This is suggested by the results of analyzes carried out by a British research team which detected the characteristic signs of the disease in the brains of cetaceans.
Among the causes of the unexplained strandings of dolphins along the Scottish coasts could be a pathology similar to Alzheimer’s disease, the most common neurodegenerative disease in humans, especially in the elderly, in which it manifests by symptoms such as memory loss, disorientation and difficulty performing normal daily activities. This is suggested by the results of analyzes carried out by a British research team which detected the presence of certain markers of the disease in the brains of at least three species of stranded cetaceans. According to a study recently published in theEuropean Journal of Neuroscience and revived by cnnthe finding supports the “sick leader” theory, that brain degeneration-induced confusion may have prompted the leader of the herd to make navigational errors that trigger mass strandings.
Alzheimer’s disease markers in the brains of stranded dolphins
For the analysis, the most in-depth and broadest in number of different species examined – five in total (Risso’s spinner dolphins, pilot whales, white-beaked dolphins, porpoises and bottlenose dolphins) – the researchers assessed some of the hallmarks of Alzheimer’s disease in 22 stranded odontocetes, highlighting that the 18 older specimens all showed the accumulation of amyloid plaques in the brain, or the presence of amyloid formations which, in humans, are closely associated with the disease . Among these cetaceans, three specimens from three different species (a pilot whale, a white-beaked dolphin and a bottlenose dolphin) also showed intra-neuronal accumulations of hyperphosphorylated tau, a protein which, in aggregate form, is a marker of cognitive decline in the patients. with Alzheimer’s disease and glial cells that cause brain inflammation.
« The simultaneous appearance of beta-amyloid plaques and an accumulation of hyperphosphorylated tau shows that these three species spontaneously develop an Alzheimer-type neuropathology. – explain the researchers in the research paper – . Their distribution in the brain is also comparable to brain regions of humans with Alzheimer’s disease.”.
The results, commented on cnn Dr Mark Dagleish, co-author of the study and senior clinician in anatomical pathology at the University of Glasgow, is “ which comes closest to demonstrating that all animals spontaneously develop the lesions associated with Alzheimer’s disease”. Specifically, the neuropathology of older specimens, similar to that of humans, suggests that marine mammals are susceptible to disease, although diagnosis can only be made in the presence of cognitive deficits that typically require assessments for cognitive impairment. , impossible in post-death.