Our Aging Immune System: Can Antioxidants Combat The Decline?

As the Thymus atrophies, we lose the ability to fields T Lymphocytes which are critical to immune functionality. Credit: NIAID 

Immune system decline is one of the more noticeable elements of aging, turning a once minor infection into a dire threat. The Thymus is an organ responsible for producing T lymphocytes, which are essential for our adaptive immune system and respond to new threats. It's long been known the thymus atrophies with age, and becomes less able to produce these T cells - to disastrous effect. New developments suggest that the decline of this organ might be due to oxidative damage and insufficient antioxidant mechanisms - leading to hope that antioxidant treatment may stave off decline. 

Anterior view of the thymus gland, an organ of the lymphatic system. Credit: Wikimedia

Anterior view of the thymus gland, an organ of the lymphatic system. Credit: Wikimedia

"The thymus begins to atrophy rapidly in very early adulthood, simultaneously losing its function.This new study shows for the first time a mechanism for the long-suspected connection between normal immune function and antioxidants."



When  a research team analysed 2 types of thymic cells in mice, which undergo similar atrophy, they found that one type were deficient in a key enzyme called catalase - leading to increased production of reactive oxygen species and consequent damage. When levels of catalase were boosted in these cells, the atrophy was delayed. More general antioxidants, including vitamin c, also appeared to ameliorate damage somewhat. While this route admittedly doesn't offer rejuvenation, it may slow immune decline considerably. It also suggests the free radical theory of aging may be applicable in certain tissues. 

More questions still remain as to why the thymus exhibits such a pronounced decline in contrast to most of the body, and whether substances like androgens accelerate this degradation. 

"There's no question that the thymus is remarkably responsive to androgens," Dr. Petrie noted, "but our study shows that the fundamental mechanism of aging in the thymus, namely accumulated metabolic damage, is the same as in other body tissues. However, the process is accelerated in the thymus by a deficiency in the essential protective effects of catalase, which is found at higher levels in almost all other body tissues."

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