Speaking at the IPC (19th International Scientific Conference on Probiotics, Prebiotics, Gut Microbiota and Health), in Krakow, last week (Jun. 22-24), Christian Roghi, co-founder at Microbiome Futures, told attendees how the five-month-young think tank is bringing together experts in microbiome health and space exploration to deliver innovations to support astronauts’ health.
“In just five months, the interest in the microbiome in space has been incredible. There is demand for the microbiome to be involved in space exploration positively, but we just don’t know how yet.”
He added: “We need the whole sector, especially the microbiome sector, to work together to answer some very difficult questions and change our mindset.”
With NASA aiming to send astronauts to Mars from as early as 2030, Roghi said a lot of work is still needed to find a solution to the biological challenge of a 24-month space mission.
“When you send someone to space, the biology breaks down and we need creative thinking and new solutions to be able to solve this issue.”
With every microbiome across the human body impacted by spaceflight, astronauts will experience degradation in muscle mass, cardiovascular health, immune function, gene expression and more.
He noted there are several factors which cause an accelerated aging process, including microgravity, high-energy cosmic radiation, as well as extreme confinement and isolation.
Roghi said astronauts are given a strict regimen of two hours daily exercise training to retain their muscle mass, yet they will still inevitably lose lean mass, revealing an opportunity for an adjunct intervention.
Microbiome-targeted solutions primarily developed for astronauts may well hold promise for populations on earth, such as those exposed to radiation, reduced movement, or confinement and isolation, he added.
Links between spaceflight and hibernation
With obvious barriers to conducting clinical studies on multiple astronauts, scientists have looked closer to home for potential microbial insights and clues for innovation.
Roghi noted hibernating animals may hold some answers as these animals’ microbiomes appear to support them to survive suspended animation and extreme environments. By mimicking how these animals slow their metabolism and halt muscle decay, scientists aim to protect astronauts from space radiation, bone loss, and psychological stress.
During hibernation, animals survive severe fasts by utilizing gut microbes that produce the enzyme urease, Roghi explained. These bacteria break down waste urea from the blood into ammonia and carbon dioxide, which the animal and microbes then synthesize into amino acids and proteins to prevent muscle wasting.
Roghi explained that by analyzing the microbiomes of animals during both their active and dormant states, scientists can isolate which bacterial pathways allow hibernators to preserve muscle mass and resist organ damage despite months of immobility.
What’s more, hibernation drastically reduces body temperature, metabolism, heart rate, oxygen consumption, and cellular activity. Researchers believe these changes may make cells less vulnerable to radiation-induced damage. This is a significant opportunity given deep-space cosmic radiation is a significant hazard for astronauts.
Hibernating bears can also increase insulin resistance seasonally to burn fat without suffering from metabolic diseases. Understanding this mechanism could help keep astronauts metabolically healthy during long, sedentary flights.
Scientists have introduced microbes from hibernating mammals into the digestive tracts of non-hibernating animals to observe if a hibernation-like state can be actively triggered. Research has shown that specific gut bacteria alone can induce decreased body temperature and lowered metabolic rate.
Discoveries from human research
The body of research in humans is also growing. Just last month, new research was published in Frontiers in Microbiology revealing the impact of parabolic flight (a specialized aircraft maneuver that simulates the weightlessness of space) on the vaginal microbiota.
Roghi also noted a landmark NASA twin study conducted in astronaut twins over a one-year mission from 2015 to 2016. They sent one sibling to space and collected stool samples from both to compare the differences before and after flight.
Results published in the journal Science, revealed a distinct shift in the balance of the two dominant bacterial phyla in the astronaut’s gut: Firmicutes and Bacteroidetes. But the microbiome fully recovered a few months after returning home.
Do answers lie with non-living strains?
Another challenge is that microbial load in spaceflight is meticulously controlled as microgravity can cause bacteria to adapt and grow more aggressively and microbial contamination in spacecraft poses risks to both crew health and onboard systems. This creates a significant challenge in taking probiotics into space.
Additionally, research is needed to determine how long probiotics can remain viable in space, especially considering space shuttles don’t contain fridges or freezers. So far, research has confirmed freeze-dried probiotics remain stable for up to 1 month and spore-forming bacteria stay stable for longer.
An opportunity therefore lies with postbiotics and prebiotics, Roghi argued. Although he noted that with the gut microbiome changing so rapidly, it could be difficult to pinpoint the appropriate prebiotic for the astronaut throughout their mission.
