Intravascular Volumes in Hypoxia During Antarctic Confinement (ANTARCV)

Alterations in Total Red Blood Cell Volume and Plasma Volume During a One-year Confinement in Antarctica: Effect of Hypoxia

This study evaluates the effect of hypoxia on blood volumes during Antarctic winter-over confinement. Half of the participants will be evaluated during sea-level winter-over confinement, while the other half will be examined during high-altitude hypoxia winter-over confinement.

Study Overview

• Status: Enrolling by invitation
• Conditions: Hypoxia; Confinement
• Intervention / Treatment: Other: carbon-monoxide rebreathing; Other: venous blood sampling; Other: physical activity monitoring; Other: apnea-hypopnea index and nocturnal oxygenation; Other: 24-hour blood pressure

Detailed Description

INTRODUCTION: Short-term space flight induces an alteration of circulating blood volumes, termed "space flight anemia" and characterized by a decrease in total red blood cell volume (RCV) and plasma volume (PV). This haematological alteration is likely to persist during a long-term space mission and impact the astronauts' health, however this question remains unexplored. During a long-term space mission, the use of hypobaric hypoxia is considered for technical reasons, however the safety of hypoxia must first be verified because this environmental condition causes substantial physiological changes, in particular changes in blood volumes that may interact with the haematological effects of microgravity.

OBJECTIVE: using the Antarctic confinement model as a high-fidelity terrestrial analogue for long-duration space missions, the investigators hypothesize that 1) sea level confinement reduces blood volume by simultaneously decreasing RCV and PV, and 2) chronic hypoxia offsets the decrease in RCV and exacerbates the decrease in PV induced by confinement.

METHODS: blood volumes will be measured via the carbon-monoxide rebreathing method, repeatedly in two groups of participants, overwintering either at Dumont d'Urville (sea level) or Concordia (altitude 3200 m). The blood viscosity will also be measured, as well as the markers of erythropoiesis and iron metabolism.

PERSPECTIVE: Documenting if some degree of hypoxia during long-duration confinement may be beneficial or unfavorable in terms of blood volume regulation is potentially relevant information for the astronauts' health and safety during long-duration space missions.

• Study Type: Interventional
• Enrollment (Anticipated): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Haute Savoie
    • Chamonix-Mont-Blanc, Haute Savoie, France, 74400
      • Ecole nationale des sports de montagne, site de l'Ecole nationale de ski et d'alpinisme

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 63 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Affiliated to a social security scheme
• Ability to communicate and read in English or in French
• Signed written informed consent form after visit with a MD

Exclusion Criteria:

• Pregnant, lactating or parturient women
• Cardiovascular, pulmonary or neuromuscular disease
• Vulnerable persons

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: hypoxia & confinement; Participants exposed to high-altitude hypoxia and confinement during a one-year stay at Concordia station, Antarctica (3200 m)	Other: carbon-monoxide rebreathing; Inhaled carbon monoxide (CO) administrated as a bolus into a rebreathing circuit serves as a marker to tag circulating hemoglobin molecules and to calculate total hemoglobin mass (Hbmass). The change in blood CO concentration from pre- to postadministration (delta carboxyhemoglobin concentration) and the dose of administrated CO allows for Hbmass determination. The other blood compartments (total red blood cell volume, plasma volume and total blood volume) are derived from Hbmass, hematocrit and/or hemoglobin concentration.; Other: venous blood sampling; venous blood sampling at rest to evaluate blood viscosity, erythropoiesis and iron metabolism; Other: physical activity monitoring; recording of physical activity by actimetry; Other: apnea-hypopnea index and nocturnal oxygenation; recorded by ambulatory sleep recording device; Other: 24-hour blood pressure; recorded by ambulatory device
Active Comparator: confinement; Participants exposed to confinement during a one-year stay at Dumont d'Urville station, Antarctica (sea level)	Other: carbon-monoxide rebreathing; Inhaled carbon monoxide (CO) administrated as a bolus into a rebreathing circuit serves as a marker to tag circulating hemoglobin molecules and to calculate total hemoglobin mass (Hbmass). The change in blood CO concentration from pre- to postadministration (delta carboxyhemoglobin concentration) and the dose of administrated CO allows for Hbmass determination. The other blood compartments (total red blood cell volume, plasma volume and total blood volume) are derived from Hbmass, hematocrit and/or hemoglobin concentration.; Other: venous blood sampling; venous blood sampling at rest to evaluate blood viscosity, erythropoiesis and iron metabolism; Other: physical activity monitoring; recording of physical activity by actimetry; Other: apnea-hypopnea index and nocturnal oxygenation; recorded by ambulatory sleep recording device; Other: 24-hour blood pressure; recorded by ambulatory device

