Clinical Applications of Nitrite

亚硝酸盐的临床应用

• 批准号: 8553407
• 负责人: Alan Schechter
• 金额: $ 51.88万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8553407
• 关键词: Affect; American; Animal Model; Animals; Ascorbic Acid; Bacteria; Biological Assay; Biological Preservation; Blood; Blood Banks; Blood Cells; Blood Circulation; Blood Platelets; Blood Vessels; Blood flow; Brain; Breathing; Cardiac; Cell model; Cells; Cerebrovascular Circulation; Clinical; Clinical Protocols; Collaborations; Consumption; Coupling; Detergents; Diet; Disease; Drug Kinetics; Endothelial Cells; Enzymes; Erythrocytes; Erythropoietin; Excision; Exhalation; FDA approved; Ferricyanides; Food; Gene Expression; Goals; Grant; Half-Life; Hemoglobin; Hemolysis; Hour; Human; Hypoxia; Image; Individual; Infusion procedures; Institutional Review Boards; Ions; Laboratory Study; Lead; Lesion; Leukocytes; Lung diseases; Mammalian Cell; Mammals; Measures; Meat Products; Medicine; Methods; Microcirculation; Molecular Profiling; National Heart, Lung, and Blood Institute; Neurons; Nitrates; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Nitrites; Nutritional; Oral cavity; Organism; Pain; Pain Origin; Patients; Physiological; Plants; Plastics; Portugal; Procedures; Process; Production; Property; Publishing; Reaction; Red Cross; Relative (related person); Rodent; Role; Severities; Sickle Cell; Sickle Cell Anemia; Solutions; Stress; Sulfhydryl Reagents; Supplementation; System; Temperature; Testing; Therapeutic; Toxicology; Transfusion; United States National Institutes of Health; Venous; Whole Blood; Work; ascorbate; base; bench to bedside; brachial artery; cell type; clinical application; diaries; extracellular; falls; ferricyanide; improved; inhaled nitric oxide; inhibitor/antagonist; macrophage; microbiome; mouse model; neuronal cell body; nitrosyl hemoglobin; oxidation; protective effect; receptor; research study; sickling; volunteer

Among the studies recently completed to characterize the role of nitrite as a possible therapeutic option in situations where there is a relative deficiency of nitrite bioactivity are our studies with a mouse model of sickle cell anemia that we have been analyzing for a number of years and our studies in collaboration with the Department of Transfusion Medicine of the NIH Clinical Center on changes in nitrite levels in stored blood. The results with the animal model have been published and will not be summarized further here. In previous studies with human red cells, we found that upon removal of these cells from the body, levels of intracellular nitrite fell rapidly with a half life of less than an hour; we devised a preservation solution using ferricyanide, a thiol reagent and a detergent and could permanetly stabilize these levels. With these methods we found that human red cells normally have a nitrite concentration of about 300 nanomolar, while whole blood levels are about one-half of this, suggesting that most blood nitrite is in erythrocytes. Using these methods we have systematically measured nitrite and nitrate levels in stored whole blood, and red cells both with and without leukoreduction, to see the effects of other components of the blood on nitrite production and or consumption. We find that nitrate levels remain very constant at about 30 micromolar but, to our surprise, we find that the initial rapid fall in nitrite levels tapers and for as long as 42 days significant nitrite levels (about 50 nanomolar) remain in the stored red cells. The levels are comparable in all three methods of storage. We are now conducting studies to establish the mechanism of partial nitrite preservation in stored blood and to see if nitrite supplementation improves the properties of these red cells. In addition, several other studies with long term goals of defining clinical uses of nitrite are being done or being planned at present. We find no evidence of a role of S-nitrosated hemoglobin in the proposed "storage lesion" affecting red blood cells used for transfusion. In collaboration with the NIH Imaging Center we have been examining the effects of changes in nitric oxide levels on blood flow and function in the brains of rodents. We have worked out conditions so that there is no change in systemic or cerebral blood flow with the administration of a nNOS inhibitor but find that their are significant changes in brain function, which is restored with certain nitric oxide donors, including nitrite ions. We are now testing the pharmacological effects of nitrite on brain function and find that nitrite can restore neurovascular coupling. Further it appears that the high levels of intracellular and extracellular ascorbate in the brain may contribute to the reduction of nitrite to generate NO and we are now testing this hypothesis with rodents that can not synthesize ascorbate themselves and thus we can control ascorbate levels by exogenous administration. We have started a project with NHLBI, NINR, and the DTM of the Clinical Center to study the role of NO depletion in causing painful crises in sickle cell anemia patients. We are measuring levels of hemolysis and evidence of NO destruction by cell-free hemoglobin to see if these parameters correlated with manifestations of the disease. We have recently received an NIH Bench/Bedside grant for this work and have developed two clinical protocols which have been approved by the appropriate IRB to administer pain diaries to sickle cell patients, to measure nitrite, nitrate and exhaled NO levels in these patients as well as gene expression profiles in their leukocytes to see if we can identify markers of pain severity. In our project in collaboration with the American Red Cross to study the role of nitrite ions in the viability and storage of human platelets we have found that there is a small change in nitrate levels during five days of room temperature storage and that nitrite levels decrease but only about to 50% levels and then remain stable; some of this appears to be leached from the plastic of the storage bags. We are studying the significance of this finding and the need for nitrite ions in the retention of platelet viability during storage. We have also completed studies of the protective effects of erythropoietin on cardiac and other cells in culture and have shown that this agent protects against hypoxia and other stresses by increasing NO production (as measured by nitrite), especially in endothelial cells, as well as the erythopoeitin receptor itself. Lastly, as part of this work we have prepared and published two reviews of the state of nitrate and nitrite in the diet as having potential nutritional benefits in protecting against cardiac and other diseases. Although it is too early to know the long effects of such supplements, there is reason to be optimistic that they may be of benefit and the concerns that limited their use in the past were not significant.

