Scientists found signs of Alzheimer’s in chimpanzees for the first time
We may not be the only living beings struggling with Alzheimer’s disease. For the first time, the plaques and tangles associated with the condition have been found in the brains of alderly chimpanzees. It is still unclear if they cause dementia in the animals.
In the brains of people with Alzheimer’s, a protein called beta-amyloid accumulates and forms sticky plaques between brain cells, according to New Scientist. These plaques trigger changes in another protein called tau and cause it to form tangles. These plaques and tangles are thought to kill brain cells together, leading to dementia. It is difficult to study the disease and develop treatments because other species don’t seem to develop plaques and tangles.
Melissa Edler, at Northast Ohio Medical University, and her colleagues have had the rare chance to study 20 brains from older chimpanzees aged 37 to 62. They discovered beta-amyloid plaques and early forms of tau tangles coexisting in 12 of the chimp brains and, similar to humans, they observed increasingly larger volumea of plaques in the chimp brains of more advanced age. It is not certain whether these plaques and tangles lead to the same kind of cognitive decline in chimpanzees that we experience.
“Our samples had been collected over decades, without any consistent or rigorous cognitive data accompanying them,” said Mary Ann Raghanti at Kent State University, Ohio, in whose lab the work was performed. “So it wasn’t possible to say whether the chimps had devastating cognitive loss or not. I’m cautious to say that they don’t get this kind of devastating decline, but we haven’t seen it yet.”
The study adds proof to the increasingly believable theory that the classic plaques and tangles of Alzheimer’s disease may be by-products of the disease, not the cause, according to Gary Kennedy, director of the Division of Geriatric Psychiatry at Albert Einstein College of Medicine in New York. Raghanti affirmed that humans might have something unique about their brain that predisposes us to cognitive decline that accompanies plaques and tangles.
“If we can identify those differences between the human and chimp brain then we might be able to pinpoint what is mediating the degeneration,” Raghanti explained. “That could be a target for drug treatment.”