Recent studies suggest that spaceflight has a profound effect on the human immune system. This system is critical for protecting against viral infection and tumor development. Research has demonstrated that the unique stressors of space may suppress complex components of astronauts’ immune functions. Exposure to microgravity and cosmic radiation increases the risk of developing many diseases. As our species ventures out on longer missions to the Moon and Mars, comprehension of these effects is more crucial than ever.
A comprehensive guide to space immunology, authored by Buck Associate Professor Dan Winer, MD, and his colleagues, outlines the mechanisms behind these changes. This guide unravels the complex ways that multiple stressors interact to alter immune cell function. The voyage puts a spotlight on the important ongoing research to ensure astronauts’ health as they journey beyond the confines of Earth.
The Challenges of Spaceflight
Spaceflight is an extreme environment. The unique stressors involved represent a plethora of factors that can negatively impact human health. Microgravity is an important physical factor known to influence cellular behavior. It could prevent correct planning of the cytoskeleton, which is important for giving cells their shape. Furthermore, cosmic radiation subjects astronauts to higher doses of radiation, leading to long-term damage to immune cells.
Changes in sleep-wake patterns further complicate matters. As we described, disrupted circadian rhythms can have profound effects on overall health and immune function. Those effects in turn, researchers study these phenomena here on Earth by recreating the conditions of spaceflight to further understand their impacts.
“Most of the classical human immunology data on spaceflight came from basic phenotyping studies—you could see that spaceflight perturbed the immune system, but there was very little known on why the immune system didn’t function well in space.” – Dan Winer
It’s a common misconception that the ISS is primarily a platform for testing technologies for human space exploration missions. To do this, they’re looking to projects such as NASA’s Twins study and SpaceX’s Inspiration 4 mission. These projects help us get experimental data that are invaluable as we continue learning how these immune systems acclimatize during and after space travel.
The Emerging Field of Astroimmunology
In response to these challenges, astroimmunology has arisen as a major subfield focused on elucidating immune function in the space environment. This new and growing discipline addresses the special challenges astronauts encounter in space. It wants to proactively create countermeasures that will preemptively protect their health. Research into the immune response under different gravitational and environmental conditions is extremely important for future exploration.
With guidance from scientific leaders researchers have started to use cutting edge techniques like multiomics, enabling them to dig even further into cellular adaptations. This has allowed scientists to pinpoint individual mechanisms that lead to space-related immune dysfunction.
“Now that investigators have brought multiomics into the work, we and others are able to identify mechanisms and hallmarks of space-related immune dysfunction.” – Dan Winer
Learning what has changed can help guide how to prepare for missions of longer duration. Learning how the immune system is able to make these adaptations can provide the know-how. Such learnings could help inform health protocols for astronauts on future long-duration expeditions to Mars and back.
Long-Term Implications for Space Travel
The consequences of impaired immune function in space might be even more severe in the case of long-duration missions. Current research underscores that as astronauts venture farther from Earth, factors like variable gravity and exposure to Martian dust may further impact immune cell function over time.
Huixan Du notes, “Spaceflight is an excellent model for accelerated aging.” He hopes to make the case that the same cellular processes are taking place in both aging and in spaceflight.
“Mitochondria don’t work as efficiently in space and start producing free radicals. These same processes happen with aging.” – Huixan Du
This very compelling parallel raises important questions about the long-term health of astronauts. It leads to imagings about how these changes go forward for them as they continue to age in a space environment.
Winer adds, “What’s special about this paper is that we provide integrated mechanistic insights into how all of these space-related stressors interface to alter immune physiology.” Although this is preliminary work, it provides a springboard for future research. It’s all about learning how to protect people from the effects of space travel on human health.
Looking Ahead
There are still many open questions, as research in this field is only in its infancy. Winer and his team have developed an impressive and in-depth resource. This powerful resource is helping scientists better understand the effects of space travel on the immune system. To support the next stages of research, the Cornell Aerospace Medicine Biobank (CAMBank) provides a biobanking model for expanded study.
“We think this paper sets the stage as a guide for future research in one of the body’s systems most impacted by spaceflight. It certainly is an exciting time to be involved in space research.” – Dan Winer
As humanity sets its sights on colonizing Mars and beyond, tackling these health challenges will be critical. Continuing research is critical to addressing the future of astronaut health and wellness. Together, they’ll make sure that astronauts journeying to deep space will have the information and equipment necessary for them to prosper.