual £34.7 billion bill due to this condition, which has tragically become the leading cause of death. Although available medications can provide relief from symptoms, they fall short of halting the disease's progression.
A Beacon of Hope
Previous research has identified irisin's presence in the brain. However, its levels are notably diminished in Alzheimer’s patients. Intriguingly, when introduced into the bloodstream, irisin has the ability to migrate to the brain, potentially wielding therapeutic powers.
Identified integrin subtypes expressed in 5-week ReN-mGAP cultures by mass spectrometry. Integrin αV and β5 highlighted in yellow. Paired t test. Western blots of integrin αV and β5 in the 3D gels of 5-week ReN-GA cultures. (CREDIT: Neuron)
Dr. Rudolph Tanzi, senior author of the study and director of the Genetics and Aging Research Unit, remarked, “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."
For those interested in delving into the specifics of this groundbreaking research, the full study is accessible in the prestigious journal, Neuron.
As society grapples with the mounting threat of Alzheimer’s, these revelations from MGH offer a glimmer of hope. Harnessing the power of exercise, understanding irisin's role, and developing innovative treatments might be the keys to turning the tide against this devastating disease.
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