The Effect of Angeli's salt on Acute Hemolysis in a Canine Model

安吉利盐对犬模型急性溶血的影响

• 批准号: 8952826
• 负责人: Charles Natanson
• 金额: --
• 依托单位: CLINICAL CENTER
• 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/8952826
• 关键词: Acute; Animals; Atherosclerosis; Binding; Biochemical; Blood; Blood Circulation; Blood Pressure; Blood flow; Breathing; Canis familiaris; Cardiac; Cell membrane; Cells; Cessation of life; Characteristics; Creatinine clearance measurement; Data; Endothelium; Equilibrium; Erythrocytes; Gases; Gastrointestinal tract structure; Goals; Health; Heart; Hemoglobin; Hemolysis; Human; Hypertension; Inflammation; Infusion procedures; Injury; Intravenous; Kidney; Laboratories; Measures; Methemoglobin; Modeling; Nitric Oxide; Nitric Oxide Donors; Nitrites; Organ; Oxidation-Reduction; Oxyhemoglobin; Paper; Peripheral; Peripheral Resistance; Physiological; Plasma; Property; Protocols documentation; Publishing; Pulmonary Vascular Resistance; Reaction; Recycling; Renal function; Risk; Role; Series; Smooth Muscle; Sodium Chloride; System; Testing; Therapeutic; Tissues; Vascular Endothelium; Vasodilation; Vasodilator Agents; Water; Whole Blood; design; heart function; hemodynamics; indexing; inhaled nitric oxide; iron nitrosyl; nitrosyl hemoglobin; pressure; prevent; vasoconstriction

The primary goal of this study is to determine the role of each component of whole blood (hemoglobin, stroma, hemoglobin + stroma) in the hypertension observed during hemolysis and then evaluate the therapeutic value of Angeli's salt (Na2N2O32-) in a canine model of acute intravascular hemolysis. Nitric oxide (NO) is a vasodilator which is constantly produced by the vascular endothelium. The amount of NO available in the circulation is, in part, regulated by the binding of NO to hemoglobin. Hemoglobin is normally contained within the red blood cell and reacts with nitric oxide at a relatively slow rate. However, the destruction of red blood cells within the circulation (intravascular hemolysis) causes the release of hemoglobin (cell-free hemoglobinh) from the red blood cell into the circulation. The cell-free hemoglobin released into the circulation during hemolysis binds to NO at a much faster rate than hemoglobin within the red blood cell. This binding of NO by cell-free hemoglobin disrupts the normal balance of NO available within the circulation resulting in vasoconstriction that decreases blood flow and leads to organ injury. Though it is not clear what role stroma (the contents of the red cell + the red cell membrane) has during hemolysis. This study will determine this role. In addition, Angeli's salt is known to react rapidly with hemoglobin to form, nitrosyl hemoglobin Fe(II)NO which does not bind NO. N2O3- (Angeli's Salt) NO2- + NO NO + Fe(II)-O2 (oxyhemoglobin in plasma) Fe(III) (methemoglobin) + Fe(III) + NO- Fe(II)-NO (iron-nitrosyl-hemoglobin) If the Angeli's salt can prevent the cell-free hemoglobin from binding NO, it may prevent the vasoconstriction and resulting organ injury that occurs during hemolysis. This study will test the ability of Angeli's salt to prevent cell-free hemoglobin binding of NO during hemolysis using the canine model of intravascular hemolysis that we successfully developed and used in two previous protocols. Our model uses a free water infusion to create intravascular hemolysis which mimics the physiologic and biochemical characteristics of acute intravascular hemolysis in the human. This model disrupts the red cell membrane within the circulation leading to the release of hemoglobin into circulation of the animal. In our model, acute intravascular hemolysis leads to changes in hemodynamics and organ function, i.e., increases in mean arterial pressure and systemic vascular resistance and decreases in heart and kidney function as measured by cardiac index and creatinine clearance respectively. Previous studies in our laboratory showed that elevated levels of cell-free hemoglobin consume NO, and therapy with inhaled nitric oxide or intravenous nitrite can limit the deleterious effects of intravascular hemolysis. Despite the demonstrated benefits, these two therapies have limitations. Inhaled nitric oxide is expensive, requires a specialized delivery system and is not readily available. Intravenous nitrite, although inexpensive and easy to administer, reacts slowly with cell free hemoglobin. Both therapies produce methemoglobin which thought not thought to be vasoactive promotes inflammation, is associated with atherosclerosis and can potentially undergo reduction and be recycled to free hemoglobin. When analyzing the effects of Angeli's salt, the action seems to have been mainly, or at least largely, due to its ability to vasodilate. Indeed, infusion of Angeli's Salt in the absence of hemolysis in this study led to substantial effects associated vasodilation whereas NO administration in the absence of hemolysis did not have this effect. In addition, while Angeli's Salt only resulted in conversion of about 20% of plasma Hb to metHb, NO inhalation led to about 80% conversion.40 Thus, both approaches could alleviate hemolysis-dependent vasoconstriction through both inactivation of vasoconstricting oxyHb and by compensatory vasodilating effects, but the degree to each of these contributes is different for each treatment. To better understand the role of cell free oxyHb and metHb in these reactions, we designed a study to determine the effects of cell-free metHb on vasocontriction and redox reactions. Our study suggest that both forms of cell-free hemoglobin are able to extravasate through endothelium and show vasoactivity outside the luminal space. We suspect that NO destruction outside of the luminal space, in the smooth muscle tissue, has a bigger effect on the observed mean blood pressure than changes in the lumen or that hemoglobin and its metabolites in tissues also have significant effects. Our study showed that cell-free metHb in the bloodstream should be considered as vasoactive substance, as it is converted into oxyHb, which can increase blood pressure by scavenging NO in the blood or tissues or by some still unclear mechanism. This series of studies has resulted in 4 published papers

