Uncovering the biology of growing old

Large study in pet dogs uncovers potential new biomarkers of aging that may one day help them—and humans—live longer, healthier lives

Tufts UniversityFacebook

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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 October 22 in Aging Cell, scientists from 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, a long-term, multi-site study of aging in these companion animals. They 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,” 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 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,” explains Promislow. “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.

 

Benjamin R. Harrison from University of Washington’s Department of Laboratory Medicine and Pathology is first author of this study. 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. Complete information on authors, funders, methodology, limitations, and conflicts of interest is available in the published paper. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funders. 

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Journal

Aging Cell

DOI

10.1111/acel.70226 

Article Title

Protein Catabolites as Blood-Based Biomarkers of Aging Physiology: Findings From the Dog Aging Project

Article Publication Date

22-Oct-2025

Can blood analyses in dogs provide insights into human aging?

Wiley

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Lab-based studies have provided lots of information on the biology of aging, but it’s unclear how lab discoveries apply to aging in the real world. Research in Aging Cell provides insights into aging based on studies in dogs.

The Dog Aging Project (DAP) is designed to identify patterns of aging and how these are shaped by the diversity of genetic and environmental variation among companion dogs.

By analyzing metabolites from blood samples of dogs in the DAP, investigators identified effects of age on more than one-third of measured metabolites. They also discovered that post-translationally modified amino acids, which are generated from protein break-down, are strongly linked with age in dogs. These molecules might be promising indicators of physiological aging. Also, the study pointed to an important role of the kidney in the relationship between age and blood metabolites.

"Because dogs age like humans, share our environment, and receive comparable healthcare, they’re an ideal model for studying aging,” said corresponding author Daniel E.L. Promislow, PhD, of Tufts University. “Our hope is that blood metabolites like those studied here have the potential to serve as powerful biomarkers for tracking the processes that drive healthy aging, not only in dogs but in humans as well.”

URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/acel.70226

 

 

Additional Information
NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.

About the Journal
Aging Cell is an open access geroscience journal publishing research addressing the biology of aging. The journal welcomes research that reports the mechanistic, molecular, and cellular aspects of the aging process, as well as the links between aging and age-related disease.

About Wiley      
Wiley is a global leader in authoritative content and research intelligence for the advancement of scientific discovery, innovation, and learning. With more than 200 years at the center of the scholarly ecosystem, Wiley combines trusted publishing heritage with AI-powered platforms to transform how knowledge is discovered, accessed, and applied. From individual researchers and students to Fortune 500 R&D teams, Wiley enables the transformation of scientific breakthroughs into real-world impact. From knowledge to impact—Wiley is redefining what's possible in science and learning. Visit us at Wiley.com and Investors.Wiley.com. Follow us on Facebook, X, LinkedIn and Instagram.

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Journal

Aging Cell

DOI

10.1111/acel.70226 

Article Title

Protein catabolites as blood-based biomarkers of aging physiology: Findings from the Dog Aging Project

Article Publication Date

22-Oct-2025

 

UK Capital's ULEZ quickly cut air pollution —high vehicle compliance may have left little room for further gains after expansion

Significant falls in NO2 and NOx – but not PM2.5 - seen following 2019 ULEZ introduction as vehicle compliance increased significantly

University of Birmingham

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People living, working and visiting London have seen substantial reductions in air pollution following the introduction of the Ultra Low Emissions Zone (ULEZ) introduced in 2019, according to a new research paper.

 

In a study published in npj Clean Air today (Weds 22 October), researchers from the University of Birmingham have created a sophisticated model for assessing the direct impact of ULEZ on air pollution in the Greater London area.

 

The team found that there were significant reductions in nitrogen-based pollutants NO2 and NOx following the introduction of ULEZ in 2019 that extended beyond the geographical boundaries of the zone, including areas that were covered by the ULEZ expansion in 2023.

 

The study found that:

• NO₂ fell by 19.6% at roadside sites in central London within three months of ULEZ1 in April 2019, 

• NOx fell by 28.8% in the same period for the same area,

• No significant impact was detected on NO2 or NOx following ULEZ expansion in 2023, and

• NO₂ and PM₂.₅ (fine particles that can enter into our lungs) pollution remains well above WHO guidelines across London. 

 

The team analysed Transport for London data on non-compliant vehicles - those that do not meet emission standards and must therefore pay a daily charge to drive within the zone - which shows that the proportion of such vehicles operating in Central London fell from 39.1% at the time of ULEZ introduction in 2019 to 27.5% within three months of its implementation.

