Responsible Center: NASA JSC
Grant Monitor: Stenger, Michael
Center Contact: 281-483-1311
Solicitation / Funding Source: 2019 HERO 80JSC019N0001-FLAGSHIP & OMNIBUS: Human Research Program Crew Health. Appendix A&B
Grant/Contract No.: 80NSSC20K1297
Project Type: GROUND
No. of Post Docs:
No. of PhD Candidates: 2
No. of Master's Candidates:
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No. of Bachelor's Degrees:
|Human Research Program Gaps:
(1) FN-401:Food as a Physiological CM - Understand and develop strategies for use of food as a physiological countermeasure (for aspects such as radiation/oxidative stress, cardiovascular health, bone, SANS, exercise, immune, MicroHost) (IRP Rev M)
(2) Micro-102:Evaluate whether deep-space radiation has an additive or synergistic effect with weightlessness/isolation/confinement on microbial types, numbers, and virulence (IRP Rev L)
|| Background: Probiotics are defined by the World Health Organization as "live microorganisms that confer a health benefit on the host when ingested in adequate amounts." Acquisition of diverse microbes from the environment is important for maintaining a healthy gastrointestinal (GI) microbiome, but astronauts' GI microbiomes change during long-term spaceflight missions. Addition of probiotics to the astronaut diet could provide an effective countermeasure. Current data is limited regarding the shelf life of probiotics during long-duration space exploration, particularly to the radiation environment of interplanetary space. Due to limited onboard refrigerator/freezer space, it would be desirable to store probiotics at ambient temperature as freeze-dried capsules. However, freeze-dried formulations of common probiotic species (e.g., Lactobacillus, Bifidobacterium) rapidly lose viability at ambient temperatures. In contrast, probiotic formulations containing spores of various Bacillus species have very long shelf lives and survive passage through the acidic environment of the stomach and small intestine with high potency. Moreover, recent clinical trials have shown that Bacillus spore probiotics are safe, can significantly improve GI symptoms, and stimulate the immune system.
Hypothesis: Exposure of probiotic bacteria to simulated space radiation will result in a decrease in survival and potency, at a rate which can be empirically measured. Probiotics containing Bacillus spores will demonstrate enhanced long-term stability and potency compared to traditional Lactobacillus- or Bifidobacterium-containing probiotics.
Aims: Using the NASA Space Radiation Laboratory (NSRL) at Brookhaven, NY, we propose to evaluate the survival and potency of Bacillus spore probiotics vs. traditional probiotic formulations following exposure to simulated Galactic Cosmic Rays (GCRSim) and Solar Particle Events (SPESim) expected to be encountered during NASA Design Reference Missions (DRMs) lasting up to 3 years. Specific aims include: A. Select appropriate freeze-dried, prepackaged probiotic formulations to test. B. Expose samples at NSRL to GCRSim and SPESim at dosages representative of a 3-year DRM, in parallel with matched lab controls and transport controls. C. Measure viability of all samples vs. exposure dose and compare data from exposed vs. control samples.
Methods: DRM-appropriate GCRSim and SPESim exposures will be performed at NSRL. Survival to radiation exposure will be measured by viable counts and live/dead staining. Survival to simulated gastric and intestinal juices will be measured by standard procedures. Comparison of datasets between traditional probiotics and Bacillus spore formulations will be performed using appropriate statistical methods.
Deliverables: The proposed study will provide data on survival kinetics of probiotic formulations to GCRSim and SPESim exposures, as well as survival to simulated passage through the upper GI tract before and after irradiation. These results will help mission planners in decisions regarding probiotic inclusion in the food system of upcoming long-duration missions.
Significance: The gut microbiome influences virtually all aspects of human health. Microbiome health and dysfunction have been associated with myriad human health conditions ranging from digestive to cardiovascular, immunological, and psychological. Thus, a healthy GI microbiome is of prime importance to astronaut health during long-duration missions. Inclusion of probiotic supplements to the astronaut diet will promote health and mitigate detrimental effects of chronic exposure to long-term spaceflight.
Human Research Roadmap Gaps addressed: MICRO-01 (We need to determine the efficacy of current countermeasures and the need for countermeasure development based on changes in microbial populations and characteristics), MICRO-02 (We need to determine if spaceflight induces changes in diversity, concentration, and/or characteristics of medically significant microorganisms associated with the crew and environment aboard the International Space Station that could affect crew health), MICRO-03 (We need to determine which medically significant microorganisms display changes in the dose-response profiles in response to the spaceflight environment that could affect crew health), MICRO-04 (We need to determine how physical stimuli specific to the spaceflight environment, such as microgravity, induce unique changes in the dose-response profiles of expected medically significant microorganisms), FOOD-01 (We need to determine how processing and storage affect the nutritional content of the food system), and FOOD-03 (We need to identify the methods, technologies, and requirements that will deliver a food system that provides adequate safety, nutrition, and acceptability for proposed long-duration Design Reference Mission operations).