What can lemurs tell us about inflammation and aging, aka "inflammaging" in humans? That's the question Elaine Guevara , a biological anthropologist who studies the evolution of life history and aging in primates, set out to understand.
In newly published research on age-related inflammation in ring-tailed and sifaka lemurs, Guevara discovered that perhaps we should rethink the inevitability of inflammaging in humans.
Although similar in many ways, ring-tailed and sifaka lemurs show differences in life pacing and lifespan, making useful comparisons. Because lemurs and humans are primates and share a common ancestor that lived millions of years ago, they offer valuable insights into human evolution.
Her findings, she said, were "surprising."
"Contrary to our predictions, neither species showed age-related change in either marker of oxidative stress. Neither lemur species exhibited age-related change in inflammation; if anything, contrary to our prediction, ring-tailed lemurs showed marginal declines in inflammation with age," Guevara said.
This finding, consistent with a few recent studies of other non-human primates, suggests that lemurs avoid the phenomenon of "inflammaging" widely observed in humans.
The study shows inflammaging is not a universal feature of primates, pointing to some differences that might suggest it turns out it's not even a universal feature of humans, according to Christine Drea , a professor of evolutionary anthropology who was one of the researchers working with Guevara.
What is Inflammaging?
As we grow older, low-grade chronic inflammation sets in, which in turn can cause health problems such as heart disease, strokes, diabetes, cancer and osteoarthritis.
Why inflammaging increases with age in humans, what causes it and how it can be prevented are answers to questions that can unlock critical information to help humans live longer and healthier lives.
Collecting Data from Lemurs
Drea said the team first had to find a way to measure oxidative stress, which can be found in blood, urine and saliva. They settled on urine.
"Our role at the beginning was planning, designing, brainstorming, comparing and getting these samples," said Drea, who has worked with the Duke Lemur Center since 1999. The Lemur Center does not allow research that will harm the animals.
The next step says Guevara is to conduct similar research with lemurs in the wild.
"There are a lot of good reasons to think that aging can be quite different in captivity and in the wild, and that in itself, is informative to evaluating the degree to which human inflammation is intrinsic versus environmental," she said.
In the meantime, Guevara says this study serves as the first step in unraveling the question of why humans are suffering from inflammatory-related and age-related conditions and finding ways to treat them.
"Neither lemur species exhibited age-related change in inflammation; if anything, contrary to our prediction, ring-tailed lemurs showed marginal declines in inflammation with age."
Elaine Guevara
With a rapidly aging global population, "these insights are essential for mitigating disability and improving quality of life in later years," she said.
Citation: "Comparison of age-related inflammation and oxidative stress in two lemur species," Elaine E. Guevara, Nicholas M. Grebe, Richard R. Lawler, Anne Crowley, Savannah Lo, Elise N. Paietta, Janet L. Huebner, Virginia B. Kraus & Christine M. Drea, Journal of Comparative Physiology B, 2 Jul 2025 DOI: 10.1007/s00360-025-01619-y
