Alzheimer’s disease is a debilitating condition that affects over 28 million people worldwide, according to the World Health Organisation.
Scientists believe the disease is caused by an abnormal build-up of amyloid proteins in and around brain cells, which leads to problems in cell functioning, causing impaired memory, learning, and communication skills.
But what’s surprising is that these proteins are also found in the brains of marine mammals like dolphins, whales, and seals. Dr Mark Dagleish, a senior clinician of Anatomic Pathology at the University of Glasgow and his colleagues wanted to investigate if these marine mammals develop neural changes similar to Alzheimer’s disease in humans.
The study, published in the European Journal of Neuroscience, found that in three of the 22 dolphins examined, all specimens accumulated amyloid plaque pathology in their brains, which can impair cognitive function. They examined samples of specific brain regions from several species of oceanic dolphins that had died after being stranded on the ocean shores in Scotland.
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Dr Dagleish told The Guardian “these are significant findings that show, for the first time, that the brain pathology in stranded odontocetes is similar to the brains of humans affected by clinical Alzheimer’s disease”
While humans are believed to be the only species that develop Alzheimer’s disease spontaneously, this study raises concerns about the vulnerability of marine mammals to this debilitating condition. It’s a sad reality that even our beloved marine creatures are not immune to the effects of Alzheimer’s disease.
Alzheimer’s is not well understood
Alzheimer’s disease has left neuroscientists scratching their heads for decades. The exact causes of Alzheimer’s disease are still not fully understood. However, it is generally believed to be caused by a combination of genetic, environmental, and lifestyle factors in humans.
But for dolphins, one theory for this phenomenon is that they continue to live for many years after they stop reproducing, which is unique compared to many other animals, The Guardian reports. Another theory stems from a 2020 study that suggested deep-diving whales are more vulnerable to Alzheimer’s-like symptoms due to the low levels of oxygen they experience while in the deep ocean.
“We were fascinated to see brain changes in aged dolphins similar to those in human ageing and Alzheimer’s disease,” said Prof Tara Spires-Jones, a member of the research team at the University of Edinburgh. She added that investigating whether these pathological changes are linked to the stranding of these animals is an intriguing and vital area for further study.
Unfortunately, it may be some time before scientists can confidently say what causes Alzheimer’s and the development of an effective method of treatment. That being said, there are some promising signs that researchers are on the right path.
Latest Alzheimer’s breakthrough
The latest breakthrough in Alzheimer’s came at the end of 2022. For the first time, a drug called Lecanemab was shown to slow the rate of cognitive decline in people with Alzheimer’s disease.
While the effect is modest, the implications are nothing short of momentous, according to researchers — this could be the turning point in Alzheimer’s research that gives hope to millions worldwide.
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The drug, developed by Professor Sir John Hardy from UCL Queen Square Institute of Neurology, works by targeting beta-amyloid, a plaque that builds up in the brains of people with Alzheimer’s disease. Amyloid affects brain cells by causing them to become overactive and signalling ongoing inflammation, which can disrupt normal processes in the brain.
Blood flow can also be affected, and other proteins in the brain can become involved. In those with genetic Alzheimer’s, this happens early because the patient makes too much amyloid precursor protein (APP.) However, it also happens in those with non-genetic Alzheimer’s but at a slower rate.
“A drug like Lecanemab becoming available on the NHS would be a massive triumph, but challenges remain around getting drugs to the right people at the right time — we need changes in our health systems infrastructure to make sure we’re ready,” Professor Hardy told UCL.
Now armed with a better understanding of Alzheimer’s disease in humans and marine mammals, researchers are well on their way towards finding a cure for this horrible disease.