Researchers here suggest that some of the detrimental effects of prolonged space missions are mediated by an increased burden of senescent cells resulting from cosmic radiation exposure. Senescent cell accumulation is a feature of aging and cancer treatments such as chemotherapy, and contributes to the progression of age-related dysfunction and disease. Senescent cells secrete an inflammatory mix of signal molecules that disrupt nearby tissue structure, alter cell behavior, and rouse the immune system into a state of chronic inflammation. Even a small number of senescent cells can have outsized effects on tissue function due to this signaling.
The increasing duration of space missions involves a progressively higher exposure of astronauts to cosmic rays, whose most hazardous component is made up of High-Atomic number and High-Energy (HZE) ions. HZE ions interact along their tracks with biological molecules inducing changes on living material qualitatively different from that observed after irradiation for therapeutic purposes or following nuclear accidents. HZE ions trigger in cells different responses initialized by DNA damage and mitochondria dysregulation, which cause a prolonged state of sterile inflammation in the tissues. These cellular phenomena may explain why spending time in
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