Spaceflight Accelerates Aging Of Human Blood-Forming Stem Cells, Study Reveals Significant Health Impacts

Recent findings have uncovered another impact of space travel on the human body. A study using samples from four SpaceX missions to the International Space Station found that spaceflight speeds up the aging of blood-forming stem cells, which are vital for blood and immune system health. These changes were observed in samples from missions between December 2021 and March 2023.

The research involved real-time monitoring of stem cells from bone marrow donors during 30 to 45-day missions. Scientists compared these spaceflown samples with those kept on Earth from the same donors. The cells in space showed reduced ability to form healthy new cells, increased DNA damage susceptibility, and signs of accelerated aging at chromosome ends.

Microgravity and heightened radiation exposure during space travel were identified as causes for these changes. Unlike Earth, where the atmosphere shields against cosmic radiation, astronauts face high-energy radiation that can damage DNA, increase cancer risk, and cause other health issues. Additionally, microgravity can lead to bone density loss and muscle atrophy.

Stem cells can develop into various cell types within the body. The study focused on tissue-specific stem cells found in many organs and tissues. These cells can give rise to specific cell types but not every type in the adult body. The studied cells, known as human hematopoietic stem and progenitor cells, produce all blood cells in bone marrow.

Dysfunction in these stem cells can impair tissue repair, reduce immune surveillance against cancer, weaken infection-fighting abilities, and shorten lifespan. During spaceflight, these cells became overactive, depleting their reserves and losing their regenerative capacity over time.

The researchers noticed inflammation signs and mitochondrial stress within the cells. Mitochondria generate energy needed for cell function. They also observed activation of normally silent genome sections called the dark genome, which maintain stability when inactive.

Variability Among Donors

The study found differences in stem cell responses to space travel based on donor variability. "Stem cell regenerative capacity was diminished but with some variability between bone marrow donors," explained Dr. Catriona Jamieson from UC San Diego School of Medicine. This suggests anti-aging resilience factors activate in some individuals' stem cells but not others.

Understanding these changes could help protect astronauts during long missions and model human aging and diseases like cancer on Earth. "We have discovered key components of human stem cell resilience that may be enhanced prior to, during and after spaceflight," Jamieson stated.

The researchers continue studying these effects during a recent SpaceX resupply mission to the space station launched last month.

With inputs from WAM