Study of the impact of long-duration space missions at the International Space Station on the astronaut microbiome - PubMed (original) (raw)

doi: 10.1038/s41598-019-46303-8.

C Mark Ott 2, Satish Mehta 2, Duane L Pierson 2, Brian E Crucian 2, Alan Feiveson 2, Cherie M Oubre 2, Manolito Torralba 1, Kelvin Moncera 1, Yun Zhang 1, Eduardo Zurek 3, Hernan A Lorenzi 4

Affiliations

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

Alexander A Voorhies et al. Sci Rep. 2019.

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.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1

Figure 1

Study experimental design. (A) Schematic representation of study experimental design. Sample collection time points are indicated on top of the scheme. Number prefixes indicate days before launch (L−), during flight in the ISS (FD) and before (R−) and after (R+) the return to Earth. Colored circles depict time points used for collection of samples specified on the left of the figure. Data types generated from samples are shown on the right. (B) Diagram depicting space missions scheduled during the study. Relative mission time points, in red, indicate the order in which inflight time points FD7 and FD180/FD360 were collected along the study. Circles denote mission start time for each astronaut that participated in this study. Yellow and grey boxes represent the six-month periods astronauts stayed in the ISS. Black numbers indicate the time in months a mission at the ISS started and ended since the beginning of the first ISS mission that contributed to the study.

Figure 2

Figure 2

Principal coordinate plots of weighted Bray-Curtis beta diversity distances across all samples collected in the study. (A) Samples colored by body or ISS surface site; The permanova p-value and R2 using body site as the independent variable is shown. (B) Human microbiome samples colored by astronaut identifier. Each microbiome is represented with a different symbol. Permanova p-value and R2 using astronaut identifier as the independent variable and stratifying by body site are indicated.

Figure 3

Figure 3

Changes in alpha diversity and richness of the astronauts’ microbiome. Boxplots depicting changes in Shannon alpha diversity (A) and Richness (B) of the five human microbiomes surveyed in this study during a mission to the ISS. Significant linear mixed-effects model p-values are depicted using mission stage Preflight as baseline.

Figure 4

Figure 4

Changes in beta diversity of the astronauts’ microbiome. Boxplots showing differences in weighted (A) and unweighted (B) Bray-Curtis beta diversity distances among microbiome samples within and between mission stages. Within_pre_in, within preflight and within inflight distances; between_pre_in, distances between preflight and inflight samples; between_pre_post, distances between preflight and postflight samples; within_pre_post, distances within preflight and within inflight samples. Linear mixed-effects model p-values ≦ 0.06 are depicted using within_pre_in or within_pre_post as baselines.

Figure 5

Figure 5

Changes in the relative abundance of bacterial genera of the astronauts’ microbiome. Changes in the microbiota of the forearm skin (A), GI (B) and nose (C) during a mission at the ISS and after the return to Earth. Colors represent different phyla; horizontal axis, logarithm of the fold change in relative abundance between preflight and inflight or postflight samples; vertical axis, bacterial genera. Black circles indicate genera belonging to the corresponding preflight core microbiome.

Figure 6

Figure 6

Variation of plasma cytokine concentrations during spaceflight and after the return to Earth. Significance values are with respect to preflight L-180 time point. op-value < 0.1; *p-value < 0.05; **p-value < 0.01; ***p-value < 0.001.

Figure 7

Figure 7

Comparative beta diversity analysis between the astronauts’ skin microbiota and environmental bacteria at the ISS. (A,B) Principal coordinate analyses of weighted (A) and unweighted (B) Bray-Curtis beta diversity of FD180/FD360 forehead and forearm skin samples (triangles) and ISS samples (circles) collected during early and late relative mission time points. Ellipses represent 95% confidence intervals. Permanova p-values and R2 values are shown. (C,D) comparative analysis of the difference in mean weighted (C) and unweighted (D) Bray-Curtis beta diversity distances between skin and ISS samples collected at FD7 (C) or FD180 (D). Welch two samples t-test p-values for each comparison are shown.

Figure 8

Figure 8

Changes in alpha diversity and richness of astronauts’ skin microbiota and environmental bacteria at the ISS during the entire duration of the study. Changes in Shannon alpha diversity (A) and Richness (B) of the ISS microbiota over time and their association with Shannon alpha diversity and Richness of forehead and forearm skin samples collected at FD7, FD180 and FD360. Pearson correlation coefficients between skin and ISS samples and correlation p-values are shown.

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