Cats can naturally develop dementia with brain changes strikingly similar to Alzheimer’s disease in humans, including toxic amyloid-beta buildup and loss of synapses.
A new study shows these similarities could make cats valuable natural models for research, potentially leading to treatments that benefit both species.
This research also revealed that brain support cells may contribute to synapse loss, and findings could help owners recognise and manage dementia symptoms in ageing pets.
Cats and dementia
Scientists have discovered how a build-up of the toxic protein amyloid-beta in the brains of cats with the condition, one of the defining features of Alzheimer’s disease. Such findings can potentially offer a clearer picture of how amyloid-beta may lead to age-related brain dysfunction and memory loss in cats.
Many older cats develop dementia, leading to behavioral changes such as increased vocalization – or meowing – confusion and disrupted sleep – symptoms similar to those seen in people with Alzheimer’s disease.
Dementia in cats, also known as feline cognitive dysfunction syndrome (CDS), is a condition that affects senior cats, leading to behavioural and cognitive changes. Common symptoms include: Disorientation and confusion, similar to Alzheimer’s disease in humans; Changes in social interaction and sleep-wake cycles; Personality changes, such as increased aggression or difficulty recognising familiar people.
To demonstrate this, scientists at the University of Edinburgh examined the brains of 25 cats of different ages after they had passed away, including those with signs of dementia. Microscopy images revealed a build-up of amyloid-beta within the synapses – connections between brain cells – of older cats and cats with dementia.
Specifically, with felines, synapses allow the flow of messages between brain cells and are vital to healthy brain function. Their loss strongly predicts reduced memory and thinking abilities in humans with Alzheimer’s disease. The researchers found evidence that astrocytes and microglia – types of support cells in the brain – engulfed or ‘ate’ the affected synapses. This process, called synaptic pruning, is important during brain development but can contribute to synapse loss in dementia.
Significance of stuyding cats
The scientists suggest the findings will help to understand and manage dementia in cats; moreover, given their similarities, this research could also contribute to the development of future treatments for people with Alzheimer’s disease.
Scientists studying Alzheimer’s disease in the past have relied heavily on genetically modified rodent models. Rodents do not naturally develop dementia, and studying cats with dementia has the potential to advance knowledge and help develop treatments for both cats and people.
Research paper
The study appears in the journal European Journal of Neuroscience, titled “Pathology Increases Synaptic Engulfment by Glia in Feline Cognitive Dysfunction Syndrome: A Naturally Occurring Model of Alzheimer\’s Disease.”
