Von Willebrand factor (VWF) and factor VIII (FVIII) complex play a pivotal role in hemostasis. A deficiency or defect of VWF causes von Willebrand disease (VWD). Recombinant (r)VWF product has proved to be effective for hemostatic treatment of VWD, but limited information is available on their role in moderating thrombus formation under flow condition. We aimed to assess thrombus formation in the presence of rVWF combined with rFVIII or pegylated-extended half-life rFVIII (peg-EHL-rFVIII) in VWD whole blood under high shear flow. Perfusion chamber experiments under high shear (2,500 s− 1) combined with immunostaining were performed using patient’s whole blood with type 1 VWD, mixed with rVWF (Vonvendi®; 1.6 IU/mL), rFVIII or peg-EHL-rFVIII (Advate® or Adynovate®; 1.0 IU/mL), or both. Similar experiments were also conducted with clinical medical devices (T-TAS®). The addition of rFVIII did not augment thrombus formation assessed by surface coverage (SC) and thrombus height (TH), whereas rVWF enhanced these parameters (SC 19.1 ± 1.1% vs. 30.1 ± 4.1%, TH 2.2 ± 0.14 μm vs. 3.6 ± 0.40 μm, respectively). The co-presence of rVWF/rFVIII was comparable to plasma-derived VWF/FVIII (Confact®, VWF:FVIII ratio = 1.6:1.0) for increasing thrombogenicity in SC (32.5 ± 4.3% vs. 38.7 ± 5.5%) and in TH (5.0 ± 0.60 μm vs. 5.5 ± 0.64 μm), respectively. The pre-incubation time with rVWF and rFVIII appeared to have a little effect on the size of thrombus. Peg-EHL-rFVIII mediated thrombus formation to similar extent as rFVIII in the co-presence of rVWF. Similar results were obtained even with T-TAS. Immunostaining demonstrated that rFVIII and peg-EHL-rFVIII were similarly co-localized with rVWF in formed thrombi, indicating that pegylation did not interfere with molecular complexes. The effects of high-level rVWF and peg-EHL-rFVIII on thrombus formation were comparable to conventional therapeutic products in a patient’s whole blood with VWD under high shear flow.

中文翻译：

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重组血管性血友病因子和标准或聚乙二醇化半衰期延长的重组因子 VIII 在高剪切流下对血栓形成的止血潜力

血管性血友病因子 (VWF) 和因子 VIII (FVIII) 复合物在止血中发挥着关键作用。VWF 缺乏或缺陷会导致血管性血友病 (VWD)。重组 (r)VWF 产品已被证明对 VWD 的止血治疗有效，但有关其在流动条件下减缓血栓形成的作用的信息有限。我们的目的是评估高剪切流下 VWD 全血中存在 rVWF 与 rFVIII 或聚乙二醇化延长半衰期的 rFVIII (peg-EHL-rFVIII) 时的血栓形成情况。使用 1 型 VWD 患者全血，与 rVWF（Vonvendi®；1.6 IU/mL）、rFVIII 或 peg-EHL-rFVIII（Advate® 或Adynovate®；1.0 IU/mL），或两者兼而有之。临床医疗设备 (T-TAS®) 也进行了类似的实验。添加 rFVIII 并不会增加通过表面覆盖率 (SC) 和血栓高度 (TH) 评估的血栓形成，而 rVWF 增强了这些参数（SC 19.1 ± 1.1% vs. 30.1 ± 4.1%，TH 2.2 ± 0.14 μm vs. 3.6 ± 0.40μm，分别）。rVWF/rFVIII 的共存与血浆衍生的 VWF/FVIII（Confact®，VWF:FVIII 比率 = 1.6:1.0）相当，可增加 SC 中的血栓形成性（32.5 ± 4.3% 对比 38.7 ± 5.5%）和 TH分别为（5.0 ± 0.60 μm 与 5.5 ± 0.64 μm）。rVWF 和 rFVIII 的预孵育时间似乎对血栓的大小影响不大。Peg-EHL-rFVIII 介导的血栓形成程度与 rVWF 共存时的 rFVIII 相似。即使使用 T-TAS 也获得了类似的结果。免疫染色证明rFVIII和peg-EHL-rFVIII在形成的血栓中与rVWF类似地共定位，表明聚乙二醇化不会干扰分子复合物。在高剪切流下，高水平 rVWF 和 peg-EHL-rFVIII 对 VWD 患者全血中血栓形成的影响与传统治疗产品相当。