As scientists worldwide continue to study the effects of spaceflight on human health and physiology, a team of researchers has found significant changes in the gut microbiome of mice aboard the ISS (International Space Station). Their findings, published in Npj Biofilms could have big implications for space travel and even space colonization.
“On earth, we understand that we host a diverse ecosystem of microorganisms which are required for a healthy human metabolism and an effective immune system,” Dr. Nicholas Brereton, a lead author of this study and a professor at University College Dublin, told The Debrief.
“As we start to understand how this ecosystem is compromised in space, we hope to be able to help enable safe long-duration spaceflight. Given the novelty and extremity of the environmental stress, aerospace medicine is also helping us learn more about how these host-gut microbiome interactions might be involved in diseases here on Earth,” Brereton said.
“As we return to the moon and reach out beyond, we’ll be taking a diverse community of life with us from Earth, and it’s inevitable that we’ll learn new insights into our own fragility and resilience.”
Studying Mice Microbiomes
In a study on the ISS, mice were kept in special habitats for either 29 or 56 days. Scientists then compared the gut bacteria of these space-traveling mice with those of mice kept on Earth under similar conditions.
“Keep in mind this means that the crew had to be trained in animal manipulation in zero gravity, quite the challenge,” Brereton adds.
The researchers then used advanced techniques to analyze the gut bacteria, identifying changes in more than 40 different species of microbes. These changes were particularly notable in bacteria that help the body manage bile acids and fatty acids, which are crucial for digesting fats and regulating cholesterol.
“We’re still very much in the dark about how the space environment directly influences the ecosystem of organisms in our bodies that are critical to health, so any expectations on our part would be poorly informed guessing – it’s very much an undiscovered country,” Brereton says.
“Similarly, there are substantial changes in astronaut physiology, and we don’t know how these might influence the gut microbiome community. Some of the biggest changes we see are in bacteria involved in bile acid and fatty acid metabolism, including more rare bacteria that are crucial bottlenecks to these specific microbiome functions.”
Preparing for Future Space Missions
As countries prepare for future missions to Mars and beyond, it’s crucial to consider these findings. Protecting astronauts’ health during long space journeys will require careful planning and possibly new treatments to maintain a healthy gut microbiome.
“We’re still in the infancy of understanding the impact of spaceflight on human physiology, and it’s important first to understand how and why the space environment seems to drive such extensive metabolic dysfunction,” Brereton adds.
Right now, he says that a range of pharmaceutical and dietary approaches are being studied, which he says will help safeguard astronaut health in the future, although the efficacy of such approaches varies.
“Studies on earth have shown how bacterial bile acid and fatty acid metabolism are essential components of human health,” Brereton said. “Seeing these substantial changes in specific microbiome species is a new piece of the puzzle which should help inform these strategies to protect astronauts.”
Kenna Hughes-Castleberry is the Science Communicator at JILA (a world-leading physics research institute) and a science writer at The Debrief. Follow and connect with her on X or contact her via email at kenna@thedebrief.org