Impacts of Microgravity Analogs to Spaceflight on Cerebral Autoregulation

Marc Kermorgant , N Nasr , Marek Czosnyka , Dina N. Arvanitis , Ophélie Hélissen , Jean-Michel Senard , Anne Pavy-Le Traon

Abstract

It is well known that exposure to microgravity in astronauts leads to a plethora physiological responses such as headward fluid shift, body unloading, and cardiovascular deconditioning. When astronauts return to Earth, some encounter problems related to orthostatic intolerance. An impaired cerebral autoregulation (CA), which could be compromised by the effects of microgravity, has been proposed as one of the mechanisms responsible for orthostatic intolerance. CA is a homeostatic mechanism that maintains cerebral blood flow for any variations in cerebral perfusion pressure by adapting the vascular tone and cerebral vessel diameter. The ground-based models of microgravity are useful tools for determining the gravitational impact of spaceflight on human body. The head-down tilt bed rest (HDTBR), where the subject remains in supine position at −6 degrees for periods ranging from few days to several weeks is the most commonly used ground-based model of microgravity for cardiovascular deconditioning. head-down bed rest (HDBR) is able to replicate cephalic fluid shift, immobilization, confinement, and inactivity. Dry immersion (DI) model is another approach where the subject remains immersed in thermoneutral water covered with an elastic waterproof fabric separating the subject from the water. Regarding DI, this analog imitates absence of any supporting structure for the body, centralization of body fluids, immobilization and hypokinesia observed during spaceflight. However, little is known about the impact of microgravity on CA. Here, we review the fundamental principles and the different mechanisms involved in CA. We also consider the different approaches in order to assess CA. Finally, we focus on the effects of short- and long-term spaceflight on CA and compare these findings with two specific analogs to microgravity: HDBR and DI.
Publication typeReview
Author Marc Kermorgant - [Institut des Maladies Métaboliques et Cardiovasculaires]
Marc Kermorgant,,
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, N Nasr - [Institut des Maladies Métaboliques et Cardiovasculaires]
N Nasr,,
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, Marek Czosnyka (FEIT / PE)
Marek Czosnyka,,
- The Institute of Electronic Systems
, Dina N. Arvanitis - [Institut des Maladies Métaboliques et Cardiovasculaires]
Dina N. Arvanitis,,
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, Ophélie Hélissen - [Institut des Maladies Métaboliques et Cardiovasculaires]
Ophélie Hélissen,,
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, Jean-Michel Senard - [Institut des Maladies Métaboliques et Cardiovasculaires]
Jean-Michel Senard,,
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, Anne Pavy-Le Traon - [Institut des Maladies Métaboliques et Cardiovasculaires]
Anne Pavy-Le Traon,,
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Journal seriesFrontiers in Physiology, ISSN 1664-042X
Issue year2020
Vol11
Pages1-12
Publication size in sheets0.55
Article number778
ASJC Classification2737 Physiology (medical); 1314 Physiology
DOIDOI:10.3389/fphys.2020.00778
Languageen angielski
Score (nominal)50
Score correctionScore reduced to 50% (because of special publication type)
Score sourcejournalList
ScoreMinisterial score = 50.0, 20-08-2020, ArticleFromJournal
Publication indicators Scopus Citations = 0; Scopus SNIP (Source Normalised Impact per Paper): 2018 = 0.986; WoS Impact Factor: 2018 = 3.201 (2) - 2018=3.921 (5)
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