Study of the impact of long-duration space missions at the International Space Station on the astronaut microbiome

Abstract

Over the course of a mission to the International Space Station (ISS) crew members are exposed to a number of stressors that can potentially alter the composition of their microbiomes and may have a negative impact on astronauts’ health. Here we investigated the impact of long-term space exploration on the microbiome of nine astronauts that spent six to twelve months in the ISS. We present evidence showing that the microbial communities of the gastrointestinal tract, skin, nose and tongue change during the space mission. The composition of the intestinal microbiota became more similar across astronauts in space, mostly due to a drop in the abundance of a few bacterial taxa, some of which were also correlated with changes in the cytokine profile of crewmembers. Alterations in the skin microbiome that might contribute to the high frequency of skin rashes/hypersensitivity episodes experienced by astronauts in space were also observed. The results from this study demonstrate that the composition of the astronauts’ microbiome is altered during space travel. The impact of those changes on crew health warrants further investigation before humans embark on long-duration voyages into outer space.

Does simulated microgravity induce significant changes in human gut microbiota? New answers with dry immersion, an innovative ground-based model.

“…It is also not surprising that Dry Immersion did not induce signi cant global composition changes at phyla levels as already reported in literature on human or murine space ight [10,23]. Indeed, the duration of DI was limited to 5-days, with nevertheless signi cant limited effects on the lean mass (-2.5% reduction).…”

“…However, these studies were only based on cultivable bacteria and not on the taxonomic pro les. Two recent NASA studies should also be highlighted: the NASA twin project, which compared one twin astronaut microbiota before, during, and after a 1-year mission on-board the International Space Station (ISS); his twin serving as a genetically matched ground control [9], and the Astronaut's Microbiome (AM) project which investigated the impact of the space ight and the con ned environment on crewmembers spending 6 months to 1 year on-board the ISS [10]. In both studies, gastrointestinal microbiota alterations and microbiome changes were observed.…”

Microbiome dynamics during the HI-SEAS IV mission, and implications for future crewed missions beyond Earth

“…Confirmed by our meta-analysis based on four selected longitudinal studies from built environment settings, increasing microbial diversity on human skin and built environment samples was not reported in offices or homes [80,82]. However, this observation could be the result of a human occupancy in confined and in more isolated built environments as this pattern was also observed in samples from crew members at the ISS (International Space Station) for samples of the forearm and gut [89] or in fecal samples during the cohabitation of US Air Force cadets [81]. Crew members C, D, E, and F started with a relatively low range of microbial diversity on their skin compared to representative studies of the skin microbiome [90,91].…”

“…Moreover, baselines of the microbiome inside the habitat, its crew and post sampling events would greatly improve evaluations of the impact of confinement on the crew and habitat surfaces. Most comparable studies, either ground-based like Mars500 [41,105] or in space aboard the ISS [24,89,106], showed a similar picture of longitudinal homogenization, composition and diversity of microbiomes.…”

Impact of a Model Used to Simulate Socio-Environmental Stressors Encountered During Spaceflight on Murine Intestinal Microbiota

“…astronauts at high risk of developing intestinal dysbiosis and a recent study on International Space Station crew members described an alteration of the composition of astronauts' microbiome during space travel [24]. Such dysbiosis could have an impact not only on immune system e ciency, but also on energy intake, nutriments assimilation and intermediary metabolisms such as those of antibiotics [25].…”