PDF(Pubmed)
Abstract：
Trauma is the leading cause of death in individuals up to 45 years of age. Alterations in platelet function are a critical component of trauma-induced coagulopathy (TIC), yet these changes and the potential resulting dysfunction is incompletely understood. The lack of clinical assays available to explore platelet function in this patient population has hindered detailed understanding of the role of platelets in TIC. The objective of this study was to assess trauma patient ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model. We hypothesized that trauma patients would have flow-regime dependent alterations in platelet function. Blood was collected from trauma patients with level I activations (N = 34) within 60 min of hospital arrival, as well as healthy volunteer controls (N = 10). Samples were perfused through a microfluidic model of injury at venous and arterial shear rates, and a subset of experiments were performed after incubation with fluorescent anti-CD41 to quantify platelets. Complete blood counts were performed as well as plasma-based assays to quantify coagulation times, fibrinogen, and von Willebrand factor (VWF). Exploratory correlation analyses were employed to identify relationships with microfluidic hemostatic parameters. Trauma patients had increased microfluidic bleeding times compared to healthy controls. While trauma patient samples were able to deposit a substantial amount of clot in the model injury site, the platelet contribution to microfluidic hemostasis was attenuated. Trauma patients had largely normal hematology and plasma-based coagulation times, yet had elevated D-Dimer and VWF. Venous microfluidic bleeding time negatively correlated with VWF, D-Dimer, and mean platelet volume (MPV), while arterial microfluidic bleeding time positively correlated with oxygenation. Arterial clot growth rate negatively correlated with red cell count, and positively with mean corpuscular volume (MCV). We observed changes in clot composition in trauma patient samples reflected by significantly diminished platelet contribution, which resulted in reduced hemostatic function in a microfluidic model of vessel injury. We observed a reduction in platelet clot contribution under both venous and arterial flow ex vivo in trauma patient samples. While our population was heterogenous and had relatively mild injury severity, microfluidic hemostatic parameters correlated with different patient-specific data depending on the flow setting, indicating potentially differential mechanistic pathways contributing to platelet hemostatic capacity in the context of TIC. These data were generated with the goal of identifying key features of platelet dysfunction in bleeding trauma patients under conditions of flow and to determine if these features correlate with clinically available metrics, thus providing preliminary surrogate markers of physiological platelet dysfunction to be further studied across larger cohorts. Future studies will continue to explore those relationships and further define mechanisms of TIC and their relationship with patient outcomes.
摘要：
创伤是45岁以下个体死亡的主要原因。血小板功能的改变是创伤诱导的凝血病（TIC）的关键组成部分，然而，这些变化和可能导致的功能障碍还没有完全理解。缺乏可用于探索该患者群体中血小板功能的临床测定阻碍了对血小板在TIC中的作用的详细了解。这项研究的目的是在微流体模型中评估创伤患者离体流量依赖性血小板止血能力。我们假设创伤患者的血小板功能会有流动机制依赖性改变。在到达医院后60分钟内，从具有I级激活的创伤患者（N=34）收集血液，以及健康志愿者对照（N=10）。在静脉和动脉剪切速率下通过微流体损伤模型灌注样品,和一部分实验在与荧光抗CD41孵育后进行定量血小板。进行完整的血细胞计数以及基于血浆的测定以量化凝血时间，纤维蛋白原，和冯·维勒布兰德因子(VWF)。采用探索性相关性分析来确定与微流体止血参数的关系。与健康对照相比，创伤患者的微流体出血时间增加。虽然创伤患者样本能够在模型损伤部位沉积大量凝块，血小板对微流体止血的贡献减弱.创伤患者的血液学和血浆凝血时间基本正常，然而D-二聚体和VWF升高。静脉微流体出血时间与VWF呈负相关,D-二聚体,和平均血小板体积（MPV），而动脉微流体出血时间与氧合呈正相关。动脉血块生长速率与红细胞计数呈负相关,与平均红细胞体积（MCV）呈正相关。我们观察到创伤患者样本中的凝块组成变化反映在血小板贡献显著减少，这导致血管损伤的微流体模型中的止血功能降低。我们观察到创伤患者样本中离体静脉和动脉血流下血小板凝块的贡献减少。虽然我们的人口是异质的，伤害严重程度相对较轻，根据流量设置，微流控止血参数与不同患者特定数据相关，表明在TIC的背景下，有助于血小板止血能力的潜在不同机制途径。生成这些数据的目的是识别出血创伤患者在血流条件下血小板功能障碍的关键特征，并确定这些特征是否与临床可用指标相关。因此，提供了生理性血小板功能障碍的初步替代标志物，以供在更大的队列中进一步研究。未来的研究将继续探索这些关系，并进一步定义TIC的机制及其与患者预后的关系。
