Astronauts are exposed to cosmic radiation and significant changes in gravity when they travel into space. In recent years, researchers have investigated the physiological effects of space travel using cutting-edge tools. This research has demonstrated that while in space, astronauts appear to be more susceptible to infection. Among other problems, astronauts on the International Space Station( ISS ) frequently experience skin rashes and respiratory problems. Additionally, astronauts release more live viruses that are commonly spread by people, such as the Epstein-Barr virus, varicella-zoster( the cause of chickenpox and shingles ), herpes-simplex-1, and the cytomegalovirus.
In recent research published in Frontiers in Immunology, researchers examined the gene expression of leukocytes, a type of white blood cell, in samples taken from three women and eleven men who spent between 2015 and 2019 living on the ISS for 4.5 to 6.5 months. Samples were taken five times after the individuals returned to Earth, four times while they were on the ISS, and once before they left. These samples were used to isolate the leukocytes.
The researchers found that when people traveled to the ISS, the expression of 15, 410 genes in leukocytes changed. These genes with different expressions were divided into two groups. When astronauts traveled to space and returned to Earth, expression of one cluster of 247 genes decreased. These genes tended to be connected to immunity. The pattern was the opposite in the other cluster of 29 genes, where gene expression increased and then decreased. These genes were connected to the structure and function of cells.
When astronauts reach space, their immune systems appear to rapidly deteriorate. The majority of genes had returned to pre-flight levels within a year of their return to Earth, and occasionally much sooner. However, gene expression does appear to recover when astronauts return.
According to the study’s authors, fluid shift, in which blood plasma moved from the lower to upper parts of the body during exposure to microgravity, is what causes gene expression to change. Additionally impacted is the fluid in the lymphatic system. After a few days in space, fluid shift reduces the plasma volume by ten to fifteen percent. There are other significant physiological changes as well, such as variations in gene expression.
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According to lead study author Dr. Odette Laneuville, an associate professor in the Department of Biology at the University of Ottawa,” the next question is how to apply our findings to guide the design of countermeasures that will prevent immune suppression while in space, particularly for long-term flight.”
According to Laneuville, if immune dysfunction and low levels of inflammation can be found during missions, astronaut health could significantly improve. This would give them the opportunity to act to stop the onset of more severe symptoms, which could be a significant issue during longer missions.
Frontiers in Immunology, a Source