The NASA Task Book

Responsible Center: NASA JSC Grant Monitor: Norsk, Peter Center Contact: Peter.norsk@nasa.gov Unique ID: 10213	Solicitation / Funding Source: 2013 HERO NNJ13ZSA002N-Crew Health OMNIBUS Grant/Contract No.: T72618 (subcontract) Project Type: GROUND Flight Program: TechPort: No	No. of Post Docs: 1 No. of PhD Candidates: No. of Master's Candidates: No. of Bachelor's Candidates:	No. of PhD Degrees: No. of Master's Degrees: No. of Bachelor's Degrees:

Human Research Program Elements:	(1) HHC:Human Health Countermeasures

Human Research Program Risks:	(1) Cardiovascular:Risk of Cardiovascular Adaptations Contributing to Adverse Mission Performance and Health Outcomes (2) SANS:Risk of Spaceflight Associated Neuro-ocular Syndrome (SANS)

Human Research Program Gaps:	(1) CV-101:Determine whether long-duration weightlessness induces cardiovascular structural and functional changes and/or oxidative stress & damage (OSaD)/inflammation, that can contribute to development of disease. (2) SANS-201:Determine if altered atmospheric conditions (e.g., elevated ambient CO2, mild hypoxia from exploration atmosphere) has a contributing role in the development of ocular manifestations.

Flight Assignment/Project Notes:	NOTE: Extended to 3/10/2016 (original end date was 10/1/2015) per R. Brady/JSC HRP (Ed., 2/22/16)

Task Description:	This proposal applies short-term hypercapnia to a head-down bed rest (HDBR) analog to more closely replicate the conditions characterizing a space exploration environment. The purpose of the study is to evaluate ocular structural and cerebral blood flow changes in healthy human subjects exposed to such environment. Commercially available sleeping cubicle provided with carbon dioxide (CO2) injection system will be used to produce hypercapnia (1% CO2). Intraocular pressure will be measured to evaluate the changes in response to a hypercarbic environment applied to HDBR. In addition, Spectral-domain optical coherence tomography (OCT) scans of the retina and the optic disc will be performed and compared to baseline conditions. Cerebral blood flow responses will be assessed using transcranial Doppler (TCD) ultrasonography. Noninvasive blood pressure waveforms and electrocardiogram will be obtained and correlated with TCD and ocular measures; in addition, they will be used with TCD to indirectly estimate the intracranial pressure by employing a novel algorithm (Non-invasive IntraCranial pressure Framework, or NICF). In conclusion, it is anticipated that this study will be able to assess a priority risk in the Human Research Program Roadmap and accelerate the understanding of the pathophysiology of the Visual Impairment and Intracranial Pressure syndrome.

Research Impact/Earth Benefits:

Task Progress & Bibliography Information FY2016

Task Progress:

Many astronauts experience ocular structural and functional changes including choroidal folds, optic disc edema, globe flattening, optic nerve sheath diameter (ONSD) distension, retinal nerve fiber layer thickening, and decreased visual acuity during long-duration spaceflight. The leading hypothesis suggests that weightlessness-induced cephalad fluid shifts may increase intracranial pressure (ICP) and contribute to these findings. An additional hypothesis implicates elevated ambient CO2 levels on the International Space Station. To investigate possible mechanisms for ocular changes we used the spaceflight analog of 6° head-down tilt (HDT) and studied eight male subjects during three 1-hour conditions: Seated, HDT, and HDT with 1% inspired CO2 (HDT+CO2). Non-invasive intracranial pressure (ICP), intraocular pressure (IOP; rebound tonometry), translaminar pressure difference (TLPD=IOP-ICP), ocular ultrasound, and optical coherence tomography (OCT) scans of the macula and the optic disc were obtained. Analysis of one-carbon pathway genetics were conducted to identify possible genetic risk factors. IOP and ICP increased and TLPD decreased during HDT, compared to Seated. Exposure to 1% CO2 during HDT+CO2 further increased IOP and decreased ICP compared to HDT, but there was no difference in TLPD between the HDT conditions. Compared to Seated, ONSD and subfoveal choroidal thickness increased during HDT, but there was no difference between HDT and HDT+CO2. There were no significant changes across conditions in visual acuity or ocular structures assessed with OCT imaging. ONSD and end-tidal PCO2 differed based on genetic polymorphisms. In conclusion, compared to Seated, acute HDT induced mild ocular changes, but acute mild-hypercapnia during HDT does not exacerbate these changes.

A manuscript (Laurie SS, Feiveson AH, Ferguson CR, Hu X, Lee SMC, May-Phillips T, Ploutz-Snyder R, Smith SM, Stenger MB, Taibbi G, Zwart SR, Vizzeri G. Effects of Short-Term Mild Hypercapnia during Head-Down Tilt on Ocular Structures, Visual Function, and Intracranial Pressure in Healthy Human Subjects) will soon be submitted to Journal of Applied Physiology.

