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: 10327638
• 负责人: David Richard Myers
• 金额: $ 38.55万
• 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/10327638
• 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; 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; base; clinical practice; cohort; demographics; diagnostic tool; 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.

项目概要/摘要 免疫性血小板减少性紫癜（ITP）的定义是在没有任何其他原因的情况下血小板计数低 每年影响超过 4,000 名美国儿童和 8,000 名成人。虽然大多数 ITP 案件都能得到解决 ITP 患者本身出血风险较高，10% 的患者经历大出血，并且 0.5% 的人经历危及生命的颅内出血。 ITP 没有生物标志物，甚至更少， 出血风险，并且所有治疗都会产生显着的副作用。这给临床医生留下了重要的 决定是否治疗的两难选择。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，低风险患者可能会遭受不必要的治疗副作用。 该提案的研究目标是研究一个新的假设，即收缩力 个体血小板与 ITP 出血表型相关，与传统使用的生物制剂无关 血液学功能的标记物或测定。使用新开发的高通量血小板收缩 细胞仪（PCC）并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 的儿科患者表明血小板力量 1) 与健康对照有显着差异， 2) 与出血密切相关（n=49 名患者），3) 同一患者随时间的变化（n=7）。使用 平均力截止值为 26nN，我们发现低力可识别 ITP 出血，灵敏度为 100% 特异性为 89.4%，仅考虑血小板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，并提议对 收缩力、血小板特征、临床特征和结果之间的关系 在单个时间点对一组新入组的 ITP 患者 (n=100) 进行为期 12 个月的前瞻性研究。 我们将具体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、治疗和缓解时间。 PCC 还提供了一个独特的机会，让您能够对患有以下疾病的患者的血小板功能有新的了解： ITP 和低力的机械基础。以前的研究作为血小板的传统工具受到阻碍 诸如聚集测定法、血小板功能分析仪或血栓弹力图等功能被混淆 ITP 中血小板计数低。我们将使用 PCC 来检验我们的假设，即内在血小板变化和 外在血浆因子改变血小板收缩力。从外部角度来看，我们的数据表明 IgG 与更严重的出血和更低的收缩力相关，此外，孵化 非自体血浆中的血小板导致收缩力较低。从内在的角度来看，我们有 研究发现，平均血小板体积低的患者血小板力较低，出血量增加。作为 机制基础尚不清楚，目标 2 旨在对这两个方面进行系统、公正的调查 可能调节血小板功能的内在和外在因素。