The human body goes through various changes in space, making it difficult to directly study organs and tissues. By analyzing small amounts of DNA and RNA molecules released from different tissues into the bloodstream while astronauts were aboard the International Space Station (ISS), researchers were able to identify these internal changes.
The growing interest in space exploration, driven by astronaut recruitment and private space travel, indicates a future where space travel will become more common. However, questions remain about the physical effects of space travel on humans. Known effects such as muscle loss, bone density reduction, and shifts in body fluid distribution are well-documented consequences of weightlessness.
Recent studies on mice and other organisms have revealed additional changes. In this particular study, blood samples were taken from six astronauts during and after their 120-day mission on the ISS to study these changes. Through a process known as “liquid biopsies,” extracellular DNA and RNA in the blood samples were examined.
Past research has indicated that mitochondria, small parts of cells, are released into the bloodstream during space missions. This study confirmed that mitochondria play a role in responding to the space environment and can be identified using a marker called CD36. This method helps in assessing the status of extracellular mitochondria and determining their cell of origin.
This approach has unveiled new insights into systemic responses to space travel, including changes in the brain, eyes, heart, vascular system, lungs, and skin. Analysis of mouse samples showed similar alterations to humans and revealed that gravitational changes trigger mitochondrial adjustments.
