Red blood cell microparticles (RMPs) to reduce bleeding following hemorrhagic stroke

 描述(申请人提供)：自发性脑出血(SICH)是中风最致命的亚型。尽管SICH的发病率和死亡率很高，但目前尚无有效的治疗方法。血肿量与30天死亡率相关。持续脑出血导致血肿扩大的高峰出现在症状出现后的前3小时，40%的≈患者可能在发病后3至24小时内持续出血。防止SICH血肿扩大一直是一个很有吸引力的治疗靶点。JY博士(合作研究员)和他的团队研究红细胞衍生的微粒(RMP)作为止血剂已有十多年。RMP有可能被用作SICH的治疗剂，因为它们促进了活动性出血部位的凝血，部分是通过与血小板的相互作用和放大接触途径的激活。本项目的目标是(R21阶段)建立高压挤压法制备的RMP的纯度、稳定性、体外有效性和药代动力学，以及(R33阶段)在临床相关的SICH动物模型中确定RMP在减少血肿体积以及改善神经预后和死亡率方面的有效性。最终目标是将这些发现转化为临床实践，以减少SICH的发病率。我们假设Sich后RMP治疗将抑制血肿生长，改善长期神经预后，并降低Sich后死亡率。初步结果支持这一假设，在胶原酶诱导的SICH模型中，在24小时测量时，RMP治疗(胶原酶注射后1小时)有效地阻止了血肿的生长。我们针对这些目标的具体目标是：R21阶段：目标1：表征RMP的纯度、体外凝血活性和稳定性(保质期)。目的：建立RMP在大鼠体内的药动学和生物分布。R33期：目的3：确定RMP预防大鼠实验性脑出血后血肿生长的最佳治疗剂量。目的4：确定RMP给药的最佳(和最大)治疗时间窗。目的：验证RMP对更接近人类SICH的自发性高血压大鼠的治疗效果。在这项建议中，RMP的疗效将通过检测血肿体积(短期实验)或脑梗塞体积(长期实验)(主要结果)以及长期神经功能和死亡率(次要结果)来评估。根据初步结果，我们相信RMP治疗将减缓SICH动物模型中的血肿生长，并改善SICH后的神经学结果。所获得的结果将提供临床前证据，证明RMP在降低Sich病后血肿生长方面的有效性，也将为后续的动物研究，并最终为人类研究提供数据。

 DESCRIPTION (provided by applicant): Spontaneous intracerebral hemorrhage (sICH) is the deadliest subtype of stroke. Despite being the cause of significant morbidity and mortality, no effective treatment for sICH exists. Hematoma volume is shown to correlate with the 30-day mortality rate. Continued cerebral bleeding leading to hematoma expansion is highest in the first 3 hours after symptom onset and may continue in ≈40% of patients between 3 and 24 hours after the onset. The prevention of hematoma expansion in sICH has been an attractive therapeutic target. Dr. Jy (Co-investigator) and his group have studied red blood cell-derived micro particles (RMP) as hemostatic agents for over a decade. RMP have the potential to be used as a therapeutic agent in sICH since they promote clotting at sites of active bleeding, in part, by interaction with platelets and by amplifying activation of the contact pathway. The goals of this project are (R21 phase) to establish the purity, stability, in vitro efficacy, and pharmacokinetics of RMP prepared by the high pressure extrusion method, and (R33 phase) to establish the efficacy of RMP in reducing hematoma volume, as well as improving neurological outcome and mortality in clinically relevant sICH animal models. The ultimate goal is to translate these findings to clinical practice in order to reduce morbidity from sICH. We hypothesize that post-sICH RMP treatment will suppress hematoma growth and improve long-term neurological outcome and reduce post-sICH mortality. Preliminary results support this hypothesis in that RMP treatment (1 h post-collagenase injection) effectively prevented hematoma growth when measured at 24 h in a collagenase-induced sICH model. Our specific aims addressing these goals are: R21 phase: Aim 1: To characterize the purity, in vitro coagulant activity and stability (shelf-life) of RMP. Aim 2: To establish the pharmacokinetic profile and bio-distribution of RMP in rats. R33 phase: Aim 3: To determine the optimum therapeutic dose of RMP in preventing hematoma growth following experimental sICH in rats. Aim 4: To determine the optimal (and maximal) therapeutic time window for RMP administration. Aim 5: To validate the efficacy of RMP therapy in in diseased spontaneously hypertensive rats, which simulate human sICH more closely. In this proposal the efficacy of RMP will be evaluated by examining hematoma volume (short-term experiments) or infarct volume (longer-term experiments) (primary outcome), and long-term neurological function and mortality (secondary outcomes). Based on preliminary results we are confident that RMP therapy will mitigate hematoma growth, as well as improve neurological outcome following sICH in our animal model. The results obtained will provide pre-clinical evidence demonstrating the efficacy of RMP in lowering post-sICH hematoma growth, and will also provide data for subsequent animal and, ultimately, human studies.