Effect of Hemopexin Therapy after Intracerebral Hemorrhage

 描述(申请人提供)：脑出血(ICH)占中风的10%-15%，并与显著的死亡率、发病率和经济成本有关。目前的治疗仅限于血肿清除、抗凝逆转、抗高血压治疗和支持性护理。死亡率统计数据证明了这一方法的不足，这些统计数据在过去20年中没有变化。越来越多的实验证据表明，血肿产生的毒素可能以延迟的方式导致了这种糟糕的结果。一种可能的毒素是高铁血红素，它从高铁血红蛋白中释放出来，以高微摩尔浓度存在于血肿中。对细胞外氯化血红素的主要防御是由血凝素(HX)提供的，这是一种糖蛋白，它以非凡的亲和力结合它，并减轻它的促氧化作用。PIS实验室最近的研究表明，与野生型小鼠相比，缺乏HX的小鼠在脑出血后遭受更严重的血肿周围损伤和神经功能障碍。然而，没有发表的研究评估外源性HX疗法在脑出血后的治疗潜力，可能是由于其可获得性有限和成本过高。这个项目的主要目标是在两个已建立的小鼠脑出血模型上测试HX治疗的效果，该项目由CSL Behring提供的n个无限制的纯化人类HX使之成为可能。初步实验表明，HX对血肿周围细胞有较强的保护作用。出血后注射。1)立体定向胶原酶或自体血注射诱导4-6月龄雄性和雌性小鼠纹状体脑出血。2或4小时后，随机将小鼠分成两组，分别用纯化的人HX或PBS载体对照进行腹腔注射。量化纹状体细胞活性、水和氯化血红素含量、血肿大小、炎性细胞数量、血脑屏障完整性、血肿周围血流，以及3天和8天后的行为缺陷。2)以年轻小鼠的剂量和时间窗结果为指导，测试18-20月龄小鼠的HX治疗效果，量化与年轻小鼠相同的结果指标和死亡率。希望该项目的结果将有助于确定脑出血后HX疗法的益处，并最终导致对一种目前几乎没有治疗选择的疾病过程进行临床试验。

 DESCRIPTION (provided by applicant): Intracerebral hemorrhage (ICH) accounts for 10-15% of strokes, and is associated with significant mortality, morbidity, and economic cost. Therapy is currently limited to hematoma evacuation when indicated, reversal of anticoagulation, antihypertensive therapy, and supportive care. The inadequacy of this approach is demonstrated by mortality statistics, which are unchanged over the past two decades. A growing body of experimental evidence suggests that toxins produced by the hematoma may contribute in delayed fashion to this poor outcome. One likely toxin is hemin, which is released from methemoglobin and is present in a hematoma in high micromolar concentrations. The primary defense against extracellular hemin is provided by hemopexin (Hx), a glycoprotein that binds it with extraordinary affinity and mitigates its pro-oxidant effect. Recent studies in the PIs laboratory have demonstrated that mice lacking Hx sustain more severe peri-hematomal injury and neurological deficits after ICH than their wild-type counterparts. However, no published studies have assessed the therapeutic potential of exogenous Hx therapy after ICH, likely due to its limited availability and prohibitive cost. The broad goal of this project, made feasible by n unrestricted gift of purified human Hx from CSL Behring, is to test the efficacy of Hx therapy in two established mouse ICH models. Preliminary experiments indicate that Hx has a robust protective effect on perihematomal cells when administered by i.p. injection after hemorrhage. Specific aims are as follows: 1) Induce striatal ICH by stereotactic collagenase or autologous blood injection in 4-6 month old male and female mice. Two or four hours later, randomly assign mice to treatment with purified human Hx or PBS vehicle control administered i.p. Quantify striatal cell viability, water and hemin content, hematoma size, inflammatory cell populations, blood-brain barrier integrity, perihematomal blood flow, and behavioral deficits 3 and 8 days later. 2) Guided by dose and time window results in younger mice, test efficacy of Hx therapy in 18-20 month old mice, quantifying the same outcome measures as in younger mice and also mortality rate. It is hoped that the results of this project will help to define the benefit of Hx therapy after ICH, and ultimately lead to clinical trials for a disease process that currently has few therapeutic options.