Chamberlain K G, Tong M, Penington D G
University of Melbourne, Department of Medicine, Victoria, Australia.
Am J Hematol. 1990 Jul;34(3):161-8. doi: 10.1002/ajh.2830340302.
The human spleen normally retains about one-third of the body's platelets in an exchangeable pool which can be released into the circulation by alpha-adrenergic stimulation. Some previous investigators concluded that the splenic platelet population was enriched in a subpopulation of large, young, dense platelets (megathrombocytes) but more recent research suggests that platelet size, age, and density are largely independent variables. In this investigation the properties of the splenic platelets were studied after their release into the circulation by acute strenuous exercise in 11 normal subjects. The exercise caused a rise in mean platelet count from 245 +/- 49 to 328 +/- 71 x 10(9)/L--a net increase of 24 +/- 6% after correction for haemoconcentration. The mean platelet volume (MPV) of citrated platelets increased from 6.38 +/- 0.78 to 6.59 +/- 0.68 fL after exercise (P less than 0.01)--a rise of 3.7 +/- 4.1% suggesting that the MPV of the splenic platelet population was about 20% greater than that of the normal circulating population. The age distribution of the platelets was studied by measuring the platelet monoamine oxidase (MAO) activity several days after irreversible inhibition by tranylcypromine, when the young platelets had normal MAO activity but the older platelets had only 20% of normal activity. The mean platelet MAO activity did not change after exercise, indicating that the age distributions of the circulating and splenic populations were very similar. The platelet contents of several putative markers of platelet age (sialic acid, serotonin, beta-thromboglobulin, beta-N-acetylglucosaminidase) were also unchanged after exercise. Modal platelet density decreased slightly but not significantly after exercise. The splenic platelet population has a larger MPV but appears to have similar age and density distributions to the basal circulating population.
人的脾脏通常将约三分之一的人体血小板保留在一个可交换池中，该池可通过α-肾上腺素能刺激释放到循环中。一些先前的研究者得出结论，脾脏血小板群体富含大的、年轻的、致密的血小板亚群（巨血小板），但最近的研究表明血小板大小、年龄和密度在很大程度上是独立变量。在本研究中，对11名正常受试者进行急性剧烈运动，使脾脏血小板释放到循环中后，研究了其特性。运动导致平均血小板计数从245±49升至328±71×10⁹/L——校正血液浓缩后净增加24±6%。枸橼酸化血小板的平均血小板体积（MPV）在运动后从6.38±0.78飞升至6.59±0.68飞升（P<0.01）——升高3.7±4.1%，表明脾脏血小板群体的MPV比正常循环群体约大20%。通过在反苯环丙胺不可逆抑制几天后测量血小板单胺氧化酶（MAO）活性来研究血小板的年龄分布，此时年轻血小板具有正常MAO活性，而老血小板仅具有正常活性的20%。运动后平均血小板MAO活性未改变，表明循环和脾脏群体的年龄分布非常相似。几种假定的血小板年龄标志物（唾液酸、5-羟色胺、β-血小板球蛋白、β-N-乙酰氨基葡萄糖苷酶）的血小板含量在运动后也未改变。运动后血小板密度模态略有下降但不显著。脾脏血小板群体的MPV较大，但年龄和密度分布似乎与基础循环群体相似。
