Long-term space flight can weaken the immune system

Long-term space flight can weaken the immune system

By 2030, NASA hopes to send humans to Mars. This is a round-trip mission, which will take up to 3 years. The only problem is that it is much longer than the astronaut has been able to stay in space in the entire history of flights. Researchers at the University of Arizona believe that such long trips can adversely affect certain cells of the astronaut's immune system.

Scientists considered the effect of space flights lasting 6 months or more on natural killer cells (NK), a type of white blood cells that kill cancer cells in the body and prevent reactivation of old viruses. Cancer is a serious threat to astronauts during long space flights due to radiation exposure.

The space station is a sterile environment, so it is difficult to catch a virus or flu. But viruses remain that are already in your body. Among them, mononucleosis or herpes, which remain with us always and are activated during a period of stress.

The researchers compared the blood samples of 8 crew members who went to the International Space Station with healthy people. Blood samples were taken before launch, during flight and after returning to Earth. The analysis showed impaired function of NK cells. On the 90th day of the flight, the cytotoxic activity of NK cells against leukemic cells was reduced by 50%. The effect seems especially strong with novice astronauts than those who have already been in space. Moreover, it was found out by chance, noting that for half the crew it was not the first flight. Differences in testimony can be explained by age or stress, because beginners are usually younger than veterans. It remains to be seen whether the reduction in the function of NK cells affects susceptibility to cancer.

The most important thing to understand is how to soften the effect. How can you prevent a blow to the immune system during space flight? And what is the main reason: stress, radiation, microgravity, an unknown factor? There is no exact answer yet, but researchers are already developing potential defenses, including nutritional or pharmacological intervention and increased exercise.

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