Altered gravity promotes platelet‐endothelial cell interactions that precede cardiovascular diseases

Our goal was to investigate the effects of hypergravity and microgravity on endothelial cell (EC) and platelet (pt) functions and EC‐pt interactions. This is significant because people subjected to altered gravity are predisposed for cardiovascular diseases (CVDs). We hypothesized that altered gravity would causes EC and pt functions to mimic CVDs. To test this, cells were subjected to 8G for 30min or 10 −2 G for 2 hours. A time course for actin realignment, thrombin generation, connexin‐43, caveolin‐1, P‐selectin and GPIIb expression was attained. EC peroxide formation was monitored. Actin preferred to align in the loading condition. The expression of adhesion molecules, connexin and caveolin were enhanced under altered gravity. Thrombin generation remained unchanged. Peroxide levels in media of EC exposed to hypergravity were significantly increased, to 27.7μM vs 18.0μM in control. Microgravity did not affect peroxide production. Experiments with inhibitors of reactive oxygen species (ROS) pathways suggested that NADPH oxidase may alter ROS production under hypergravity. Thus, hypergravity caused mild oxidative stress generation and altered gravity caused cells to mimic pathologies seen during CVDs.