Astronauts experience clinically significant brain changes after traveling into space, a new study shows. This is reported by Free News with reference to a study in the journal JAMA Neurology.

Long-term stay in space not only leads to muscle atrophy and decreased bone density, but also has a long-term effect on the brain. Previous three-year studies have confirmed this. However, it is not known whether the observed structural changes in the brain are harmless or clinically significant.

German, Swedish and Russian scientists conducted a joint study in which they assessed the structural integrity of the human brain using blood markers in astronauts after returning from a long mission. It turned out that prolonged stay in space leads to the fact that the brain shows strong signs of brain injury, and it also ages faster than ordinary people.

Scientists examined longitudinal blood samples from five astronauts who, on average, were on board the ISS for 169 days (5.5 months). All employees donated blood immediately before the flight and immediately after returning to Earth. Two more samples were taken one and three weeks after landing.

In the blood samples, the scientists found significant increases in several brain-specific proteins, in particular, during the first week after return, compared to the pre-mission baseline values. These proteins indicate damage to long nerve fibers in the white matter of the human brain and glial cells.

Scientists also noted a decrease in tau protein (a marker of gray matter), which persisted even three weeks after the astronaut returned to Earth. The researchers explain that this is all in favor of a complex brain response to being in space, not just one type of tissue.

“Our results point to mild but long-term brain injury and potentially accelerated neurodegeneration,” explains study co-author Professor Peter zu Eilenburg of Ludwig-Maximilian University.

The reason for the increase in specific brain proteins may lie in the impaired venous outflow of the head under microgravity conditions. This mechanism can, over time, lead to an increase in cerebrospinal fluid volume and pressure on the white and gray matter. The scientists note that further research is needed to figure out how to reduce the effects of microgravity on the human brain in order to minimize neurological risks on long missions. “This must be done before we start planning a trip to Mars,” the experts conclude.