Citizen science hopes to add healthier years to dog lives
Owners of older dogs often wish their elderly pet could be granted a few more years to trot along on a walk, chase a ball, even dig up the backyard. Dogs have much shorter lives compared to people. But until now, it seemed that little could be done to prevent many of the effects of aging that sideline older pet dogs.
Extending the happiest years of canine lives is the goal of the Dog Aging Project, a scientific effort recently launched at the University of Washington.
The project leaders are Matthew Kaeberlein and Daniel Promislow of the Department of Pathology. Both are internationally recognized experts in the biology of aging. Both also have dogs of their own.
Promislow understands what other dog owners are going through as he witnesses his dog, Silver, slowing down month by month on his usual runs. His other dog, Frisbee, while still rambunctious, is also considered an older dog. Like many people, Kaeberlein and Promislow have experienced first-hand the heartbreaking decline of their beloved companions.
The primary goal of the Dog Aging Project is to improve the well-being of dogs, they said, not to look for human health links.
“We want to do this because people feel a strong attachment to their companion animals. Dogs are part of the family,” the researchers said. Even many veterinarians and animal organizations list dogs with their owner’s last names, like Fluffy Grabowski or Spot St. Pierre.
Of course, the researchers note, improving the healthy longevity of dogs will have tangible benefits on the quality of life for humans. As Kaeberlein said, "Anything we learn about how to slow aging in humans is an added bonus."
The Dog Aging Project has two parallel aims: a lifelong study of aging and a healthy-aging intervention trial. In the lifelong study (also referred to as a longitudinal study) scientists will track the health of pet dogs to undersand how genetic and environmental factors influence healthspan and canine longevity. Healthspan is the period of life spent in good health and free from chronic disability or disease. That work that will last a decade or more.
In the near term, UW researchers plan to test, with the assistance of veterinarians and pet owners, low doses of a medication called rapamycin that has been shown to have some anti-aging and healthspan-lengthening effects in mice.
Dogs in the initial rapamycin intervention study will be around 7 to 9 years and weigh about 70-to-90 pounds. One reason for concentrating on big dogs is because they, like tall or heavy-set people, tend not to live as long as their compact counterparts, explained Kaeberlein, who provides a home for a large German Shepard named Dobby. A little dog may be around for up to 16 years, whereas a hefty, barrel-chested dog, like a Saint Bernard,has a lifespan of about 7 to 8 years.
The shorter life-expectancy and greater disease burden in large dogs will allow the researchers to detect improvements in age-related problems like heart and kidney disease earlier on. Cancers, in particular, are more common on older, big dogs. Rapamycin appears to be particularly effective at reducing cancer during aging.
It’s likely that the initial, short-term rapamacin study, aimed at determining dosing and detecting improvments in heart function, will have only a few breeds in its patient mix. This will allow a study population of dogs that are genetically similar and, based on readily available breed information, prone to the same diseases of old age.
The researchers hope to initiate a larger ramamycin study with several hundred dogs later in 2015. That study would incorporate a variety of purebreeds as well as mixed-breed dogs. In addition to improving the health of the aged dogs, Kaeberlein expects rapamycin to increase life expectancy by two or more years.
"It's important to understand that we aren't talking about making your dog live forever, or even as long as a person," Kaeberlein said. "But I think anyone who lives their dog would agree that two or three additional years with them is priceless."
Rapamycin, originally isolated from bacteria on Easter Island, is used to prevent organ rejection in transplant patients and to treat some forms of cancer. A growing number of studies suggest that the compound can increase life expectancy, delay the onset of many diseases associated with aging, and can restore vitality to elderly animals.
“We’re not just trying to make dogs live longer. We don’t want to extend the dogs’ suffering from late-life debilitating diseases,” Promislow said. “We’re looking for a longer health span – the period of later life during which the older dog still remains vigorous. We don’t know for sure if it will work, but we have a hunch that rapamycin might improve the quality of life for older dogs."
Mouse data and human data indicate that rapamycin can decrease cancer rates and improve immune function, which often declines during old age. Researchers will also be checking to see if it protects or improves heart function in older dogs.
Although rapamycin can have significant side effects at the doses used to prevent organ transplant rejection, the low doses for this study are expected to cause minimal, if any, side effects.
"Safety of the dogs is our utmost concern," Kaeberlein said. All treatments will be performed under the guidance and care of clinical veterinarians.
The researchers are currently building a team with both community and academic veterinarians to guide the Dog Aging Project, including both the rapamycin study and the longitudinal study.
The researchers explained that the longitudinal dog aging study is comparable to similar studies that have been carried out in people, such ast the Framingham Heart Study or the Baltimore Longitudinal Study of Aging, which have gathered health and medical data on a population of people over several decades to learn what influences the development – and avoidance – of common chronic diseases of middle age and old age.
“A large scale dog aging study of this nature would have a much shorter time frame. Within three years we should start to have useful findings, compared to the wait of 20 to 30 years that human aging studies require,” the researchers said.
Both projects, Kaeberlein said, are opportunities for pet owners to become involved in citizen science by enrolling their dogs or by supporting dog aging research. “ Unlike much scientific research, the average person who loves dogs can play an important role in this study. If many people sign up their dog, donate a small amount or help spread the work, together everyone has the possibility to do great things.”
The team has created the Dog Aging Project website where dog owners can learn more about the project, request additional information, and submit their dog for consideration.