Barisano, G., Sepehrband, F., Collins, H. R., Jillings, S., Jeurissen, B., Taylor, J. A., Schoenmaekers, C., De Laet, C., Rukavishnikov, I., Nosikova, I., Litvinova, L., Rumshiskaya, A., Annen, J., Sijbers, J., Laureys, S., Van Ombergen, A., Petrovichev, V., Sinitsyn, V., Pechenkova, E., … Wuyts, F. L. (2022). The effect of prolonged spaceflight on cerebrospinal fluid and perivascular spaces of astronauts and cosmonauts. Proceedings of the National Academy of Sciences of the United States of America, 119(17), 1–3. https://www.jstor.org/stable/27151469
Barisano’s study investigates the impacts of long term spaceflight on brain and cerebrospinal fluid compartments and visual acuity. He aims to determine if spaceflight volumetrically alters astronauts’ perivascular spaces (PVS) and, if so, he then aims to identify if there is a relationship between PVS dilation and spaceflight-linked changes in the subarachnoid space at the vertex (VSA) and lateral ventricles. His main focus is on whether these spaceflight-associated changes are related to development of spaceflight-associated neuro-ocular syndrome (SANS). He utilizes MRI scans and FreeSurfer post-processing mechanisms to compare pre- and post-flight PVS, VSA, and lateral ventricle (LV) volumes of around 40 astronauts and cosmonauts as well as 13 volunteers who stayed on earth. His findings were that spaceflight significantly increased the volume of basal ganglia PVS and white matter PVS (WMPVS). Additionally, the astronauts also exhibited lateral ventricle enlargement and decreased subarachnoid space at the vertex, which is found to be correlated with WM-PVS enlargement. This is likely due to the long-term exposure to microgravity, affecting the astronauts’ cerebral spinal fluid–interstitial fluid circulation in PVS, potentially damaging their cerebral drainage systems. Barisano concludes that longduration spaceflight results in changes of WM-PVS, which is linked to SANS. He also emphasizes the importance of a gravitationally maintained brain fluid homeostasis. There were a few confounding variables in that some of the astronauts adopted lower body negative pressure sessions and exercised with resistive exercise devices. The effects of these techniques on the brain are unknown, so they may have some relation to the WM-PVS changes detected in the astronauts.
Author's Note
This study is novel in that the relationship between WM-PVS alterations and SANS has not been previously researched. Barisano’s findings are impactful and will likely contribute to future designing countermeasure strategies to protect astronaut neurological and visual health during future long-duration missions, while also providing valuable insight into cerebrospinal fluid dynamics relevant to neurological conditions on Earth. I find this article particularly fascinating because the spaceflight environment–characterized by microgravity, constrained daily routines, isolation, sleep cycle alterations–create unique conditions that can’t be studied on Earth. It is inspiring that Barisano is able to research WM-PVS alterations and SANS while leveraging such an extreme environment. The full methods were straightforward and replicable. I think that FreeSurfer postprocessing is an extremely useful tool, and seeing it implemented in innovative studies like these is interesting. I do think that the sample size is limited due to astronaut population. However, the findings are likely credible due to the the consistency of WM-PVS changes across subjects. A future direction Barisano could take would be to follow-up on these astronauts. He could study whether WM-PVS and CSF change after returning to Earth. This would help scientists determine if long-term spaceflight causes permanent structural changes or just temporary neuroadaptation. I think that this paper is an excellent source for understanding CSF and perivascular space alterations in microgravity. Other than the extensive abbreviations, the article was not hard to follow. I would recommend this paper to any high-schooler who is curious about brain structure and neurological health.