Uncovering The Biology Of Growing Old

Story by Tufts University

October 24, 2025

New research from the Dog Aging Project uncovers potential new biomarkers of aging that may one day help them — and humans — live longer, healthier lives.

Scientists have long sought measurable signs in the body, called biomarkers, that reliably reveal our biological age or predict future health issues. Now, a new study in dogs — an ideal model for this research because they share our genetic diversity, diseases, and home environments — has uncovered molecular clues that could shed light on how aging unfolds in pets and people alike.

For the study published in Aging Cell, scientists from the Texas A&M College of Veterinary Medicine & Biomedical Sciences (VMBS), the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University, University of Washington, and other institutions analyzed blood samples from a group of nearly 800 dogs enrolled in the Dog Aging Project (DAP), a long-term, multi-site study of aging in these companion animals.

“The Dog Aging Project is a terrific example of the kind of collaboration that is so important to scientific discovery,” said Dr. Kate Creevy, the DAP’s chief veterinary officer and a professor in the VMBS’ Department of Small Animal Clinical Sciences.

“At Texas A&M, we have the veterinary expertise to communicate directly with participating volunteer dog owners who provide information about their dogs, and to help their primary care veterinarians collect and submit blood and other samples. Our basic biology colleagues at Tufts and the University of Washington have the expertise to analyze and interpret the metabolomic profiles reported in this exciting study. Working together we can achieve so much more than either group could accomplish alone,” she said.

The study found that about 40% of the small molecules circulating in dogs’ blood change with age.

“These molecules, known as metabolites, are basically the building blocks of life,” said Dr. 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 researchers found that one type of rarely studied metabolite, called post-translationally modified amino acids (ptmAAs), appeared strongly linked with aging across dogs of all breeds, sizes, and sexes. “These metabolites are created in two ways in the body,” Promislow said. “The bacteria in our guts can make ptmAAs as we digest our food, or they can show up when proteins break down.”

While the source of these ptmAAs is still a mystery, the authors find clear indication that kidney function is critical. Kidneys normally filter the byproducts of protein breakdown out of the blood. And when the team looked closer at markers of kidney function in the dogs’ blood and urine, they found that as kidney function declines, ptmAAs build up — possibly explaining why some dogs age more healthily than others and offering clues for humans, too.

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.

###

For more information about the Texas A&M College of Veterinary Medicine & Biomedical Sciences, please visit our website at vetmed.tamu.edu or join us on Facebook, Instagram, and Twitter.

Contact Information: Jennifer Gauntt, Director of VMBS Communications, Texas A&M College of Veterinary Medicine & Biomedical Sciences, jgauntt@cvm.tamu.edu, 979-862-4216

You May Also Like