这项研究的主要目的是确定全血（血红蛋白，基质，血红蛋白 +基质）在溶血期间观察到的高血压中的每个成分的作用，然后评估急性血管内血解性血液解体犬模型中Angeli盐（NA2N2O32-）的治疗价值。一氧化氮（NO）是一种血管扩张剂，由血管内皮不断产生。循环中没有可用的量部分由NO与血红蛋白的结合所调节。血红蛋白通常包含在红细胞内，并以相对较慢的速率与一氧化氮反应。然而，循环中红细胞的破坏（血管内溶血）导致血红蛋白（无细胞血红蛋白）从红细胞释放到循环中。 溶血期间释放到循环中的无细胞血红蛋白的结合速度比红细胞内的血红蛋白快得多。 通过无细胞血红蛋白的NO结合破坏了循环中NO的正常平衡，导致血管收缩减少血液流动并导致器官损伤。 尽管尚不清楚基质（红细胞 +红细胞膜的含量）在溶血中具有什么作用。这项研究将决定这一角色。此外，已知Angeli的盐与血红蛋白迅速反应形成，硝基血红蛋白Fe（II）不结合NO。 N2O3-（Angeli's Salt）No2- +否 NO + Fe（II）-O2（等离子体中的Oxyhehemoglobin）Fe（iii）（甲基血红蛋白） + Fe（III） + NO- FE（II）-NO（硝基 - 血红蛋白铁） 如果Angeli的盐可以防止无细胞的血红蛋白结合NO，则可以防止血管收缩和导致的器官损伤在溶血期间发生。这项研究将测试Angeli盐使用血管内溶血的犬模型在溶血过程中预防无细胞血红蛋白结合的能力，我们成功地开发并使用了两种先前的方案。我们的模型使用自由水输注来创建血管内溶血，从而模仿人类急性血管内溶血的生理和生化特征。 该模型破坏了循环中的红细胞膜，导致血红蛋白释放到动物的循环中。在我们的模型中，急性血管内溶血会导致血液动力学和器官功能的变化，即平均动脉压和全身血管抗性的增加，并分别通过心脏指数和肌酐清除率衡量心脏和肾功能。 我们实验室中先前的研究表明，无细胞血红蛋白消耗的水平升高，对一氧化氮或静脉一氧化硝酸盐的治疗可能会限制血管内溶血的有害作用。 尽管有证明的好处，但这两种疗法仍有局限性。 吸入一氧化氮很昂贵，需要一个专门的输送系统，并且不容易获得。 静脉注射亚硝酸盐虽然廉价且易于施用，但与无细胞的血红蛋白反应缓慢。 两种疗法都会产生高铁血红蛋白，认为不认为是血管活性会促进炎症，与动脉粥样硬化有关，并有可能减少并回收为游离血红蛋白。 在分析安吉利盐的影响时，该动作似乎主要是或至少是由于其血管舒张的能力。 实际上，在这项研究中没有溶血的情况下输注安吉利的盐会导致与血管舒张相关的实质性作用，而在没有溶血的情况下没有给药。此外，虽然安吉利的盐只会导致约20％的血浆Hb转化为MethB，但没有导致大约80％的转化。40因此，这两种方法都可以通过使oxoxyhb的血管造成的氧气和补偿性血管降低的效果来减轻依赖性血管依赖性血管收缩，但对于每个贡献了这些贡献，都有不同的贡献。 为了更好地理解无细胞无氧和MECHB在这些反应中的作用，我们设计了一项研究，以确定无细胞甲虫对血管结构和氧化还原反应的影响。我们的研究表明，两种形式的无细胞血红蛋白都能够通过内皮外出外出并在腔内空间外显示血管活性。我们怀疑，在平滑肌组织中，没有破坏对观察到的平均血压的影响比管腔的变化更大，或者在组织中的血红蛋白及其代谢物也具有重大影响。我们的研究表明，血液中无细胞的甲虫应被视为血管活性物质，因为它被转化为oxyhb，可以通过清除血液或组织中的NO或通过某些仍然不清楚的机制来增加血压。 这一系列研究导致了4篇发表论文