Astronaut blood samples suggest long-term exposure to weightlessness causes brain damage

New research comparing blood samples taken from five Russian astronauts before and after long term missions to ISS suggests that weightlessness can cause brain damage.

Published in JAMA Neurology, the new research looked at five male Russian cosmonauts. Each spent an average of 169 days in space. Blood samples were taken from each subject before leaving Earth, and then at three points after returning.

Five different blood-based biomarkers were measured, each known to correlate with some kind of brain damage. Three biomarkers in particular were found to be significantly elevated after the cosmonauts returned to Earth – neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and a specific type of amyloid beta protein.

The researchers hypothesize the increases in NfL and GFAP levels may indicate a type of neurodegeneration called axonal disintegration. Elevated NfL levels are currently being investigated as a way of detecting the earliest stages of brain damage associated with Alzheimer’s disease.

It must be emphasized that the research did not find brain damage, only data within the blood samples that is often associated with brain damage. More research is required to determine if these biomarkers indicate the same thing in space as they do on Earth.