Clinical Applications of Nitrite and Nitrate

亚硝酸盐和硝酸盐的临床应用

基本信息

批准号：
10700665
负责人：
Alan Schechter
金额：
$ 64.5万
依托单位：
NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
依托单位国家：
美国
项目类别：
财政年份：
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/10700665
关键词：
Acute Adsorption Affect Agonist Animal Model Animals Ascorbic Acid Back Beets Biological Assay Blood Blood Platelets Blood Vessels Blood coagulation Blood flow Blood specimen Canis familiaris Chronic Clinical Clinical Research Collaborations Critical Care Diet Dietary Intervention Dietary Nitrite Disease Dry Eye Syndromes Enzymes Erythrocytes Exercise Eye Family suidae Food Frequencies Functional disorder Glaucoma Health Benefit Hemoglobin Hormones Human Human Microbiome Human Volunteers Hypoxia Individual Infusion procedures Ingestion Inhalation Institutional Review Boards Ions Isotopes Juice Label Laboratories Lacrimal gland structure Learning Legal patent Liquid substance Liver Lung Macular degeneration Mammalian Cell Mass Spectrum Analysis Measurement Measures Meat Products Medical center Medicine Metabolic Metabolic Pathway Metabolism Methods Muscle National Institute of Diabetes and Digestive and Kidney Diseases Nitrates Nitric Oxide Nitrites Nitrogen Oxides Nutritional Ophthalmology Oxygen Pathway interactions Patient Agents Patients Performance Persons Pharmaceutical Preparations Pharmacology Phosphorylation Physicians Physiologic Intraocular Pressure Physiological Plant Roots Plants Process Production Property Protocols documentation Publications Publishing Pulmonary Hypertension Pump Reaction Reporting Rest Retina Rodent Safety Sampling Sickle Cell Skeletal Muscle Study models Surface Surgeon Syndrome Testing Texas Thalassemia Therapeutic Therapeutic Agents Time Tissues Tracer United States National Institutes of Health Universities Vegetables Visit Work XDH gene absorption cardiovascular effects clinical application clinically significant dietary dietary nitrate eye pharmacology genetic manipulation human subject human tissue hypertensive improved inhaled nitric oxide metabolic abnormality assessment muscle physiology nutrition older patient oxidation preservation vascular bed vasodilator-stimulated phosphoprotein volunteer

项目摘要

The results of nitrite infusions in normal volunteers and NO inhalation in experimental animals suggest that NO can be transported as a hormone and thus has the potential to be a pharmacological agent (i.e., a drug). Howeve, the relatively small vascular effects of NO in our sickle cell patients is likely due to the presence of circulating hemoglobin and that this contributes to the pathophysiology of this and other chronic and acute hemolytic syndromes, especially the pulmonary hypertension complications which we have found to be severe and of high frequency in older patients. We also find that NO-bioactivity destruction appears to occur in tissues to a much greater extent than in the vascular bed. We have also been fortunate in being able to use the Critical Care Medicine Department canine facility and test inhaled nitrite and nitrate ions in hypoxic dogs to see if administering NO bioactivity in this way would be therapeutically possible. We tested nitrate as there is evidence that pulmonary tissue has some levels of enzymes, such as xanthine oxido-reductase that can reduce nitrate ions to nitrite and NO. We have found strong effects of nitrite inhalation on both pulmonary and systemic parameters, as has been reported for other animal models, but the effects of nitrate are only seen intermittently. These results have just been published. However, we also find that dietary limitations of nitrate and nitrite lower these levels greatly (more than in blood or liver and more than many genetic manipulations) and that return of these ions to the diet results in rapid accumulation and, indeed, in some cases an "overshoot" of the levels. Detailed metabolic studies of nitrate-nitrite-NO metabolism in animals and people require tracer studies which may be approached using non-toxic heavy isotopes. Our collaborators in Newcastle are developing protocols to do this in animals and eventually in human subjects. They have sent us samples from various animal ingestion studies and we are using our highly sensitive and accurate chemi-luminescence methods to quantity nitrate and nitrite levels in these blood samples. (One of their staff visited our laboratory for several weeks to learn how to do these assays.) Early human studies have examined the effects of ascorbic acid on dietary nitrate and nitrite absorption. Our collaborators in Bangkok have administered low levels of nitrite to thalassemia patients and we have worked with them to show that VASP phosphorylation is affected, as a parameter for measuring platelet inhibition (as described in DK 025104). Most encouraging, we have established a robust collaboration with a muscle physiology group in Exeter, UK and we have been measuring the levels of nitrate at rest and with exercise in the human tissues and have confirmed that our animal results obtain for human subjects, including the high levels of nitrate in muscle and its decrease with robust exercise. We believe that muscle levels of nitrate must be considered in dietary interventions, for pharmacological effects or for affecting performance. These results have also been recently published. Several new projects have very recently been initiated. First, we are working with groups at NIH who are studying the human microbiome to see if any of these agents have a particularly robust effect on NO metabolic pathways. We are also working with the NIDDK mass spectroscopy to follow 15N labelled nitrate in the various animal models. We have begun measuring nitrate and nitrite levels in whole rodent eyes as a beginning of measuring these levels in various compartments of the eye in larger animal models and perhaps in human samples. Our new results in porcine studies very importantly at MedStar suggest that the lacrimal glands pump nitrate ions from blood into the tears where several processes could convert it to nitrite and/or NO for adsorption into the eye. We have extensive studies planned with the Veterinary staff of MedStar to track NO metabolic pathways in these eyes and how administration of nitrate via various paths affect these levels. We believe that this process contributes to the normal function of the retina and eye and may be useful as therapy of conditions such as glaucoma and macular degeneration. Recently we have been working with the NIDDK mass spectrometry unit to study these processes with 15N-labeled nitrate. These animal model studies have led to clinical studies with the Department of Ophthalmology at the University of Texas Southwestern Medical Center to obtain tears from individuals with normal ocular function, and later with the "dry eye syndrome" and other conditions to see how our animal model results jibe with normal and abnormal human eye processes.

