Exercise May Protect Against Alzheimer’s

Henrietta Strickland
February 12, 2019

The reason for this was not known. It was hypothesized that irisin could play a role in energy metabolism of the body. But newer research found that the hormone may also promote neuronal growth in the brain's hippocampus, a region critical for learning and memory. Now evidence shows that exercise produces another hormone that may improve memory and protect against Alzheimer's disease, according to a study co-led by Ottavio Arancio, MD, PhD, a researcher at Columbia University's Vagelos College of Physicians and Surgeons and Taub Institute for Research on Alzheimer's Disease and the Aging Brain.

U.S. and Brazilian scientists found lower levels of the hormone in the brains of Alzheimer's patients compared with healthy individuals.

Arancio and his colleagues looked for a link between irisin and Alzheimer's. The experiments showed that irisin protects the brain's synapses and memory. When irisin levels were raised, there was an improvement in brain health, the researchers noted. The researchers developed an optic probe that glows over 100 times more brightly when it detects fiber or fibrils of amyloid beta proteins; the concentrated light then oxidizes the fibers to prevent them from accumulating in the brain and affecting patient cognitive ability, and a specific binding site for the harmful proteins was identified which may pave the way for new drug treatments.

Beta amyloid accumulation leads to the development of cognitive disorders, thus far drugs created to target these proteins have not shown relative efficacy. In experiments initiated on mice, it was found that daily swimming activities lasting no less than five weeks inhibited the development of memory deficits, this was despite infusions of beta-amyloid, a protein linked to Alzheimer's. This means that despite the pathology, irisin has the capacity to stop the progressive memory loss associated with Alzheimer's disease say the researchers.

The researchers noticed that the positive benefits that came from swimming were cancelled out when they blocked irisin with the beta-amyloid injections.

Dr James Pickett, head of research at the UK's Alzheimer's Society charity, said: "Although this study was only in mice, it adds to mounting evidence of the relationship between lifestyle factors, like physical fitness, and dementia". But that's not possible for many people, especially those with age-related conditions like heart disease, arthritis, or dementia.

Bolstering irisin, either with drugs or through exercise, could provide a "novel strategy" for preventing cognitive decline in patients with Alzheimer's disease, said the scientists.

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