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On a typical weekday, Elizabeth Head spends almost seven hours watching a dozen beagles play with colored blocks.

A neuroscientist and professor at the University of Kentucky College of Medicine, Head is performing a study to see if she and her team can stave off the beagles’ cognitive decline. At the university’s Sanders-Brown Center on Aging, four researchers spend each week observing 45 beagles between the ages of four and eight as the dogs take 30-minute turns playing games inside a big wooden box, staring down two large, Lego-like blocks colored yellow and blue. On some days, the dogs’ job is to nudge the yellow block out of the way to reveal a treat. Then researchers reverse the task, hoping the beagles will nudge the blue block to get their tasty prize.

Beagles usually live until about age 13. Depending on how these beagles perform on learning and memory tasks over the next several years, Head will learn whether the drug they’re receiving can preserve their cognitive abilities. The drug in question, called tacrolimus is an immunosuppressant that’s approved by the Food and Drug Administration (FDA) to prevent tissue rejection in organ transplant patients. Human studies have shown that transplant patients who take tacrolimus for decades tend to be protected from the brain plaques and protein accumulation characteristic of Alzheimer’s. Since the brains of dogs with dementia look similar to those of humans, Head hopes the dog study may provide clues as to human longevity, too.

“There’s a lot of angst about the idea of playing around with the aging process.”

“Strangely enough, it turns out dogs can model events in the human brain naturally and spontaneously,” Head says. “I think that means that what we learn from dogs will translate to people.”

In other words, if the tacrolimus in Head’s beagle experiment works, she’ll not only have gathered data on some of the predictors of cognitive decline — she will also have a lead on a drug that could be studied for the treatment of Alzheimer’s in people.

Novel as it sounds, Head’s experiment is just one of several ongoing aging studies being performed on dogs. Another immunosuppressant drug, rapamycin, is the focus of a multi-year study called the Dog Aging Project, the data from which is being parsed for clues about how to make our four-legged pals live longer and healthier lives.

Why and how humans age has been a subject of inquiry for millennia, but it wasn’t until 1974 that the National Institutes of Health formed its Institute on Aging. Since then, research has accelerated, thanks to scientific advances — and the deep pockets — that make this kind of research possible. In recent years, many Silicon Valley companies, including companies like Google and Facebook, have paid ample attention to the field of aging research, even going so far as to fund their own ventures to delay, slow, or even outsmart the human aging process.

“There’s a lot of angst about the idea of playing around with the aging process,” says Matt Kaeberlein, PhD, a pathology professor at the University of Washington and co-director of the Dog Aging Project. “Dogs could play an important role both in showing us how to accomplish similar things in people, but also convincing people that slowing aging is actually possible.”


Dogs have long been go-to subjects for researchers studying certain human diseases. Many of the techniques used in medicine today were first developed in canines: The success of bone marrow transplants, for instance, which provide new stem cells for patients suffering from blood cancers like leukemia and lymphoma, were initially borne out of preclinical trials on dogs.

According to a 2007 article in the journal Veterinary and Comparative Oncology, dogs replaced mice in bone marrow transplantation research because of their “random-bred nature, large body size, longer life span, wide genetic diversity, and well-mixed gene pool.” Dogs are the only other mammal to have that particular mix of features.

The genetic differences between many animals and humans are quite small, which is why aging researchers and companies often use mice in laboratory trials. Yet mice live for about two years, so aging-related diseases often need to be induced for research purposes. Dogs, on the other hand, develop age-related diseases over time without any coaxing. They also absorb drugs in a way that’s virtually identical to humans.

“Dogs have a lot of potential to inform human health that’s simply not available to many other species that we work with,” says Kate Creevy, a veterinarian and the chief veterinary officer on the Dog Aging Project. “They get a number of diseases spontaneously that are identical to diseases in people. You can learn how to deal with that disease in a dog, and then export that therapy to people.”

A good example of this type of translational therapy happens at Colorado State University’s Flint Animal Cancer Center. There, veterinarians sometimes work arm-in-arm with oncologists treating human patients. According to Rodney Page, DVM, a veterinarian and director of the Flint Animal Cancer Center, the sorts of cancers that dogs get — skin cancer, breast cancer, lymphoma — mimic the cancers that humans develop.

“Dogs’ cancers are sometimes as complicated under the microscope as human cancers are,” Page says. “What we’re beginning to find is that we can investigate questions in companion animals that are not only good for them, but also affect people.”

“I suspect that if we demonstrate a benefit in dogs, somebody will do research in people.”

The Golden Retriever Lifetime Study, run by the Morris Animal Foundation, has enrolled some 2,900 pet golden retrievers in every state of the continental U.S. The youngest dogs in the study are three, while the oldest are seven. There’s no sort of intervention in this study; owners don’t give their dogs any special medication or change up their daily routines. Instead, the foundation is capturing as much data as it possibly can. Owners fill out detailed, 200-question surveys every year to catalog things about the dogs’ home environments, food, behavior, and genetics, the last supplied in the form of biological data — blood, stool samples, and the like — contributed by the dogs’ family vets.

By the end of the study, the foundation will have nearly 5 million data points. Already, an in-house epidemiologist at the foundation is planning to publish three papers on the causes of death in younger golden retrievers, unusual cancers that arise in younger retrievers, and salient behavioral characteristics in young retrievers.

“The aging stuff is going to take a while because we don’t have enough old dogs yet,” says Kelly Diehl, DVM, the foundation’s acting vice president for scientific programs. “But there are things we could learn from dogs that could extend our lifespan and also the quality of life.”

In the Dog Aging Project so far, researchers have seen improvement in cardiac function with no evidence of side effects after 10 weeks, which was the first phase of the overall study. Cardiac function will be monitored in a second phase, along with activity and energy levels via GPS trackers embedded in dogs’ collars. Phase three, which Kaeberlein says could begin as early as late 2018, will feature a 10,000-dog longitudinal study, similar in nature to the golden retriever study being conducted by the Morris Animal Foundation. Of that group, 600 dogs will partake in a blind, placebo-controlled clinical trial. In mice, rapamycin sometimes leads to a 25 percent increase in lifespan, defined in this case as healthier functioning even with age. Kaeberlein and Creevy are looking for the same effect in dogs.

“It’s fairly obvious to anybody who looks at it that if this drug has a benefit in dogs, it is reasonable to imagine that it has a similar benefit in people,” Creevy says. “I suspect that if we demonstrate a benefit in dogs, somebody will do research in people.”


Dog-related aging research is in its infancy, and it’s an open question whether any of the findings will translate into meaningful human investigations. But these studies do have one key advantage over ongoing aging research with human subjects: they take much less time to complete. In 10 to 12 years, researchers stand to amass data about aging in dogs that would take more than 70 years to learn about in people.

“You have to put people on a drug or prevention for 20 years or longer, and we don’t have a perfect test to see who’s going to develop a disease, and who isn’t,” Head says.

The world of human aging research is still quite new, and often falls along a predictable fault line: Is it better to tackle aging by homing in on specific, age-related diseases? Or should time be spent tackling aging en masse, by trying to develop an intervention that preserves overall youthfulness in a person who’s growing chronologically older?

In dog studies, researchers don’t have to choose. Over the life of one poodle, for instance, the Dog Aging Project will capture the whole trajectory: the early life of the dog and what its environment was like, the diseases the dog developed as it aged and the potential reasons why, and whether rapamycin had any sort of effect on the dog’s overall health.

“If we’re successful, we’ll have an intervention for people who want to have the opportunity to have their dogs’ lifespan extended,” says Kaeberlein. “And if that comes to fruition, that will go a long way to bringing the science of aging mainstream.”