BC-mediated delivery of thromboprophylaxis

没有抗血栓药物（ATA）是安全和有效的，在许多患者的综合风险， 急性血栓形成和出血，例如，在手术后的早期。为了满足这一未满足的需求，我们 开发执行两个主要功能的药物递送系统（DDS）：A）阻止ATA访问关闭- 靶位点，例如，手术后形成止血栓，而B）优化药代动力学， 将ATA递送到随后的血栓中，其中ATA被凝血酶激活。ATA融合单- 靶向红细胞（RBC）的单链片段（scFv）与这些载体结合， 阻断/输送功能。概念验证出现在预先存在和新生凝块的模型中 在动物身上。在这里，我们设计了靶向人RBC的人源化scFv/ATA，并将在 人源化微流体系统（HMF），在表达人源化靶表位的转基因（TG）小鼠中 在血细胞中，以及在离体人肺的灌注中。我们将追求三个目标。目标1。RBC 加载中我们将表征加载到RBC上的scFv/ATA：A）结合（拷贝/细胞，开/关动力学）; B） 对RBC功能性、生物相容性和生物力学的影响;以及，B）调节RBC的分布。 循环中RBC之间的scFv/ATA。我们还将描述生物力学因素调节 RBC/ATA输送和对血凝块动力学和结构的影响，特别是RBC/ATA的影响 硬化，由药物负荷或患者的内在病理生理变化引起， 血目标2.机械的洞察力。我们将审问以前未被承认但批判性地 RBC/ATA工作的各个方面，特别是它们与血管内皮的相互作用， 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在 体内模型、微流体模型和离体人肺灌注模型。目标3。评价 获益/风险比。我们正在开发在小鼠EBC中表达人RBC决定簇的TM小鼠， 为了在体内研究负载在“人RBC”上的scFv/ATA：A）PK/BD，补体激活， TG小鼠中RBC/ATA的吞噬细胞摄取和血管粘附; B）定义时间窗/程度 人RBC/ATA在TG小鼠动脉与静脉血栓形成模型中的抗血栓形成作用; B）确认RBC/ATA的安全性。我们将检测scFv/ATA的不良反应，包括 红细胞为了消除潜在的问题，如果有必要，我们将使用更温和的加载方案。在一起， 这些研究将推进一种新的缓解方法的机制见解和临床翻译， 通过提供一种新的易处理的方法， 了解血栓的发展和提供细胞定向治疗的合理方法

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