Control of Neonatal Circulation

新生儿循环的控制

基本信息

批准号：
8435653
负责人：
CHARLES W. LEFFLER
金额：
$ 38.97万
依托单位：
UNIVERSITY OF TENNESSEE HEALTH SCI CTR
依托单位国家：
美国
项目类别：
财政年份：
1985
资助国家：
美国
起止时间：
1985-04-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8435653
关键词：
Address Aftercare Agonist Antioxidants Asphyxia Asphyxia Neonatorum Astrocytes Attenuated Bilirubin Blood Circulation Blood Vessels Blood flow Brain Carbon Monoxide Cephalic Cerebrovascular Circulation Cerebrum Cessation of life Collection Coupling Data Depressed mood Detection Development Disease Endothelial Cells Excitatory Amino Acids Failure Family suidae Functional disorder Glutamates Healthcare Heme Human Hypoxia In Vitro Injury Intervention Intracranial Hemorrhages Investigation Ischemia Laser Scanning Confocal Microscopy Mass Fragmentography Measures Mediating Mediator of activation protein Mental Depression Microcirculation Modeling Morbidity - disease rate Muscle function Neonatal Neonatal Brain Injury Neurological outcome Newborn Infant Oxygenases Patch-Clamp Techniques Perinatal Perinatal Brain Injury Prevention Production Reactive Oxygen Species Regulation Reperfusion Therapy Research Ryanodine Receptors Seizures Signal Transduction Slice Smooth Muscle Smooth Muscle Myocytes Stimulus Survivors System Techniques Technology Testing Topical application Vasodilation arteriole cerebrovascular cost cytokine disability fetal heme oxygenase-1 heme oxygenase-2 improved in vivo inhibitor/antagonist injured mortality novel novel strategies prevent public health relevance research study response

项目摘要

DESCRIPTION (provided by applicant): Investigation of mechanisms involved in perinatal asphyxia-induced cerebrovascular dysfunction is important because fetal and neonatal asphyxia can cause of perinatal brain damage and failure of blood flow regulation is a critical component. Carbon monoxide (CO) from astrocyte heme oxygenase (HO) is important in regulation of newborn cerebral circulation and preliminary data suggest HO products can provide cerebrovascular and astrocytic protection from asphyxia-induced damage. The research proposed pursues the unifying hypothesis that, in newborn brain, asphyxia disrupts astrocyte CO signaling and cerebral arteriolar smooth muscle (VSM) Ca2+ signaling and/or BKCa channel activity causing cerebrovascular dysfunction, while elevation of cytoprotective CO and bilirubin limit the dysfunction. To test this hypothesis, four specific hypotheses will be tested using a novel asphyxia model in newborn pigs: 1. Asphyxia injures astrocytes causing loss of CO-mediated dilation of pial arterioles, 2. Asphyxia depresses cerebral VSM CO-induced Ca2+ sparks, BKCa channel activity, and dilation, 3. Reactive oxygen species (ROS) are major contributors to asphyxia-induced astrocyte and VSM injury, and 4. Cytoprotective CO and bilirubin reduce asphyxia-induced ROS and post-asphyxia astrocyte and VSM dysfunction. Techniques will be used that allow investigation of intact newborn cerebral microcirculation in vivo, isolated pressurized cerebral arterioles, and freshly isolated astrocytes, microvessels and smooth muscle cells. Such research is unique by studying intact cerebral circulation, production of CO by intact brain and isolated astrocytes and microvessels, and investigating, at the cellular level, mechanisms responsible cerebral vascular dysfunction. In addition, experimental interventions that may attenuate cerebrovascular malfunction caused by asphyxia are examined. Cranial windows allow observation of microcirculation, collection of cortical CSF and topical application of agonists, precursors and inhibitors. CO production in vivo and in vitro is identified and quantified by gas chromatography-mass spectrometry. Astrocytes, cerebral arterioles, and cerebral arteriole smooth muscle cells isolated from control and post-asphyxia brains allow study of ROS, CO production, arteriolar reactivity, and vascular smooth muscle function. Global cytosolic Ca2+ and Ca2+ sparks in brain slices, intact arterioles and VSM will be studied using fluorescent indicator technology with a dual excitation, single emission system and laser scanning confocal microscopy, respectively. Patch clamp techniques will be used to examine BKCa channel activity. These studies are important because disorders of the cerebral circulation in the newborn period are major causes of sickness and death and can result in lifelong disabilities in survivors.

描述（申请人提供）：围产期窒息引起的脑血管功能障碍的机制研究非常重要，因为胎儿和新生儿窒息可导致围产期脑损伤，而血流调节失败是一个关键组成部分。来自星形胶质细胞血红素加氧酶 (HO) 的一氧化碳 (CO) 对于调节新生儿脑循环非常重要，初步数据表明 HO 产品可以提供脑血管和星形胶质细胞免受窒息引起的损伤的保护。该研究提出了一个统一的假设，即在新生儿大脑中，窒息会破坏星形胶质细胞CO信号传导和脑小动脉平滑肌（VSM）Ca2+信号传导和/或BKCa通道活性，导致脑血管功能障碍，而细胞保护性CO和胆红素的升高则限制了功能障碍。为了检验这一假设，将使用新生猪的新型窒息模型来测试四个具体假设：1.窒息损伤星形胶质细胞，导致 CO 介导的软脑膜小动脉扩张丧失，2.窒息抑制脑 VSM CO 诱导的 Ca2+ 火花、BKCa 通道活性和扩张，3. 活性氧 (ROS) 是窒息引起的星形胶质细胞和 VSM 损伤的主要贡献者，4.细胞保护性 CO 和胆红素可减少窒息诱导的 ROS 以及窒息后星形胶质细胞和 VSM 功能障碍。将使用能够研究体内完整的新生儿脑微循环、分离的加压脑小动脉以及新鲜分离的星形胶质细胞、微血管和平滑肌细胞的技术。此类研究的独特之处在于，它研究了完整的脑循环、完整的大脑以及分离的星形胶质细胞和微血管产生的二氧化碳，并在细胞水平上研究了脑血管功能障碍的机制。此外，还研究了可能减轻窒息引起的脑血管功能障碍的实验干预措施。颅窗可以观察微循环、收集皮质脑脊液以及局部应用激动剂、前体和抑制剂。通过气相色谱-质谱法对体内和体外的 CO 产生进行鉴定和定量。从对照和窒息后大脑中分离出的星形胶质细胞、脑小动脉和脑小动脉平滑肌细胞可以研究 ROS、CO 产生、小动脉反应性和血管平滑肌功能。将分别使用具有双激发、单发射系统和激光扫描共聚焦显微镜的荧光指示剂技术来研究脑切片、完整小动脉和 VSM 中的整体胞质 Ca2+ 和 Ca2+ 火花。膜片钳技术将用于检查 BKCa 通道活性。这些研究很重要，因为新生儿时期的脑循环障碍是疾病和死亡的主要原因，并可能导致幸存者终身残疾。