NOVEL PEG-HEMOGLOBIN MODIFICATION FOR BLOOD REPLACEMENT

这一第二阶段提案的目标是生产和测试根据第一阶段(HL 62818-01)配制的一种新的聚乙二醇化血红蛋白溶液，长期目标是将该溶液商业化，用于基于氧气传输和血液扩张特性的血液替代疗法。血红蛋白溶液的关键物理化学性质已被定义为在血液置换中有效发挥作用。这是由于没有血管收缩反应，这是一种副作用，这是目前处于临床试验中的商业血红蛋白氧气载体的规则，而不是例外。有效溶液的主要性质是：L)高粘度，2)高胶体渗透压，3)高氧亲和力。第一阶段研究使用新的马来酰亚胺聚乙二醇化化学法配制了一种特定的血红蛋白溶液。这一第二阶段的应用计划生产这种蛋白质的中试批次(特定目标1)，并使用人工毛细血管系统测试体外扩散氧传输(特定目标2)，在大鼠模型中评估血压反应、心输出量和预防组织缺氧(特定目标3)，以及评估对微循环的影响，包括功能毛细血管密度、血管直径、血管内和组织氧合的直接测量，以及仓鼠模型中的一氧化氮水平(特定目标4)。建议的商业应用：用聚乙二醇改性血红蛋白的方法有很大的潜力开发成用作血液替换液的商业产品。这种产品可以用于紧急情况、战时或任何无法获得血液的时候。此外，这种产品有可能价格低廉，并与接受者普遍兼容。

The goal of this Phase II proposal is to produce and test a new pegylated hemoglobin solution formulated under Phase I(HL 62818-01) with the long-term goal to commercialize this solution for blood replacement therapies based on oxygen transport and blood expansion properties. Critical physicochemical properties of hemoglobin solutions have been defined that work effectively at blood replacement. This is due to the absence of a vasoconstrictive response, a side-effect that is the rule rather than the exception for commercial hemoglobin-based oxygen carriers now in clinical trials. Key properties for an effective solution are: l) high viscosity, 2) high colloid osmotic pressure, and 3) high oxygen affinity. Phase I research formulated a specific hemoglobin solution using new, maleimide pegylation chemistry. This Phase II application proposes to produce pilot-scale batches of this protein (Specific Aim 1), and to test for in vitro diffusive oxygen transport using an artificial capillary system (Specific Aim 2), evaluation of blood pressure responses, cardiac output, and prevention of tissue hypoxia in a rat model (Specific Aim 3), and evaluation of effects on the microcirculation, including functional capillary density, vessel diameters, direct measurements of intravascular and tissue oxygenation, and NO levels in a hamster model (Specific Aim 4). PROPOSED COMMERCIAL APPLICATIONS: The method to modify hemoglobin with polyethylene glycol has significant potential to be developed into a commercial product for use as a blood replacement fluid. Such a product can be used in emergencies, wartime, or anytime blood is not available. Moreover, this product has the potential to be inexpensive and universally compatible with recipients.