Can We Slow the Aging Process in Dogs?
Pilot data suggests that a new drug may improve longevity in dogs.
Posted Jan 01, 2017
Perhaps it is because it is the new year's season, and everyone is celebrating a renewal and a new start, that some people get to thinking about the aging process. Or perhaps it is because I myself am getting on in age (although the rumors that I had a pet stegosaurus when I was a boy are false). Or perhaps it is because I was musing about a well-loved dog named Dancer who lived longer than any other dog that I have owned and, if he had lived for one more week, he would've been 16 years of age. Or perhaps it is because I just saw a trailer for a movie called "A Dog's Purpose" which is based on the 2010 novel of the same name by W. Bruce Cameron. It involves several stories about a dog who lives with an owner, bonds with him, helps him, then grows old and dies only to be reincarnated as a different dog with a new owner. It appeared to me that this could be an incredibly uplifting film except for the fact that one has to watch a beloved dog grow old and die over and over again.
Whatever the reason, it was still the New Year's season, and I was ruminating about all of this in a mumphy way. I was comforted by the glass of single malt scotch that I was sipping while in the company of an old friend who is also a colleague of mine. I suggested "You know all the things that have affected my dogs, cancer, heart disease, organ failure, and the canine equivalent of Alzheimer's disease, have one risk factor in common and that is aging. If we could just slow the aging process in dogs we could stave off all of these fatal diseases and have a useful longer time with our pets."
He swirled the scotch in his own glass and replied "Well if that's what you're thinking about, you should be a happy man." He then went on to tell me about a research project that was being conducted by Matt Kaeberlein, a researcher studying the biology of aging at the University of Washington with the help of a colleague, Daniel Promislow. His research involves the testing of a drug called rapamycin, which was being suggested as an anti-aging medication. The interesting part is that it is currently being tested in dogs.
I added a bit more scotch to his glass to encourage him and he continued, "A few years ago I ran into David Harrison of the Jackson Laboratory, at Bar Harbor, Maine. He was involved in some of the original research*. He told me that around the year 2000 scientists developed some new tools of molecular biology and started tinkering with the complex cellular pathways that regulate lifespan in a number of species. By removing genes that produced certain proteins, or adding genes that produced others, researchers found they could actually extend the lives of simple living things such as yeast, roundworms and fruit flies. Obviously we can't manipulate genes in complex animals like dogs or humans as easily, however some researchers, like Dr. Kaeberlein demonstrated that rapamycin, suppressed one of the crucial proteins in yeast, resulting in a longer life span without removing a gene. According to Harrison, he and his research group set out to test rapamycin in a more complex animal, namely mice. As he tells it they ran into a problem which turned out to be a fortunate accident. They were having trouble formulating the drug so that it could be easily consumed. As a result the mice were 20 months old, which is the mouse equivalent of around 60 years of human age, when the trial began. What they found was their longest lived mice survived about 12 percent longer than the control animals which meant that the drug was not only effective in prolonging life, but could still be helpful if it was given to older animals. So Kaeberlein has moved on to pilot test the drug in dogs.
"Now here's the part that might interest you as a psychologist [rather than just as a dog lover I suppose]. Apparently getting money for research on aging and life extension is not all that easy. People readily understand if their mother dies of cancer that then it might be useful and productive to contribute money for research on cancer. It's harder for them to hook up the links which go something like 'my mother was older, and it was the effects of her aging that predisposed her to getting cancer, so maybe I should contribute money for research on aging.' That is why Kaeberlein was having difficulty getting funding to do his research. He actually helped to pay for the pilot study on dogs with his own money — funds that he received from the University of Washington for turning down an offer from another university which would have taken him away from them.
"I understand that Kaeberlein is an owner of two dogs himself, and this may have been part of the motivation for working so hard to cobble together the funding for this pilot study. But apparently he also felt that exposing dog lovers to the idea that aging might be delayed in their pets might be a useful strategy to help generate popular support for this kind of anti-aging research. I read somewhere where there was an interview with Kaeberlein in which he said something like (and I am paraphrasing) 'Many of us in the biology of aging field feel like it is underfunded, certainly relative to the impact on human health that it might have. However we reasoned that if the average pet owner sees there is a way to significantly delay aging in their pet, maybe it might have a helpful impact on policy decisions and that could affect research funding.' It appears that he was right in some ways. Certainly the interest of dog lovers was apparent since the pilot study required only 40 dogs and over 1500 dog owners applied to participate in the trial of rapamycin.
"In any event, the results of the pilot project are in and at least one paper has been delivered at a scientific meeting. The results are promising. For example, it was reported that compared with the hearts of dogs in the control group, the hearts of those dogs who took the drug were now pumping blood more efficiently, and there were no negative side effects. So Kaeberlein and his research team are now ramping up for a much larger study which should involve something around 450 dogs over a five-year span — if they get the funding of course."
I found that my friend's information about this research actually lightened my mildly depressed post holiday mood. So I sipped a bit more scotch and told him, "Well in that case maybe when 'A Dog's Purpose' hits the movie theaters I will go to see it. After all any film with Dennis Quaid and a bevy of dogs can't be all that bad, can it?"
Stanley Coren is the author of many books including: Gods, Ghosts and Black Dogs; The Wisdom of Dogs; Do Dogs Dream? Born to Bark; The Modern Dog; Why Do Dogs Have Wet Noses? The Pawprints of History; How Dogs Think; How To Speak Dog; Why We Love the Dogs We Do; What Do Dogs Know? The Intelligence of Dogs; Why Does My Dog Act That Way? Understanding Dogs for Dummies; Sleep Thieves; The Left-hander Syndrome
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* Data from: Harrison DE, Strong R, Sharp ZD, et al. (2009). Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature. 460(7253):392-5. doi: 10.1038/nature08221