Schnoor Brian, Papa Anne-Laure
Department of Biomedical Engineering, The George Washington University, Washington, DC, United States.
Front Bioeng Biotechnol. 2022 Aug 19;10:941817. doi: 10.3389/fbioe.2022.941817. eCollection 2022.
Lyophilized platelets have been explored as a potential hemostatic agent due to their long-term ambient storage capabilities that make them readily available in various scenarios. Additionally, their high biocompatibility and the key role of platelet interactions in various clinical conditions make them a promising platform for drug delivery. To explore these applications and for wider clinical deployment, the interactions between lyophilized platelets and fresh platelets must be examined. This project characterized receptor expression on the lyophilized platelet surface and their ability to bind fibrinogen using flow cytometry. The effect of lyophilized platelets on aggregation of unaltered platelets was assessed using light transmission aggregometry while the effect on adhesion was evaluated using static and microfluidic assays. Lyophilized platelets maintained significant levels of GPIIb and GPVI receptors on their surface, though the expression was reduced from fresh platelets. Additionally, lyophilized platelets maintained GPIb expression similar to fresh platelets. Furthermore, 15.8% of the lyophilized platelets exhibited the active conformation of the GPIIb/IIIa receptor, indicating a significant increase over fresh platelets. Lyophilized platelets also exhibited an increase in exposed phosphatidylserine and fibrinogen binding. Despite the effect of lyophilized platelets in promoting the adhesion of fresh platelets on a collagen-coated surface, their net effect was inhibitory on platelet aggregation. This study demonstrates that lyophilized platelets can have paradoxical effects on platelet adhesion and aggregation, which could have an impact for clinical applications. Detailed characterization and engineering of these effects will be important for their continued development as a drug delivery platform.
冻干血小板因其长期常温储存能力，使其在各种情况下都易于获取，已被探索作为一种潜在的止血剂。此外，它们具有高生物相容性以及血小板相互作用在各种临床病症中的关键作用，使其成为一个有前景的药物递送平台。为了探索这些应用并实现更广泛的临床应用，必须研究冻干血小板与新鲜血小板之间的相互作用。本项目使用流式细胞术对冻干血小板表面的受体表达及其结合纤维蛋白原的能力进行了表征。使用透光比浊法评估冻干血小板对未改变血小板聚集的影响，同时使用静态和微流控分析评估其对黏附的影响。冻干血小板表面维持了显著水平的糖蛋白IIb（GPIIb）和糖蛋白VI（GPVI）受体，尽管其表达量低于新鲜血小板。此外，冻干血小板维持了与新鲜血小板相似的糖蛋白Ib（GPIb）表达。此外，15.8%的冻干血小板呈现出GPIIb/IIIa受体的活性构象，表明相较于新鲜血小板有显著增加。冻干血小板还表现出暴露的磷脂酰丝氨酸增加以及纤维蛋白原结合增加。尽管冻干血小板在促进新鲜血小板在胶原包被表面的黏附方面有作用，但其对血小板聚集的净效应是抑制性的。本研究表明，冻干血小板对血小板黏附和聚集可能产生矛盾的影响，这可能对临床应用产生影响。对这些影响进行详细表征和工程设计对于其作为药物递送平台的持续发展至关重要。
