Moderate exercise based on artificial gravity preserves orthostatic tolerance and exercise capacity during short-term head-down bed rest.

Numerous countermeasures have been proposed to minimize microgravity-induced physical deconditioning, but their benefits are limited. The present study aimed to investigate whether personalized aerobic exercise based on artificial gravity (AG) mitigates multisystem physical deconditioning. Fourteen men were assigned to the control group (n=6) and the countermeasure group (CM, n=8).

Simulated Microgravity Promotes Angiogenesis through RhoA-Dependent Rearrangement of the Actin Cytoskeleton.

Background/aims: Microgravity leads to hydrodynamic alterations in the cardiovascular system and is associated with increased angiogenesis, an important aspect of endothelial cell behavior to initiate new vessel growth. Given the critical role of Rho GTPase-dependent cytoskeleton rearrangement in cell migration, small GTPase RhoA might play a potential role in microgravity-induced angiogenesis.

Methods: We examined the organization of actin filaments by FITC-conjugated phalloidin staining, as well as the expression and activity of RhoA by quantitative PCR and Western blot, in human umbilical vein endothelial cells (HUVECs) under normal gravity and simulated microgravity.

The Impact of Simulated Weightlessness on Endothelium-Dependent Angiogenesis and the Role of Caveolae/Caveolin-1.

Background/aims: The potential role of caveolin-1 in modulating angiogenesis in microgravity environment is unexplored.

Methods: Using simulated microgravity by clinostat, we measured the expressions and interactions of caveolin-1 and eNOS in human umbilical vein endothelial cells.

Results: We found that decreased caveolin-1 expression is associated with increased expression and phosphorylation levels of eNOS in endothelial cells stimulated by microgravity, which causes a dissociation of eNOS from caveolin-1 complexes.

Clinorotation enhances autophagy in vascular endothelial cells.

Individuals exposed to extended periods of spaceflight or prolonged 6° head-down-tilt bed rest often suffer from health hazards represented by cardiovascular deconditioning. Many studies have reported that alterations in vascular endothelial cells contribute to cardiovascular dysfunction induced by microgravity. Autophagy, a lysosomal degradation pathway, serves an adaptive role for survival, differentiation, and development in cellular homeostasis, and can be triggered by various environmental stimuli.