New research shows that space travel may accelerate aging in the human body by impacting blood-forming stem cells, vital for immune and overall health. A NASA-funded study analyzed stem cells from bone marrow donors sent on four SpaceX missions to the International Space Station, each lasting 30 to 45 days. Compared to identical samples kept on Earth, the space-flown cells exhibited reduced regenerative capacity, DNA damage, and accelerated aging at the ends of their chromosomes. The findings highlight how microgravity and cosmic radiation could compromise astronauts’ long-term health, particularly their immune system, tissue repair, and lifespan.
Stem cells and their role in human health
Human hematopoietic stem and progenitor cells, found in bone marrow, generate all blood cells—including oxygen-carrying red cells, immune white cells, and platelets. Dysfunction in these cells can impair tissue repair, weaken immunity, and increase susceptibility to infections and cancers. Maintaining their regenerative capacity is essential for overall longevity and resilience. The study revealed that stem cells in space became overactive, depleting reserves needed for regeneration. They showed signs of mitochondrial stress, inflammation, and activation of normally silent sections of the genome, known as the dark genome, which may destabilize cellular function. These changes suggest that space travel accelerates cellular aging and reduces the body’s ability to recover from damage.
Individual variability in response
Notably, the response to spaceflight differed among donors. Some individuals’ stem cells showed better resilience, suggesting that inherent anti-aging mechanisms may protect against the stressors of space. This variability indicates that some astronauts could be more vulnerable to the long-term effects of space travel than others. The findings underscore the need for strategies to protect astronaut health during extended missions to the Moon, Mars, or beyond. Understanding how space conditions affect stem cells could guide development of countermeasures, such as shielding, pharmaceuticals, or personalized medical protocols, to mitigate accelerated aging and immune dysfunction.
