Brereton N J B, Pitre F E, Gonzalez E
Institut de Recherche en Biologie Végétale, University of Montreal, Montreal, QC H1X 2B2, Canada.
Canadian Centre for Computational Genomics (C3G), Department of Human Genetics, McGill University, 740 Dr. Penfield Avenue, Montréal, QC H3A 0G1, Canada.
Comput Struct Biotechnol J. 2021 Apr 23;19:2223-2235. doi: 10.1016/j.csbj.2021.03.040. eCollection 2021.
Maintaining astronaut health throughout long-duration spaceflight is essential to the feasibility of a manned mission to Mars. The ground-based Mars500 experiment investigated long-duration health by isolating six astronauts for 520 days, the longest controlled human confinement study conducted to date. After 520 days, astronauts had uniform strength and lean body mass losses, and increased fasting plasma glucose, calprotectin, and neutrophil levels characteristic of intestinal inflammation but previous analyses revealed no common significant changes in gut microbiota. This study reanalysed data from early (days 7-45) and late (days 420-520) faecal samples and identified 408 exact sequence variants (ESVs), including 213 shared by all astronauts. Thirty-two ESVs were significantly differentially abundant over time, including depletion of keystone resistant starch degrading, anti-inflammatory and insulin sensitivity-associated species, such as , , , , , and , and enrichment of yet-to-be-cultured bacteria. Additionally, the extraordinary experimental confinement allowed observation of microbiota potentially shared between astronauts and their habitat. Forty-nine species were shared, representing 49% and 12% of the human and environmental microbiome diversity, respectively. These findings reveal the microbiota which significantly altered in relative abundance throughout confinement, including species known to influence inflammation and host glucose homeostasis consistent with astronaut symptoms. Identification of microbiome alterations after 520 days of isolation represents a missing piece connecting Mars500 astronaut physiological studies. Knowledge of the impact of long-term confinement upon the human microbiome helps to improve our understanding of how humans interact with their habitats and is a valuable step forward towards enabling long-duration spaceflight.
在长期太空飞行中维持宇航员的健康对于载人火星任务的可行性至关重要。地面模拟火星500天试验通过将6名宇航员隔离520天来研究长期健康状况，这是迄今为止进行的最长时间的受控人类禁闭研究。520天后，宇航员出现了一致的力量和瘦体重下降，空腹血糖、钙卫蛋白和中性粒细胞水平升高，这些都是肠道炎症的特征，但之前的分析显示肠道微生物群没有共同的显著变化。本研究重新分析了早期（第7 - 45天）和晚期（第420 - 520天）粪便样本的数据，鉴定出408个精确序列变体（ESV），其中213个为所有宇航员所共有。32个ESV随时间有显著差异丰富度变化，包括关键的抗性淀粉降解菌、抗炎菌和胰岛素敏感性相关菌种的减少，如[具体菌种名称未给出]、[具体菌种名称未给出]、[具体菌种名称未给出]、[具体菌种名称未给出]、[具体菌种名称未给出]和[具体菌种名称未给出]，以及未培养细菌的富集。此外，这种特殊的实验禁闭条件使得能够观察到宇航员与其栖息地之间可能共有的微生物群。共有49种菌种是共享的，分别占人类和环境微生物群多样性的49%和12%。这些发现揭示了在整个禁闭期间相对丰度发生显著变化的微生物群，包括已知会影响炎症和宿主葡萄糖稳态的菌种，这与宇航员的症状相符。确定隔离520天后微生物群的变化是连接火星500天宇航员生理研究的缺失环节。了解长期禁闭对人类微生物群的影响有助于增进我们对人类与其栖息地相互作用方式的理解，是朝着实现长期太空飞行迈出的宝贵一步。
