A review led by Professor Simon Lovestone, theme lead at the NIHR Oxford Health Biomedical Research Centre, has found the first unambiguous signs of Alzheimer’s disease in a wild animal.

“It is very rare to find signs of full-blown Alzheimer’s Disease in non-human brains,” said Professor Lovestone, who is a researcher within the Oxford University Department of Psychiatry and is the Informatics / Digital Health theme lead at the NIHR Oxford Health BRC. “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.”

Like humans, dolphins are almost unique in living long after they are capable of having children. Most animals tend to die shortly after the end of their fertile years.

In a study published in the journal Alzheimer’s and Dementia, researchers tested the idea that living long after the end of fertility might be linked to Alzheimer’s Disease.

The team (which included scientists from the Universities of St. Andrews, Edinburgh, Florida, and Oxford) found signs of Alzheimer’s Disease in the brains of dolphins which had died after washing up ashore on the Spanish coast.

The team think that humans and dolphins are near-uniquely susceptible to Alzheimer’s Disease because of alterations in how the hormone insulin works in these species. Insulin regulates the levels of sugar in the blood, and sets off a complex chemical cascade known as insulin signalling.

Professor Lovestone:

We think that in humans, insulin signalling has evolved, with 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.

“Our study suggests that dolphins and orcas (who also have a long post fertility life span) are similar to humans in many ways,” says Professor Lovestone. “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.”

Professor Lovestone now hopes to use this understanding to improve the way we test new drugs for Alzheimer’s Disease.

Media coverage

Dementia in dolphins could give clues to Alzheimer’s in humans, The Times, 25/10/2017
Researchers at the University of Oxford have found that dolphins can develop Alzheimer’s disease. ‘It is very rare to find signs of full-blown Alzheimer’s disease in non-human brains,’ said Professor Simon Lovestone. The team suggests that changes in insulin signalling may play a role in triggering Alzheimer’s.