 

The composition of London’s vehicle fleet continued to change in the following years. By the time the ULEZ expansion was introduced in 2023, only 7.4% of vehicles on the road across London were classified as non-compliant. Three months later, this figure had fallen further to 4.2%.

 

Chengxu Tong, a PhD student from the University of Birmingham and first author of the study said: “The introduction of ULEZ in central London in 2019 has been effective in improving air quality. Importantly, our analysis reveals that these benefits are not confined to the designated zone, but extend beyond its boundaries, indicating a wider spill-over effect.” 

 

Using machine learning, the team were able to remove the potential impacts of the weather on variations in air pollution during the time of the study. 124 sites across London captured hourly air pollution data across multiple years that enabled the research team to look at the introduction of ULEZ (called ULEZ1 in the paper) in 2019, and the major expansion of ULEZ (called ULEZ3) in 2023.

 

Professor Zongbo Shi from the University of Birmingham, who oversaw the study, said: “When ULEZ was introduced in central London, there was a rise in the number of compliant vehicles on the road. This contributed to the spillover effect on air quality beyond central London. Furthermore, the commitments to expansions may have encouraged earlier transitions to cleaner vehicles, which likely explained the limited additional impacts of 2023 ULEZ expansion on air quality. This is known as “anticipation effect” – where the benefits of a policy are already being seen before its formal implementation.  

 

“Here, we showed that ULEZ is an important step, but it is not enough on its own. London still faces air pollution levels well above WHO health-based guidelines, requiring coordinated actions across multiple sectors, including from industrial, commercial, residential and agricultural sources”

 

Dr Suzanne Bartington, an Associate Professor from the University of Birmingham and a senior co-author of the study said: "While it is encouraging that ULEZ did reduce NO2 and NOx pollution across London over the study period, it is an ongoing cause for public health concern that London and many major cities around the world.

 

“It’s important to highlight that the current ULEZ approach does not fully address significant traffic related public health issues, such as PM2.5 pollution. As a result, we need to see a modal shift to more active travel and public transport to reduce the number of vehicles on the road, which could reduce non-tailpipe-related PM2.5 emissions and improve public health.

 

The study was partially funded through WM-Air, supported by the Natural Environment Research Council’s Regional Impact from Science of the Environment (RISE) initiative. WM-Air has been working with partners to bring research organisations together with businesses, policy bodies and other actors contributing to economic development specific to their location, to deliver significant regional impact from NERC environmental science. Previous studies from WM-Air have highlighted major contributions of domestic woodburning to PM2.5 emissions, and that air pollution in the West Midlands has caused up to 2300 premature deaths each year.

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Journal

npj Clean Air

DOI

10.1038/s44407-025-00030-9 

Article Title

Further improvement in London’s air quality demands more than the Ultra Low Emission Zone policy

Article Publication Date

22-Oct-2025

 

Retreating glaciers may send fewer nutrients to the ocean

A study comparing two Alaskan glaciers finds the retreating glacier’s runoff is less nutritious for marine life

University of California - San Diego

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image: 

Northwestern Glacier has retreated approximately 15 kilometers (nine miles) since 1950.

 

 

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Credit: Credit: Kiefer Forsch/Scripps Institution Of Oceanography

The cloudy, sediment-laden meltwater from glaciers is a key source of nutrients for ocean life, but a new study suggests that as climate change causes many glaciers to shrink and retreat their meltwater may become less nutritious. 

Led by scientists at UC San Diego’s Scripps Institution of Oceanography, the study finds that meltwater from a rapidly retreating Alaskan glacier contained significantly lower concentrations of the types of iron and manganese that can be readily taken up by marine organisms compared to a nearby stable glacier. These metals are scarce in many parts of the ocean including the highly productive Gulf of Alaska, and they are also essential micronutrients for phytoplankton, the microorganisms that form the base of most marine food webs.

The findings, published today in Nature Communications and funded by the National Science Foundation (NSF), are limited to just two glaciers in Alaska, but they suggest that climate change-driven glacial retreat could alter the role glaciers play in delivering nutrients to the ocean. 

“If we can duplicate these findings elsewhere, the impacts go beyond our scientific understanding of glaciers,” said Sarah Aarons, a geochemist at Scripps who co-authored the study. “This could impact the productivity of really significant marine ecosystems, which could have long term implications for the health of major fisheries.” 

