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

 描述（由申请人提供）：自发性脑内出血（sICH）是卒中中最致命的亚型。尽管sICH是显著发病率和死亡率的原因，但目前尚无有效的治疗方法。血肿体积与30天死亡率相关。导致血肿扩大的持续脑出血在症状发作后的前3小时内最高，约40%的患者可能在发作后3 - 24小时内持续出血。预防sICH的血肿扩大已成为一个有吸引力的治疗目标。Jy博士（合作研究者）和他的团队研究红细胞衍生微粒（RMP）作为止血剂已有十多年。RMP有可能用作sICH的治疗药物，因为它们部分通过与血小板相互作用和通过增强接触途径的激活来促进活动性出血部位的凝血。本项目的目的是（R21阶段）确定通过高压挤出法制备的RMP的纯度、稳定性、体外疗效和药代动力学，以及（R33阶段）确定RMP在临床相关sICH动物模型中减少血肿体积以及改善神经学结局和死亡率的疗效。最终目标是将这些发现转化为临床实践，以降低sICH的发病率。我们假设，sICH后RMP治疗将抑制血肿生长，改善长期神经系统结局并降低sICH后死亡率。初步结果支持这一假设，因为在胶原酶诱导的sICH模型中，当在24小时测量时，RMP处理（胶原酶注射后1小时）有效地防止了血肿生长。我们实现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（有效期）。目的2：建立RMP在大鼠体内的药代动力学和生物分布。R33阶段：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5：在更接近人类sICH的患病自发性高血压大鼠中验证RMP治疗的疗效。在本提案中，将通过检查血肿体积（短期实验）或梗死体积（长期实验）（主要结局）以及长期神经功能和死亡率（次要结局）来评价RMP的疗效。基于初步结果，我们相信RMP治疗将减轻血肿生长，并改善我们动物模型中sICH后的神经系统结局。获得的结果将提供临床前证据，证明RMP在降低sICH后血肿生长方面的疗效，还将为后续动物研究和最终人体研究提供数据。

 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.