Newswise — ITHACA, N.Y. – As the winter months approach, nearly 100 Alaskan sled dogs between the ages of 8 and 13 – former athletes past their glory days – are participating in a $4.2 million study at Cornell University in a quest for one of the holy grails of medicine: how to slow aging.

Study co-leads Heather Huson, professor of animal genetics, and John Loftus, professor of small animal medicine, are trying to determine whether a drug that inhibits an enzyme called reverse transcriptase can mitigate aging and extend life in older dogs.

The project will serve as a proof of principle for whether reverse transcriptase inhibitors could be an elixir. If confirmed, new finely tuned drugs could be developed for both dogs and humans. The federally approved drug being tested in the sled dog project is commonly prescribed to people for viral infections.

To test the drug’s effectiveness, Huson and Loftus have been quantifying aging in the dogs every six months through three avenues – immune function, behavior and physical condition. All of the tests are noninvasive or minimally invasive.  

“While we love dogs, and we care about extending the life span of dogs for its own right, this is also a really good model for people, hopefully, in the future,” Loftus said.

Dogs and humans share similar lifestyles and aging-related diseases like cancer and cognitive dysfunction and serve as a model for studying Alzheimer’s disease.

Originally, the researchers proposed to study pet dogs. But maintaining a uniform diet for all participants and trusting owners to administer the drug consistently proved too unreliable.

“We had the idea instead to create a colony of dogs we had control over,” Huson said. They realized athletic dogs were housed in groups, in kennels, and as they age, owners kept their best dogs and often sold the rest to hobbyists or as pets.

The dogs are kenneled at the Baker Institute for Animal Research at Cornell. In March 2019, the researchers collected the first baseline data.

Researchers are testing two types of immune responses: adaptive responses that react quickly to infections; and innate responses where the immune system recognizes and delivers specific antibodies to fight a pathogen that previously entered the body. They are also checking blood for increases in markers for inflammation.

Four cognitive dysfunction behavioral tests involve an empty behavioral testing room with a video camera to record lone dogs as they encounter such things as a stranger sitting still in a chair, a familiar or novel toy, or a mirror.

For physical tests, dogs are fitted with a racing harness and are trained to run on a treadmill with heart rate and electrocardiogram monitors. The treadmill has special sensors under the belt to record the pressure of each footfall, to detect limping that could come with arthritis. Another test times dogs as they pull one-and-a-half times their weight a distance of 40 yards using a pull harness.

It will take years to gather enough data for the researchers to make a definitive statement about the drug’s effects, but funds have already been allotted to provide the dogs with a high quality of life until they die of natural causes.

This project was funded through private donations from the Vaika Foundation, a nonprofit group of scientists and veterinarians on a mission to extend the health and life span of domestic animals.

For more information, see this Cornell Chronicle story.

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