Bibliography:

Description: (Last Updated: 04/24/2019)

Show Cumulative Bibliography


Articles in Peer-reviewed Journals	Laurie SS, Vizzeri G, Taibbi G, Ferguson CR, Hu X, Lee SMC, Ploutz-Snyder R, Smith SM, Zwart SR, Stenger MB. "Effects of short-term mild hypercapnia during head-down tilt on intracranial pressure and ocular structures in healthy human subjects." Physiol Rep. 2017 Jun;5(11):e13302. https://doi.org/10.14814/phy2.13302 ; PubMed PMID: 28611153; PubMed Central PMCID: PMC5471441 , Jun-2017

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Project Title: Effects of Short-Term Hypercapnia During Head-Down Bed Rest on Ocular Structures and Cerebral Blood Flow in Healthy Human Subjects

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Fiscal Year: FY 2015
Division: Human Research
Research Discipline/Element:
HRP HHC:Human Health Countermeasures

Start Date: 01/12/2015
End Date: 03/10/2016
Task Last Updated: 04/27/2015

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Principal Investigator/Affiliation: Vizzeri, Gianmarco M.D. / The University of Texas Medical Branch

Address:

Ophthalmology
700 University Blvd
Galveston , TX 77550-5552

Email: givizzer@utmb.edu
Phone: 409-747-5426
Congressional District: 14
Web:

Organization Type: UNIVERSITY
Organization Name: The University of Texas Medical Branch
Joint Agency:
Comments:

Co-Investigator(s)
Affiliation:

Stenger, Michael Ph.D.	Wyle Laboratories, Inc.
Zanello, Susana Ph.D.	Universities Space Research Association
Ploutz-Snyder, Robert Ph.D.	Universities Space Research Association

Project Information: Grant/Contract No. T72618 (subcontract)

Responsible Center: NASA JSC Grant Monitor: Norsk, Peter Center Contact: Peter.norsk@nasa.gov Unique ID: 10213	Solicitation / Funding Source: 2013 HERO NNJ13ZSA002N-Crew Health OMNIBUS Grant/Contract No.: T72618 (subcontract) Project Type: GROUND Flight Program: TechPort: No	No. of Post Docs: No. of PhD Candidates: No. of Master's Candidates: No. of Bachelor's Candidates:	No. of PhD Degrees: No. of Master's Degrees: No. of Bachelor's Degrees:

Human Research Program Elements:	(1) HHC:Human Health Countermeasures

Human Research Program Risks:	(1) Cardiovascular:Risk of Cardiovascular Adaptations Contributing to Adverse Mission Performance and Health Outcomes (2) SANS:Risk of Spaceflight Associated Neuro-ocular Syndrome (SANS)

Human Research Program Gaps:	(1) CV-101:Determine whether long-duration weightlessness induces cardiovascular structural and functional changes and/or oxidative stress & damage (OSaD)/inflammation, that can contribute to development of disease. (2) SANS-201:Determine if altered atmospheric conditions (e.g., elevated ambient CO2, mild hypoxia from exploration atmosphere) has a contributing role in the development of ocular manifestations.

Flight Assignment/Project Notes:	NOTE: Extended to 3/10/2016 (original end date was 10/1/2015) per R. Brady/JSC HRP (Ed., 2/22/16)

Task Description:	This proposal applies short-term hypercapnia to a head-down bed rest (HDBR) analog to more closely replicate the conditions characterizing a space exploration environment. The purpose of the study is to evaluate ocular structural and cerebral blood flow changes in healthy human subjects exposed to such environment. Commercially available sleeping cubicle provided with carbon dioxide (CO2) injection system will be used to produce hypercapnia (1% CO2). Intraocular pressure will be measured to evaluate the changes in response to a hypercarbic environment applied to HDBR. In addition, Spectral-domain OCT scans of the retina and the optic disc will be performed and compared to baseline conditions. Cerebral blood flow responses will be assessed using transcranial Doppler (TCD) ultrasonography. Noninvasive blood pressure waveforms and electrocardiogram will be obtained and correlated with TCD and ocular measures; in addition, they will be used with TCD to indirectly estimate the intracranial pressure by employing a novel algorithm (Non-invasive IntraCranial pressure Framework, or NICF). In conclusion, it is anticipated that this study will be able to assess a priority risk in the Human Research Program Roadmap and accelerate the understanding of the pathophysiology of the Visual Impairment and Intracranial Pressure syndrome.

Research Impact/Earth Benefits:

Task Progress & Bibliography Information FY2015

Task Progress:

New project for FY2015.

Bibliography:

Description: (Last Updated: 04/24/2019)

Show Cumulative Bibliography

None in FY 2015

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