Lopes A A, Ferraz de Souza B, Maeda N Y
Heart Institute, School of Medicine of the University of São Paulo, Brazil.
Thromb Haemost. 2000 May;83(5):683-7.
In pulmonary hypertension, defective von Willebrand factor protein (vWF) lacking large multimers is present in circulation. This is associated with evidence of chronic endogenous platelet activation. Since asialo vWF has been shown to promote platelet activation and aggregation, we decided to investigate possible changes in the sialic acid content of plasma vWF in patients with precapillary pulmonary hypertension. vWF-associated sialic acid was measured indirectly as a wheat germ agglutinin-reactive substance (WGA-RS, Western blotting), and directly, as a thiobarbituric acid-reactive substance (TBA-RS, spectrophotometric reading). In the sixteen patients we studied (ages 8-45 yr), circulating vWF concentration was 2.18 times normal (p <0.001). However, patient vWF subunit contained 19% (WGA-RS) to 24% (TBA-RS) less sialic acid than the normal protein (p <0.05 for both determinations). In five patients, vWF-associated sialic acid was below 50% normal. We conclude that circulating vWF is hyposialylated in precapillary pulmonary hypertension and speculate that this might influence its interaction with platelets in vivo in these patients.
在肺动脉高压患者中，循环系统中存在缺乏大分子量多聚体的有缺陷的血管性血友病因子蛋白（vWF）。这与慢性内源性血小板激活的证据相关。由于去唾液酸vWF已被证明可促进血小板激活和聚集，我们决定研究毛细血管前肺动脉高压患者血浆vWF唾液酸含量的可能变化。vWF相关唾液酸通过间接作为麦胚凝集素反应性物质（WGA-RS，蛋白质印迹法）和直接作为硫代巴比妥酸反应性物质（TBA-RS，分光光度读数）来测量。在我们研究的16名患者（年龄8 - 45岁）中，循环vWF浓度是正常水平的2.18倍（p <0.001）。然而，患者vWF亚基的唾液酸含量比正常蛋白少19%（WGA-RS）至24%（TBA-RS）（两种测定方法的p均<0.05）。在5名患者中，vWF相关唾液酸低于正常水平的50%。我们得出结论，毛细血管前肺动脉高压患者循环中的vWF唾液酸含量减少，并推测这可能会影响其在这些患者体内与血小板的相互作用。
