Moncada S, Vane J R
Fed Proc. 1979 Jan;38(1):66-71.
Prostacyclin (PGI2) generated by the vascular wall is a potent vasodilator, and the most potent endogenous inhibitor of platelet aggregation so far discovered. Prostacyclin inhibits platelet aggregation by increasing cyclic AMP levels. Prostacyclin is a circulating hormone continually released by the lungs into the arterial circulation. Circulating platelets are, therefore, subjected constantly to prostacyclin stimulation and it is via this mechanism that platelet aggregability in vivo is controlled. Moreover, phosphodiesterase inhibitors such as dipyridamole or theophylline exert their antithrombotic actions by potentiating circulating prostacyclin. The prostacyclin:thromboxane A2 ratio is important in the control of thrombus formation; manipulation of this ratio by small doses of aspirin (which will inhibit mainly platelet cyclooxygenase), a selective inhibitor of thromboxane formation, or the dietary use of a fatty acid like eicosapentaenoic acid (which would be the precursor for a delta17-prostacyclin (PGI3) but is transformed by the platelets into nonaggregating thromboxane A3) might have beneficial effects as antithrombotic therapies. Prostacyclin has interesting potential for clinical application in conditions where enhanced platelet aggregation is involved or to increase biocompatibility of extracorporeal circulation systems.
血管壁产生的前列环素（PGI2）是一种强效血管扩张剂，也是迄今为止发现的最有效的内源性血小板聚集抑制剂。前列环素通过提高环磷酸腺苷水平来抑制血小板聚集。前列环素是一种循环激素，由肺持续释放到动脉循环中。因此，循环中的血小板不断受到前列环素的刺激，正是通过这种机制，体内血小板的聚集能力得以控制。此外，双嘧达莫或茶碱等磷酸二酯酶抑制剂通过增强循环中的前列环素发挥其抗血栓作用。前列环素与血栓素A2的比例在血栓形成的控制中很重要；通过小剂量阿司匹林（主要抑制血小板环氧化酶）、血栓素形成的选择性抑制剂，或饮食中使用二十碳五烯酸等脂肪酸（它是δ17-前列环素（PGI3）的前体，但被血小板转化为不具聚集性的血栓素A3）来调节这一比例，可能作为抗血栓治疗具有有益效果。前列环素在涉及血小板聚集增强的病症中或提高体外循环系统生物相容性方面具有有趣的临床应用潜力。
