How aging cripples the immune system

From KurzweilAI:

Thymus1Aging cripples the production of new immune cells, decreasing the immune system’s response to vaccines and putting the elderly at risk of infection, but antioxidants in the diet may slow this damaging process. That’s a new finding by scientists from the Florida campus of The Scripps Research Institute (TSRI), published in an open-access paper in the journal Cell Reports. The problem is focused on an organ called the thymus, which produces T lymphocytes (a type of white blood cell) — critical immune cells that must be continuously replenished so they can respond to new infections. “The thymus begins to atrophy rapidly in very early adulthood, simultaneously losing its function,” said TSRI Professor Howard Petrie. “This new study shows for the first time a mechanism for the long-suspected connection between normal immune function and antioxidants.”

How antioxidant enzyme deficiency leads to metabolic damage

Scientists have been hampered in their efforts to develop specific immune therapies for the elderly by a lack of knowledge of the underlying mechanisms of this process. To explore these mechanisms, Petrie and his team developed a computational approach for analyzing the activity of genes in two major cell types in the thymus — stromal cells and lymphoid cells — in mouse tissues, which are similar to human tissues in terms of function and age-related atrophy. The team found that stromal cells were specifically deficient in an antioxidant enzyme called catalase. That resulted in elevated levels of the reactive oxygen byproducts of metabolism, which cause accelerated metabolic damage.*

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