NOVEL PEG-HEMOGLOBIN MODIFICATION FOR BLOOD REPLACEMENT

本II期提案的目标是生产和测试在I期（HL 62818-01）下配制的新型聚乙二醇化血红蛋白溶液，长期目标是将该溶液商业化，用于基于氧转运和血液膨胀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工作。这是由于没有血管收缩反应，这是一种副作用，对于目前在临床试验中的商业血红蛋白氧载体来说，这是规则而不是例外。有效溶液的关键性质是：1）高粘度，2）高胶体渗透压，和3）高氧亲和力。I期研究使用新的马来酰亚胺聚乙二醇化化学物质配制特定的血红蛋白溶液。该II期申请建议生产该蛋白质的中试规模批次（具体目标1），并使用人工毛细血管系统测试体外扩散氧转运（具体目标2），在大鼠模型中评价血压反应、心输出量和预防组织缺氧（具体目标3），以及评价对微循环的影响，包括功能性毛细血管密度、血管直径、血管内和组织氧合的直接测量，和仓鼠模型中的NO水平（具体目标4）。拟议的商业应用：用聚乙二醇修饰血红蛋白的方法具有开发成用作血液置换液的商业产品的显著潜力。这种产品可以在紧急情况下使用，战时，或任何时候血液无法获得。此外，该产品具有价格低廉和与接受者普遍相容的潜力。

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.