Cell free Hemoglobin, lipid oxidation and Nitric oxide in Sickle Cell Disease

本项目将研究血浆血红蛋白在Sickle中观察到的血管反应改变中的作用。 细胞疾病（SCO）。红细胞溶解导致血浆血红蛋白水平增加，参与血管 功能障碍，这样的过程可能会导致血管并发症的SCO，如肺 高血压血红蛋白介导的血管功能障碍的机制包括一氧化氮（NO） 氧合血红蛋白清除和高铁血红蛋白脂质氧化，两者都存在于血浆中 上合组织患者。本提案的长期目标是了解溶血在 通过检查NO、脂质氧化和溶血之间的相互作用来研究SCO的病理学。我们假设 溶血将通过NO和脂质氧化途径介导血管功能障碍。这将是 在四个具体目标中解决：1）详细检查正常血浆中血红蛋白和血红素的命运， 上合组织患者的血浆检查正常人血浆的氧化态和氧化性， 在危机和一个月的后续行动与SCO的个人。2)研究NO和亚硝酸盐在 调节正常个体血浆中血红素介导的脂质氧化和抗氧化剂消耗， SCO患者3)亚硝酸盐对小鼠血浆脂质氧化及动脉功能的影响 严重SCO和遗传性球形红细胞增多症（HS）模型。4)检查二十二碳六烯酸的影响 (an omega-3脂肪酸对严重SCO小鼠模型血浆脂质氧化和血管功能障碍的影响 和HS。实验将在体外系统中进行，在使用来自SCO个体的血浆的系统中， 以及SCO和HS小鼠模型。HS小鼠表现出严重的溶血表型，但表现出不同的 比SCO小鼠的病理学。我们将使用这种比较来梳理由于 单独的溶血和需要SCO表型的其他方面的那些。专业技术 包括电子顺磁共振光谱、基于NO的化学发光 检测、极谱氧测量、液相色谱和其他分析和组织学 技术.实验将探讨溶血在SCO中的作用以及膳食营养不良的后果。 干预相对于NO和脂质氧化轴的假设。预计数据 从这些研究中获得的信息将为SCD的未来治疗提供有价值的信息。

This project will examine the role of plasma hemoglobin in altered vascular responses observed in Sickle Cell Disease (SCO). Red cell lysis leads to increases in plasma hemoglobin levels that participate in vascular dysfunction, and such processes may lead to vascular complications of SCO such as pulmonary hypertension. Mechanisms for hemoglobin-mediated vascular dysfunction include nitric oxide (NO) scavenging by oxyhemoglobin and lipid oxidation by methemoglobin, both of which are present in plasma from SCO patients. The long term objective of this proposal is to understand the role of hemolysis in the pathology of SCO by examining the interplay between NO, lipid oxidation and hemolysis. We hypothesize that hemolysis will mediate vascular dysfunction through both NO and lipid-oxidation pathways. This will be addressed in four Specific Aims: 1) Examine in detail the fate of hemoglobin and heme in normal plasma and plasma from individuals with SCO. Examine the oxidation state and oxidizability of plasma from normals and individuals with SCO both in crisis and at a one month follow-up. 2) Examine the role of NO and nitrite in modulating heme-mediated lipid oxidation and antioxidant depletion in plasma from normal individuals and patients with SCO. 3) Examine the effect of nitrite on plasma lipid oxidation and arterial dysfunction in murine models of severe SCO and hereditary spherocytosis (HS). 4) Examine the effects of docosahexaenoic acid (an omega-3 fatty acid) on plasma lipid oxidation and vascular dysfunction in murine models of sever SCO and HS. Experiments will be conducted in in vitro systems, in systems using plasma from SCO individuals, and in mouse models of SCO and HS. The HS mice gave a severe hemolytic phenotype but exhibit different pathology than the SCO mice. We will use this comparison to tease apart the effects that are due to hemolysis alone and those which require additional aspects of the SCO phenotype. Specialist techniques that will be used include electron paramagnetic resonance spectroscopy, chemiluminescence based NO detection, polarographic oxygen measurements, liquid-chromatography and other analytical and histological techniques. Experiments will explore the role of hemolysis in SCO and the consequences of dietary intervention with respect to both the NO and lipid oxidation axis of the hypothesis. It is anticipated that data derived from these studies will provide valuable information with regard to future treatments of SCD.