Clinical trial NCT04106401: Intravascular Volumes in Hypoxia During Antarctic Confinement
Official title: Alterations in Total Red Blood Cell Volume and Plasma Volume During a One-year Confinement in Antarctica: Effect of Hypoxia
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Hypoxia
Confinement
Keywords: total red blood cell volume
plasma volume
total hemoglobin mass
total blood volume
Lead sponsor: Ecole Nationale des Sports de Montagne
Sponsor class: OTHER
Collaborators: name: Center for Physical Activity Research, University Hospital of Copenhagen, Denmark
name: Laboratory Mobility, aging & exercise (MOVE) -EA 6314, Faculty of Sport Sciences, University of Poitiers, France
name: Department for Biomedical Sciences for Health, University of Milan School of Medicine, Milan, Italy
name: HP2 Laboratory, INSERM, Grenoble Alpes University, CHU Grenoble Alpes, Grenoble, France
First posted: 2019-09-27
Enrollment: 24
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Intervention model description: one group wintering at sea level and one group wintering at high altitude
Primary purpose: BASIC_SCIENCE

Brief summary: 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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: total hemoglobin mass
timeFrame: 15 months
measure: total red blood cell volume
timeFrame: 15 months
measure: total blood volume
timeFrame: 15 months
measure: plasma volume
timeFrame: 15 months
Secondary outcomes:
measure: blood viscosity
timeFrame: 15 months
measure: serum erythropoietin
timeFrame: 15 months
measure: serum hepcidin
timeFrame: 15 months
measure: serum erythroferrone
timeFrame: 15 months
measure: serum transferrin saturation
timeFrame: 15 months
measure: serum ferritin
timeFrame: 15 months
measure: serum soluble transferrin receptor
timeFrame: 15 months
measure: Physical activity
timeFrame: 15 months
measure: Apnea-hypopnea index
timeFrame: 15 months
measure: Nocturnal oxygenation
timeFrame: 15 months
measure: 24-hour blood pressure
timeFrame: 15 months
Other outcomes:
Locations:
city: Chamonix-Mont-Blanc
country: France
facility: Ecole nationale des sports de montagne, site de l'Ecole nationale de ski et d'alpinisme
state: Haute Savoie
Study officials:
References: