What Dogs Tell Us About Longevity

Drs. Daniel Promislow and Matt Kaeberlein are professors at the University of Washington involved in the study of aging. They also happen to share a love of dogs.

These serious scientists have a lot in common, including the fact that it’s easy to get them talking about dogs— especially the UW’s Dog Aging Project. The project’s motto is “Longer, Healthier Lives for All Dogs.”

You could say it started with a photo of a tiny Chihuahua walking with a gigantic Great Dane fifty times its size.

Promislow remembers seeing the photo on the cover of the journal Science back in 2007. Promislow had already started working on size and lifespan. “In mammals, it’s the larger species that are longer lived, except dogs are the opposite,” he says. Very small dogs tend to live much longer than very large dogs. “When I saw that photo, I wondered why dogs did things backward in terms of size.”

Promislow witnessed this phenomenon in his own dogs. “We have one dog, Frisbee. Our other dog, Silver, died about a year-and-a half ago. Silver was a 70-pound Weimaraner; Frisbee is a 40-pound mutt.” At 12, Frisbee is still lively. He used to go running with both dogs, but by age seven or eight, Silver had slowed down considerably. “In a way, the differences between the two of them illustrate what we are learning in our own research,” explains Promislow. “Pure bred dogs and larger dogs tend to be shorter lived.”

A lifelong love of dogs is influencing Dr. Matt Kaeberlein’s work, as well. “I’ve always been a dog person,” says Kaeberlein. He and his wife, Dr. Tammi Kaeberlein (also a research scientist and active on the project), have three dogs (Dobby, a German Shepherd, Chloe, a Keeshond and Betty, a mutt rescued through Old Dog Haven). “They are part of the family. Along with our human children, two boys, we have a houseful,” he remarks.

Promislow and Kaeberlein co-direct the Dog Aging Project. They and a network of pet owners, veterinarians, scientific partners and sponsors are working to understand and increase the healthy lifespan of pet dogs.

So far, the results are encouraging; the implications offer a tantalizing glimpse into increasing longevity in humans.

“It’s pretty reasonable to expect a potential increase in the healthy lifespan of dogs by 30 per cent or more,” says Kaeberlein. As any dog lover will tell you, they’ll take whatever extra healthy time with their dog they can get. “Four to five more years is significant,” he adds. Promislow and Kaeberlein believe adding these extra years is within reach today.

“Since grad school, my scientific research has focused on the biology of aging and trying to understand the biological mechanism of aging,” explains Kaeberlein. His research shows that low doses of the FDA approved drug rapamycin, used to help prevent rejection in transplant patients and to fight cancer, slows aging and extends lifespan in several organisms with few or no side effects. Kaeberlein reasoned that rapamycin could also work on other animals, including dogs.

How did Promislow and Kaeberlein come together to develop the Dog Aging Project?

“The idea for the Dog Aging Project was first conceived of three-and-a-half years ago over the course of about six months,” explains Kaeberlein. “When Daniel and I started talking, that’s when it really took off. He had already received a small grant from the National Institutes of Health to create networking groups to discuss the idea of using dogs as a model for aging.”

Part of the reasoning for using dogs to study aging is that what takes decades to study in humans will take only years to study in dogs. Dogs and humans share the same environment and share many of the same maladies of old age. Plus, the healthcare system for dogs throughout the country is second only to humans. “Dogs are a lot more like people than a mouse in a lab is,” says Promislow.

He recalls his work at the University of Georgia before moving to Seattle. “My background is in evolutionary genetics, and I have researched aging since grad school,” he says. Georgia has a great veterinarian school, where Dr. Kate Creevy was teaching. “She and I got ahold of a large data set on the age of death, breed, size and sex of dogs.” Their landmark study provided the first comprehensive look at causes of death in more than 80 breeds of dogs. They were contacted by the National Institutes of Health (NIH) to put together a planning grant to use dogs as a model of aging. “We started holding annual meetings right around the time that I moved to the University of Washington,” says Promislow, who grew up in Vancouver B.C. (‘a Northwesterner, born and bred’).

“Matt and I started talking about it, and he got excited about clinical trials that could increase the lifespan of dogs.”

“Daniel and I had a series of conversations,” explains Kaeberlein. “I was fascinated with the longitudinal side of the project that Daniel was working on. But what I got most excited about was taking it a step further…not just learn about aging in dogs, but to actually do something about it—target the aging process directly. That was the big ‘aha’ moment for me.”

Their two projects—one a longitudinal study of aging in dogs to understand how genetics and the environment impact the aging process, the other a series of intervention trials aimed at preventing disease and extending the healthy longevity in dogs—together form the Dog Aging Project.

