Tackling Immune System Dysfunction— from Multiple Angles

European Space Agency (ESA) astronaut Alexander Gerst and NASA astronaut Serena Auñón-Chancellor, perform a Functional Immune Blood Sample Draw at the Human Research Facility (HRF), in the Columbus Module. The Functional Immune investigation analyzes blood and saliva samples to determine the changes taking place in crew members’ immune systems during flight. (Credits: NASA)

HOUSTON (NASA PR) — Getting sick is no fun for anyone, but it especially taxes crew members aboard the ISS. Protecting crew health is important as NASA prepares for long-duration, deep-space missions. The human immune system is a complex web of biological structures and processes; decreased activity in one piece of it can change overall disease risk. Studies have shown microgravity causes modifications in the human immune system. Figuring out why and how this occurs could help not only astronauts, but people affected by immune dysfunction here on Earth.

Many investigations aboard the space station have studied the effect of microgravity on immune system health. For example, the Functional Immune investigation analyzes blood and saliva samples to identify changes taking place in crew members’ immune systems during flight, and compares the data with self-reported health information. This unique look at subtle changes in the immune system that may occur before symptoms show up, whether in space or on the ground, may help scientists pinpoint the onset of illness so they can suggest monitoring strategies or treatments to boost the immune system––and prevent full-blown infections and diseases.

T-cells, a type of white blood cell, play a role in activating the body’s immune system. The T-Cell Activation in Aging investigation sent T-cells to the space station, then analyzed changes in their gene response back on the ground to help determine what causes depression of the human immune system in microgravity. Results support the development of better protective measures to keep crews healthy during long space missions, especially those beyond Earth orbit, well out of the reach of major medical facilities. Better understanding of immune system activation and suppression also supports improved treatment for autoimmune diseases such as arthritis and diabetes, and the natural decline of the immune system as people age.

European Space Agency astronaut Andre Kuiper, shown here in the Human Research Facility, prepares samples for the Integrated Immune study. Samples received during the Functional Immune investigation will be used to determine the changes taking place in crew members’ immune system during spaceflight. (Credits: NASA)

Another investigation, Integrated Immune, tested a strategy to measure white blood cell count and stress hormones in crew members during spaceflight onboard the space station. Researchers found increases in red blood cell count, mean corpuscular volume, hemoglobin, and platelet concentration on long-duration flights. This suggests that reports of reduction in these blood elements represent early adaptation to microgravity, and that spending more time in space may somewhat compensate for those reductions. The monitoring techniques of this investigation have potential benefit in infection epidemics and remote locations on Earth, as well.

Multi-Omics evaluates how the space environment and prebiotics affect immune function. This investigation combines data obtained from measuring changes in the gut microbiological composition, metabolites profiles, and the immune system. Recent studies indicate that imbalance in gut microbiota composition results from a variety of environmental stresses and could lead to immune dysfunction. This meta-analysis of the gut microbiota from crew members should result in better understanding of any immune dysfunction they experience. The investigation may identify potential bacterial or metabolic biomarkers for immune dysfunction, which could help the development of a method to restore gut microbiota imbalance and, in turn, immune system function.

Microbiome examines the individual microbiome, or the collection of microbes living in and on the human body at any given time. Researchers use periodic samples taken from different parts of the body and the space station to monitor crew member microbiomes and immune system function, and their interaction with the unique space station environment. The data enable assessment of the likelihood and consequences of alterations in the microbiome due to extreme environments, and the related human health risks. In addition to potentially lowering health risks during future space explorations, this study could benefit people who live and work in extreme environments on Earth. Results also could advance research in preliminary detection of diseases, alterations in metabolic function, and immune system deficiency.

European Space Agency (ESA) astronaut Samantha Cristoforetti working on the T-Cell Activation in Aging experiment in the Columbus Module. (Credits: NASA)

Rodents such as mice and rats are “model organisms” whose characteristics make them easy to maintain, reproduce and study in the laboratory. Every model organism has been widely studied, and each has a well-documented and well-understood genetic makeup. Results from research on one model organism would likely be much the same if conducted on another similar organism. Model organisms tend to be plentiful and inexpensive, have short generation times (i.e., produce offspring in a short time), and grow relatively quickly. They are generally less complex than organisms for which they serve as the stand-in, thus making it easier to examine the research problem in question. Model organisms are essential for much research on human health, which would be impractical or unethical to conduct with human subjects

The underlying mechanisms behind immune dysfunction caused by living in space are not well understood. These and other investigations aim to figure out those mechanisms and use that understanding to help people stay healthy––in space and on the ground.

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