(ORDO NEWS) — Long-duration spaceflight alters fluid-filled spaces along veins and arteries in the brain, according to a new study from the University of Oregon Health and Science and scientists around the country.
“These results are important for future space exploration,” said study author Juan Piantino, MD, assistant professor of pediatrics (neurology) at OHSU School of Medicine. “It also makes you think about some of the basic fundamental questions of science and how life evolved on Earth.”
The study took images of the brains of 15 astronauts before and after long-term work on the International Space Station.
The researchers used magnetic resonance imaging to measure the perivascular space – the space around blood vessels – in the astronauts’ brains before their launch and just after their return.
They also took repeat MRI measurements one, three and six months after returning. Images of astronauts were compared with images of the same perivascular space in the brains of 16 earthlings.
Comparing before and after images, they found an increase in perivascular spaces in the brains of first time astronauts in space, but found no difference between astronauts who had previously worked aboard an Earth-orbiting space station.
“Experienced astronauts may have achieved some kind of homeostasis,” Piantino said.
In all cases, the scientists found no balance or visual memory problems that could be indicative of a neurological deficit in the astronauts, despite differences measured in the perivascular spaces of their brains.
Comparing a large group of astronauts, this study is the first comparative analysis of an important aspect of brain health in space.
The Brain in Space
Human physiology is based on the fact that life evolved over millions of years, being tied to the gravitational pull of the Earth. In space, the normal flow of cerebrospinal fluid in the brain is altered by the force of gravity.
“We’ve all adapted to using gravity to our advantage,” Piantino said. “Nature didn’t put our brains in our feet – she put them high up. If you take gravity out of the equation, how does that affect human physiology?”
The researchers decided to find out by measuring the perivascular spaces through which cerebrospinal fluid enters the brain.
These spaces are an integral part of the brain’s natural clearing system that occurs during sleep. Known as the glymphatic system, this brain-wide network clears metabolic proteins that might otherwise accumulate in the brain. According to scientists, this system works optimally during deep sleep.
The perivascular spaces measured in the brain represent the “hardware” of the glymphatic system. The increase in these spaces occurs with aging, and is also associated with the development of dementia.
The researchers used a method developed in the laboratory of co-author Lisa K. Silbert, MD, professor of neurology at OHSU School of Medicine, to measure changes in perivascular spaces using MRI scans.
According to Piantino, the results of the study could be useful in diagnosing and treating terrestrial diseases associated with cerebrospinal fluid, such as hydrocephalus.
“These results help not only to understand the fundamental changes that occur during space flight, but also to help people on Earth suffering from diseases that affect the circulation of cerebrospinal fluid,” Piantino said.
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