正常志愿者中亚硝酸盐输注的结果和实验动物中没有吸入的结果表明，不能将不作为激素运输，因此有可能成为药理学剂（即药物）。霍夫（Howeve），NO在我们的镰状细胞患者中的血管作用相对较小，可能是由于存在循环血红蛋白而导致的，这有助于这种以及其他慢性和急性溶血综合征的病理生理学，尤其是肺动脉高压并发症，尤其是我们发现的老年患者的频率很严重，并且老年患者的频率很严重。我们还发现，与血管床相比，没有生物活性破坏在组织中发生的程度要大得多。我们也很幸运能够使用重症监护医学部门犬类设施，并在低氧犬中测试吸入亚硝酸盐和硝酸盐离子，以查看是否可以治疗任何生物活性。我们测试了硝酸盐，因为有证据表明肺组织具有一定水平的酶，例如黄嘌呤氧化还原酶，可以将硝酸盐离子降低至亚硝酸盐，否。正如其他动物模型报道的那样，我们发现亚硝酸盐吸入对肺和全身参数的强烈影响，但硝酸盐的作用仅在间歇性地看到。这些结果刚刚发布。但是，我们还发现，硝酸盐和亚硝酸盐的饮食局限性大大降低了这些水平（比血液或肝脏中的饮食限制大大降低了这些水平，并且比许多遗传操作都大得多），并且这些离子返回饮食会导致快速积累，实际上，在某些情况下，在某些情况下是“过度冲刺”。对动物和人的硝酸盐非代谢的详细代谢研究需要使用无毒的重量同位素进行示踪剂研究。我们在纽卡斯尔的合作者正在开发协议，以在动物和人类受试者中进行此操作。他们向我们发送了来自各种动物摄入研究的样品，我们正在使用高度敏感和准确的化学致效率方法来对这些血液样本中的硝酸盐和亚硝酸盐水平进行数量。（他们的一名员工访问了我们的实验室数周，以学习如何进行这些测定法。）早期人类研究检查了抗坏血酸对硝酸饮食和亚硝酸盐吸收的影响。我们在曼谷的合作者对Thalassexymia患者的亚硝酸盐含量低，我们与他们合作表明VASP磷酸化受到影响，作为测量血小板抑制的参数（如DK 025104所述）。最令人鼓舞的是，我们与英国埃克塞特的肌肉生理组建立了强大的合作，我们一直在衡量静止和运动中的硝酸盐水平，并确认我们的动物成果是人类受试者获得的，包括肌肉中的硝酸盐水平的高水平及其在强大的运动中降低。我们认为，必须在饮食干预，药理作用或影响性能的情况下考虑硝酸盐的肌肉水平。这些结果也最近发布了。最近启动了几个新项目。首先，我们正在与NIH的小组合作，他们正在研究人类微生物组，以查看这些药物中的任何一种是否对无代谢途径具有特别强大的影响。我们还与NIDDK质谱法合作，遵循各种动物模型中标记为硝酸盐的15N。我们已经开始在整个啮齿动物的眼睛中测量硝酸盐和亚硝酸盐水平，作为在大型动物模型以及人类样品中的各种眼睛隔室中测量这些水平的开始。我们在猪研究中非常重要的是，我们在MEDSTAR上非常重要的结果表明，泪腺从血液中泵送到眼泪中，几个过程可以将其转换为亚硝酸盐和/或不将其转化为眼睛。我们计划与Medstar的兽医人员进行了广泛的研究，以跟踪这些眼睛中没有代谢途径，以及通过各种途径的硝酸盐给药如何影响这些水平。我们认为，这个过程有助于视网膜和眼睛的正常功能，并且可能是对青光眼和黄斑变性等疾病的治疗。最近，我们一直在与NIDDK质谱单元合作，用15N标记的硝酸盐研究这些过程。这些动物模型研究导致了德克萨斯大学西南医学中心眼科科的临床研究，以获得正常的眼功能的人的眼泪，后来又有“干眼综合征”和其他条件，以查看我们的动物模型如何导致正常和异常人类眼部的人的动物模型。