Erythrocyte deformability and aggregation responses to intermittent and continuous artificial gravity exposure

Area of Science:

• Space Medicine
• Cardiovascular Physiology
• Hematology

Background:

• Artificial gravity (AG) protocols enhance aviator g-tolerance and are explored as countermeasures for prolonged spaceflight.
• The effects of AG on red blood cells (RBCs), crucial for microcirculation, remain largely uninvestigated.

Purpose of the Study:

• To investigate the impact of continuous (CONT) and intermittent (INTER) artificial gravity on RBC deformability and aggregation.
• To assess the influence of AG on RBC nitrite levels and microcirculation parameters.

Main Methods:

• Nine male subjects underwent two AG protocols (+2Gz) using a human centrifuge: CONT (30min constant) and INTER (repeated intervals).
• Blood samples were collected pre- and post-intervention to analyze basal parameters, RBC nitrite, deformability, aggregation, and shear rate at minimum aggregation (γ at dIsc min).
• Orthostasis effects were controlled by comparing with a 46-min resting period in five additional subjects.

Main Results:

• AG protocols did not alter basal blood parameters or RBC nitrite levels.
• The INTER AG protocol showed no significant effects on tested RBC parameters.
• The CONT AG protocol significantly increased RBC aggregation but did not notably affect RBC deformability or γ at dIsc min.

Conclusions:

• Continuous artificial gravity may adversely affect the RBC system, particularly at higher G-forces.
• Intermittent AG appears to be a more suitable countermeasure than continuous AG for prolonged spaceflight due to its minimal impact on RBC function.