DEVELOPMENT OF A NOVEL WHOLE BLOOD COAGULATION ASSAY

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在过去的40年里，我们对血液凝固的理解发生了重大变化。 新的，更有效的抗血小板和抗凝药物已经推出。 尽管药物治疗有了创新，但我们的标准实验室止血测定并不能反映我们对凝血机制的新见解，也不能作为这些新药的适当实验室监测。 目前的临床实验室检测是在不含血小板的血浆样本上进行的。 越来越明显的是，全血是用于分析凝血的最合适的患者样本。Hemodyne止血分析系统（H.A.S.）使用定量物理技术分析全血样品。 以前的研究表明，由H.A.S.不仅反映了血凝块的结构质量，而且还反映了凝块形成过程中血小板的功能。 H.A. S是第一个在血凝块形成过程中定量评估血小板功能的体外系统。 由于最近引入了非常有效的抗血小板和抗凝药物，监测其效果的能力越来越重要。 这些强效药物在疗效和毒性之间的治疗窗口非常窄。 虽然它们能有效控制高凝状态下的血栓形成，但它们的相对效力会增加大出血的风险。 不幸的是传统的监测参数（即，PT、aPTT、INR）不能测量或预测疗效或毒性。 因此，临床医生无法充分（或安全地）监测这些新药物治疗的安全性或有效性。 虽然在正常患者中可能不需要对某些抗凝剂（如低分子量肝素（LMWH））进行常规监测，但在伴有出血风险因素（例如，肝或肾功能不全患者）。 我们在终末期肾病（ESRD）受试者中进行的令人信服的初步数据表明，暴露于LMWH依诺肝素后，抗凝反应增强。 对于这些特殊人群，临床医生迫切需要一种廉价的检测方法，可以快速测量疗效并预测毒性风险。 我们相信H.A.S.可以发挥这一作用，并改善对这些患有凝血障碍的特殊人群的护理。通过这样做，这将使临床医生能够定制抗凝治疗，以实现成功的结果，同时防止不良出血事件。 这些结果应该会降低医疗费用。 这项研究有两个具体目标。 第一项研究涉及使用Hemodyne止血分析系统，以确定增加依诺肝素剂量后抗Xa因子活性与凝血酶生成时间（TGT）的体内关系（0.25、0.50和1.0 mg/kg）在两组受试者中：1）无肾功能不全的正常健康受试者;和2）终末期肾病受试者（ESRD;肌酐清除率< 10 mL/min）。 第二个目标是确定Hemodyne止血分析系统表征依诺肝素1 mg/kg单次给药后12小时内凝血酶生成时间的组间（对照组与ESRD组）差异的能力。 所有先前和当前的血小板功能测量都必须通过表征这些重要的凝血参数，即H.A.S.是一种灵敏、新颖的全血检测试剂盒，可监测各种疾病状态和抗凝治疗患者的凝血状态。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Over the last 40 years, our understanding of blood coagulation has changed significantly. Newer, more potent antiplatelet and anticoagulant medications have been introduced. Despite the innovation of drug therapy, our standard laboratory assays of hemostasis do not reflect our new insights into the clotting mechanism, and do not serve as adequate laboratory monitors for these new drugs. Current clinical laboratory assays are performed on plasma samples that do not contain platelets. It is becoming increasingly apparent that whole blood is the most appropriate patient sample for analyzing coagulation. The Hemodyne Hemostasis Analysis System (H.A.S.) analyzes whole blood samples using quantitative physical techniques. Previous investigations have shown that the parameters measured by the H.A.S. reflect not only the structural qualities of the blood clot, but also platelet function during clot formation. The H.A.S. is the first ex vivo system to quantitatively assess platelet function during clot formation. Due to the recent introduction of very potent antiplatelet and anticoagulant medications, the ability to monitor their effects is increasingly important. These potent drugs have a very narrow therapeutic window between efficacy and toxicity. Although they effectively control thrombosis in hypercoagulable conditions, their relative potency increases the risk of major hemorrhage. Unfortunately conventional monitoring parameters (i.e., PT, aPTT, INR) cannot measure or predict efficacy or toxicity. Thus, clinicians cannot adequately (or safely) monitor these new drug therapies for safety or efficacy. While the routine monitoring of some anticoagulants (such as low molecular weight heparin (LMWH)) may not be necessary in normal patients, the importance of documenting adequate and safe clinical response is critical in complex patients with concurrent risk factors for hemorrhage (e.g., patients with hepatic or renal dysfunction). We have compelling preliminary data conducted in end-stage renal disease (ESRD) subjects that demonstrate an enhanced anticoagulant response following exposure to the LMWH enoxaparin. For these special populations, clinicians desperately need an inexpensive assay that can quickly measure efficacy and predict risk of toxicity. We believe the H.A.S. can serve this role, and improve the care to these special populations with coagulation disorders. By doing so, this would allow clinicians to tailor anticoagulant therapy to achieve successful outcomes while preventing adverse bleeding events. These outcomes should result in reduced healthcare costs. This study has two specific aims. The first involves using the Hemodyne Hemostasis Analysis System , to define the in vivo relationship of antifactor Xa activity to thrombin generation time (TGT) following increasing doses of enoxaparin (0.25, 0.50 and 1.0 mg/kg) in two groups of subjects: 1) normal, healthy subjects without renal dysfunction; and 2) subjects with end-stage renal disease (ESRD; creatinine clearance < 10 mL/min) on maintenance hemodialysis. The second goal is to determine the ability of the Hemodyne Hemostasis Analysis System to characterize intergroup (control versus ESRD) differences in thrombin generation time over 12 hours following single dose enoxaparin 1 mg/kg. All previous and current measures of platelet function must be performed with clotting by characterizing these important clotting parameters, the H.A.S. is a sensitive, novel, whole blood assay that monitors coagulation status in various disease states and in patients on anticoagulant therapy.