Spending an extended period of time in space may elevate the presence of biomarkers that have been connected to brain damage, according to new research published in JAMA Neurology.
Researchers through the Institute of Biomedical Problems of the Russian Academy of Sciences took blood samples from five male cosmonauts at multiple points before and after their roughly six-month assignments to the International Space Station. Of the five different indicators of brain damage they monitored in these blood samples, three were significantly raised after the astronauts returned home.
“What this finding is letting us know is that that space flight might be having similar effects on the brain as other sort of insults to the head,” says Dr. Cheryl Wellington, a Professor in the Department of Pathology and Laboratory Medicine at the University of British Columbia. Wellington was not involved in this research project.
The research found significantly elevated levels of three different proteins that have all been connected to brain damage: elevated blood levels of neurofilament light (NFL) have been associated with multiple types of brain damage including concussions, stroke, and neurodegenerative disease like Alzheimer’s and Parkinson’s; glial fibrillary acidic protein (GFAP), which may be an indicator of inflammation in the brain; and Amyloid-βeta 40, a protein connected to Alzheimer’s disease.
Wellington warns that while the presence of these biomarkers is concerning, science has not yet determined a specific concentration or threshold that indicates the severity of the damage.
“We don’t really have any way to kind of put into context, for example, is it as bad as a concussion or worse, etc. So that’s where we need to do a lot further research,” she says. “…We see an elevated number, but we don’t know…how to interpret that information yet.”
These biomarkers were elevated even at the three-week mark, which may indicate that if there was damage to the brain, it’s not immediately healing. Most biomarkers have a half-life of much less time, so the levels were expected to decrease.
Microgravity affects the brain
This research comes on the heels of a study published in Nature this past February, which found that long spans of time spent in space cause significant changes to the brain and central nervous system, including the position of the brain in the skull, tissue volume, and the flow of cerebrospinal fluid.
What causes it?
Exposing the human body to weak gravity on the space station, known as microgravity, is believed to be the culprit behind much of this damage. Microgravity is thought to cause fluid redistribution, which in turn puts stress on the delicate neural tissues and processes that keep our brains healthy.
While more research is needed on a larger pool of astronauts to determine the long-term consequences of space flight and exposure to microgravity, Wellington says that this marks a very promising step forwards in protecting astronauts’ health.
“What’s really promising about this kind of test approach is that often when we look at brain health, we need to do things like an MRI or really complex analyses,”she says. “And you really cannot put an MRI machine into space… Eventually an astronaut might be able to prick their finger and test these biomarkers while they’re in space and monitor how they’re doing more in real time compared to just pre- and post-flight.”