Effects of microgravity and hypergravity on platelet functions

Department of Biological Science and Technology, Beijing University of Aeronautics and Astronautics, 37 Xueyuan Road, Haidian district, Beijing 100083, China.
Thrombosis and Haemostasis (Impact Factor: 5.76). 06/2009; 101(5):902-10. DOI: 10.1160/TH08-11-0750
Source: PubMed

ABSTRACT 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.

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    • "In hypergravity conditions plants developed changes in orientation of cortical microtubules and in the metabolism of anti-gravitational cell wall polysaccharides with the modification of body shape and the regulation of cell wall rigidity [5]. Glycoprotein Ib-alpha surface expression and its association with the cytoskeleton were significantly increased in hypergravity-exposed platelets with the increase of their function [6]. In human T cells, ground-based studies to investigate the effect of hypergravity (1.8 g and 9 g) did not reveal any effect on cell cycle control signaling [1]. "
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    ABSTRACT: Maintaining a good health requires the maintenance of a body homeostasis which largely depends on correct functioning of thyroid gland. The cells of the thyroid tissue are strongly sensitive to hypogravity, as already proven in mice after returning to the earth from long-term space missions. Here we studied whether hypergravity may be used to counteract the physiological deconditioning of long-duration spaceflight. We investigated the influence of hypergravity on key lipids and proteins involved in thyroid tissue function. We quantified cholesterol (CHO) and different species of sphingomyelin (SM) and ceramide, analysed thyrotropin (TSH) related molecules such as thyrotropin-receptor (TSHR), cAMP, Caveolin-1 and molecule signalling such as Signal transducer and activator of transcription-3 (STAT3). The hypergravity treatment resulted in the upregulation of the TSHR and Caveolin-1 and downregulation of STAT3 without changes of cAMP. TSHR lost its specific localization and spread throughout the cell membrane; TSH treatment facilitated the shedding of α subunit of TSHR and its releasing into the extracellular space. No specific variations were observed for each species of SM and ceramide. Importantly, the level of CHO was strongly reduced. In conclusion, hypergravity conditions induce change in CHO and TSHR of thyroid gland. The possibility that lipid rafts are strongly perturbed by hypergravity-induced CHO depletion by influencing TSH-TSHR interaction was discussed.
    PLoS ONE 05/2014; 9(5):e98250. DOI:10.1371/journal.pone.0098250 · 3.23 Impact Factor
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    • "Platelet aggregation and platelet adhesion to von Willebrand factor were significantly decreased after platelets were exposed to simulated microgravity. Conversely, these platelet functions were increased after platelets were exposed to hypergravity [18]. It is possible to think that the effect of gravity changes on a complete (multicellular) organism, where multiple mechanisms of functional regulation are present, is more complex. "
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    ABSTRACT: It is generally known that bone loss is one of the most important complications for astronauts who are exposed to long-term microgravity in space. Changes in blood flow, systemic hormones, and locally produced factors were indicated as important elements contributing to the response of osteoblastic cells to loading, but research in this field still has many questions. Here, the possible biological involvement of thyroid C cells is being investigated. The paper is a comparison between a case of a wild type single mouse and a over-expressing pleiotrophin single mouse exposed to hypogravity conditions during the first animal experiment of long stay in International Space Station (91 days) and three similar mice exposed to hypergravity (2Gs) conditions. We provide evidence that both microgravity and hypergravity induce similar loss of C cells with reduction of calcitonin production. Pleiotrophin over-expression result in some protection against negative effects of gravity change. Potential implication of the gravity mechanic forces in the regulation of bone homeostasis via thyroid equilibrium is discussed.
    PLoS ONE 12/2012; 7(12):e48518. DOI:10.1371/journal.pone.0048518 · 3.23 Impact Factor
  • Thrombosis and Haemostasis 06/2009; 101(5):799. DOI:10.1160/TH09-03-0183 · 5.76 Impact Factor
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