Maquelin K N, Berckmans R J, Nieuwland R, Schaap M C, ten Have K, Eijsman L, Sturk A
Department of Cardiopulmonary Surgery, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
J Thorac Cardiovasc Surg. 1998 May;115(5):1160-5. doi: 10.1016/s0022-5223(98)70416-7.
Several investigators have reported decreased expression of glycoprotein Ib on the platelet surface during coronary artery bypass grafting, but others could not confirm this finding. Because platelet glycoprotein Ib functions as an adhesion receptor for von Willebrand factor and other adhesive proteins, this decreased expression may explain excessive postoperative blood loss. In this study the expressions of glycoprotein Ib and other platelet activation markers were studied in the systemic and pericardial blood of seven patients undergoing coronary artery bypass grafting. Pericardial blood was recently shown to have high activation levels of fibrinolytic and coagulation pathways; we hypothesized that this local blood activation might be paralleled by extensive platelet activation and associated disappearance of glycoprotein Ib.
Expression of platelet surface antigens was determined by whole-blood double-label flow cytometry.
Glycoprotein Ib expression in systemic blood decreased 10% (p = 0.03) from preoperative levels at the start of cardiopulmonary bypass and 30% (p = 0.04) before release of the aortic crossclamp. Expression in pericardial blood at these times decreased by 50% and 51%, respectively (p = 0.003, p = 0.009). No changes were observed in the expression of the platelet activation antigens CD62P (P-selectin, indicating platelet alpha-granular release) and CD63 (indicating lysosomal release) or in binding of monoclonal antibody PAC-1 (detecting the fibrinogen-binding receptor conformation of the glycoprotein IIb-IIIa complex).
Glycoprotein Ib disappeared from the platelet surface during bypass grafting, most notably in pericardial blood. No increased expression of CD62P, CD63, or PAC-1 was found, indicating the absence of general platelet activation.
几位研究者报告称，在冠状动脉旁路移植术中血小板表面糖蛋白Ib的表达会降低，但其他研究者无法证实这一发现。由于血小板糖蛋白Ib作为血管性血友病因子和其他黏附蛋白的黏附受体发挥作用，这种表达降低可能解释术后出血过多的现象。在本研究中，对7例接受冠状动脉旁路移植术患者的体循环血液和心包血液中糖蛋白Ib及其他血小板活化标志物的表达进行了研究。最近研究表明心包血液具有较高水平的纤溶和凝血途径活化；我们推测这种局部血液活化可能与广泛的血小板活化及糖蛋白Ib的相关消失同时出现。
通过全血双标记流式细胞术测定血小板表面抗原的表达。
在体外循环开始时，体循环血液中糖蛋白Ib的表达较术前水平降低了10%（p = 0.03），在主动脉阻断钳松开前降低了30%（p = 0.04）。此时心包血液中的表达分别降低了50%和51%（p = 0.003，p = 0.009）。血小板活化抗原CD62P（P选择素，表明血小板α颗粒释放）和CD63（表明溶酶体释放）的表达或单克隆抗体PAC-1的结合（检测糖蛋白IIb-IIIa复合物的纤维蛋白原结合受体构象）均未观察到变化。
在旁路移植术中糖蛋白Ib从血小板表面消失，在心包血液中尤为明显。未发现CD62P、CD63或PAC-1表达增加，表明不存在全身性血小板活化。
