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Ambitious project will shed light on the aging process in dogs

As dogs get older, they experience many of the same symptoms as aging humans do, including such conditions as arthritis, diabetes and dementia. But while large research projects exist that investigate factors correlated with healthy aging in humans, similar studies on dog aging have not yet been undertaken. In fact, we do not even know what defines “normal aging” for our canine companions.

How old is your dog in terms of human years, and is it healthy for its age? These questions are currently not easy to answer. The accepted wisdom is that a “dog year” is roughly equivalent to seven human years, making a one-year-old puppy comparable in age to a seven-year-old child. This would mean that an 11-year-old elderly dog is comparable to a 77-year-old senior citizen. But it’s actually much more complicated than this, say experts.

Dogs do not all age at the same rate. Big dogs tend to age faster – maybe 10 times faster than humans – while small breeds may live to 20 years old and experience aging about five times faster than humans. 

A team of international scientists is now building an unprecedented research platform to help answer these questions. Known as the Dog Aging Project (DAP), this involves collecting data from tens of thousands of dogs of all sizes, breeds and backgrounds in order to assess the roles of genetics, environment and lifestyle on the aging process. The specific details of this ambitious research were published in a recent scientific article in the journal Nature.

Dog owners are invited to enrol their dogs in the project and to contribute data relating to the health, lifestyle and environment of their dogs. A dog will remain enrolled for at least 10 years, during which time regular and extensive surveys will take place. The researchers will also collect environmental information, electronic veterinary medical records, genome-wide sequence information, clinicopathology and molecular phenotypes derived from blood cells, plasma and faecal samples. 

There are already 32,000 dogs enrolled in the DAP, ranging in age from young puppies to unusually old individuals. These canine citizen scientists are collectively known as the “DAP Pack.” It is hoped that, since dogs share the same environment as humans but have much shorter lifespans, the insights gained into the aging process in dogs may have benefits for understanding aging in humans as well.

“This is a very large, ambitious, wildly interdisciplinary project that has the potential to be a powerful resource for the broader scientific community,” said Joshua Akey, a professor in Princeton’s Lewis-Sigler Institute for Integrative Genomics and a member of the Dog Aging Project’s research team. “Personally, I find this project exciting because I think it will improve dog, and ultimately, human health.”

“We are sequencing the genomes of 10,000 dogs,” Akey said. “This will be one of the largest genetics data sets ever produced for dogs, and it will be a powerful resource not only to understand the role of genetics in aging, but also to answer more fundamental questions about the evolutionary history and domestication of dogs.”

Once a dog is enrolled in the program, the owner is required to complete annual surveys and take measurements of the dog’s weight and height for the duration of the project. In addition, swabs of the dog’s cheek cells must be submitted for DNA analysis. The dog will visit a veterinarian regularly and vets across the country will submit fur, fecal, urine and blood samples of the dogs involved in the research. 

The data and analyses will all be made available in an open-source dataset that will be available to the public and to veterinarians and scientists who wish to develop tools for assessing how well a specific dog is aging. 

“We are still recruiting dogs of all ages, all breeds — purebred or mixed breeds, all sizes, all across the United States,” said William Thistlethwaite, a graduate student who works with Akey in the Lewis-Sigler Institute. “Especially puppies and young dogs up to 3 years old.”

The researchers hope that the data will help them to identify specific biomarkers of canine aging. Ideally, these would be useful in understanding the processes involved in human aging as well. 

Dr. Daniel Promislow is the principal investigator for the National Institute on Aging grant that funds the project, and a professor of biology at the University of Washington College of Arts and Sciences and of laboratory medicine and pathology at the UW School of Medicine.

“Given that dogs share the human environment and have a sophisticated health care system but are much shorter-lived than people, they offer a unique opportunity to identify the genetic, environmental and lifestyle factors associated with healthy lifespan,” said Dr. Promislow.

One particular aspect of the research outlined in the recently published paper is the super-centenarian study that involves only the 300 oldest dogs in the DAP pack and aims to identify the keys to their longevity. 

“One part of the project that I am super excited about is a ‘super-centenarian’ study, comparing the DNA of exceptionally long-lived dogs to dogs that live to the average age for their breed,” said Akey. “This is the first study of its kind in dogs (to my knowledge), and I think it’s a clever way of trying to find genetic differences that contribute to exceptional longevity.”

Within a few months, the team plans to open their enormous dataset – fully anonymized – to share with scientists around the world. Researchers from many different fields will have the opportunity to contribute to the study in countless different ways, based on their interests.

“It is an honor to share our work with the scientific community,” said Kate Creevy, lead author on the paper and DAP’s chief veterinary officer. “The Dog Aging Project is creating a resource with the power to transform veterinary medicine, aging research, and many scientific and non-scientific fields of inquiry.”

By Alison Bosman, Staff Writer

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