title: Erythrocyte deformability and aggregation responses to intermittent and continuous artificial gravity exposure.
abstract: Artificial gravity protocols are used to improve g-tolerance of aviators and discussed as countermeasure during prolonged space flight. Little is known about the impact of artificial gravity on the red blood cells (RBC). The purpose of the study was to test how artificial gravity affects RBC deformability and aggregation, which are important determinants of microcirculation. Nine male subjects were exposed to two hypergravity protocols using a short arm human centrifuge: a continuous (CONT) protocol with constant +2Gz for 30min and an intermittent (INTER) protocol with repeated intervals of +2Gz and rest. Blood was sampled pre and post interventions to measure basal blood parameters, RBC nitrite, RBC deformability, aggregation, and to determine the shear rate balancing aggregation and disaggregation (γ at dIsc min). To test for orthostasis effects, five male subjects were asked to stay for 46min, corresponding to the length of the centrifuge protocols, with blood sampling pre and post intervention. Artificial gravity programs did not affect basal blood parameters or RBC nitrite levels; a marker for RBC deformability influencing nitric oxide. The INTER program did not affect any of the tested parameters. The CONT program did not remarkably affect RBC deformability or γ at dIsc min but significantly aggravated aggregation. Orthostasis effects were thus excluded. The results indicate that continuous artificial gravity, especially with higher g-forces applied, may negatively affect the RBC system and that for a prolonged space flight intermittent but not continuous artificial gravity might represent an appropriate countermeasure.
authors.affiliation: Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany. Electronic address: m.grau@dshs-koeln.de.
authors.forename: Grau
authors.initials: G
authors.lastname: Marijke
authors.affiliation: Department of Movement-Neuroscience, Institute of Movement and Neurosciences, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany.
authors.forename: Abeln
authors.initials: A
authors.lastname: Vera
authors.affiliation: Department of Movement-Neuroscience, Institute of Movement and Neurosciences, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany; Institute of Professional Sport Education and Sport Qualifications, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany.
authors.forename: Vogt
authors.initials: V
authors.lastname: Tobias
authors.affiliation: Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany.
authors.forename: Bloch
authors.initials: B
authors.lastname: Wilhelm
authors.affiliation: Department of Movement-Neuroscience, Institute of Movement and Neurosciences, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany.
authors.forename: Schneider
authors.initials: S
authors.lastname: Stefan
mesh_terms: D000328:Adult; D004903:Erythrocyte Aggregation / Q000502:physiology*; D004907:Erythrocyte Deformability / Q000502:physiology*; D018470:Gravity, Altered / Q000009:adverse effects*; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism
chemical_list: D009573:Nitrites; D009569:Nitric Oxide
keywords: Artificial gravity; Human; Red blood cell aggregation; Red blood cell deformability; Red blood cells