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\n Spaceflight makes certain human stem cells age faster, a new study has found, furthering scientists\u2019 understanding of the potential effects of space exploration on the human body.\n <\/p>\n
\n Stem cells are found throughout the body, and they can make more of themselves or turn into other specialized cells \u2014 including blood, brain or bone cells \u2014 for maintenance and repair.\n <\/p>\n
\n \u201cIn space, stem cells decline in function,\u201d said lead study author Catriona Jamieson, director of the Sanford Stem Cell Institute and professor of medicine at the University of California, San Diego School of Medicine. \u201cThey actually reduce their ability to renew themselves or regenerate, and that\u2019s an important thing to be able to know for long-term space missions.\u201d\n <\/p>\n
\n The study, which NASA funded in part, was performed during four International Space Station resupply missions that SpaceX operated from late 2021 to early 2023. The research published Thursday in the journal Cell Stem Cell<\/a>.\n <\/p>\n \n \u201cThis is the first study that looks at how stem cells behave in space, in low Earth orbit, in real time,\u201d Jamieson added, noting that this kind of research could have a direct impact on health management for astronauts poised to go to space.\n <\/p>\n \n \u201cIt\u2019s important to study stem cell health and see who\u2019s likely to be able to withstand the rigors of space \u2014 it\u2019s stressful to get up, it\u2019s stressful to come down, and it\u2019s stressful to be up there.\u201d\n <\/p>\n \n NASA conducted one of the first experiments on the effects of spaceflight on stem cells<\/a> in 2010 using the space shuttle Discovery. Called the Stem Cell Regeneration Experiment, it investigated how microgravity affected the ability of mice\u2019s embryonic stem cells to make other types of cells.\n <\/p>\n \n In the new study, researchers examined bone marrow stem cells donated by patients undergoing hip replacement surgery. The stem cells, which are directly connected to the health of the immune system and the blood, were placed on a sterile sponge matrix, housed in specially developed bioreactors the size of a cell phone. On board the International Space Station, the cells were constantly monitored by an artificial intelligence system, which could detect their state in real time.\n <\/p>\n \n \u201cOur stem cells should be asleep (inactive) 80% of the time to retain their full function,\u201d Jamieson said. However, that wasn\u2019t the case in space, where microgravity and cosmic radiation had an influence on their well-being.\n <\/p>\n \n \u201cThe stem cells woke up, and they didn\u2019t go back to sleep, and they became functionally exhausted,\u201d she added. \u201cIf our stem cells become exhausted under conditions of stress like microgravity, then they won\u2019t function to make a proper immune system.\u201d\n <\/p>\n \n Some of the cells in the study sustained up to 45 days of spaceflight, and because they were more active than normal, they burned through their energy reserves and showed signs of accelerated aging. Their ability to generate new cells was also reduced, and, according to Jamieson, they began activating normally hidden sections of DNA called repetitive elements or the \u201cdark genome.\u201d<\/a>\n <\/p>\n \n \u201cUnder conditions of stress, really strong stress, we activate these repetitive elements,\u201d Jamieson said. \u201cThese are retroviruses that invaded our genomes thousands and thousands of years ago and represent 55% of our DNA. They send the stem cells into a death spiral. The cells just feel overstressed. They have a crisis. They age too quickly.\u201d\n <\/p>\n \n This is similar to the stem cell stress that Jamieson, who is also a medical doctor, observes in the cells of patients with preleukemic disorders. Jamieson tries to stop these cells in their tracks before they turn into full-blown leukemia, a type of blood cancer.\n <\/p>\n \n Jamieson, a veteran of space stem cell research who has worked on nine missions so far, is planning future studies that will look at practical countermeasures for the aging process.\n <\/p>\n \n \u201cWe can actually use these bioreactors, or avatars for stem cell health, to predict who\u2019s likely to do well and who\u2019s likely to do extremely badly in space \u2026 and develop countermeasures,\u201d she added, noting some upcoming clinical trials for potential medications to counteract the effects of this dark genome activity.\n <\/p>\n \n The good news is that stem cells can recover from the accelerated aging once an astronaut returns to Earth, according to preliminary results from a separate, upcoming study, although the recovery takes about a year.\n <\/p>\n \n The research can also have a beneficial impact for cancer patients as their stem cells exhibit some of the same stress-related damage that the new study has detected in the stem cells in space. \u201cI think this is an important tool for us to accelerate the pace of (cancer) research,\u201d Jamieson said.\n <\/p>\n \n For astronauts, these findings mean that long missions could weaken the blood and immune systems, potentially raising health risks, said Arun Sharma, a stem cell biologist and an associate professor of biomedical sciences at Cedars-Sinai Medical Center in California. Sharma, who was not involved with the study, agreed with Jamieson that the findings may help scientists understand the aging process and develop new therapies that slow or reverse it.\n <\/p>\n \n The study provides strong evidence of the potential damage that radiation exposure and microgravity can have on stem cells, highlighting the possible health risks associated with long-range space expeditions, said Luis Villa-Diaz, an assistant professor in the biological sciences and bioengineering departments at Oakland University in Michigan. Villa-Diaz was also not involved in the research.\n <\/p>\n \n \u201cThe good news is that knowing the potential negative effects that low Earth orbit has on (stem cell) aging and function gives us directions to address these issues and develop strategies to prevent or counteract these effects, and support future space exploration,\u201d he added. \u201cThis often translates into biomedical advances that can be applied to patients on Earth.\u201d\n <\/p>\n \n While earlier space research on stem cells suggested vulnerabilities in more indirect or limited ways, this study provides much clearer evidence of aging, said Elena Kozlova, a professor in the department of immunology, genetics and pathology at Sweden\u2019s University of Uppsala.\n <\/p>\n \n Kozlova, who was also not part of the new research, noted that not all studies on stem cells in space point in the same direction. Her own research<\/a> with early developmental stem cells on microgravity research rockets \u2014 operated by the Swedish Space Corporation \u2014 showed an increase in growth-associated genes.\n <\/p>\n \n That finding, she added, suggests that under certain conditions spaceflight may even promote a more youthful state in some stem cell populations.\n <\/p>\n![\"Researchers](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/09\/st-media-spx24-snfd-approved-1.jpg\")
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