Comparative Analysis of Spaceflight Analog Settings and Spaceflight Data in Exploring Changes in the Human Microbiome

Abstract

Spaceflight presents great opportunities and challenges. One important factor in long-term missions (>1 year) to distant destinations is the health and fitness of astronauts. The gut microbiome is an important parameter in this endeavor since it is associated with the immune system, bone and muscle function, and emotional well-being — all factors of concern in long-term missions. However, the taxonomic and functional changes of the gut microbiome, and its specific effects on systemic pathways, remain unclear and require further definition. To gain more knowledge in this field, space analogs are used as a tool to increase sample size. In this thesis, a combined approach of a meta-analysis and joint-analysis was conducted to find current common trends among space and space analogs and to evaluate the usefulness of space analogs, specifically head-down tilt bed-rest studies. Results showed mostly inconsistencies, expect for increased convergence in-between samples and significant dynamics of members of the Clostridia and Bacteroidia classes. To clearly understand the role and dynamics of the gut microbiome in spaceflight, an increased sample size – for example through space analog studies – next to improved and standardized sampling and processing of samples is needed, as well as publicly available data to compare those dynamics.