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: 10470249
• 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/10470249
• 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; 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)介导的血栓前综合征， 高发病率和高死亡率。“致病”血小板活化与“致病”活化区别的生化基础 抗体和“良性”非激活的HIT抗体还没有被很好地理解。这导致了显著的 诊断上的挑战和过度使用非肝素替代抗凝有更糟糕的 出血情况比肝素好。尽管目前使用直接凝血酶治疗，但HIT的结果并不理想 抑制药：三分之一的受影响患者发生血栓形成，十分之一的患者死亡。建议进行的研究 将探讨HIT病理生理学、诊断和治疗领域中尚未回答的关键问题。对于目标1， 我们假设存在多种功能类别的HIT抗体：(1)致病抗体 识别经PF4处理的具有或不具有对PF4-肝素复合体反应的血小板，以及(2)良性腹水 可识别PF4-肝素，但不能识别经PF4处理的血小板。我们将鉴定和鉴定这些抗体 通过基于层析的方法从患者样本中分离类，将产生新的HIT单抗 这些功能类别中的每一种抗体。所产生的单抗将被检测 HIT小鼠模型的致病性和结果将与它们的血清学特征相关。获取 处理正常供者的血小板是限制功能性“黄金”可获得性的主要挑战 标准“在HIT中测试。在目标2中，我们将开发一种使用患者自己的血小板的快速HIT诊断测试 用PF4/肝素治疗。这将有助于医院内的命中诊断导致早期检测到这种情况 条件。目前使用的非肝素替代抗凝剂不能解决最近端事件 HIT：HIT抗体激活血小板。鉴于此，突破性血栓形成常见于 患者正在接受治疗，因此是使用了强有力的非肝素抗凝剂造成的意外出血。 在目标3中，我们将使用不同硫化程度的血小板衍生和合成软骨素硫酸盐和 测定糖链长度以评价其体外抑制HIT抗体介导的血小板活化的能力 改善HIT小鼠模型中的血小板减少症。在目标1中，我们希望成功地分离和 表征多个功能类别的命中抗体，这将提出选择性检测的新方法 只有致病的。开发和优化一种使用患者自身血小板的诊断方法 AIM 2将改变基于血小板激活的HIT测试，将其从参考实验室转移到 环境到医院内的环境。最后，目标3中描述的研究将引入一类新的 HIT的治疗方法是硫酸软骨素，它可以预防血栓形成，但与目前的疗法不同，它不会 增加出血的风险。总之，我们预计这项提案的所有三个目标都将导致 对HIT的病理生理、诊断和治疗有重大影响。