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EXPERIMENT INFORMATION

Integrative Physiology of VIIP: Cardiopulmonary, Sleep, and Cognitive Function Assessment During Hypercapnic Bed Rest (VIIP_Bedrest_Analog)
Principal Investigator
Research Area:
Behavior and performance
Biomedical countermeasures
Physiology
Species Studied
Scientific Name: Homo sapiens Species: Human

Description
OBJECTIVES:
Approximately 37-51% of long-duration crewmembers on the International Space Station (ISS) experience changes to the eyes indicative of Spaceflight Associated Neuro-ocular Syndrome (SANS, formerly vision impairment intracranial pressure (VIIP) syndrome). These symptoms include choroidal folds, optic disk edema, globe flattening, optic nerve sheath diameter distension, and hyperopic shift. It is not clearly understood what causes SANS or how it develops. Flight investigations have brought some understanding, but there is currently no successful ground analog for SANS. Although head-down tilt (HDT) bed rest has been effective in simulating microgravity, this analog has not been able to induce the ocular changes observed in long-duration flight crews. One possible explanation for this difference is that aboard the ISS, crewmembers are chronically exposed to elevated carbon dioxide (CO2) levels. The bed rest studies to date have not been carried out in a hypercapnic ambient environment.

The objectives for this investigation are to determine if:

  1. Thirty days of HDT bed rest combined with elevated ambient CO2 cause changes to the eyes consistent with SANS development and whether other physiological changes occur and correlate with SANS symptoms.
  2. Thirty days of HDT bed rest combined with elevated ambient CO2 cause changes in cognitive function, mood, or anxiety and whether these changes correlate with the development of SANS symptoms.
  3. Thirty days of HDT bed rest combined with elevated ambient CO2 cause sleep disruption or alterations in circadian and ultradian rhythms, and whether these changes correlate with the development of SANS symptoms.
  4. One-carbon pathway single nucleotide polymorphisms (523 SNPs of the 85 major genes) and measures of related biochemistry and targeted metabolomics, are associated with physiological responses to CO2 exposure during head-down tilt bed rest.

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Data Information
Data Availability
Archiving in progress. Data is not yet available for this experiment.

Parameters
1C Polymorphisms (G,T,A,C)
Anterior globe diameter
Arterial partial pressure of carbon dioxide (PaCO2)
Choroid thickness
Choroidal fold development
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Ground 05/01/2009 In Progress

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
09/30/2015
Proposal Source
NNJ14ZSA001N-MIXEDTOPICS