Modesti P A, Colella A, Cecioni I, Costoli A, Biagini D, Migliorini A, Neri Serneri G G
Clinica Medica I, Center for Heart and Thrombosis Research, University of Florence, Italy.
Am Heart J. 1995 May;129(5):873-9. doi: 10.1016/0002-8703(95)90106-x.
The current study was designed to investigate the number and affinity of platelet thromboxane A2/prostaglandin H2 (TxA2/PGH2) receptors in patients with unstable angina and, if any, the role played by the increased thrombin formation that is a common finding in these patients. Measurements taken during active unstable angina but not those taken during inactive angina showed an increase number (p < 0.001), without changes in affinity, of platelet TxA2/PGH2 receptors, evaluated as the binding capacity of iodine 125-PTA-OH, a stable TxA2 analogue. Moreover patients with active angina had higher plasma concentrations of fibrinopeptide A (FPA) (p < 0.0001), which were significantly related to the number of platelet TxA2/PGH2 receptors (r = 0.76; p < 0.01). Heparin infusion but not aspirin treatment promptly normalized the number of TxA2/PGH2 receptors and significantly reduced plasma FPA concentrations. In an in-vitro study thrombin in a concentration similar to that found in vivo significantly increased the number of platelet TxA2/PGH2 receptors (p < 0.01), whereas heparin did not affect TxA2/PGH2 receptors. These results have important therapeutic implications and indicate the preferential use of heparin rather than aspirin during the acute phase of unstable angina.
本研究旨在调查不稳定型心绞痛患者血小板血栓素A2/前列腺素H2（TxA2/PGH2）受体的数量和亲和力，以及（若存在的话）这些患者中常见的凝血酶生成增加所起的作用。在不稳定型心绞痛发作期进行的测量显示，以稳定的TxA2类似物碘125-PTA-OH的结合能力评估，血小板TxA2/PGH2受体数量增加（p<0.001），而亲和力无变化；而非发作期进行的测量则未显示此现象。此外，不稳定型心绞痛发作期患者的血浆纤维蛋白肽A（FPA）浓度更高（p<0.0001），且与血小板TxA2/PGH2受体数量显著相关（r=0.76；p<0.01）。输注肝素而非使用阿司匹林治疗可迅速使TxA2/PGH2受体数量恢复正常，并显著降低血浆FPA浓度。在一项体外研究中，与体内浓度相似的凝血酶显著增加了血小板TxA2/PGH2受体数量（p<0.01），而肝素对TxA2/PGH2受体无影响。这些结果具有重要的治疗意义，表明在不稳定型心绞痛急性期优先使用肝素而非阿司匹林。
