GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY AND SEPSIS

葡萄糖-6-磷酸脱氢酶（G6PD）缺乏症是人类最常见的遗传多态性。一种临床上重要的变异是A型缺乏症，在10-12%的非裔美国人中存在。G6PD是细胞氧化还原状态的主要支持者。我们对年轻非裔美国创伤患者的临床调查显示，严重创伤后，A- G6PD缺乏症易导致菌血症败血症的发展，炎症反应增强，贫血恶化。这种缺陷也改变了创伤诱导的单核细胞反应。我们将探讨缺损对脓毒症相关的多器官功能障碍/衰竭和重大创伤后死亡率的影响。我们将测试红细胞功能受损和网状内皮/单核吞噬细胞系统激活状态的改变是否导致了这种缺乏的不良临床效果。该研究使用G6PD缺陷和非缺陷的人内皮细胞（HUVEC）、单核细胞和中性粒细胞以及动物模型。假设：1：严重创伤后，G6PD缺陷患者败血症相关死亡率高于非缺陷患者。G6PD缺陷患者的不良临床过程与单核细胞产生抗炎细胞因子减少、溶血增加和红细胞变形能力降低有关。这项前瞻性队列研究将比较G6PD缺陷和非缺陷患者在重大创伤后的临床参数（ISS bbbb13）以及代表白细胞促炎/抗炎平衡的细胞因子模式的时间依赖性变化。红细胞变形能力、脂质过氧化、亚硝基化蛋白、亚硝基硫醇和谷胱甘肽含量的变化也将随之发生。2：氧化应激后，G6PD缺陷的内皮细胞和单核细胞比非缺陷细胞表现出增强的促炎反应。氧化还原依赖性转录因子（NFkB,AP1,SP1）和氧化还原状态（GSH/GSSG）的激活以及伴随的细胞因子产生的变化将在缺血-再氧化或化学诱导的氧化应激后确定缺陷和非缺陷HUVEC和单核细胞。3. G6PD缺乏使内皮细胞的抗氧化能力比吞噬细胞的抗氧化能力下降更严重，从而导致吞噬细胞介导的内皮功能障碍增强。吞噬细胞介导的内皮细胞凋亡/损伤将在共培养中使用缺陷或非缺陷细胞进行测量。在动物模型中使用特定的G6PD抑制剂将测试内皮细胞功能障碍。研究将阐明G6PD缺乏症的临床不良反应是否表现为损伤后死亡率升高和器官功能障碍恶化。该研究将揭示重要的和新的潜在机制信息，包括红细胞功能障碍，单核细胞活化，氧化还原调节基因表达的作用，这些都是创伤患者G6PD缺乏症的不良临床效应的原因。

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human genetic polymorphism. A clinically significant variant is the type A deficiency present in 10-12% of African Americans. G6PD is a major supporter of cellular redox status. Our clinical investigations on young African American trauma patients revealed that after severe trauma, the type A- G6PD deficiency predisposes to the development of bacteremic sepsis, an augmented inflammatory response and worsens anemia. The defect also alters the trauma-induced monocyte responses. We will investigate the impact of the defect on the sepsis-associated multiple organ dysfunction/failure and mortality after major trauma. We will test if a compromised RBC function and an altered activation status of the reticolo-endothelial/monoculear phagocyte system contribute to the adverse clinical effects of the deficiency. The study use G6PD deficient and nondeficient human endothelial cells (HUVEC), monocytes and neutrophils and an animal model. Hypotheses: 1: After severe trauma, the sepsis-associated mortality is greater in G6PD deficient patients than non-deficient patients. The adverse clinical course of G6PD deficient patients is associated with a diminished production of anti- inflammatory cytokines by monocytes, increased hemolysis, and decreased RBC deformability. The prospective cohort study will compare the clinical parameters in G6PD deficient and nondeficient patients after major trauma (ISS>13) and the time dependent changes in cytokine patterns representative of the proinflammatory/anti-inflammatory balance in leukocytes. Alterations in RBC deformability, lipid peroxidation, nitrosylated protein, nitroso-thiol and glutathione content will also be followed. 2: After oxidative stress, G6PD deficient endothelial cells and monocytes display an augmented pro-inflammatory response compared to non-deficient cells. Activation of redox-dependent transcription factors ( NFkB,AP1,SP1) and redox status (GSH/GSSG) and the accompanying changes in cytokine production will be determined after ischemia- reoxygenation or chemically-induced oxidative stress in deficient and non-deficient HUVEC and monocytes. 3. G6PD deficiency diminishes the antioxidant capacity of endothelial cells more severely than the antioxidant capacity of phagocytes which results in an enhanced phagocyte-mediated endothelial dysfunction. Phagocyte-mediated endothelial cell apoptosis/injury will be measured in co-cultures using deficient or non-deficient cells. Using specific inhibitors of G6PD in an animal model will test endothelial cell dysfunction. The studies will elucidate if the adverse clinical effects of G6PD deficiency are manifested in elevated mortality and worsening organ dysfunction after injuries. The study will reveal important and novel information on the potential mechanisms, including RBC dysfunction, monocyte activation, and the role of redox regulated gene expression that is responsible for the adverse clinical effects of G6PD deficiency in trauma patients.