To Herb Krohn, a railroad worker in Seattle, no living creatures are more precious than his four dogs. "From the day you get your dog, you worry about the day you're going to have to say goodbye," he says.
So three years ago, when he saw an article about a new study called the Dog Aging Project--a trial designed to test a drug that might help dogs live longer--he volunteered his four-legged friends.
One of his pups, Lola, made the cut. Three times a week for 10 weeks, Krohn fed his puffy chow chow a pill covered in peanut butter. He didn't know whether the pills were the real deal or a placebo--that's the way good studies are designed, after all--but he monitored her closely, keen to see what, if anything, would happen. "If any creature deserves to have immortality, it's dogs," he says. Currently, the average life span of a domestic dog is about 12 years.
The drug being tested is called rapamycin. It's an immunosuppressant that has already shown incredible promise in lab animals. At low doses, it's shown to increase the life spans of mice by 25% while conferring on them a sprightliness that belies their age.
Unfortunately, rapamycin does not yet appear to perform such magic in humans. For now, the drug is used mainly on organ-transplant recipients and people with certain kinds of cancer, because of the serious side effects it can trigger in humans. But it doesn't cause serious side effects in lab animals, and thanks to the Dog Aging Project, scientists will soon know if that's true of dogs too.
If the drug works, it could mean that veterinarians may one day prescribe rapamycin to healthy older dogs, increasing not just the length of their life but also the quality, says Matt Kaeberlein, a co-director of the study and professor of pathology at the University of Washington. "What we're really talking about is keeping the dog healthier longer so that they don't have these chronic diseases and disabilities to go along with aging," he says. "If we can do this, it will have a significant impact on the quality of life for people who love their dogs."
In mouse studies, 10 weeks on the drug was all it took to make an old mouse's heart function like that of a much younger mouse. And according to early results from the Dog Aging Project, soon to be published, the same may be true for canines. About 70% of dogs that took the highest dose of the drug were also noticeably more active.
"It's really encouraging," Kaeberlein says. "It doesn't mean those dogs are going to live longer, but it certainly is suggestive that some of the effects of rapamycin on age-related function are shared between dogs and mice."
Before the drug is available to all of Krohn's dogs (and yours), more research is needed. In the trial's next phase, which begins in March, the team will study 50 more dogs and follow them for a full year, adding in other metrics. Mouse research shows that rapamycin can improve age-related cognitive decline, for instance, and Kaeberlein wants to know whether it can help keep dogs sharp too.
These studies are part of a small but growing movement to expand scientific knowledge about the lives--and deaths--of dogs. The Golden Retriever Lifetime study, for example, which began in 2015, is following 3,000 dogs throughout their lives in search of genetic and lifestyle links to cancer, which kills more than half of all golden retrievers. Kaeberlein's team plans to do something similar: a 10-year study following 10,000 dogs to understand why some live a long time while others get sick and die young.
Humans have something to learn from the data too. "A lot of the aging process in dogs is also shared with people," Kaeberlein says. "It's hard to imagine an animal that shares your environment to a greater extent than your dog."
As for Lola, the lionesque chow chow, things are looking up. It turned out she was on rapamycin, not the control, and Krohn says she seemed to become a lot more affectionate. They'll have to wait until Phase 2 to see why a dog's eagerness to cuddle would be affected, but Kaeberlein suspects it may be a sign of better brain function.
Now Krohn is trying to enroll Lola in the next round of Dog Aging Project studies. "I want to make sure she stays on it," he says. "It's worth it to try to help man's best friend be their best friend a little longer."