Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment

Study Overview
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Brief Summary
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Human immune function and intestinal microbiota are suggested to be altered within long-duration stay in space. Accumulated evidences on earth support that Lactobacillus casei strain Shirota (LcS) is a promising probiotic strain on improvement of immune function and intestinal microbiota. This study aims to investigate the impact of long-duration spaceflight as well as intake of LcS on the international space station (ISS), on immune system and intestinal microbiota in astronauts.

Official Title
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Study for Evaluating the Impact of Continuous Consumption of Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment

Conditions
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Immune Function and Intestinal Microbiota

Intervention / Treatment
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* Dietary Supplement: Probiotic capsule


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals who are scheduled to stay on the ISS for at least 3 months Individuals who fully understand the study protocol and provide written informed consent for the study participation Exclusion Criteria: Individuals who routinely use antibiotic, laxative, and/or bowel regulating medicine Individuals who participate in other research that competes with this study in terms of the purpose and field, e.g., study with dietary management or intake of bifidobacteria/lactic acid bacteria, oligosaccharides, antibiotic, laxative, and/or bowel regulating medicine

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LcS group<br>Consuming probiotic capsule | Dietary Supplement: Probiotic capsule<br>* Continuously take five capsules containing freeze-dried LcS on ISS for four weeks, from four weeks before the return (R-4W) to one day before the return (R-1d)<br>|
| No Intervention: Control group<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Longitudinal changes in the number of LcS in feces | Number of LcS in feces will be assessed by PMA-qPCR, during pre-flight, in-flight and post-flight. | 9-18 months | 
| Longitudinal changes in the level of immune markers | Levels of immune markers in blood/saliva will be assessed by ELISA and bioassay, during pre-flight, in-flight and post-flight. | 9-18 months | 
| Longitudinal changes in numbers and composition of intestinal microbiota | Numbers and composition of bacteria in feces will be assessed by RT-qPCR/qPCR and next generation sequencer analysis, during pre-flight, in-flight and post-flight. | 9-18 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Astronauts, Probiotics, Immune function, Intestinal microbiota