Human Cerebral Vascular Autoregulation and Venous Outflow In Response to Microgravity-Induced Cephalad Fluid Redistribution (Cephalad Fluid Redistribution) - 06.06.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Many crew members experience altered vision and increased pressure inside their heads during spaceflight, suggesting that the brain’s structure and function change in response to microgravity. However, there is almost no data describing what happens to the brain as a result of long-term exposure to microgravity. The Human Cerebral Vascular Autoregulation and Venous Outflow In Response to Microgravity-Induced Cephalad Fluid Redistribution (Cephalad Fluid Redistribution) investigation uses magnetic resonance imaging (MRI) to study the redistribution of fluid toward the head (cephalad) as well as within the head (intracranial) and changes in brain structure and blood flow to the brain that result from long-duration stays on the International Space Station.
Science Results for Everyone
Information Pending

The following content was provided by Donna Roberts, M.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom:

Principal Investigator(s)
Donna Roberts, M.D., Medical University of South Carolina, Charleston, SC, United States

Co-Investigator(s)/Collaborator(s)
Truman Brown, Ph.D., Medical University of South Carolina, Charleston, SC, United States

Developer(s)
NASA Johnson Space Center, Human Research Program, Houston, TX, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

Research Benefits
Earth Benefits, Scientific Discovery, Space Exploration

ISS Expedition Duration


Expeditions Assigned
Information Pending

Previous Missions
Information Pending

^ back to top

Experiment Description

Research Overview

  • Due to the loss of gravitational hydrostatic pressure gradients, astronauts experience large cephalad (headward) fluid shifts during long-term stays in microgravity. Local changes in Starling forces also lead to shifts between fluid compartments.
  • The consequences of microgravity-induced fluid redistribution on the brain have not yet been fully investigated and are poorly understood but may include alterations in brain structure, intracranial pressure (ICP), microstructure of the brain tissue, the cerebral blood vessels and function, and crew performance.
  • In particular, cephalad fluid shifts and blood redistribution may result in altered brain compliance, cerebrospinal fluid (CSF) flow dynamics and cerebral vascular autoregulation.
  • Researchers suspect that microgravity-induced fluid redistribution may result in changes in ICP regulation and cerebral vascular reactivity; however, despite extensive investigations into the physiologic changes occurring during microgravity exposure, an essential gap exists in the knowledge of brain structure and function during spaceflight as there is almost no data concerning intracranial adaptation to long-term microgravity.
  • This experiment employs advanced MRI analyses to: 1) characterize weightlessness-induced intracranial volume changes (brain, CSF) following adaptation to long-term spaceflight, and 2) assess for potential resultant hemodynamic changes (cerebral perfusion) in the brain.

Description
The consequences of microgravity-induced fluid redistribution on the brain have not yet been fully investigated, and are poorly understood, but may include alterations in brain and ocular structure, intracranial pressure (ICP), microstructure of the brain tissue, the cerebral blood vessels and function, and crew performance. In particular, cephalad fluid shifts and blood redistribution may result in altered brain compliance, cerebrospinal fluid (CSF) flow dynamics, and cerebral vascular autoregulation. According to the NASA Human Research Roadmap, researchers suspect that microgravity-induced fluid redistribution may result in changes in ICP regulation and cerebral vascular reactivity. The overall goal of this project is to characterize microgravity-induced intracranial volume changes (brain, CSF) following adaptation to long-term spaceflight, and to assess potential resultant hemodynamic changes (cerebral perfusion) in the brain. In order to fully characterize intracranial adaptation to long-term microgravity, the experiment uses magnetic resonance imaging (MRI) at various time points prior to, and after, exposure to long-term microgravity.

^ back to top

Applications

Space Applications
Elevated pressure inside the skull and disturbed vision, which is likely related to the increased pressure, are two major health risks for crew members, but scientists do not fully understand the consequences of fluid redistribution to and within the brain that results from microgravity. This investigation studies how cerebral fluid shifts in response to microgravity, providing new information that could guide preventive measures or treatments for increased pressure inside the head. Results from this investigation are important for future long-duration missions to the moon, Mars or asteroids, which could be jeopardized if crew members’ vision is compromised.

Earth Applications
Some patients on Earth experience unexplained intracranial hypertension, or increased pressure inside the skull, which can cause disabling headaches and changes to vision. In extreme cases, the high pressure can cause injury to the optic nerve, resulting in vision loss. Similar symptoms plague crew members returning to Earth after long-duration trips to space. Studying how the brains of astronauts are affected by microgravity-related fluid redistribution can provide new insight into the underlying changes involved in high intracranial pressure and potentially benefit patients with this condition on Earth.

^ back to top

Operations

Operational Requirements and Protocols
This study uses retrospective analyses of medical data and imagery.

^ back to top

Decadal Survey Recommendations

Information Pending

^ back to top

Results/More Information

Information Pending

^ back to top

Results Publications

    Roberts DR, Albrecht MH, Collins HR, Asemani D, Chatterjee AR, Spampinato MV, Zhu X, Chimowitz MI, Antonucci MU.  Effects of spaceflight on astronaut brain structure as indicated on MRI. New England Journal of Medicine. 2017 November 2; 377(18): 1746-1753. DOI: 10.1056/NEJMoa1705129. PMID: 29091569.

^ back to top

Ground Based Results Publications

^ back to top

ISS Patents

^ back to top

Related Publications

^ back to top

Related Websites

^ back to top


Imagery

image
MRI of the brain obtained before (Panel A) and after (Panel B) this astronaut had undergone long-duration spaceflight on the International Space Station. MRI of the brain obtained before (Panel C) and after (Panel D) short-duration spaceflight on the space shuttle show no change in the appearance of the sulci at the vertex (Roberts DR, NEJM, 2017).

+ View Larger Image


image
Map of brain perfusion (CBF – Cerebral Blood Flow).

+ View Larger Image


image
Magnetic resonance (MR) image of the brain.

+ View Larger Image