Hypergravity results in human platelet hyperactivity

ABSTRACT

Thrombotic diseases or fatalities have been reported to occasionally occur underconditions of hypergravity although the mechanism is still unclear. To investigate theeffect of hypergravity on platelets that are the primary players in thrombus formation,platelet rich plasma (PRP) or washed platelets were exposed to hypergravity at8 G for 15 minutes. No platelet aggregation was induced by 8 G alone, whereas ristocetinor collagen-induced platelet aggregation was significantly increased. Thenumber of platelets adherent to immobilized fibrinogen and the area of plateletsspreading on von Willbrand factor (VWF) matrix were increased simultaneously.Flow cytometry assay indicated that integrin áIIbâ3 was partially activated in 8 Gexposedplatelets, but there was no significant difference in P-selectin surface expressionbetween platelets treated with 8 G and 1 G control. The results indicate thathypergravity leads to human platelet hyperactivity, but fails to incur essential plateletactivation events, suggesting a novel mechanism for thrombotic diseases occurringunder hypergravitional conditions(AU)