A groundbreaking study involving hundreds of pet dogs may hold important clues about how both animals and humans age. Researchers have identified a series of molecular markers that appear to change as dogs grow older, offering new insight into the biology of aging and potentially paving the way for longer, healthier lives.
Scientists have long sought biological indicators—known as biomarkers—that can accurately reflect a person’s or animal’s true biological age rather than just their years lived. In this latest research, scientists working with dogs found measurable differences in molecules within the bloodstream that correspond with age-related changes. Because dogs share many genetic similarities and environmental factors with humans, these findings could ultimately help both species.
The study, published in Aging Cell on October 22, was conducted by teams from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, the University of Washington, and several collaborating institutions. Using blood samples from nearly 800 dogs enrolled in the Dog Aging Project, researchers analyzed thousands of small molecules circulating in their blood. Roughly 40 percent of these molecules varied with age, indicating that specific metabolic patterns may play a role in how aging unfolds.
“These molecules, known as metabolites, are basically the building blocks of life,” said Daniel Promislow, senior author of the study and scientific advisor at the HNRCA. “They serve as the raw materials for forming proteins, DNA, and other cellular components, and play a critical role in keeping cells alive.”
Among the findings was a group of little-known compounds called post-translationally modified amino acids, or ptmAAs, which appeared closely linked to aging across dogs of all breeds, sizes, and sexes. “These metabolites are created in two ways in the body,” explained Promislow. “The bacteria in our guts can make ptmAAs as we digest our food, or they can show up when proteins break down.”
The study suggests that kidney function may be an important factor influencing how these molecules accumulate. The kidneys filter waste products from the bloodstream, and researchers noticed that dogs with reduced kidney performance had higher concentrations of ptmAAs. This buildup could be a marker of aging at the molecular level and might help explain why some dogs experience a decline faster than others.
Now that scientists have identified how metabolite levels differ between young and old dogs, the next step is to monitor these changes in the same animals over time. The research team plans to study how gut bacteria and muscle mass affect these biomarkers and whether the same chemical patterns appear in humans.
By tracking long-term data from thousands of dogs, researchers hope to determine if these molecular signatures can predict how quickly an individual is aging and whether potential anti-aging treatments can slow that process.
“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,” said Promislow.
The study, supported by several research foundations and the National Institute on Aging, marks a major step toward understanding the shared biology that connects human and canine longevity.