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A newly identified hormone could hold the secret to slowing biological aging—and making cancer treatments far more effective.
Inflammaging is a chronic, low-grade inflammation that develops throughout the body with age. It’s been linked to many leading causes of illness and death, like cancer, metabolic conditions, and cardiac and neurodegenerative diseases. However pervasive, scientists have struggled to fully understand what causes the inflammation—and, perhaps more importantly, how to reverse its impact.
A new study from the Keck School of Medicine at the University of Southern California published in the peer-reviewed journal Nature Communications identified the thymus, a small organ involved in immune system development, as a key player in inflammaging.
The thymus is located just behind the breastbone and produces a key hormone called thymulin, which regulates inflammation. With age, thymulin decreases while inflammation increases, allowing diseases like cancer to progress.
The scientists at USC found that by increasing thymulin levels in mice, their rates of cancer survival improved and it even made immunotherapy treatments more effective.
“This is the first evidence of a substance that is naturally produced in the thymus, declines with age, and has the power to reverse age-related inflammation,” said Fumito Ito, professor of surgery and immunology and immune therapeutics at the Keck School of Medicine and lead author of the study, in a statement.
Past studies have already suggested a link between the thymus and chronic inflammation, but these researchers went further, finding the biological mechanism potentially responsible for the process. One day, thymulin could even be used in clinical trials to treat cancer, among other diseases.
Investigating youth
The study relied, in part, on an uncommon research method: heterochronic parabiosis. This approach requires researchers to surgically join an older mouse to a younger one, so they share blood flow.
They found that the procedure reduced inflammation in the older mice—suggesting that parts of the younger blood may help reverse age-related decline.
The researchers looked at both human blood samples and mouse models, analyzing the genes involved with both aging and longevity. They found a shortlist linked to cytokines—small protein messengers that regulate inflammation—and found a surprising pattern: Mice that did not have these genes had problems with the thymus.
They found that thymulin is important in the body’s regulation of cytokines—seeing that, additionally, cytokines increase as thymulin levels fall with age.
Although the thymus is best known for producing the T-cells responsible for the immune system’s defense against infections, the findings show it can also account for age-related inflammation.
Looking at older mice with cancer, they found that when thymulin was added, the immune response against tumors was boosted, improving overall survival.
Future implications
These findings raise new questions about the hormone’s role in age-related diseases. Inflammaging is linked to a long list of conditions, including diabetes, cancer, and Alzheimer’s disease. Ito said in the statement that the research team plans to further investigate the role of thymulin in chronic diseases.
Currently, there are many treatments available that are marketed as anti-inflammatory and anti-aging options—but these focus on suppressing the inflammatory pathways or getting rid of aging cells. The potential treatment that Ito and team are creating is different, he told Inc.
Their possible treatment involves “restoring an age-related endocrine signal that normally helps maintain immune homeostasis,” Ito says. “Rather than broadly suppressing inflammation, our findings suggest that thymulin may help restore a physiological regulatory mechanism that is progressively lost during aging.”
This post originally appeared at inc.com.
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