The SpaceX Inspiration4 mission saw two men and two women orbit Earth for three days in September 2021 – and now, a study has revealed the impact of space travel on the body’s immune system
A recent study has unveiled the havoc that space can wreak on the human body, including impacts on blood, cells, and the immune system.
The research drew data from the SpaceX Inspiration4 mission, which in 2021 saw two men and two women orbiting Earth for three days. The findings revealed that space travel disrupts the immune system, sparking inflammatory responses and significant disruption to cells.
The brief, high-altitude spaceflight led to the production of both documented and previously unseen cytokines. Cytokines, generated by the immune system, are vital for immune responses and muscle regulation but aren’t typically associated with inflammation.
Some of these cytokines were identified as exerkines, proteins produced during exercise by muscles. There was also a notable increase in myokines, proteins originating from skeletal muscle cells, suggesting a physiological response to microgravity rather than purely an immune response, reports the Mirror.
READ MORE: SpaceX launches Falcon 9 rocket carrying 20 Starlink satellites from Vandenberg Air Force Base
READ MORE: Astronaut’s return could be postponed by 90 days as Boeing struggles to find a fix for Starliner
Non-muscle tissues didn’t show any changes in inflammation-related proteins. However, the soleus muscle located at the back of the leg displayed a significant increase in muscle exertion. Additionally, the tibialis anterior muscle at the front of the leg showed an increase in interleukins, crucial for activating immune cells.
Upon landing, the most substantial increase was observed in the pro-inflammatory cytokine Interleukin 5, further pointing to muscles as the source of the cytokines in the Inspiration4 crew.
Blood samples taken before and after the journey showed cell-specific and sex-specific responses to spaceflight. There were increases in Interleukin 6, Interleukin 10, and MCP-1, a pro-inflammatory molecule, which matched changes seen in astronauts from longer missions.
Several other pro-inflammatory proteins also significantly increased. However, proteins like fibrinogen, crucial for blood clot formation, and hemoglobin, which carries oxygen, did not change significantly.
Scientists also observed that B-cell receptor mutations increased post-flight. These mutations, often caused by inflammatory stimuli or antigens, suggest that B-cells become more active after space travel, producing antibodies to neutralize harmful substances.
Cell differentiation, where young cells take on specialized roles, was reduced in CD4 and CD8 T cells, a type of white blood cell critical for infection defense. Upon returning to Earth, the astronauts showed higher concentrations of inflammation-related cytokines, balanced by an increase in anti-inflammatory cytokines.
The researchers also noted significant changes in proteins related to the migration of monocytes and neutrophils, which travel to injury sites. Recent studies have hinted that women could be tougher than men when it comes to the rigors of space travel and might bounce back quicker after touching down on Earth. Researchers put this idea to the test by examining gene activity in both genders.
Men showed more signs of gene disruption, hinting that women may indeed be sturdier against the stress of space. The study also uncovered signs of an immune system reaction to space conditions within the Inspiration4 mission data. “We found that 18 cytokines/chemokines related to inflammation, aging, and muscle homeostasis changed after spaceflight,” noted the team.
Although the group studied was small, the consistent cellular and molecular changes observed provide a trove of information for future research and protective strategies for astronauts.
While the Inspiration4 journey wasn’t specifically intended to evaluate the overall safety of space travel for everyday people, the results gleaned from it could steer the direction of upcoming scientific inquiries.