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
total hemoglobin mass	Physiological parameter, corresponding to the total amount of circulating hemoglobin, expressed in grams, and determined with the 10-min carbon-monoxide rebreathing method and blood carboxyhemoglobin measurements (expressed in %).	15 months
total red blood cell volume	Physiological parameter, corresponding to the total volume of circulating red blood cells, expressed in liters, and derived from total hemoglobin mass, hematocrit (expressed in fraction) and hemoglobin concentration (expressed in gram per deciliter).	15 months
total blood volume	Physiological parameter, corresponding the the total volume of blood, expressed in liters, and derived from total red blood cell volume and hematocrit.	15 months
plasma volume	Physiological parameter, corresponding to the total volume of plasma, expressed in liters, and derived from total blood volume and total red blood cell volume.	15 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood viscosity	Physiological parameter, corresponding to the dynamic viscosity of whole blood, expressed in centipoises, and determined by a cone/plate viscometer	15 months
serum erythropoietin	Physiological parameter, corresponding to the serum concentration of erythropoietin expressed in milli-International unit per ml, determined by a specific biological assay.	15 months
serum hepcidin	Physiological parameter, corresponding to the serum concentration of hepcidin, expressed in mmol per liter, determined by a specific biological assay.	15 months
serum erythroferrone	Physiological parameter, corresponding to the serum concentration of erythroferrone, expressed in ng per ml, determined by a specific biological assay.	15 months
serum transferrin saturation	Physiological parameter, corresponding to the serum transferrin saturation, expressed in %, derived from serum iron concentration (in µg/dl) and transferrin concentration (in mg/dl)	15 months
serum ferritin	Physiological parameter, corresponding to the serum concentration of ferritin, expressed in ng per ml, determined by a specific biological assay.	15 months
serum soluble transferrin receptor	Physiological parameter, corresponding to the serum concentration of soluble transferrin receptor, expressed in nmol per liter, determined by a specific biological assay.	15 months
Physical activity	Physiological parameter, corresponding to the level of daily energy expenditure, expressed in kilocalories per kg per day, determined by accelerometry.	15 months
Apnea-hypopnea index	Physiological parameter, corresponding to apnea-hypopnea events, expressed in events per hour, recorded by an ambulatory sleep recording device.	15 months
Nocturnal oxygenation	Physiological parameter, corresponding to pulse oxygen saturation, expressed in %, recorded by an ambulatory sleep recording device.	15 months
24-hour blood pressure	Physiological parameter, corresponding to the mean arterial blood pressure over 24 hours, expressed in mmHg, recorded by an ambulatory device	15 months

Collaborators and Investigators

• Sponsor: Ecole Nationale des Sports de Montagne
• Collaborators: Center for Physical Activity Research, University Hospital of Copenhagen, Denmark; Laboratory Mobility, aging & exercise (MOVE) -EA 6314, Faculty of Sport Sciences, University of Poitiers, France; Department for Biomedical Sciences for Health, University of Milan School of Medicine, Milan, Italy; HP2 Laboratory, INSERM, Grenoble Alpes University, CHU Grenoble Alpes, Grenoble, France

Study record dates

Study Major Dates

• Study Start (Actual): September 27, 2019
• Primary Completion (Anticipated): December 31, 2022
• Study Completion (Anticipated): December 31, 2022

Study Registration Dates

• First Submitted: September 23, 2019
• First Submitted That Met QC Criteria: September 25, 2019
• First Posted (Actual): September 27, 2019

Study Record Updates

• Last Update Posted (Actual): September 13, 2022
• Last Update Submitted That Met QC Criteria: September 10, 2022
• Last Verified: September 1, 2022

More Information

Terms related to this study

• Keywords: total red blood cell volume; plasma volume; total hemoglobin mass; total blood volume
• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Hypoxia; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Antimetabolites; Gasotransmitters; Carbon Monoxide
• Other Study ID Numbers: 2018-A03243-52

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No