Scientists discover Alzheimer’s disease in dolphins

For the first time, scientists have discovered evidence of Alzheimer’s disease in a wild animal, after detecting ‘full-blown’ symptoms in the brains of dolphins.

Dolphins, like humans, are somewhat unique in that they can go on living for many years after they are capable of reproducing.

And, the findings now suggest Alzheimer’s may be among the costs of a long lifespan.

The study suggests alterations in insulin function may leave both humans and dolphins susceptible to the disease.

For the first time, scientists have discovered evidence of Alzheimer’s disease in a wild animal, after detecting ‘full-blown’ symptoms in the brains of dolphins. Study suggests alterations in insulin function may leave both humans and dolphins susceptible to the disease. Stock image

WHO IS AFFECTED BY ALZHEIMER’S DISEASE? 

The CDC has reported that in 2013, five million Americans had Alzheimer’s.

However, by 2050 this number is supposed to nearly triple, hitting 14 million.

The disease is one of the top ten leading causes of death in the US, coming in fifth among people aged 65 to 85.

The symptoms usually appear when a person is around 60 years old.

Researchers believe that genetics play a role in the disease’s onset, and they are also studying whether or not diet and environmental factors influence who is diagnosed with it.

Unlike the death rates for cancer and heart disease, that of Alzheimer’s is rising. 

‘It is very rare to find signs of full-blown Alzheimer’s disease in non-human brains,’ said Professor Simon Lovestone, an old age psychiatrist from Oxford Health NHS Foundation Trust.

‘This is the first time anyone has found such clear evidence of the protein plaques and tangles associated with Alzheimer’s disease in the brain of a wild animal.’

In the study, an international team of researchers examined the bodies of dolphins who had died after washing ashore on the Spanish coast.

This revealed dolphins also exhibit the tell-tale signs of Alzheimer’s – notably, the beta amyloid protein plaques and ‘tangles’ of another protein, tau.

According to the team, this is likely associated with insulin function.

Insulin regulates sugar levels in the blood, and triggers what’s known as ‘insulin signalling.’

Changes in insulin signalling in humans and other mammals can cause diabetes.

While studies have found that extreme calorie restriction in mice and fruit flies could alter this process, and extend lifespan, the new findings suggest doing so could also put some animals at greater risk for Alzheimer’s.

‘We think that in humans, the insulin signalling has evolved to work in a way similar to that artificially produced by giving a mouse very few calories,’ says Profesor Lovestone.

‘That has the effect of prolonging lifespan beyond the fertile years, but it also leaves us open to diabetes and Alzheimer’s disease.

‘Previous work shows that insulin resistance predicts the development of Alzheimer’s disease in people and people with diabetes are more likely to develop Alzheimer’s.

‘But our study suggests that dolphins and orcas (who also have a long post fertility life span) are similar to humans in many ways; they have an insulin signalling system that makes them an interesting model of diabetes, and now we have shown that dolphin brains show signs of Alzheimer’s identical to those seen in people.’

Dolphins, like humans, are somewhat unique in that they can go on living for many years long after they are capable of reproducing. And, the findings now suggest Alzheimer¿s may be among the costs of a long lifespan. Stock image

Dolphins, like humans, are somewhat unique in that they can go on living for many years long after they are capable of reproducing. And, the findings now suggest Alzheimer’s may be among the costs of a long lifespan. Stock image

The researchers say the new findings could pave the way for better approaches to treating the disease, offering a potential new avenue for testing Alzheimer’s drugs.

Until now, the disease had never been spotted in a wild animal.

‘At the moment, even in mice which have been genetically engineered to have the plaques associated with Alzheimer ’s disease, there are no tangles, and very little damage to brain cells,’ said Professor Lovestone.

‘This makes it difficult to find new ‘targets’ for curing the disease, as well as studying how a potential drug can change the disease.

‘But if altered insulin signalling can make an animal more susceptible to Alzheimer ’s disease, we might be able produce mice that are a true model of the disease, which we can then test to find new treatments.’ 

Read more at DailyMail.co.uk