'I Help Dogs Live Longer Lives'

Frisbee was one of these dogs who just loved everybody. Whenever somebody came to visit, she immediately went up to them and shared the love. She was an incredibly healthy and active dog for most of her 16 years, but in the last few years we saw her steadily decline. It was hard to watch.

Frisbee developed multiple chronic conditions. She almost died two years ago of pancreatitis, and I became one of those owners who cooks their dog's food. We had a special diet for her, she was on various medicines and she pulled through. But she also had cataracts, hearing loss, lipomas on her skin, incontinence and cognitive dysfunction.

Her osteoarthritis made it impossible for her to walk. There was a day where my stepson and I took her on her walk, across the street from where we live in Seattle, Washington. Frisbee lay down and she couldn't get up. She looked at us, and we knew it was time for her to be put down. It was a very hard decision.

Frisbee's recent passing made me even more determined to figure out how we can ensure dogs live the healthiest life possible right up until the end. I am the co-director of the Dog Aging Project, a long-term study, in collaboration with more than 40,000 dog owners, that seeks to understand the factors that shape healthy aging in dogs. We hope this understanding will mean we can help dogs live healthier, for longer.

Dr. Daniel Promislow With His Dog
Dr. Daniel Promislow with his dog, Frisbee. Dr. Promislow is co-director of the Dog Aging Project.

Our efforts to help dogs live longer

About 99 percent of the dogs enrolled in our project are part of an observational study. However, we have just launched a clinical trial, for which we are hoping to recruit 580 older, large-breed dogs, to see if a drug can help older dogs live longer.

The drug, rapamycin, inhibits a protein called mTOR. This protein usually senses the amount of nutrients that are available in a cell and, when there's not much food around, the protein makes the decision to shut down growth and become stress-resistant. Rapamycin "tricks" the cell or organism into thinking there isn't much food available, and induces the stress resistant—and long-lived—state.

We already have evidence from previous studies that rapamycin increases the lifespan of mice, worms and fruit flies. Our study, where half of the dogs will be given the drug while the other half receive a placebo, will monitor whether the drug can extend an older dog's life and also improve their heart or cognitive function.

Three years from now, we should have a good idea of whether the drug works. If it is successful, we could add two or three healthy years to a dog's life, as a best-case scenario. The emphasis here is on those being healthy years—extending what we call their "healthspan," rather than their lifespan. Our goal is not to make dogs live forever, but to try and help dogs be healthier for longer.

Predicting cancer risk and serious diseases

The clinical trial is just one part of the bigger picture of our project. The vast majority of our study is observational, with dog owners monitoring their dogs' health, lifestyle, environment and diet, every year of their life. We believe that understanding these environmental, biological and behavioral factors, and seeing how they are associated with healthy aging, will help dogs live healthier and longer lives.

For a small subset of dogs, we also collect blood, urine, hair and fecal samples, in the hope of identifying biomarkers that could help us predict or diagnose diseases at an earlier stage.

We are already seeing clear signals of what happens as dogs age. In general, larger dogs are at greater risk of cancer. Meanwhile, all dogs, regardless of size, show declines in activity levels as they age. Likewise, we have found that dogs that are in their later years tend to have a set of symptoms similar to Alzheimer's disease, which we call Canine Cognitive Dysfunction.

Dr. Daniel Promislow with Dr. Matt Kaeberlein
Dr. Daniel Promislow with Dr. Matt Kaeberlein and their respective dogs. Dr. Promislow and Dr. Kaeberlein are the founders and co-directors of the Dog Aging Project.

Our study is still relatively new, and we're currently analyzing the second year of our data. However, because dogs don't live as long as humans, I believe by our third or fourth year, when our middle-aged dogs start to move into older age, we will be able to test hypotheses about what causes some dogs to live healthier for longer than other dogs.

For instance, we have already observed that dogs that live in rural communities tend to spend more time active and outside than dogs that live in urban and suburban areas. We do not yet know whether that has health consequences, but in a few years' time we might be able to make that link.

There are many people who are interested in our potential findings. Dog owners obviously want to figure out how to help their dogs live longer, healthier lives. However, there are others who want to know what this could mean for human aging.

Our research could one day prove useful in enriching human life, too. Dogs get the same diseases that humans do, and they live in our environment. So studying the environmental risk factors in dogs could help us identify similar ones in humans. Our hope, therefore, is that this is just the beginning.

Dr. Daniel Promislow has been studying aging for the past 30 years, since he was a graduate student at Oxford University. He is the co-director of the Dog Aging Project at the University of Washington School of Medicine. To get involved in the project, visit their website: dogagingproject.org.

All views expressed in this article are the author's own.

As told to Katie Russell.