Department of Clinical Immunology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, OX3 7LJ, UK,
Eur J Appl Physiol. 2014 May;114(5):1067-73. doi: 10.1007/s00421-014-2837-6. Epub 2014 Feb 11.
Hypoxia is known to induce the release of microparticles in vitro. However, few publications have addressed the role of hypoxia in vivo on circulating levels of microparticles. This randomised, controlled, crossover trial aimed to determine the effect of mild hypoxia on in vivo levels of circulating microparticles in healthy individuals.
Blood was obtained from 51 healthy male volunteers (mean age of 26.9 years) at baseline altitude (490 m) and after 24 and 48 h at moderate altitude (2,590 m). The order of altitude exposure was randomised. Flow cytometry was used to assess platelet-poor plasma for levels of circulating microparticles derived from platelets, endothelial cells, leucocytes, granulocytes, monocytes, red blood cells and procoagulant microparticles.
Mean (standard deviation) oxygen saturation was significantly lower on the first and second day after arrival at 2,590 m, 91.0 (2.0) and 92.0 (2.0) %, respectively, compared to 490 m, 96 (1.0) %, p < 0.001 for both comparisons. A significant decrease in the levels of procoagulant microparticles (annexin V+ -221/μl 95 % CI -370.8/-119.0, lactadherin+ -202/μl 95 % CI -372.2/-93.1), platelet-derived microparticles (-114/μl 95 % CI -189.9/-51.0) and red blood cell-derived microparticles (-81.4 μl 95 % CI -109.9/-57.7) after 48 h at moderate altitude was found. Microparticles derived from endothelial cells, granulocytes, monocytes and leucocytes were not significantly altered by exposure to moderate altitude.
In healthy male individuals, mild hypobaric hypoxia, induced by a short-term stay at moderate altitude, is associated with lower levels of procoagulant microparticles, platelet-derived microparticles and red blood cell-derived microparticles, suggesting a reduction in thrombotic potential.
已知缺氧会在体外诱导微粒体的释放。然而，很少有文献报道过在体内缺氧对循环中微粒体水平的影响。这项随机、对照、交叉试验旨在确定轻度缺氧对健康个体体内循环中微粒体水平的影响。
从 51 名健康男性志愿者（平均年龄 26.9 岁）在基线海拔（490 米）和在中度海拔（2590 米）暴露 24 小时和 48 小时后获得血液。海拔暴露的顺序是随机的。使用流式细胞术评估血小板缺乏血浆中源自血小板、内皮细胞、白细胞、粒细胞、单核细胞、红细胞和促凝血微粒体的循环微粒体的水平。
到达 2590 米后的第一天和第二天，平均（标准差）氧饱和度分别显著降低，分别为 91.0（2.0）和 92.0（2.0）%，而在 490 米时为 96（1.0）%，p<0.001，两次比较均如此。在中度海拔 48 小时后，发现促凝血微粒体（膜联蛋白 V+ -221/μl 95%CI -370.8/-119.0，乳黏附素+ -202/μl 95%CI -372.2/-93.1）、血小板衍生的微粒体（-114/μl 95%CI -189.9/-51.0）和红细胞衍生的微粒体（-81.4μl 95%CI -109.9/-57.7）的水平显著降低。暴露于中度海拔后，源自内皮细胞、粒细胞、单核细胞和白细胞的微粒体没有明显改变。
在健康男性个体中，由短期暴露于中度海拔引起的轻度低氧血症与促凝血微粒体、血小板衍生的微粒体和红细胞衍生的微粒体水平降低有关，表明血栓形成潜力降低。
