Leveraging platelet contraction cytometry for immune thrombocytopenia

利用血小板收缩细胞术治疗免疫性血小板减少症

• 批准号: 10548892
• 负责人: David Richard Myers
• 金额: $ 38.51万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-15 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10548892
• 关键词: Actins; Adult; Affect; Basic Science; Biological Assay; Biological Markers; Blood Coagulation Disorders; Blood Platelets; Cells; Characteristics; Child; Clinical; Clinical Data; Cytometry; Data; Development; Diagnostic; Disease remission; Enrollment; Exposure to; Fractionation; Genetic Transcription; Goals; Hematology; Hemorrhage; Idiopathic Thrombocytopenic Purpura; Immature Platelet; Immune; Immunoglobulin G; Immunologic Markers; Impairment; Incubated; Individual; Intracranial Hemorrhages; Investigation; Lead; Life; Life Experience; Longitudinal Studies; Measures; Monitor; Morphology; Myosin ATPase; Nature; Outcome; Outcome Study; PAC1 phosphatase; Patient Care; Patient risk; Patients; Phenotype; Physicians; Plasma; Platelet Activation; Platelet Count measurement; Platelet Function Tests; Platelet Transfusion; Platelet aggregation; Process; Proteomics; Publishing; Quality of Care; Research; Resolution; Risk; Sampling; Series; Specificity; Structure; Symptoms; Techniques; Testing; Thrombelastography; Thrombocytopenia; Thrombocytopenic Purpura; Time; Treatment Side Effects; Validation; Visit; Work; clinical practice; cohort; demographics; droplet sequencing; experience; high risk; improved; insight; novel; pediatric patients; platelet function; prospective; side effect; tool; unnecessary treatment

PROJECT SUMMARY/ABSTRACT Defined by low platelet count in the absence of any other cause, immune thrombocytopenic purpura (ITP) affects over 4,000 US children and 8,000 adults each year. While the majority of ITP cases resolve themselves, patients with ITP have an enhanced risk of bleeding, with 10% experiencing major bleeding, and 0.5% of experiencing life-threatening intracranial hemorrhage. There is no biomarker for ITP or much less, bleeding risk, and all treatments involve significant side effects. This leaves clinicians with a significant dilemma in deciding whether or not to treat. Patients who are ultimately at high risk may not receive treatment until serious bleeding occurs, and low risk patients may be exposed to unnecessary treatment side effects. The research objective of this proposal is to investigate a novel hypothesis, namely, that the contractile force of individual platelets correlates with bleeding phenotype in ITP, independent of traditionally used biological markers or assays of hematological function. Using a newly developed high-throughput platelet contraction cytometer (PCC) to measure single platelet contractile forces in parallel, our latest results of a study of pediatric patients with primary ITP suggests that platelet forces 1) vary significantly from healthy controls, 2) strongly correlate with bleeding (n=49 patients) and 3) change over time in the same patient (n=7). Using an average force cutoff value of 26nN, we found that low forces identified bleeding in ITP with 100% sensitivity and 89.4% specificity, with a specificity improvement to 94% when only considering patients with a platelet count <40,000 uL. Aim 1 builds on this preliminary data and proposes a rigorous investigation into the relationship between contractile force, platelet characteristics, clinical characteristics, and outcomes by studying a cohort of newly enrolled ITP patients (n=100) at a single time point and prospectively for 12 months. We will specifically see if platelet contractile force correlates with bleeding score, immature platelet fraction, platelet activation, platelet morphology, patient demographics, treatments, and time to resolution. The PCC also offers a unique opportunity to gain new insights into the function of platelets from patients with ITP and mechanistic underpinnings of low force. Previous studies were hindered as traditional tools of platelet function such as aggregometry, platelet functional analyzers, or thromboelastography are confounded by the low platelet count in ITP. We will use the PCC to test our hypothesis that both intrinsic platelet changes and extrinsic plasma factors modify platelet contractile force. From an extrinsic perspective, our data has shown that IgG correlates with more severe bleeding and lower contractile forces, and furthermore that incubating platelets in non-autologous plasma leads to lower contractile forces. From an intrinsic perspective, we have found that patients with low mean platelet volume have lower platelet force and increased bleeding. As the mechanistic underpinnings are unclear, Aim 2 seeks to perform systemic, unbiased investigation into both the intrinsic and extrinsic factors that may modulate platelet function.

项目总结/摘要 免疫性血小板减少性紫癜（ITP）定义为在没有任何其他原因的情况下血小板计数降低， 每年影响超过4,000名美国儿童和8,000名成年人。虽然大多数ITP病例都能解决 ITP患者本身出血风险增加，10%的患者发生大出血， 0.5%发生危及生命的颅内出血。ITP没有生物标志物或少得多， 出血风险，所有治疗都涉及严重的副作用。这给临床医生留下了一个重要的 决定是否治疗的两难境地。最终处于高风险的患者可能不会接受治疗 直到发生严重出血，低风险患者可能会暴露于不必要的治疗副作用。 这项建议的研究目的是调查一个新的假设，即， 单个血小板与ITP出血表型相关，独立于传统使用的生物学方法 血液学功能的标志物或测定。使用新开发的高通量血小板收缩 流式细胞仪（PCC）平行测量单个血小板收缩力，我们的最新研究结果， 患有原发性ITP的儿科患者提示血小板力1）与健康对照显著不同， 2)与出血密切相关（n=49例患者）; 3）同一患者随时间变化（n=7）。使用 平均力截止值为26 nN，我们发现低力识别ITP出血的灵敏度为100 和89.4%的特异性，当仅考虑具有血小板的患者时，特异性提高至94%。 计数<40，000 uL。目标1建立在这些初步数据的基础上，并提出了一个严格的调查， 收缩力、血小板特征、临床特征和结局之间的关系， 在单个时间点前瞻性研究一组新入组的ITP患者（n=100）12个月。 我们将特别观察血小板收缩力是否与出血评分、未成熟血小板分数、 血小板活化、血小板形态、患者人口统计学、治疗和消退时间。 PCC还提供了一个独特的机会，以获得新的见解，从患者的血小板功能， ITP和低力的机械基础。以往的研究作为血小板的传统工具受到阻碍 功能，如聚集测定法、血小板功能分析仪或血栓弹性描记术， ITP血小板计数低。我们将使用PCC来检验我们的假设，即固有的血小板变化和 外源性血浆因子改变血小板收缩力。从外在的角度来看，我们的数据显示， IgG与更严重的出血和更低的收缩力相关，此外， 非自体血浆中的血小板导致较低的收缩力。从内在的角度来看， 发现平均血小板体积低的患者血小板力较低，出血增加。为 机械基础尚不清楚，目标2旨在对这两个问题进行系统的，公正的调查， 可能调节血小板功能的内在和外在因素。