Fetal Hypoxemia and Endothelium Derived Nitric Oxide

胎儿低氧血症和内皮源性一氧化氮

基本信息

批准号：
7640960
负责人：
LOREN P THOMPSON
金额：
$ 33.75万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
1993
资助国家：
美国
起止时间：
1993-05-01 至 2011-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7640960
关键词：
Adult Affect Age Anemia Angiopoietin-2 Animal Model Animals Apoptosis Birth Weight Blood Pressure Brain Cardiac Cardiac Myocytes Cardiac Output Cardiovascular system Carotid Arteries Cavia Cells Chronic Coronary Coronary Circulation Coronary artery Cyclic GMP Cyclic GMP-Dependent Protein Kinases Data Disease Environment Fetal Heart Fetus Gene Expression Gene Proteins Generations Heart Heart Ventricle Human Hypertension Hypoxemia Hypoxia IL6 gene Immunofluorescence Immunologic In Situ Nick-End Labeling Injury Ischemia Link Malnutrition Measures Mediating Messenger RNA Morbidity - disease rate Mothers Nitric Oxide Nitric Oxide Pathway Nitric Oxide Synthase Pathway interactions Perfusion Physiology Play Preparation Prevention Protein Analysis Protein Isoforms Proteins Recovery Reperfusion Therapy Research Personnel Risk Role Site Staining method Stains Stress Testing Time Vascular Endothelial Growth Factor Receptor-1 Vascular Endothelial Growth Factor Receptor-2 Vascular Endothelial Growth Factors Weight Weight Gain angiogenesis base cytokine fetal fetus hypoxia in utero inhibitor/antagonist mortality myocardial hypoxia offspring postnatal pregnant prenatal programs protein expression research study response stressor

项目摘要

DESCRIPTION (provided by applicant): Fetal hypoxia is a leading cause of fetal morbidity and mortality. The ability of the fetus to adapt to hypoxic stress is critical for its survival. Nitric oxide (NO) plays an important role in cardioprotection as an important modulator of both coronary flow and cardiac contractility, and gene expression of NO synthase (NOS) is hypoxia-sensitive. We hypothesize that chronic hypoxia upregulates the NOS pathway in fetal hearts inducing cardioprotection by increasing eNOS-derived NO in the coronary circulation and cardiac injury by iNOS-derived NO in the cardiomyocytes of the ventricle. To test this, pregnant guinea pigs will be exposed to chronic hypoxia (10.5%O2 for 14d duration) and hearts of fetuses will be examined in 5 specific aims: Aim 1) To test the hypothesis that chronic hypoxia increases coronary and cardiac gene expression of NOS and angiogenesis in the fetal guinea pig heart. Gene/protein expression of the NOS/cGMP/PKG pathway will be quantified and proteins localized using immunofluorescence in normoxic (NMX) and hypoxic (HPX) fetal hearts. Aim 2) To test the hypothesis that chronic hypoxia induces cardiac injury in the fetal guinea pig heart. Apoptosis (Bax/Bcl2 expression, TUNEL) and coronary angiogenesis (VEGF, VEGFR1, VEGFR2, Ang1, Ang2 expression) will be quantified and functional responses of coronary flow and contractile force measured in isolated fetal heart preparations. Aim 3) To test the hypothesis that in utero inhibition of iNOS-derived NO and ROS generation protects the fetal heart from hypoxia-induced injury. NOS and ROS inhibitors will be administered to pregnant mothers and the in utero effect on fetal heart gene expression and coronary/contractile function measured. Aim 4) To test the hypothesis that iNOS-derived NO stimulates ROS generation in isolated fetal cardiomyocytes (FCM). The mechanism of iNOS-derived NO in stimulating ROS will be studied in cultured FCM derived from NMX and HPX fetal hearts. Aim 5) To test the hypothesis that prenatal hypoxia increases arterial blood pressure in the guinea pig offspring via the iNOS pathway. Radiotelemetry of blood pressure and cardiac gene expression/functional responses of hearts of age-matched offspring will be measured. We propose that hypoxia alters NOS expression in the fetal heart contributing to adaptive and maladaptive responses, both pre- and postnatally. This will identify iNOS-derived NO synthesis as a target pathway for fetal survival.

描述（由申请人提供）：胎儿缺氧是胎儿发病和死亡的主要原因。胎儿适应缺氧应激的能力对其生存至关重要。一氧化氮（NO）作为冠状动脉血流和心肌收缩力的重要调节剂，在心脏保护中发挥着重要作用，并且一氧化氮合酶（NOS）的基因表达对缺氧敏感。我们推测，慢性缺氧上调胎儿心脏中的 NOS 通路，通过增加冠状动脉循环中 eNOS 衍生的 NO 诱导心脏保护，并通过心室心肌细胞中 iNOS 衍生的 NO 诱导心脏损伤。为了测试这一点，将怀孕的豚鼠暴露于慢性缺氧（10.5%O2，持续 14 天），并以 5 个具体目的检查胎儿的心脏：目的 1) 检验慢性缺氧会增加冠状动脉和心脏基因表达的假设。豚鼠胎儿心脏中的 NOS 和血管生成。将使用常氧 (NMX) 和低氧 (HPX) 胎儿心脏中的免疫荧光对 NOS/cGMP/PKG 通路的基因/蛋白质表达进行定量并定位蛋白质。目的 2) 检验慢性缺氧导致豚鼠胎儿心脏损伤的假设。将量化细胞凋亡（Bax/Bcl2 表达、TUNEL）和冠状血管生成（VEGF、VEGFR1、VEGFR2、Ang1、Ang2 表达），并测量离体胎儿心脏制剂中冠状动脉血流和收缩力的功能反应。目标 3) 检验以下假设：在子宫内抑制 iNOS 衍生的 NO 和 ROS 生成可保护胎儿心脏免受缺氧引起的损伤。怀孕母亲将接受 NOS 和 ROS 抑制剂的治疗，并测量其对胎儿心脏基因表达和冠状动脉/收缩功能的宫内影响。目标 4) 检验 iNOS 衍生的 NO 刺激离体胎儿心肌细胞 (FCM) 中 ROS 生成的假设。将在源自 NMX 和 HPX 胎儿心脏的培养 FCM 中研究 iNOS 衍生的 NO 刺激 ROS 的机制。目标 5) 检验产前缺氧通过 iNOS 途径增加豚鼠后代动脉血压的假设。将测量年龄匹配后代心脏的血压和心脏基因表达/功能反应的无线电遥测。我们认为缺氧会改变胎儿心脏中的 NOS 表达，从而导致出生前和出生后的适应性和适应不良反应。这将确定 iNOS 衍生的 NO 合成作为胎儿存活的目标途径。