Nav: Home

NASA Twins Study finds spaceflight affects gut bacteria

April 11, 2019

Research from NASA's landmark Twins Study found that extended spaceflight affects the human gut microbiome.

During his yearlong stay on the International Space Station (ISS), astronaut Scott Kelly experienced a shift in the ratio of two major categories of bacteria in his gut microbiome. The diversity of bacteria in his microbiome, however, did not change during spaceflight, which the Northwestern University-led research team found encouraging.

Gut health affects digestion, metabolism and immunity; and, more recently, changes in the microbiome have been linked to changes in bones, muscles and the brain.

The study's finding could help physicians and researchers pinpoint and implement ways to protect astronauts' and space tourists' microbiomes during long bouts of space travel, such as during the much-anticipated mission to Mars. These countermeasures could include pre-, pro- and postbiotics.

"We cannot send humans to Mars without knowing how spaceflight affects the body, including the microbes traveling with humans to Mars," said Northwestern's Fred W. Turek, who led the microbiome study. "And we need to know sooner rather than later. The plan is to send people to Mars in 2035, so we cannot wait until 2033 to gain this information."

Northwestern's gut microbiome research was one study out of ten that will publish Friday (April 12) in one comprehensive paper in the journal Science. Each study examines one aspect of how spaceflight affects the human body, including changes in gene expression, bone density, immune system responses and telomere dynamics.

"There were ten teams of researchers but only one article," said Martha Vitaterna, first author of the Northwestern study. "This multi-system, integrated analysis over time is one thing that makes the Twins Study unique and powerful. We can see which things change together in the human body."

Comparing the twins

From 2015 to 2016, Scott Kelly became the first American astronaut to spend nearly one full year in space. Scott Kelly and his identical twin brother, retired astronaut Mark Kelly participated in the unprecedented yearlong investigation, conducted by NASA's Human Research Program. Mark Kelly provided a baseline for observation on Earth, and Scott Kelly provided a comparable test case in space.

Turek and Vitaterna looked at how the composition of bacteria in Scott Kelly's gut changed over time and space. The pair collected two fecal samples from Scott Kelly before he left for space, four during the year in space and three after he returned to Earth.

"We did compare Scott with Mark, which was interesting," said Turek, the Charles and Emma Morrison Professor of Neurobiology in Northwestern's Weinberg College of Arts and Sciences and director of the Center for Sleep and Circadian Biology. "But the real comparison was looking at Scott's samples from before, during and after flight. That's probably the most valuable information we have."

Importance of gut health

Often called a "new organ system," the gut's microbiome is a complex community of microorganisms -- including bacteria, viruses and fungi -- that live in the digestive tract. Only within the past 10 years have researchers started to realize how the microbiome's health and diversity affects the rest of the human body. Altering the microbiome can lead to alterations in the bone, muscle and brain.

"The influence that bacteria have on all other systems of the body is really remarkable," said Vitaterna, a research professor of neurobiology at Northwestern. "There are studies that link changes in the gut microbiome with neurological and physiological conditions, like Alzheimer's disease, Parkinson's disease, autism and schizophrenia. By protecting the gut, we can protect all these other systems."

More than 90 percent of the gut's bacteria belong to one of two broad categories: Firmicutes or Bacteroidetes. Both categories contain a mix of both good and bad bacteria. The ratio between Firmicutes and Bacteroidetes in Scott Kelly's microbiome experienced a pronounced shift during spaceflight -- the number of Firmicutes increased while Bacteroidetes decreased. This shift was among the greater compositional change that the researchers noted in Scott Kelly's microbiome, which returned to normal after he came back to Earth.

"There was some kind of wholesale shift in remodeling of the structure of this community of microorganisms," Vitaterna said. "We cannot say whether it's good or bad."

What caused the shift?

A number of variables could have influenced Scott Kelly's microbiome while in space, including microgravity, increased radiation, shifts in circadian rhythms, decreased sleep time, lack of air circulation, the stress of living in an enclosed space and an altered diet. Turek and Vitaterna were concerned that Scott Kelly's diet in space, which comprised mostly freeze-dried, irradiated, pre-packaged foods, would decrease the diversity in his microbiome. Initially, diet does not appear to matter as much as the researchers worried.

This result mirrored mouse studies the Northwestern pair conducted in the past. Whereas Scott and Mark Kelly did not eat the same foods during the yearlong study, mice in previous studies ate the exact same diet. Still, the space mice experienced shifts in their gut microbiomes compared to the control mice on Earth.

Turek believes microgravity is most likely responsible for the change. "We think that microgravity has an effect on the bacteria," he said. "That's what we want to determine going forward."
-end-
Turek and Vitaterna collaborated with researchers from the University of Illinois-Chicago and Rush University Medical Center in Chicago.

Northwestern University

Related Bacteria Articles:

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.