The Shrinking Gland That Helps You Live Longer
The humble thymus doesn’t get a lot of press. In fact, most people probably couldn’t point it out on their own body (hint: it’s in the middle of your upper chest). But two new studies published in Nature indicate that this small organ could play an important role in our longevity.
Often overlooked, the thymus acts as a sort of finishing school for T cells (in fact, the “T” in “T-cells” comes from “thymus”). After being produced in the bone marrow, immature T cells migrate to the thymus to mature and differentiate into helper T cells, killer T cells, memory T cells, etc.
The thymus is particularly active during childhood, when your immune system encounters all sorts of new antigens, but after puberty it begins to atrophy and eventually undergoes a process called “involution.” During involution, thymus tissue is replaced by fatty tissue (much like using your child’s bedroom for storage after they go off to college). Because the thymus appears to deactivate in this way, it has been dismissed in research – until now.
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Using artificial intelligence to analyze CT scans, researchers at Mass General Brigham in Boston measured the size, shape and composition of the thymuses of more than 2,500 healthy adults participating in the renowned Framingham Heart Study. This allowed them to assign each person a “thymic health score.” The team found that people with higher mood health scores had significantly better health outcomes, including a 50% lower risk of death, a 63% lower risk of cardiovascular death, and a 36% lower risk of developing lung cancer compared to those with lower mood health scores.
So what’s going on?
Researchers believe that when thymic health and T cell diversity decline, the body’s ability to fight new threats like cancer and other diseases also declines. Killer T cells, in particular, are responsible for identifying and eliminating cancer cells and virus-infected cells.
In another study, researchers examined the importance of the thymus in cancer patients treated with immunotherapy. Because immunotherapy recruits the patient’s own T cells to fight cancer, they believed those with healthier thymuses would mount a more robust defense. Studying the thymuses of more than 1,200 lung cancer patients found they were right. Patients with better mood health had about a 37 percent lower risk of cancer progression and a 44 percent lower risk of death.
What can you do to keep your thymus healthy for as long as possible? Lifestyle factors such as smoking, obesity, and inactivity were associated with decreased thymic health, but the researchers did not test whether changing them improved thymus performance. (Nevertheless, these factors are already associated with a whole host of other health problems, so it couldn’t hurt to make a change.)
Researchers hope these new studies will spark renewed interest in the thymus, and possibly new treatment options.
“The thymus has been neglected for decades and may be a missing piece to explain why people age differently and why cancer treatments fail in some patients,” study author Hugo Aerts said in a statement. “Our results suggest that thymic health deserves much more attention and could open new avenues for understanding how to protect the immune system as we age.”
That’s a lot to put on an incredibly shrinking organ, but it might be worth it.
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