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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/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死亡率。区分“致病性”血小板激活的生化基础。抗体和“良性”非激活 HIT 抗体的关系尚不清楚。诊断挑战和过度使用非肝素替代抗凝药物会导致病情恶化尽管目前使用直接凝血酶治疗，但 HIT 的出血情况仍不理想。抑制剂：三分之一的受影响患者出现血栓，十分之一的患者死亡。将探索 HIT 病理生理学、诊断和治疗领域中尚未解答的关键问题。我们捕获了多种功能类别的 HIT 抗体的存在：(1) 致病性抗体识别 PF4 处理的血小板，对 PF4-肝素复合物有或没有反应，以及 (2) 良性腹肌识别 PF4-肝素，但不识别经 PF4 处理的血小板我们将识别并表征这些抗体。通过基于色谱法从患者样本中分离来进行分类，并将生成新型 HIT 单克隆抗体将测试每个功能类别中生成的单克隆抗体。 HIT 小鼠模型中的致病性和结果将与其血清学特征相关。处理正常供体血小板是一个重大挑战，限制了功能性“黄金”的可用性在目标 2 中，我们将使用患者自身的血小板开发一种快速 HIT 诊断测试。用 PF4/肝素治疗这将有助于“院内”HIT 诊断，从而及早发现这种情况。目前使用的非肝素替代抗凝剂不能解决最近发生的事件。 HIT：HIT 抗体激活血小板，因此突破性血栓形成常见于以下疾病。接受治疗的患者等因使用强效非肝素抗凝剂而导致意外出血。在目标 3 中，我们将使用各种硫酸化水平的血小板衍生和合成硫酸软骨素，糖长度来评估它们在体外抑制 HIT 抗体介导的血小板活化的能力，并改善 HIT 小鼠模型中的血小板减少症在目标 1 中，我们期望成功分离和表征 HIT 抗体的多种功能类别，这将提出选择性检测的新方法仅使用患者自身的血小板开发和优化诊断方法。目标 2 将改变基于血小板激活的 HIT 测试，将其从参考实验室移出最后，目标 3 中描述的研究将引入一类新的环境。 HIT 疗法，硫酸软骨素，可以预防血栓形成，但与目前的疗法不同，不会总之，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、诊断和治疗产生重大影响。