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Mammals (other)
Alzheimer’s disease-like pathological lesions in an aged bottlenose dolphin (Tursiops truncatus)
  1. Ioanna Stylianaki1,
  2. Anastasia T Komnenou2,
  3. Dimitrios Posantzis3,
  4. Konstantina Nikolaou4 and
  5. Nikolaos Papaioannou1
  1. 1 Department of Pathology, Aristotle University of Thessaloniki, Thessaloniki, Greece
  2. 2 Department of Comparative Ophthalmology-Exotic and Wildlife Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
  3. 3 Attica Zoo Park, Athens, Greece
  4. 4 Laboratory of Productive Agriculture, Division of Crop Production, Department of Agricultural Technology, Technological Educational Institute of Epirus, Arta, Greece
  1. Correspondence to Dr Nikolaos Papaioannou; nikpap{at}


Alzheimer’s disease (AD) is the most common neurodegenerative disorder causing dementia. AD-like pathological lesions have been described in human and in several other animal species. In this study, we report AD-like pathological changes observed in the brain of a 40-year-old dolphin (Tursiups truncatus), boosting dolphins as a promising natural model of AD. The amyloid β (Aβ) was detected immunohistochemically as intraneuronal depositions, parenchymal accumulations and limited deposits in the wall of meningeal and parenchymal vessels. Also, neuronal tau positive labelling was noticed. This is the first report to show ΑpoE immunopositive reaction in dolphins. Glial fibrillary acidic protein positive astrocytes were also observed. Our findings are indicative of early AD or mild cognitive impairment pathology. So, they strongly reinforce the statement that dolphins could be a natural animal model of AD due to their lifespan, brain lesions and Αβ homology with the human peptide.

  • ageing
  • neuropathology
  • dolphins
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  • Contributors IS carried out all the necropsy, and histo and immuno techniques. Moreover, she wrote the paper. KN and DP treated the dolphin. KN was involved in the immuno techniques. NP coordinated and contributed in all the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.

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