Protective alleles and precision healthcare in crewed spaceflight

Abstract

Common and rare alleles are now being annotated across millions of human genomes, and omics technologies are increasingly being used to develop health and treatment recommendations. However, these alleles have not yet been systematically characterized relative to aerospace medicine. Here, we review published alleles naturally found in human cohorts that have a likely protective effect, which is linked to decreased cancer risk and improved bone, muscular, and cardiovascular health. Although some technical and ethical challenges remain, research into these protective mechanisms could translate into improved nutrition, exercise, and health recommendations for crew members during deep space missions.

Fig. 1. Increasing time and breadth of astronauts.

A The cumulative number of astronauts who have been in space, plotted by the year of their first mission. B Boxplots representing the age of astronauts on their first mission plotted by the decade of their first mission. C Boxplots representing the cumulative amount of time an astronaut spent in space plotted against the number of missions in which they have participated. Blue signifies male and pink signifies female astronauts in all plots. Data was scraped from supercluster.com on September 20th, 2021. Only astronauts who spent time in space and crossed the Kármán line are displayed.

Fig. 2. Spaceflight health risk countermeasures.

Examples of health-risk categories that warrant precision countermeasures to improve the physical fitness of both spaceflight participants and terrestrial humankind. From left to right: examples of common spaceflight ailments related to the health-risk category; examples of spaceflight countermeasures related to the health-risk category; examples of terrestrial populations that could benefit from improved precision countermeasures related to the health-risk category. Created with BioRender.com released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license.

Fig. 3. Literature review of evidence for protective alleles.

Literature review and its key findings for a subset of alleles that may be linked to health protective effects, many of which occur naturally in the human population. From left to right: the gene name; example protective phenotypes; whether a polymorphism has been linked to the protective phenotype; whether the protective phenotype typically relates to over, under, or variant function of the gene; the level of evidence of protection for the variant on Earth (green icons) or in space (blue icons); and examples of known harmful associations with this allele. We further include if the gene or its related pathway can be targeted with exercise or nutrition (purple icon), has been studied in clinical trials (green icon), or has been observed to alter function during spaceflight. Only the highest level of evidence we found is displayed, with in vivo being defined as stronger evidence than in vitro, and health benefits for human subjects being defined as higher evidence than health benefits for rodent subjects. Empty cells indicate instances in which we were unable to find moderate evidence based on current literature. Partly created with BioRender.com released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license. More details and literature references are provided in the Supplementary Data.