Scientists have recently observed for the first time that, on an epigenetic level, astronauts age more slowly during long-term simulated space travel than they would have if their feet had been planted on Planet Earth.
“Many of us assume that being exposed to radiation or other harm in space would be reflected by increased aging. But there’s also been a lot of research that has shown the opposite,” said Jamaji C. Nawanaji-Enwerem, Berkeley Public Health postdoctoral fellow and first author of a study published in Cell Reports in November 2020. The study reviewed data from the six participants of the Mars-500 mission, a simulated space travel and residence experiment launched by the European Space Agency in 2010.
In space, people usually experience environmental stressors like microgravity, cosmic radiation, and social isolation, which can all impact aging. Studies on long-term space travel often measure aging biomarkers such as telomere length and heartbeat rates, not epigenetic aging. To fill in the gap, Nawanaji-Enwerem and his team members took the novel step to look at epigenetic biomarkers such as DNAmPhenoAge, a robust marker of disease risk, and DNAmGrimAGE, a predictor of mortality risk.
The findings show that space mission duration will lead to a slower aging process, which looks like a good thing. “But if the mission goes on for longer, it can actually be a bad thing for you,” said Nawanaji-Enwerem.
“It also informs future research in terms of what biomarkers of aging are important to measure,” said Andres Cardenas, study co-author and assistant professor of Environmental Health Sciences at Berkeley Public Health.
During the Mars-500 experiment, six astronaut crews stayed in an isolated space and lived as if they were on Mars for 520 days. Cosmic radiation and microgravity were not replicated in the experiment, so the slower aging process found by scientists is caused by social isolation and other relative effects.
Although it’s not clear why space travel would lead to slower epigenetic aging, the findings will be valuable for understanding the health implications for future space travel.
“It’s not if, but when, we’re going to transition to space living,” said Cardenas.