This exceptional finding could also elucidate why such neurodegenerative diseases are specific to humans and is not fully evident in other species, including our closest evolutionary relative, the chimpanzee.
Headed by Rebecca Rosen, a doctoral student at Yerkes and Lary Walker, PhD, a neuroscientist and research professor at Yerkes, the study's findings may pave the way for new treatments.
It was during a routine post-mortem study of an aged, female chimpanzee that died of natural causes, that the researchers made their findings. They also discovered deposits of beta-amyloid protein in plaques and blood vessels of the chimp's brain tissue; however, these changes were infrequent in comparison to Alzheimer's disease in humans.
"We've seen these plaques in aged chimpanzees before, but this is the first time researchers have found both hallmark features of Alzheimer's disease--plaques and neurofibrillary tangles--in a nonhuman primate," explained Walker.
Characterised by of dementia, Alzheimer's disease is considered progressive and fatal. And it is the brain plaques and tangles linked with the disease that are considered as prime suspects in damaging and killing nerve cells that cause memory loss and dementia.
"Alzheimer's disease has a huge number of potential causes. By studying the development of human features of the disease that occur naturally in nonhuman primates, we may be able to isolate what makes people so susceptible to neurodegenerative disease and identify targets for therapeutics," said Rosen.
The study is described in the online issue of the Journal of Comparative Neurology.