Stranded dolphins show signs of Alzheimer’s disease in the brain: ScienceAlert

Scientists have discovered markers Alzheimer’s disease disease in the brains of three different species of dolphins found dead, stranded on land.

Evidence for mass stranding of whales exists since before our own recorded historybut why dolphins and whales swim in groups remains a permanent mystery.

Although a direct link was found between marine sonar and some beaked whalesand some individual animals washed ashore by the water are clearly not well, some with a belly full of plastic wastemost mass strandings provide little or no clues.

Toothed whales (Odontocetes) divide the number traits with peopleincluding (in at least five species that we know of) menopause. Their ability to live beyond their reproductive years means they can also be susceptible to late-onset diseases.

Alzheimer’s is the most common cause of disability in aging people, gradually impairing memory, learning and communication. Now it appears that a similar plight may befall our aquatic mammal cousins.

“I have always been interested in the answer to the question: do only humans get dementia?” he says neurobiologist Frank Gunn-Moore from the University of St Andrews in Scotland.

“Our findings answer this question because they show that the potential pathology associated with dementia is indeed not only seen in patients.”

Leiden University biologist Marissa Vacher and colleagues examined the brains of 22 stranded dolphins to look for biochemical markers present in humans with Alzheimer’s disease. These include amyloid-beta plaques, which until it is no longer considered a direct cause diseases are still present in increased numbers among those who have them; and clusters tau proteins with hyperphosphorylation – when phosphate groups have been added to all possible binding sites on the protein molecule.

They found accumulations of amyloid-beta plaques and hyperphosphorylated tau in three dolphins, each from a different species: the long-finned pilot whale (Globicephala melas), white-beaked dolphin (Lagenorhynchus albirostris) and common bottlenose dolphin (Tursiops truncated). These individuals also had signs of aging such as worn or missing teeth and an increase in the ratio of white to gray matter in brain tissue.

Moreover, the locations of the brain lesions found in the dolphins matched the equivalent areas seen in humans with Alzheimer’s disease.

Although the researchers were unable to confirm a diagnosis of Alzheimer’s disease because they could not test the levels of cognitive impairment in the deceased animals, there is no data on the accumulation of either protein in people without the disease.

“We were fascinated to see brain changes in aging dolphins similar to those seen in human aging and Alzheimer’s disease,” he says Neuroscientist from the University of Edinburgh Tara Spiers-Jones.

Such as dolphins extremely social animals, it is possible that they help group members who start to struggle with their brains. This means there is a chance they will survive longer, allowing the disease to progress further than in solitary species, the researchers note.

Dolphin stranding is common in one of the studied species, Mr. molassessupporting ‘patient-leader‘ theory of this mysterious, fatal behavior.

“In humans, the first symptoms of cognitive decline associated with AD include confusion of time and place and a poor sense of direction,” Vacher and colleagues explain in your work.

“If he is the leader of the group Mr. molasses suffered from similar cognitive decline associated with a neurodegenerative disorder, which could lead to disorientation resulting in the pod being carried into shallow water and subsequent stranding.”

However, “whether these pathological changes contribute to the stranding of these animals is an interesting and important question for future work,” Spiers-Jones concludes.

This research was published in European Journal of Neuroscience.