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Red Blood Cell Function in Nitric Oxide Biotransport

红细胞在一氧化氮生物转运中的功能

基本信息

批准号：
7456844
负责人：
MAHENDRA KAVDIA
金额：
$ 20.78万
依托单位：
UNIVERSITY OF ARKANSAS AT FAYETTEVILLE
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-06-01 至 2011-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7456844
关键词：
Area Binding Bioavailable Biochemical Biological Availability Bioreactors Blood Substitutes Blood Vessels Cell Communication Cell membrane Cell physiology Chronic Consumption Data Development Electrodes Endothelium Erythrocytes Evaluation Experimental Models Functional disorder Goals Hemoglobin Hemolysis Immune response Knowledge Lead Measures Metabolism Methods Microcirculation Nitrates Nitric Oxide Nitrites Oxygen Physiological Physiology Platelet Aggregation Inhibition Play Production Public Health Pulmonary Hypertension Purpose Rate Reaction Regulation Research Research Personnel Role Septic Shock Sickle Cell Anemia Simulate Site Smooth Muscle Soluble Guanylate Cyclase Solutions Study models Testing Therapeutic aqueous base design glycosylated-nitric oxide complex hemoglobin A hemodynamics in vivo neurotransmission nitrate novel

项目摘要

DESCRIPTION (provided by applicant): Our long-term goal is to quantify nitric oxide (NO) transport in the microcirculation in physiology and pathophysiology. In vascular wall, endothelium-derived nitric oxide reaches smooth muscle where it can activate soluble guanylate cyclase (sGC) and modulate vascular tone. The level of bioavailable NO are maintained by its production and consumption in the microcirculation. Despite intense research on the transport of NO from the production site (endothelium) to the target site (smooth muscle), question remains on whether and how significant amount of endothelium-derived NO reaches smooth muscle in the presence of efficient NO scavenger red blood cells (RBCs) in vascular lumen. The proposed research will provide functional relationship between hemodynamic and biochemical parameters in NO and RBC interaction. The Specific Aims for the proposed research are 1) to determine the role of oxygenation on NO interaction with RBC and 2) to quantify the differences in NO end-products formation from NO interaction with free Hb and RBC Hb. Based on the preliminary data, the hypotheses we will test are that (a) NO interaction with oxygenated RBCs will result in higher nitrite formation rate as compared to nitrite formation rate of NO interaction with deoxygenated RBCs, (b) oxygenated RBCs will have higher total NO concentration as compared to total NO concentration of deoxygenated RBCs, and (c) hemoglobin bound in the RBC membrane (RBC-hemoglobin) will results in higher total NO concentration and thus will have higher NO bioavailability as compared to that of free hemoglobin solution or RBC solution containing small amount of free Hb. For testing these hypotheses, we will use a novel bioreactor that simulates in vivo interactions of NO and RBCs. We will compare interaction products of NO with oxygenated- and deoxygenated- RBCs, presence of free hemoglobin with RBCs, and free hemoglobin. We will measure the reaction products of NO including intermediate products (s-nitrosohemoglobin & nitrosyl-Hb) and end-products (nitrite & nitrate) using chemiluminescence method. We will measure the gaseous and aqueous NO concentration using an NO electrode. We will additionally use UV/Vis spectrophotometric spectrum to quantify these concentration. By designing a new experimental model for studying biochemical interactions of NO and RBCs, we will advance the knowledge of biomedical researchers on these molecular interactions. This may lead to evaluation of therapeutics in areas as diverse as sickle cell anemia, pulmonary hypertension, septic shock, and blood substitutes. PUBLIC HEALTH RELEVANCE: Nitric oxide (NO) plays important roles in numerous physiological functions including regulation of vascular tone, neurotransmission, immune response and inhibition of platelet aggregation. The proposed research will significantly advance our fundamental understanding of NO metabolism in the microcirculation and provide biomedical researchers a new experimental model for studying biochemical interactions of NO and RBCs. The proposed research will also quantify the effect of free Hb on the NO metabolism. This knowledge is critical to the development of hemoglobin based oxygen carrier and the understanding the effects of chronic hemolysis in sickle cell disease and pulmonary hypertension.

描述（由申请人提供）：我们的长期目标是量化生理学和病理生理学中微循环中的一氧化氮（NO）转运。在血管壁中，内皮源性一氧化氮到达平滑肌，在那里它可以激活可溶性鸟苷酸环化酶（sGC）并调节血管张力。生物可利用的NO水平通过其在微循环中的产生和消耗来维持。尽管对NO从产生部位（内皮）到靶部位（平滑肌）的转运进行了大量研究，但在血管腔中存在有效的NO清除剂红细胞（RBC）的情况下，是否以及如何显著量的内皮源性NO到达平滑肌仍然存在问题。本研究将提供血液动力学与生化参数在NO与RBC相互作用中的函数关系。所提出的研究的具体目的是：1）确定氧合对NO与RBC相互作用的作用; 2）量化NO与游离Hb和RBC Hb相互作用形成NO终产物的差异。基于初步数据，我们将检验的假设是（a）与NO与脱氧RBC相互作用的亚硝酸盐形成速率相比，NO与氧合RBC相互作用将导致更高的亚硝酸盐形成速率，（B）与脱氧RBC的总NO浓度相比，氧合RBC将具有更高的总NO浓度，和（c）结合在RBC膜中的血红蛋白（RBC-血红蛋白）将导致更高的总NO浓度，因此与游离血红蛋白溶液或含有少量游离Hb的RBC溶液相比，将具有更高的NO生物利用度。为了验证这些假设，我们将使用一种新型的生物反应器，模拟体内的NO和红细胞的相互作用。我们将比较NO与氧合和脱氧红细胞的相互作用产物，红细胞中游离血红蛋白的存在，以及游离血红蛋白。我们将用化学发光法测定NO的反应产物，包括中间产物（S-亚硝基血红蛋白和亚硝基血红蛋白）和终产物（亚硝酸盐和硝酸盐）。我们将使用NO电极测量气态和水溶液中的NO浓度。我们将另外使用UV/维斯分光光度光谱来定量这些浓度。通过设计一个新的实验模型来研究NO和红细胞的生物化学相互作用，我们将推进生物医学研究人员对这些分子相互作用的认识。这可能会导致在镰状细胞性贫血，肺动脉高压，感染性休克和血液替代品等不同领域的治疗评估。公共卫生关系：一氧化氮（NO）在调节血管张力、神经传递、免疫应答和抑制血小板聚集等多种生理功能中发挥重要作用。该研究将大大推进我们对微循环中NO代谢的基本理解，并为生物医学研究人员研究NO和RBC的生化相互作用提供新的实验模型。拟议的研究还将量化游离Hb对NO代谢的影响。这些知识对于血红蛋白氧载体的开发和理解慢性溶血在镰状细胞病和肺动脉高压中的作用至关重要。