Bode Arthur P, Fischer Thomas H
Department of Pathology and Laboratory Medicine, East Carolina University, The Brody School of Medicine, Greenville, NC 27858, USA.
Artif Cells Blood Substit Immobil Biotechnol. 2007;35(1):125-33. doi: 10.1080/10731190600974962.
Starting with the work of Klein et al. in the early 1950s, there has been a concerted effort to apply the process of freeze-drying for the preservation of platelets in order to provide hemorrhagic patients with a stable infusible hemostatic agent to stop bleeding. The original attempts did not preserve platelet structural integrity and proved to be of little clinical benefit. However, it was known that fixation by various cross-linking agents rendered platelets able to withstand structurally intact the stresses of lyophilization but with (assumed) complete loss of functionality. Read and coworkers showed that fixed and freeze-dried platelets could respond to ristocetin-induced agglutination, and thus devised a widely accepted assay for von Willebrands factor that demonstrated that reconstituted platelets participated well in this in vitro model of an important interaction in primary hemostasis. This review chronicles the efforts of the authors to refine the fixation process so that the freeze-dried and reconstituted platelets retain fundamental hemostatic properties necessary to stop bleeding. The resultant product has demonstrated correction or reduction of the bleeding times in animal models with platelet deficits including the thrombocytopenic rabbit model of Blajchman and coworkers, a canine cardiopulmonary bypass model of open-heart surgery at East Carolina University (ECU), and a porcine trauma model at The University of North Carolina at Chapel Hill (UNC-CH) involving exsanguination and complete blood exchange with a hemoglobin-based oxygen carrier (HBOC). In addition, it has been shown that the fixation process kills viruses and bacteria spiked into the platelet suspension, indicating that the final material may indeed be the first truly sterile cellular transfusion product. The initial goal for clinical benefit is to prevent exsanguination and hypovolemic shock in combat casualties of armed services personnel, for whom platelet transfusions are most often unavailable. Commercial interests are being brought to bear by Entegrion Inc. (formerly known as Hemocellular Therapeutics Corporation) to transfer this technology to a scaleable manufacturing platform for the production of Stasix, a pharmaceutical preparation of fixed and freeze-dried platelets for intravenous or topical use in the arrest of active hemorrhage in a wide variety of patients with a platelet-related bleeding diathesis. It has taken fifty+ years from the first attempt at making a clinically useful freeze-dried platelet preparation to get to the rapidly-approaching clinical trials of Stasix; stabilization of the platelets has been the key to realizing this advance.
从20世纪50年代初克莱因等人的工作开始，人们就一直在协同努力应用冷冻干燥工艺来保存血小板，以便为出血患者提供一种稳定的可输注止血剂来止血。最初的尝试未能保持血小板的结构完整性，且证明临床益处不大。然而，已知通过各种交联剂固定可使血小板在结构上完整地承受冻干的压力，但（假定）功能完全丧失。里德及其同事表明，固定并冻干的血小板能够对瑞斯托霉素诱导的凝集作出反应，从而设计出一种广泛接受的血管性血友病因子检测方法，该方法证明重构后的血小板能很好地参与这一初级止血中重要相互作用的体外模型。这篇综述记录了作者们为优化固定工艺所做的努力，以使冻干并重构后的血小板保留止血所需的基本特性。最终产品已在包括布莱奇曼及其同事的血小板减少兔模型、东卡罗来纳大学（ECU）的犬类心脏直视手术体外循环模型以及北卡罗来纳大学教堂山分校（UNC-CH）的猪创伤模型（涉及放血并用基于血红蛋白的氧载体（HBOC）进行全血置换）等血小板缺乏的动物模型中证明可纠正或缩短出血时间。此外，已表明固定工艺可杀死添加到血小板悬液中的病毒和细菌，这表明最终产品可能确实是首个真正无菌的细胞输注产品。临床益处的最初目标是预防武装部队战斗伤员的失血和低血容量性休克，对于这些伤员，血小板输注往往无法获得。恩泰里恩公司（前身为血细胞治疗公司）正利用商业利益将这项技术转移到一个可扩展的生产平台，以生产Stasix，这是一种固定并冻干血小板的药物制剂，可静脉内或局部使用，用于阻止各种患有血小板相关出血素质患者的活动性出血。从首次尝试制备具有临床实用性的冻干血小板制剂到Stasix迅速进入临床试验已过去了五十多年；血小板的稳定化一直是实现这一进展的关键。
