Hemoglobin-based antidotes for the treatment of carbon monoxide poisoning

项目摘要/摘要 一氧化碳中毒仍然是死亡和残疾的主要原因，影响到50,000人 仅在美国就待了一年。暴露在汽车或家用发电机尾气中的受害者被从火灾中转移或获救 只有两种选择：100%氧气或通过救护车或医疗后送直升机转移到专门的 配有应急高压氧舱的设施。因为大约只有300个高压氧 可用于一氧化碳中毒患者的中心，在进入和开始治疗方面固有的延误极大地限制了 功效。事实上，即使接受高压氧治疗，也有1-2%的患者死亡，25%的存活患者表现出 长期的神经认知损伤。目前还没有针对一氧化碳中毒的护理解毒剂。 在目前的提案中，Globin Solutions，Inc.将寻求完成一种新的临床前开发 基于人血红蛋白的高CO亲和力衍生物的CO中毒的解毒治疗， 包括剥离血红蛋白(S-Hb)和NEM修饰的Hb(NEM-Hb)。政府资助的持续工作 匹兹堡大学的NIH证明了极高亲和力的基于血红素的分子可以 从红细胞和组织线粒体中隔离一氧化碳，以逆转一氧化碳中毒的全身缺氧。 我们发现突变的人脑红蛋白(NGB)具有近乎不可逆转的CO结合亲和力。这 分子包括四个点突变(NGB-H64Q-CCC)，允许高浓度和静脉注射 输液。Ngb-H64Q-ccc与CO≈的结合强度是Hb的500倍。NGB-H64Q-CCC在CO-2中的输注 中毒小鼠体内红细胞一氧化碳排除量从25分钟增加到25秒，反转 低血压，存活率从不到10%增加到85%以上，随后肾脏迅速消除 共结合的NGB-H64Q-CCC。这些发现提供了概念的证据，即基于血红素的清道夫分子 具有很高的CO结合亲和力，可作为CO中毒的潜在解毒剂。在进一步的工作中，高 人血红蛋白的CO亲和衍生物，包括剥离的血红蛋白(S-Hb)和NEM修饰的 血红蛋白(NEM-Hb)可用于一氧化碳中毒的治疗。这些分子可以从 过期的血液单位以低成本。在这里，我们建议进行实验，以确定S-Hb的疗效和安全性 NEM-Hb对CO中毒小鼠模型的治疗作用性能最好的分子将进一步 发展成为一项全面的IND临床前计划：在小鼠身上确定药代动力学和安全性 和非人类灵长类动物；经认证的良好制造程序规模化生产；以及验证质量 并进行重复性分析。珠蛋白解决方案公司将利用最近的一轮首轮融资来分担成本 这笔拨款中建议的项目费用用于向美国FDA申请IND，并使其能够在人体试验中率先进行。 总体而言，这些拟议的研究符合NHLBI和NIH高度推进的使命 有影响力的、有意义的和新颖的研究，具有改善公共健康的巨大潜力。对这些功能的支持 提出的研究有可能改变我们目前对一氧化碳中毒患者的治疗模式。

Project Summary/Abstract Carbon monoxide (CO) poisoning remains a major cause of death and disability, affecting 50,000 persons a year in the U.S. alone. Victims removed from fires or rescued after exposure to car or home generator exhaust only have two options: 100% oxygen or transfer via ambulance or medical evacuation helicopter to a specialized facility with emergency hyperbaric oxygen chamber. As there are approximately only 300 hyperbaric oxygen centers available for CO poisoned patients, inherent delays in access to and initiation of therapy greatly limit efficacy. In fact, even with hyberbaric oxygen therapy, 1-2% of patients die and >25% of surviving patients exhibit long-term neurocognitive impairments. There is no point-of-care antidote for CO poisoning currently available. In the present proposal, Globin Solutions, Inc. will seek to complete preclinical development of a novel antidotal therapy for CO poisoning based on the use of high CO affinity derivatives of human hemoglobin, including stripped hemoglobin (S-Hb) and NEM-modified hemoglobin (NEM-Hb). On-going work funded by the NIH at the University of Pittsburgh demonstrates that extremely high affinity heme-based molecules can sequester CO from red blood cells and tissue mitochondria to reverse the systemic hypoxia of CO poisoning. We discovered a near-irreversible CO-binding affinity of mutationally engineered human neuroglobin (Ngb). This molecule includes four point mutations (Ngb-H64Q-CCC) allowing for high concentration and intravenous infusion. Ngb-H64Q-CCC binds CO ≈ 500 times more strongly than Hb. Infusions of Ngb-H64Q-CCC in CO- poisoned mice enhanced CO removal from red blood cells in vivo from 25-minutes to 25-seconds, reversed hypotension, increased survival from less than 10% to over 85%, and were followed by rapid renal elimination of CO-bound Ngb-H64Q-CCC. These findings provide proof of concept, that heme-based scavenger molecules with very high CO binding affinity can be developed as potential antidotes for CO poisoning. In further work, high CO affinity derivatives of human hemoglobin, including stripped hemoglobin (S-Hb) and NEM-modified hemoglobin (NEM-Hb) could be used for the treatment of CO poisoning. These molecules can be produced from expired blood units at a low cost. Here we propose experiments to determine efficacy and safety of S-Hb and NEM-Hb in the treatment of CO poisoning in our mouse models. The best performing molecule will be further developed into a full IND enabling preclinical program: determine pharmacokinetics and safety profiles in mouse and non-human primates; certified Good Manufacturing Procedure production at scale; and validating quality and reproducibility assays. Globin Solutions, Inc. will leverage a recent Series A funding round to cost-share the project expenses proposed in this grant for an IND application to the US FDA and to enable first in human trials. Overall, these proposed studies are in keeping with the mission of the NHLBI and NIH to advance highly impactful, significant, and novel studies that have great potential to improve the public health. Support for these proposed studies has the potential to change our current paradigm for the management of CO poisoning patients.