Domestic cats (Felis catus) develop the same patterns of brain shrinkage and neurological decline as aging humans, and scientists think that makes them an ideal window into dementia and aging.
Januel et al. leveraged 3,754 observations extracted from age-related brain variation, blood chemistry profiles, and other data to equate ages across the lifespan of humans and cats. Image credit: Sci.News / Makieni777 / Rise-a-mui / Alexas_Fotos / Dorothe / Vaclav Zavada / Artem Makarov / Daga Roszkowska / Birgit / Pasi Mammela.
Cats can live relatively long lives and there is some evidence they may share aging patterns with humans.
According to AnAge, the maximum lifespan in humans (i.e. 122.5 years) is nearly twice that of great apes (e.g. 68 years in chimpanzees).
Domestic cats, like humans, also have a longer maximum lifespan (30 years) than closely related species, e.g. the European wildcat (Felis silvestris) (19 years).
Also, there are an estimated 600 million cats worldwide.
“We focus on cross-species age alignments across the lifespan of humans and cats with a particular focus on aging because cats live long lives and they are numerous, suggesting we may study them in large enough samples to assess whether their ages can be mapped onto a human in their 80s and beyond,” said Auburn University researcher Christine Charvet and colleagues.
For the study, the authors examined 3,754 data points collected across humans, cats and other mammalian species.
These data point covered brain imaging, blood chemistry, disease-related patterns and behavioral milestones such as eye opening and the onset of playful behavior.
The MRI work showed cats and humans share similar age-related changes in brain structure, including overall shrinkage, expansion of the ventricles (the hollow spaces inside the brain filled with fluid), and other structural alterations.
These brain changes are found in conditions commonly associated with aging. Both humans and older cats can develop age-related neurodegenerative changes later in life.
“It was interesting to see that cats show patterns of age-related brain atrophy similar to those observed in humans,” said University of Bath Ph.D. candidate Brier Rigby Dames.
“These findings add to growing evidence that companion animals can provide valuable insights into aging.”
Rather than using simple age ratios, the researchers developed a sophisticated biological model based on measurable age-related changes.
This approach reveals that aging in both species does not progress at a constant rate but instead speeds up or slows down at different life stages.
Using this model, the scientists found that aging patterns later in life align particularly closely between the two species; that an 80-year-old human equates to a 15-year-old cat; and that not all animals reach the equivalent of human old age, but domestic cats do.
“A growing number of cat owners are requesting advanced brain imaging for their pets to diagnose disease, providing an excellent opportunity to study aging animals living alongside humans in real-world environments,” said Dr. Ryan Gibson, a veterinary neurologist at Auburn University.
“This expanded clinical access creates meaningful opportunities for translational research (research that bridges the gap between scientific findings and healthcare), improving our understanding of aging and neurologic disease in ways that can benefit both feline and human patients.”
“There’s potential to develop large-scale veterinary health databases for companion animals, analogous to human health databases such as the UK Biobank,” Rigby Dames said.
“These kinds of resources could enhance our ability to study aging and disease using real-world clinical and owner-reported data collected across species.”
The findings appear in the journal Biology Open.
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Capucine Januel et al. Cat brains age like humans: translating time shows pet cats live to be natural models for human aging. Biol Open 15 (6): bio062604; doi: 10.1242/bio.062604
