New approaches to the pathophysiology, diagnosis and management of heparin-induced thrombocytopenia

肝素诱导的血小板减少症的病理生理学、诊断和治疗的新方法

• 批准号: 10276062
• 负责人: Anand Padmanabhan
• 金额: $ 39.75万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10276062
• 关键词: Affect; Alpha Granule; American Society of Hematology; Antibodies; Anticoagulant therapy; Anticoagulants; Anticoagulation; Antigens; Area; Benign; Binding; Biochemical; Biological Assay; Blood Platelets; Blood specimen; Cessation of life; Characteristics; Chondroitin Sulfate A; Chondroitin Sulfates; Chromatography; Coagulation Process; Complex; Dangerousness; Data; Development; Diagnosis; Diagnostic; Diagnostic Procedure; Diagnostic tests; Disease; Early Diagnosis; Environment; Enzyme-Linked Immunosorbent Assay; Epidemic; Evaluation; Event; Functional disorder; Generations; Goals; Gold; Hemorrhage; Heparin; Heparin Binding; Heterogeneity; Hospitals; In Vitro; Institution; Laboratories; Lead; Length; Life; Mediating; Methods; Monoclonal Antibodies; Morbidity - disease rate; Outcome; P-Selectin; PF4 Gene; Pathogenesis; Pathogenicity; Pathway interactions; Patient Isolation; Patients; Platelet Activation; Proteins; Research; Research Infrastructure; Research Personnel; Risk; Sampling; Serology; Serotonin; Specificity; Sulfate; Surface; Syndrome; Testing; Therapeutic; Thrombin; Thrombocytopenia; Thrombosis; Time; Whole Blood; Work; accurate diagnosis; base; drug candidate; heparin-induced thrombocytopenia; improved; in vivo; inhibitor/antagonist; innovation; insight; mortality; mouse model; murine monoclonal antibody; new therapeutic target; novel; novel strategies; prevent; rapid diagnosis

PROJECT SUMMARY/ABSTRACT Heparin-induced thrombocytopenia (HIT) is a severe, antibody (ab)-mediated prothrombotic syndrome with high morbidity and mortality. The biochemical basis of the distinction between “pathogenic” platelet-activating antibodies and “benign” non-activating HIT antibodies is not well understood. This results in significant diagnostic challenges and in excessive use of non-heparin alternative anticoagulation that have worse bleeding profiles than heparin. Outcomes in HIT are suboptimal despite current therapy with direct thrombin inhibitors: One-third of affected patients develop thrombosis and one in ten patients dies. The proposed studies will explore key unanswered questions in areas of HIT pathophysiology, diagnosis and treatment. For Aim 1, we hypothesize the existence of multiple functional classes of HIT antibodies: (1) Pathogenic antibodies that recognize PF4-treated platelets with or without reactivity to PF4-heparin complexes, and (2) Benign abs that recognize PF4-heparin but not platelets treated with PF4. We will identify and characterize these antibody classes by chromatography-based isolation from patient samples and will generate novel HIT monoclonal antibodies in each of these functional classes. Generated monoclonal antibodies will be tested for pathogenicity in a HIT mouse model and results will be correlated with their serologic characteristics. Obtaining and processing normal donor platelets is a major challenge that limits the availability of functional “gold standard” testing in HIT. In Aim 2, we will develop a rapid HIT diagnostic test using the patient’s own platelets treated with PF4/heparin. This will facilitate “in-hospital” HIT diagnosis leading to early detection of this condition. Currently used non-heparin alternative anticoagulants do not address the most proximal event in HIT: Activation of platelets by HIT antibodies. Given this, breakthrough thrombosis is frequently seen in patients under treatment and so is unintended bleeding caused by the potent non-heparin anticoagulants used. In Aim 3, we will use platelet-derived and synthetic chondroitin sulfates of various sulfation levels and saccharide lengths to evaluate their ability to inhibit HIT-antibody mediated platelet activation in vitro and to ameliorate thrombocytopenia in a HIT murine model. In Aim 1, we expect to successfully separate and characterize multiple functional classes of HIT antibodies which will suggest new ways to selectively detect only the pathogenic ones. Developing and optimizing a diagnostic method using the patient’s own platelets in Aim 2 will transform platelet-activation based HIT testing by moving it from the reference laboratory environment to the in-hospital setting. Finally, studies described in Aim 3 will introduce a new class of therapeutics in HIT, chondroitin sulfates, that will prevent thrombosis, but unlike current therapies, will not increase the risk of bleeding. In summary, we anticipate that all three aims of this proposal will lead to a significant impact on pathophysiology, diagnosis and treatment of HIT.

项目摘要/摘要 肝素诱导的血小板减少症（HIT）是一种严重的抗体（AB）介导的促血栓性综合征， 高发病和死亡率。 “致病”血小板激活之间区别的生化基础 抗体和“良性”非激活抗体抗体尚不清楚。这导致了重要的 诊断挑战和过多使用非肝素的替代抗凝治疗 出血比肝素。热门的结果是直接凝血酶的次优目的当前治疗 抑制剂：三分之一受影响的患者发生血栓形成，十分之一的患者死亡。提出的研究 将在HIT病理生理，诊断和治疗领域探讨关键的未解决问题。对于目标1， 我们假设存在多种功能类HIT抗体的存在：（1）致病性抗体 公认的PF4处理的血小板对PF4-肝素复合物有或没有反应性，以及（2）良性ABS 识别PF4 heparin，但不能识别使用PF4处理的血小板。我们将识别并表征这些抗体 从患者样品中基于色谱分离的类别，将产生新的命中单克隆 这些功能类别中的每一个中的抗体。生成的单克隆抗体将进行测试 命中小鼠模型中的致病性，结果将与其血清学特征相关。获得 处理普通供体血小板是限制功能性可用性的主要挑战 标准“命中率”。在AIM 2中，我们将使用患者自己的血小板进行快速的诊断测试 用PF4/肝素治疗。这将有助于“院内”命中诊断，从而提前发现 健康）状况。目前使用的非肝素替代抗凝剂并未解决最近端事件 命中：通过命中抗体激活血小板。鉴于此，突破性血栓经常在 受到治疗的患者是由有效的非肝素抗凝剂引起的意外出血。 在AIM 3中，我们将使用各种硫酸水平的血小板来源和合成软骨素硫酸盐和 糖的长度以评估其在体外抑制命中抗体介导的血小板激活的能力 在热门鼠模型中改善血小板减少症。在AIM 1中，我们希望成功分开，并且 表征多个功能类Hit抗体的类别，这些抗体将提出选择性检测的新方法 只有病原体。使用患者自己的血小板开发和优化诊断方法 AIM 2将通过从参考实验室移动基于血小板激活的命中测试 环境到院内环境。最后，AIM 3中描述的研究将引入新的类别 热门疗法，软骨素硫酸盐，可以防止血栓形成，但与目前的疗法不同，不会 总而言之，我们预计该提案的所有三个目标都将导致 对HIT的病理生理学，诊断和治疗的重大影响。