“We’ve been analyzing existing data sets, and now we’re excited to develop our own,” says Promislow, who is in the process of submitting a grant proposal to fund a large-scale study, which would be the first comprehensive, detailed study of aging in dogs. “Lifespan is affected by hundreds of genes and environmental factors. “To understand how, you need to study a population in which genes, environment and aging rate all vary,” says Promislow. The new study, which aims to enroll 10,000 pet dogs from across the country, will do just that. “I am really excited about studying what influences whether a dog will be a healthy ager or not,” he adds.

Promislow’s grant itself is complex. “The first big question the new study will answer is to discover what the genes and environmental factors are that impact how we age. The second question will look at the mechanisms of aging. The third question is can we intervene and manipulate the mechanisms of aging to slow it down,” says Promislow.  Kaeberlein suggests that the data could help lead to targeted, preventable health approaches to improve dogs’ health before they are sick.

Both Promislow and Kaeberlein are excited that their project encourages citizen science. “We see a tremendous opportunity to get people involved in science and excited about the science of aging, called geroscience, including involvement in schools,” says Promislow.

Moving Forward

The Phase 1 Rapamycin Intervention Trial, a 10-week study based in Seattle, was the first trial of its kind aimed at increasing lifespans outside of the lab. Participating dogs are closely monitored by veterinary professionals during all phases of the studies.

“These are people’s pets,” says Kaeberlein. “Phase 1 shows that we can do it safely and that dog owners will participate. We had far more people interested than we could accommodate.

Scientifically, it seemed to work,” he adds. “Age-related heart-function improved and there were no significant side effects. The study raised optimism that rapamycin will reduce cancer, and improve cognitive and kidney function, as well” explains Kaeberlein. “But we don’t know the answers yet, because the first phase was only a 10-week study.”
The Project will soon be enrolling dogs into the year-long Phase 2 trial at Texas A&M, where the Project’s lead veterinarian, Dr. Kate Creevy, works.

But, as Kaeberlein clarifies, it’s the Phase 3 trial, a five-year study that is really designed to answer the most important questions: Will taking rapamycin increase lifespan and delay age-related disease.

The Dog Aging Project is still looking for funding for the longer trial. “We could start within the next two months if we had the funding,” says Kaeberlein.

People often ask if their own dogs can take rapamycin. Kaeberlein’s answer: “What I tell people is that rapamycin is experimental, and I suggest they wait until the study is done. However, our data suggest rapamycin poses few risks and is likely to help dogs lives longer and be healthier. I understand why many people don’t want to wait. They can always try to find a vet willing to prescribe rapamycin, but many vets are not familiar with it. It is a prescription drug, and it is not approved for that use.”

Another common question is if rapamycin will translate into longer, healthier lives for cats. “Nothing about rapamycin suggests it won’t work in cats,” says Kaeberlein. The work is likely to expand to other pets.

“It’s definitely the case that what we learn about healthy aging in dogs will likely translate to our understanding of what influences healthy aging in people,” he adds. “But our pets are so important to us and improving healthy lifespans in pets has its own intrinsic value.”

The second part of the Project, the longitudinal study, is expected to provide a vast amount of information on the aging process, including more information on whether certain diets are associated with longer lifespans and chronic disease. “There is shockingly little information out there on what is a good diet for older dogs,” says Kaeberlein.

In the meantime, Kaeberlein and Promislow stress that pet owners can influence their own pet’s healthy aging right now. “Obesity can be a problem,” says Promislow. “Feeding your dogs the right amount of food and taking them for walks are important.”

Regular veterinary exams are also important, as well as noticing changes such as when your pet slows down. “This could be a sign of arthritis or other pain. In many cases, your veterinarian can help,” says Kaeberlein.

“Sterilized dogs tend to live longer. They are much less likely to die of infectious disease and trauma, but more likely to die of cancer,” explains Promislow.

Do these researchers on aging offer longevity advice for humans?

“Most people know that they should exercise and that they shouldn’t eat or drink too much. Nutrition and exercise are key for healthy aging,” advises Kaeberlein.

Promislow agrees. “That is the wonderful thing about this project. What the science of human aging tells us so far is that we benefit from three things: a healthy diet, keeping fit and social engagement. Those are my three pieces of advice,” he adds. “If someone discovered a pill that could make people live on average five years longer, that person would become very rich. But in this country, if everyone had an optimum diet, exercise regime and social network…in that sense we already have a ‘pill,’ but it takes some effort to take it,” he laughs.

You may not be able to pick up an anti-aging pill at your local drugstore, but within 10 years it is possible that the Dog Aging Project will help the aging field to increase the quality and length of life for both dogs and people.

 MORE INFORMATION
• The Dog Aging Project has continued since this article was first published in 2018. For more information and updates, visit dogagingproject.com

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