A massive study of nearly 800 dogs reveals that specific blood molecules tied to kidney function and gut microbes may hold the key to understanding aging, offering new clues that could benefit both canine and human health. Credit: Shutterstock
A large study in pet dogs has uncovered potential new biomarkers of aging that could one day help both dogs and humans live longer, healthier lives.
Scientists have long searched for biological indicators, known as biomarkers, that can accurately reflect a person’s true biological age or signal potential health problems before they appear. In a new study, researchers working with dogs, an excellent model for aging research because they share much of our genetic makeup, diseases, and even living environments, have discovered molecular evidence that could help explain how the aging process develops in both animals and humans.
In research published on October 22 in Aging Cell, scientists from the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University, the University of Washington, and collaborating institutions examined blood samples from nearly 800 dogs participating in the Dog Aging Project, a large-scale, ongoing study of canine aging. Their analysis revealed that roughly 40% of the small molecules present in a dog’s bloodstream vary with age, suggesting that these molecular changes may hold important clues about how aging progresses.
Aging and Unusual Metabolites
“These molecules, known as metabolites, are basically the building blocks of life,” says Daniel Promislow, a senior scientist and scientific advisor at the HNRCA and the study’s senior author. “They serve as the raw materials for forming proteins, DNA, and other cellular components, and play a critical role in keeping cells alive.”
The research team identified a specific and little-studied group of metabolites known as post-translationally modified amino acids (ptmAAs) that showed a strong connection to aging in dogs of all breeds, sizes, and sexes. “These metabolites are created in two ways in the body,” explains Promislow. “The bacteria in our guts can make ptmAAs as we digest our food, or they can show up when proteins break down.”
Although the exact source of these ptmAAs remains uncertain, the study points to kidney function as a key factor. The kidneys are responsible for filtering the byproducts of protein breakdown from the bloodstream. When the researchers examined kidney-related markers in the dogs’ blood and urine, they discovered that ptmAAs tended to accumulate as kidney performance declined. This buildup could help explain why some dogs experience healthier aging than others and may also provide valuable insights into the human aging process.
Tracking Dogs Over Time
Now that the researchers have compared younger and older dogs to see how their blood chemistry differs at a snapshot in time, the researchers plan to follow changes in metabolites in the same dogs over several years. The scientists will seek to identify gut microbes that might change in abundance with age and influence the ptmAAs. They also are interested in using owner-provided data to determine if changes in muscle mass—a common phenomenon in both aging dogs and people—are linked to these ptmAAs.
By tapping longitudinal data from many different molecular measures, the researchers aim to understand whether these biomarkers truly track the pace of aging and predict future health or longevity—and study if potential anti-aging treatments change these biomarkers. The team also hopes to compare these patterns with how metabolites change in people.
“We have a tremendous opportunity to understand the causes and consequences of aging and to discover ways to ensure that both species enjoy the healthiest aging trajectory possible,” Promislow says.
Reference: “Protein Catabolites as Blood-Based Biomarkers of Aging Physiology: Findings From the Dog Aging Project” by Benjamin R. Harrison, Maria Partida-Aguilar, Abbey Marye, Danijel Djukovic, Mandy Kauffman, Matthew D. Dunbar, Blaise L. Mariner, Brianah M. McCoy, Yadid M. Algavi, Efrat Muller, Shiri Baum, Tal Bamberger, Dan Raftery, Kate E. Creevy, , Anne Avery, Elhanan Borenstein, Noah Snyder-Mackler and Daniel E. L. Promislow, 22 October 2025, Aging Cell.
Research reported in this article was supported by the National Institutes of Health’s National Institute on Aging under award number U19AG057377, and by the Glenn Foundation for Medical Research, the Tiny Foundation Fund at Myriad Canada, the WoodNext Foundation, the Dog Aging Institute, and a cooperative agreement with the U.S. Department of Agriculture’s Agricultural Research Service.
