Is spaceflight-induced immune dysfunction linked to systemic changes in metabolism?

Recent research has uncovered that astronauts' immune cells in their spleens show increased activity even though there are fewer of these important defenders after space travel. This is surprising because we usually expect less cell count to mean reduced function, but it seems the remaining cells work harder and faster when needed. This study looked at how this change happens by examining astronauts' immune system before they went into space (pre-flight), during their time in orbit or on a long trip outside Earth’s atmosphere (in flight), right after landing back home, and then again one day later when the effects of being away from gravity are gone. The scientists found that astronaut spleen cells reacted more strongly to invaders like bacteria than before they left for space travel or even a few days into their journey among stars. This heightened response is important because it shows how our bodies try to protect us in extreme environments, but also raises questions about the long-term impact on astronaut health and immune system functioning after returning from such trips.

This research paper investigates the effects of spaceflight on immune function and metabolism in astronauts. The study focuses particularly on how microgravity conditions impact anoxidative burst activity within splenocytes, despite significant decreases in cell counts post-mission. Notably, this work did not isolate phagocytic populations for analysis but instead utilized a comprehensive approach incorporating metabolomics and genomics data to understand the broader physiological changes occurring during spaceflight. The methodology employed included various assays such as immune dysfunction tests, intra-abdominal fat measurements via MRI scans, blood sampling for hormone levels (ACTH), urine analysis for ACTH excretion rates and metabolites like cystathiolones. The researchers also examined the expression of genes related to glutathione synthesis pathways in splenocytes before flight, immediately after landing back on Earth, as well as at 24-hour intervals postflight for up to seven days.