Cat Brains Age Like Human Brains – A Key to Understanding Cognitive Decline

Cat Brains Age Like Human Brains – A Key to Understanding Cognitive Decline

Um the mysteries of human aging To decipher it, researchers might want to look at the cat dozing on their couch rather than at one Lab rat.

In older cats, the brains show signs of atrophy and cognitive decline, which are much more consistent with the changes seen in older people than the changes in the brains of aging mice. These findings were presented last month at the Lake Conference on Comparative and Evolutionary Neurobiology near Seattle, Washington.

The results are part of a larger project called Translating time, that the Brain development of over 150 mammal species and is now being expanded to include data on aging. The hope is that these data will help researchers understand the causes of age-related diseases, particularly those that affect the brain Alzheimer, to decipher.

“To address challenges in human medicine, we need to draw from a variety of model systems,” says Christine Charvet, a comparative neuroscientist at Auburn University College of Veterinary Medicine in Alabama, who presented the work. "Cats, lemurs, mice are all useful. We shouldn't concentrate our efforts on one."

Age in dog-friendly years

The Translating Time project began in the 1990s as a tool for developmental biologists. 1 The project's scientists collected data on how long it takes the brain to reach various developmental milestones in a variety of mammals and used this data to graph the relative development of two species over time. This can help researchers link observations of animal development to corresponding human ages.

Over the years, however, researchers have repeatedly asked Charvet if they could also access the database Changes in the brain as animals age could expand.

Scientists have long been frustrated by the limitations of standard laboratory models when it comes to understanding human aging and its impact the unique human brain to understand. Mice live only a few years — not long enough to accumulate much of the damage that is thought to cause some neurodegenerative diseases in humans. In addition, mice could have mechanisms that humans lack Deposits of misfolded proteins known as plaques, a hallmark of Alzheimer's disease, says Melissa Edler, a comparative neurobiologist at Kent State University in Ohio.

The evolutionary mismatch between mice and humans may be one reason why efforts to develop therapies to treat the disease have often failed, says Elaine Guevara, who studies evolutionary genetics in primates at Duke University in Durham, North Carolina. “ Mice do not develop the classic features of Alzheimer's disease ", she says. "Their brains are completely different than ours."

Our pets, ourselves

Service animals could be an alternative solution. They live longer than mice, share the environment with their owners and are susceptible to human diseases including obesity and diabetes. The Dog Aging Project, conducted by researchers at the University of Washington in Seattle and Texas A&M University in College Station, is tracking tens of thousands of service dogs to learn more about how their genetics, lifestyle and environment influence aging.

But Centuries of breeding have influenced aging and disease in dogs, says Charvet. Cats often live slightly longer than dogs, she adds, and are generally not bred as heavily for certain traits - some of which also increase the risk of disease.

That's why Charvet and her colleagues started collecting data from veterinary practices and zoos and launched an initiative called the Catage Project, which asks cat owners to provide data about theirs Pets to submit.

So far, they have collected health records and blood test results from thousands of cats and performed brain scans on more than 50. Using their own data and published literature, the team fills in events along the nonlinear relationship between cat and human ages. For example, a one-year-old cat is roughly equivalent to an 18-year-old human. However, in the following year, a cat only ages about 4 “human years,” reaching a maturity roughly equivalent to that of a 22-year-old human.

At 15 years old, a cat is an octogenarian in human years. Some cats experience cognitive decline by then, and brain scans collected by the team show changes in brain volume in older cats that are similar to changes in older people, Charvet says. Previous work has also shown that cats can accumulate plaques and strands of abnormal proteins similar to those that characterize Alzheimer's disease in humans.

Diverse models

Ultimately, researchers could develop a variety of model systems for different aspects of aging and neurodegeneration, says Edler. Although mice are poor models for some aspects of human aging, they will still be valuable because it is so easy for researchers to conduct genetic experiments on the rodents, she says.

Other animals, such as cats or certain non-human primates, may be better models for other aspects of brain aging. Caleb Finch, who studies life history evolution at the University of Southern California in Los Angeles, argues for more intensive study of naked moles, which live surprisingly long for small rodents and very low cancer rates have.

“Cats are useful,” says Charvet. "But they will only be useful up to a certain point. Other model systems are also necessary."

1. Finlay, B. L. & Darlington, R. B. Science 268, 1578-1584 (1995).

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