Experiencing the death of a family dog is a miserable rite of passage for children and adults alike, but now scientists are conducting trials to try and increase the lifespan of pets.
Evolutionary geneticists at the University of Washington have been studying the ageing process of animals and they believe that common drugs could help increase longevity.
Some dogs have been known to survive until they are 29, and in the wild they live longer than household pets, so scientists are confident that animals have it in them to stay healthy for longer than they do presently.
“If we can understand how to improve the quality and length of life, it’s good for our pets and good for us. It’s win-win”
Dog Ageing Project, at the University of Washington
One drug which is causing increasing excitement is rapamycin, an anti-rejection medicine used in patients who have undergone kidney transplants and which has been shown to extend the life of mice by more than 25 per cent. If successful it could see dogs living for an extra four years.
Rapamycin has an anti-inflammatory effect and also helps cells get rid of waste, clearing rubbish from the body.
Trials have now begun on 32 middle-aged golden retrievers, Labradors and German shepherd dogs to see if the adding low doses of rapamycin to their food could improve health and slow down ageing. Scientists are hoping to see improvements in heart and immune function, body weight and mental ability.
The dog trials will also provide new evidence that the drug could also work for humans.
Dr Daniel Promislow, a geneticist on the Dog Ageing Project, at the University of Washington, told the journal Science: “If we can understand how to improve the quality and length of life, it’s good for our pets and good for us. It’s win-win.”
“If rapamycin has a similar effect in dogs – and it’s important to keep in mind we don’t know this yet – then a typical large dog could live two to three years longer, and a smaller dog might live four years longer.
“More important than the extra years, however, is the improvement in overall health during aging that we expect rapamycin to provide.”
Dr Daniel Promislow, a geneticist on the Dog Ageing Project
Dr Daniel Promislow from the University of Washington
Scientists are still unsure why some animals live longer than others. Aristotle believed that elephants outlasted mice because they contained more liquid and so took longer to dry up.
In more recent times, it was thought that animals with higher metabolic rates, and quicker heartbeats, live shorter lives because essentially their body clock is running faster. However some animals with fast heart rates, such as parrots, do not seem to conform to the rule. Macaws, for instance, have been known to live beyond 100 years old.
Some scientists believe that some animals live longer than others simply because they have had few predators for millions of years. It also explains why larger animals tend to have longer lifespans. Solitary creatures, such as wild cats, also do better because they are less likely to catch disease than if they lived in larger packs.
Many researchers are currently working on extending the lifespan of humans and next year trials will begin to test whether the diabetes drug metforming could increase longevity.
Dr Matt Kaeberlein, director of the healthy ageing and longevity research institute at the University of Washington, said if humans were going to live longer then they would want their pets to be around for longer as well.
“For millions of people, pets are part of our family,” said Dr Kaeberlein. “Unfortunately, companion animals such as dogs and cats age rapidly and have life expectancies that are far too short.
“Research in the biology of aging has made tremendous strides over the past several years. Interventions have been discovered that are capable of slowing aging and extending lifespan in small mammals such as mice and rats.
“These same interventions could provide our pets with several years of additional healthy, youthful life.
“Imagine what you could do with an additional two to five years with your beloved pet in the prime of his or her life. This is within our reach today.”
Scientists believe that dog lifespans are likely to be getting longer anyway, because of better nutrition and veterinary care.
Joao Pedro de Magalhaes, a biogerontologist at the University of Liverpool believes that breakthroughs could eventually see treasured pets living for hundreds of years.
“I don’t think there is a set maximum longevity for any species,” he said: “The real question is how far can we go. Maybe a thousand years from now you could have dog that lives 300 years.”