Effects of microgravity and hypergravity on platelet functions.
Many serious thrombotic and haemorrhagic diseases or fatalities have been documented in human being exposed to microgravity or hypergravity environments, such as crewmen in space, roller coaster riders, and aircrew subjected to high-G training. Some possible related organs have been examined to explore the mechanisms underlying these gravity change-related diseases. However, the role of platelets which are the primary players in both thrombosis and haemostasis is unknown. Here we show that platelet aggregation induced by ristocetin or collagen and platelet adhesion to von Willebrand factor (VWF) were significantly decreased after platelets were exposed to simulated microgravity. Conversely, these platelet functions were increased after platelets were exposed to hypergravity. The tail bleeding time in vivo was significantly shortened in mice exposed to high-G force, whereas, was prolonged in hindlimb unloaded mice. Furthermore, three of 23 mice died after 15 minutes of -8 Gx stress. Platelet thrombi disseminated in the heart ventricle and blood vessels in the brain, lung, and heart from the dead mice. Finally, glycoprotein (GP) Ibalpha surface expression and its association with the cytoskeleton were significantly decreased in platelets exposed to simulated microgravity, and obviously increased in hypergravity-exposed platelets. These data indicate that the platelet functions are inhibited in microgravity environments, and activated under high-G conditions, suggesting a novel mechanism for gravity change-related haemorrhagic and thrombotic diseases. This mechanism has important implications for preventing and treating gravity change-related diseases, and also suggests that special attentions should be paid to human actions under different gravity conditions.
Dai
Kesheng
K
Department of Biological Science and Technology, Beijing University of Aeronautics and Astronautics, 37 Xueyuan Road, Haidian district, Beijing 100083, China. kdai@buaa.edu.cn
Wang
Yuedan
Y
Yan
Rong
R
Shi
Quanwei
Q
Wang
Zhicheng
Z
Yuan
Yanhong
Y
Cheng
Hong
H
Li
Suping
S
Fan
Yubo
Y
Zhuang
Fengyuan
F
D000244:Adenosine Diphosphate; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D003094:Collagen; D003599:Cytoskeleton / Q000378:metabolism; D006470:Hemorrhage / Q000097:blood* / Q000209:etiology; D006487:Hemostasis; D019417:Hindlimb Suspension; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000097:blood; D051379:Mice; D023421:Models, Animal; D019007:P-Selectin / Q000378:metabolism; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D019038:Platelet Glycoprotein GPIb-IX Complex; D012310:Ristocetin; D013026:Space Flight; D013927:Thrombosis / Q000097:blood* / Q000209:etiology / Q000473:pathology; D013997:Time Factors; D018474:Weightlessness Simulation / Q000009:adverse effects*; D014841:von Willebrand Factor / Q000378:metabolism
D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D019007:P-Selectin; D019038:Platelet Glycoprotein GPIb-IX Complex; C094990:adhesion receptor; D014841:von Willebrand Factor; D012310:Ristocetin; D000244:Adenosine Diphosphate; D003094:Collagen