As glaciers grind across bedrock some of the pulverized rock and sediment they create flows into the ocean via glacial runoff. The sediments contained in glacial runoff are an important source of trace metal micronutrients like iron and manganese for coastal marine ecosystems in Alaska, Antarctica, Greenland and other high-latitude regions. These nutrients fuel phytoplankton growth, which forms the base of the marine food web and absorbs many tons of planet-warming carbon dioxide.

The world’s glaciers are threatened by climate change, which is causing most to lose ice and shrink. The researchers behind the study wanted to investigate whether all this rapid ice loss and retreat changed the nutrient content of glacial meltwater.

To investigate, the researchers traveled to two adjacent fjords on Alaska's Kenai Peninsula in May 2022. Each fjord contained a glacier, but one was stable and the other had retreated approximately 15 kilometers (nine miles) since 1950. Crucially, because the two glaciers were so close together, they were each grinding over the same bedrock. This meant the source material for the sediment carried by the glaciers’ meltwater was nearly identical, creating a natural experiment that allowed the team to isolate the influence of glacial retreat on nutrient content. 

The team collected surface water samples, suspended sediments and iceberg material from the stable glacier, named Aialik Glacier, and the retreating glacier, named Northwestern Glacier.

The researchers analyzed the chemical composition of their samples with a particular focus on metals including manganese and iron as well as the element phosphorus which is also a key nutrient. The analysis also revealed whether these elements were present in chemical forms that made them bioavailable or able to be absorbed and utilized by living organisms.  

Despite both glaciers eroding the same underlying bedrock, the team found striking differences between their sediment plumes. The stable Aialik Glacier produced sediments where approximately 18% of iron and 26% of manganese existed in bioavailable forms. In contrast, Northwestern Glacier's sediments contained lower fractions of bioavailable iron (13%) and manganese (14-15%). 

The retreating glacier's sediments showed signs of extensive chemical weathering and depletion of reactive metals as well as other evidence of prolonged interactions between water and rock. 

The researchers said their findings suggest that for the glacier that has retreated inland, meltwater and sediments take longer to reach the ocean, providing more opportunities for chemical interactions that could transform any iron and manganese into less bioavailable states.

 

“The longer you have water in contact with rock or sediments the more chemical breakdown or weathering takes place,” said Aarons. “So a retreating glacier might be sending more sediment to the ocean but with lower concentrations of bioavailable nutrients like iron because more weathering is occurring.” 

In this view, the eroded bedrock being sent into the ocean by the stable glacier is “fresher” and contains more bioavailable nutrients because it has spent less time interacting with water and other materials.

Most ocean terminating glaciers worldwide are losing ice as climate change progresses, so if the patterns observed at these Alaskan fjords prove consistent across glaciers the implications could be significant — particularly for regions like the Gulf of Alaska and the Southern Ocean which support productive fisheries and where iron is a scarce nutrient.

"We see very clear geochemical differences between these two glacier systems that we link to their state of retreat," said Kiefer Forsch, the study’s lead author who conducted the research as a postdoctoral fellow at Scripps and is now at the University of Southern California. "However, this is a snapshot of two glaciers in one region. Understanding whether these patterns hold across glaciers elsewhere in the world with different bedrock types and stages of retreat will require more research."

Aarons also emphasized the importance of the government support that enabled this research. 

“This research would not have been possible without funding from the National Science Foundation and cooperation with the National Park Service,” said Aarons. “Funding from NSF allows us to understand how this landscape is responding to a warming planet, and has a direct impact upon the many people who subsist on these lands and visit these glacial fjords for their abundant and diverse wildlife.”

The researchers suggest that future work should analyze meltwater sediment for multiple glacier systems at different stages of retreat to clarify whether the results from these two Alaskan fjords can inform predictions about ecosystem responses to continued glacier retreat worldwide.

In addition to Aarons and Forsch, Angel Ruacho of the US Environmental Protection Agency co-authored the study. Ruacho conducted the research while completing a postdoctoral fellowship at the University of Washington.

Ice collected from Northwestern Glacier’s fjord with sediment frozen inside. 

Credit: Kiefer Forsch

Melting ice collected from the glaciers inside a clean room to avoid contaminating the samples. 

Credit

Credit: Kiefer Forsch/ Scripps Institution of Oceanograph

Journal

Nature Communications

Article Title

Tidewater cycle drives alpine glacial sediment plume geochemistry

Article Publication Date

22-Oct-2025