Ogiwara K, Nogami K, Hosokawa K, Ohnishi T, Matsumoto T, Shima M
Department of Pediatrics, Nara Medical University, Kashihara, Japan.
Haemophilia. 2015 Jan;21(1):71-80. doi: 10.1111/hae.12610.
The diagnosis of von Willebrand disease (VWD) is difficult due to the wide spectrum of clinical phenotypes associated with this disorder. We have analysed and characterized haemostatic function in VWD patients using a microchip-based flow chamber system. Microchips coated with either collagen [platelet (PL)-chip] or collagen/thromboplastin [atherome (AR)-chip] were used to evaluate platelet thrombus formation at 1000 s(-1) and fibrin-rich platelet thrombus formation at 240 s(-1) respectively. Blood samples from an asymptomatic patient with VWD type 1 [von Willebrand factor (VWF): RCo 3.2%; bleeding score (BS 2] displayed normal thrombus formation in both PL- and AR-chips, whereas blood from a symptomatic type 1 patient (VWF: RCo 14%, BS 9) had significantly delayed capillary occlusion. Nearly complete suppression of the flow pressure increase was observed in symptomatic patients with VWD type 2A (BS 13) and 2N (BS 27), whereas no flow pressure was found for the type 3 patient (BS 6). Fibrin-rich platelet thrombus formation was only weakly increased by the in vitro addition of factor VIII (FVIII) to blood samples from the type 3 patient, but was normalized by the addition of VWF/FVIII. The in vivo effects of treatment with desmopressin or VWF/FVIII for the symptomatic patients were analysed using two types of microchips. The PL-chip was highly sensitive for patients' VWF-mediated platelet functions, whereas the AR-chip allowed assessment of overall haemostatic ability, including sensitivity to both VWF and FVIII. The combined analysis with PL- and AR-chips may be potentially useful for the diagnosis of VWD based on clinical phenotypes, and for monitoring drug effects.
血管性血友病（VWD）的诊断较为困难，因为该疾病具有广泛的临床表型。我们使用基于微芯片的流动腔系统分析并表征了VWD患者的止血功能。分别使用涂有胶原蛋白的微芯片[血小板（PL）芯片]或胶原蛋白/凝血活酶的微芯片[动脉粥样硬化（AR）芯片]，来评估在1000 s⁻¹时血小板血栓形成情况以及在240 s⁻¹时富含纤维蛋白的血小板血栓形成情况。来自一名无症状1型VWD患者的血样[血管性血友病因子（VWF）：RCo 3.2%；出血评分（BS 2）]在PL芯片和AR芯片中均显示出正常的血栓形成，而来自一名有症状1型患者的血样（VWF：RCo 14%，BS 9）的毛细血管闭塞明显延迟。在有症状的2A型（BS 13）和2N型（BS 27）VWD患者中观察到流动压力增加几乎完全受到抑制，而3型患者（BS 6）则未检测到流动压力。对于3型患者的血样，体外添加凝血因子VIII（FVIII）仅使富含纤维蛋白的血小板血栓形成略有增加，但添加VWF/FVIII后则恢复正常。使用两种类型的微芯片分析了去氨加压素或VWF/FVIII对有症状患者的体内治疗效果。PL芯片对患者VWF介导的血小板功能高度敏感，而AR芯片可评估包括对VWF和FVIII敏感性在内的整体止血能力。结合PL芯片和AR芯片进行分析，可能对基于临床表型的VWD诊断以及监测药物效果具有潜在的应用价值。
