Study Reveals Spaceflight Accelerates Aging in Human Stem Cells

La Jolla, California — A new study funded by NASA has found that exposure to spaceflight accelerates aging in human stem cells. This research enhances scientists’ understanding of how space exploration may affect the human body over time.

Lead author Catriona Jamieson, director of the Sanford Stem Cell Institute at the University of California, San Diego School of Medicine, explained, “In space, stem cells decline in function. They reduce their ability to renew themselves, which is vital knowledge for long-term space missions.”

The study, published Thursday in a scientific journal, was based on research conducted during four International Space Station resupply missions operated by SpaceX between late 2021 and early 2023. Jamieson noted that this was the first study observing stem cell behavior in real time in low Earth orbit.

The researchers investigated bone marrow stem cells donated by patients undergoing hip replacement surgery. These cells, linked to immune and blood health, were monitored aboard the International Space Station using a special artificial intelligence system.

According to Jamieson, “Our stem cells should be asleep 80% of the time to retain full function.” However, in the microgravity environment of space, the cells were more active than usual, leading to functional exhaustion. Jamieson emphasized that exhaustion under stress, such as microgravity and cosmic radiation, compromises stem cell functionality.

Some stem cells in the study remained in space for up to 45 days and displayed signs of accelerated aging and reduced ability to generate new cells. “These cells have a crisis and age too quickly,” Jamieson added.

This accelerated aging phenomenon resembles stress seen in stem cells of patients with preleukemic disorders, which is a focus of Jamieson’s research. She aims to develop countermeasures to combat the aging process observed in space.

Preliminary findings related to recovery from accelerated aging indicate that stem cells can return to normal function after astronauts return to Earth, although this process may take about a year.

Arun Sharma, a stem cell biologist at Cedars-Sinai Medical Center, highlighted that the findings suggest long missions could weaken astronauts’ blood and immune systems, presenting health risks for future space expeditions.

Luis Villa-Diaz, an assistant professor at Oakland University, noted the potential biomedical advances this research could yield for patients on Earth. “Knowing the negative effects of low Earth orbit on stem cell function gives us directions to develop strategies to support future space exploration,” he said.

In contrast, other research on stem cells in space has produced varied conclusions, with some showing increased growth in specific stem cell populations, indicating that conditions in space may also promote youthfulness in some areas.