BC-mediated delivery of thromboprophylaxis

没有一种抗血栓药物(ATA)对许多合并有血栓形成风险的患者是安全有效的。 急性血栓形成和出血，例如在手术后早期。为了解决这一未得到满足的需求，我们 开发药物输送系统(DDS)，执行两个主要功能：a)阻止ATA进入OFF- 靶点，例如，手术后形成的止血塞，而B)优化药代动力学和 将ATA输送到随后的血栓中，ATA被凝血酶激活。ATA融合了单- 针对红细胞(RBC)的链片段(ScFv)与这些执行双重任务的载体结合 阻塞/传送功能。概念验证正在预先存在的和新生的血栓模型中出现 在动物身上。在这里，我们设计了针对人RBC的人源化ScFv/ATA，并将在 人源化微流控系统(HMF)在表达人源化靶位的转基因(TG)小鼠中的应用 在血细胞上，以及在离体人肺的灌流中。我们将追求三个目标。目标1.红细胞 正在装车。我们将表征单链抗体/ATA在红细胞上的负载：A)结合(拷贝/细胞，开/关动力学)；B) 对红细胞功能、生物相容性和生物力学的影响；以及，B)分布的调节 循环中RBC之间的ScFv/ATA。我们还将对生物力学因素进行表征 RBC/ATA传递及其对血栓动力学和结构的影响，特别是RBC的影响 硬化症，由药物负荷或患者体内固有的病理生理变化引起 血。目标2.机械的洞察力。我们将审问以前未被承认但又具有批判性的问题 RBC/ATA的工作机制，特别是它们与血管内皮细胞的相互作用和 将药物货物转移到这些和其他血管细胞。在这个目标中，我们将使用标准鼠标 活体模型、微流体模型和离体人肺灌流模型。目标3.评估 收益/风险比率。我们正在开发在小鼠EBC中表达人RBC决定簇的TM小鼠， 为了研究体内负载单链抗体/ATA的人RBC：A)PK/BD，补体激活， TG小鼠RBC/ATA的吞噬细胞摄取和血管黏附；B)确定时间窗/范围 人RBC/ATA在TG小鼠动静脉血栓形成模型中的抗血栓作用； B)确认RBC/ATA的安全性。我们将检测ScFv/ATA的不利情况，包括 RBC。为了化解潜在的问题，如有必要，我们将使用更良性的加载方案。一起， 这些研究将推进机械洞察力和临床翻译的新方法，以缓解 通过提供一种新的、易处理的方法来治疗目前无保护措施的患者的血栓形成 了解血栓的发展和提供细胞导向治疗的合理方法

No anti-thrombotic agent (ATA) is safe and effective in the many patients at a combined risk of acute thrombosis and bleeding, e.g., in the early post-surgery period. To address this unmet need, we develop drug delivery systems (DDS) executing two main functions: A) Block access of ATA to off- target sites, e.g., hemostatic plugs formed after surgery, while B) Optimize pharmacokinetics and deliver ATA into subsequent thrombi, where ATA is activated by thrombin. ATA fused with single- chain fragments (scFv) targeted to red blood cells (RBC) bind to these carriers that execute dual blocking/delivering function. Proof-of-concept is emerging in models of pre-existing and nascent clots in animals. Here we devise humanized scFv/ATA targeted to human RBC and will test them in a humanized microfluidic system (HMF), in transgenic (TG) mice expressing humanized target epitopes on blood cells, and in the perfusion of isolated human lungs. We will pursue three aims. Aim 1. RBC loading. We will characterize scFv/ATA loading onto RBC: A) Binding (copies/cell, on/off kinetics); B) Effect on RBC functionality, biocompatibility and biomechanics; and, B) Regulation of distribution of scFv/ATA between RBC in circulation. We also will characterize biomechanical factors modulating RBC/ATA delivery and effect on clot dynamics and structure, in particular, impact of RBC rigidification, caused by either drug loading or by intrinsic pathophysiological changes in patient's blood. Aim 2. Mechanistic insights. We will interrogate previously unrecognized yet critically aspects of the RBC/ATA workings, in particular their interaction with vascular endothelium and transfer of the drug cargo to these and other vascular cells. In this Aim we will use standard mouse in vivo models, microfluidic model and perfusion of isolated human lungs model. Aim 3. Appraisal of benefit/risk ratio. We are developing TM mice expressing human RBC determinants in mouse EBC, in order to study scFv/ATA loaded on "human RBC" in vivo: A) PK/BD, complement activation, phagocyte uptake and vascular adhesion of RBC/ATA in TG mice; B) Define the time window/extent of anti-thrombotic effect of human RBC/ATA in models of arterial vs venous thrombosis in TG mice; B) Affirm the safety of RBC/ATA. We will detect adversities of scFv/ATA including abnormalities of RBC. To defuse potential issues, if necessary, we will use more benign loading regimen. Together, these studies will advance mechanistic insights and clinical translation of a novel way to mitigate thrombosis in currently unprotected patients by providing a new and tractable approach to understanding thrombus development and a rational approach to deliver cell-directed therapeutics