在最近完成的研究中，亚硝酸盐作为一种可能的治疗选择，在亚硝酸盐生物活性相对缺乏的情况下，我们的研究与镰状细胞性贫血的小鼠模型，我们已经分析了多年，我们的研究与美国国立卫生研究院临床中心输血医学部合作，对储存血液中亚硝酸盐水平的变化。 动物模型的结果已发表，此处不再进一步总结。 在以前对人类红细胞的研究中，我们发现从体内取出这些细胞后，细胞内亚硝酸盐的水平迅速下降，半衰期不到一小时;我们设计了一种使用铁氰化物，硫醇试剂和洗涤剂的保存溶液，可以永久稳定这些水平。 通过这些方法，我们发现人类红细胞的亚硝酸盐浓度通常约为300纳摩尔，而全血水平约为这个浓度的一半，这表明大多数血液亚硝酸盐存在于红细胞中。 使用这些方法，我们系统地测量了储存的全血和红细胞中的亚硝酸盐和硝酸盐水平， 在没有白细胞减少的情况下，观察血液中其他成分对亚硝酸盐产生和/或消耗的影响。 我们发现硝酸盐水平保持非常恒定，约为30微摩尔，但令我们惊讶的是，我们发现亚硝酸盐水平的最初快速下降逐渐减少，并且长达42天，储存的红细胞中仍存在显著的亚硝酸盐水平（约50纳摩尔）。 所有三种储存方法中的水平相当。 我们现在正在进行研究，以建立储存血液中部分亚硝酸盐保存的机制，并观察亚硝酸盐补充剂是否能改善这些红细胞的特性。 此外，目前正在进行或计划进行其他几项旨在确定亚硝酸盐临床用途的长期目标的研究。我们没有发现证据表明S-亚硝化血红蛋白在影响输血用红细胞的“储存损伤”中的作用。 在与NIH成像中心的合作中，我们一直在研究一氧化氮水平的变化对啮齿动物大脑血流和功能的影响。我们已经制定了条件，使得在施用nNOS抑制剂的情况下全身或脑血流量没有变化，但发现它们是脑功能的显著变化，这是用某些一氧化氮供体（包括亚硝酸根离子）恢复的。 我们现在正在测试亚硝酸盐对大脑功能的药理作用，发现亚硝酸盐可以恢复神经血管耦合。此外，似乎脑中细胞内和细胞外抗坏血酸盐的高水平可能有助于亚硝酸盐的减少以产生NO，我们现在正在用自身不能合成抗坏血酸盐的啮齿动物来测试这一假设，因此我们可以通过外源性给药来控制抗坏血酸盐水平。 我们与NHLBI、NINR和临床中心的DTM一起启动了一个项目，研究NO耗竭在引起镰状细胞贫血患者疼痛危象中的作用。 我们正在测量溶血水平和无细胞血红蛋白对NO破坏的证据，以确定这些参数是否与疾病的表现相关。我们最近收到了NIH Bench/Bedside补助金 为了这项工作，我们已经开发了两个临床协议，这两个协议已经得到了适当的IRB的批准，用于对镰状细胞患者进行疼痛日记，测量这些患者的亚硝酸盐，硝酸盐和呼出的NO水平，以及他们白细胞中的基因表达谱，看看我们是否可以识别疼痛严重程度的标志物。 在我们与美国红十字会合作的项目中， 亚硝酸根离子在人血小板的存活力和储存中的作用我们已经发现，在室温储存的5天期间，硝酸根水平有很小的变化，亚硝酸根水平降低，但仅为约50%的水平，然后保持稳定;其中一些似乎是从储存袋的塑料中滤出的。 我们正在研究这一发现的意义，以及在储存过程中保持血小板活力对亚硝酸根离子的需求。 我们还完成了促红细胞生成素对培养的心脏细胞和其他细胞的保护作用的研究，并表明该试剂通过增加NO的产生（如通过亚硝酸盐测量的）来保护免受缺氧和其他应激，特别是在内皮细胞中，以及在内皮细胞中。 它本身就是一种新的受体。 最后，作为这项工作的一部分，我们准备并发表了两篇关于饮食中硝酸盐和亚硝酸盐状态的评论，认为它们在预防心脏病和其他疾病方面具有潜在的营养益处。虽然现在要知道这些补充剂的长期效果还为时过早，但有理由乐观地认为，它们可能是有益的，过去限制它们使用的担忧并不严重。