Dementia: Expert discusses the signs and symptoms
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Dementia currently afflicts around 850,000 people in the UK, but the burden is expected to climb sharply in coming years, with the number of worldwide dementia sufferers set to reach 152 million by 2050. A new study has identified how Irisin, a recently discovered hormone, could counter the effects of mental decline, and pave the way for effective therapy.
There is growing evidence that exercise can change the brain’s anatomy, physiology and function.
Improvements to cerebral flow regulation and cardiorespiratory fitness could significantly improve memory and executive function, which holds great significance for dementia sufferers.
Combining morning exercise with brief walks throughout the workday, could also deliver promising results for short term memory.
The protective effect of physical exercise on the brain may be ascribed, to some extent, to the release of Irisin.
READ MORE: Dementia symptoms: 10 early signs of dementia you shouldn’t ignore
A study, conducted in mice, found that a hormone produced by the muscles during exercise could improve the health and function of neurons.
As the hormone crossed into the rodent’s brains, researchers observed an enhancement in thinking and memory both in healthy rodents and those with an animal equivalent of Alzheimer’s.
The team noted this was in part caused by alterations of neurons in the hippocampus, the part of the brain associated with verbal memory and learning.
Previous studies had concluded that sweat-inducing workouts could produce new cells in the hippocampus, increasing its volume and improving long-term memory, however, this study was the first of its kind to explore the role of Irisin.
Christiane Wrann, an HMS assistant professor of medicine and leader of the Program in Neuroprotection in Exercise at Mass General, said: “Preserving cognitive function is a major challenge in an increasingly ageing population.
“Exercise is known to have positive effects on brain health, which is why identifying key mediators of those neuro-protective benefits, like irisin, has become a critical goal of research.
“For the first time, we showed that soluble irisin, and not its full-length parent protein FNDC5, is sufficient to confer the benefits of exercise on cognitive function.
“These effects can possibly go well beyond what exercise itself can bring.
“This is particularly important inasmuch as irisin, a small natural peptide, would be much easier to develop into a therapeutic than the much larger membrane-bound protein FNDC.
”Furthermore, the team were able to demonstrate that the genetic deletion of irisin impairs cognitive function in ageing and Alzheimer’s disease.
The researchers said the findings that irisin treatment was effective in Alzheimer’s disease mouse model, even after the development of significant pathology, could alter the trajectory of memory loss with ageing and pave the way for new therapy.
Wrann added: “This could have implications for interventions in humans with Alzheimer’s disease where therapy typically starts after patients have become symptomatic.
The hormone is secreted from muscles in response to exercise and mediates some beneficial effects of exercise in humans, according to the study.
Furthermore, the hormone is believed to be able to change the biochemical environment in the brain, by acting directly on the organ’s glial cells.
Co-author of the study, Rudolph Tanzi, explained: “It’s hard to imagine anything better for brain health than daily exercise, and our findings shed new light on the mechanism involved: protecting against neuroinflammation, perhaps the biggest killer of brain neurons as we age.
“Since irisin does not specifically target amyloid plaques, but rather neuroinflammation directly, we’re optimistic it could have beneficial effects on neurodegenerative disease beyond just Alzheimer’s.”
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