Bioengineering Design of Artificial Blood

描述（由申请人提供）：在第一阶段，本BRP中的工作证明，MP4（PEG修饰的血红蛋白）克服了基于修饰血红蛋白的血液替代品开发的最重要障碍，即血管收缩。MP4通过O2转运和维持功能性毛细血管密度的组合促进组织氧合，尽管其具有违反直觉的特性，包括增加O2亲和力、粘度和onglomerate压力。MP4在使动物从严重的、不受控制的出血中复苏的能力方面上级血液，并且在人体临床试验中已被证明是安全的。在本申请中，我们将测试MP4是血红素配体O2、一氧化碳（CO）和一氧化氮（NO）的有效载体的假设，并将进行相关的生理学研究，以了解其作为血液替代品的有效性并鉴定其使用的新的临床应用。我们将测试PEG-Hb制剂是血管扩张剂的假设，其以与Hb清除NO无关的方式与循环相互作用。我们建议，MP4的属性是部分由于增加亚硝酸还原酶活性和NO运输。我们将开发一种使用MP4输送CO的方法，并利用CO-MP4即使在高温下也非常稳定，使其在创伤现场使用中具有价值。项目1有一个GMP设施，提供一致的质量和性能的MP4。它将开发和生产新的PEG-Hb化合物，目标是在不增加胶体渗透压的情况下优化浓度，并增加O2输送能力，从而增加MP4在更广泛临床应用中的适用性。将通过生化分析、数学建模和大鼠全身实验（包括对心肌梗死的影响）筛选特性。项目2将研究PEG-Hbs对糖萼完整性的影响，PEG-Hbs的存在如何影响活性氧（ROS），并将研究PEG-Hb和增强血浆粘度的联合作用。MP4将用作CO的递送载体，以在缺血和出血期间提供细胞保护。微循环研究将使用清醒仓鼠窗室模型，直接测量O2和NO水平、血管流量和直径以及功能性毛细血管密度。这项研究结合了输血的生理分析，工程运输过程和机械转导的基础知识，以及两个实验室超过12年的合作经验。有效的血液替代品将大大提高民用和军事环境中输血的安全性和有效性，简化和简化输血医学。将开发一种新型血液替代品的应用，该替代品基于微血管流动、心脏和肾脏功能、内皮修复和血红素配体（O2、NO和CO）的递送的增强，提供对缺血的根本不同的治疗。

DESCRIPTION (provided by applicant): In the first period, work in this BRP demonstrated that MP4 (PEG-modified hemoglobin) overcomes the most significant hurdle to the development of modified hemoglobin-based blood substitutes, namely vasoconstriction. MP4 promotes tissue oxygenation through a combination of O2 transport and maintenance of functional capillary density in spite of its counterintuitive properties, including increased O2 affinity, viscosity and oncotic pressure. MP4 is superior to blood in its ability to resuscitate animals from severe, uncontrolled hemorrhage, and it has been shown to be safe in human clinical trials. In this present application we will test the hypothesis that MP4 is an effective carrier of the heme ligands O2, carbon monoxide (CO) and nitric oxide (NO), and will carry out the related physiological studies in order to understand its effectiveness as a blood substitute and identify new clinical applications for its use. We will test the hypothesis that PEG-Hb formulations are vasodilators which interact with the circulation in ways not related to NO scavenging by Hb. We propose that MP4's properties are in part due to an increased nitrite reductase activity and NO transport. We will develop a procedure for using MP4 to deliver CO and exploit that CO-MP4 is exceptionally stable, even at elevated temperatures, making it valuable in field use for trauma. Project 1 has a GMP facility that provides MP4 of consistent quality and properties. It will develop and produce new PEG-Hb compounds with goals to optimize concentration without increasing colloid osmotic pressure and augment O2 delivery capacity so as to increase the applicability of MP4 to a wider range of clinical uses. Properties will be screened via biochemical analysis, mathematical modeling, and systemic experiments in rats including the effect on myocardial infarction. Project 2 will examine PEG-Hbs' effects on the glycocalyx integrity, how PEG-Hbs' presence influences reactive O2 species (ROS), and will investigate the combined effect of PEG-Hb and enhanced plasma viscosity. MP4 will be used as a delivery vehicle for CO to provide cellular protection during ischemia & hemorrhage. Microcirculation studies will use the awake hamster window chamber model, with direct measurements of O2 and NO levels, flow and diameter in blood vessels and functional capillary density. This research combines physiological analysis of transfusion, fundamentals of engineering transport processes and mechanotransduction with the expertise of two laboratories with more than 12 years of collaboration. Effective blood substitutes will significantly increase the safety and efficacy of blood transfusions in civilian and military settings, streamline and simplify transfusion medicine. Applications for a new type of blood substitute will be developed, one that provides a fundamentally different treatment of ischemia, based on enhancement of microvascular flow, cardiac and renal functions, repair of the endothelium and delivery of heme ligands (O2, NO and CO).