PERINATAL PULMONARY HYPERTENSION: DEVELOPMENT MEDIATORS

描述(由申请人提供)：肺血流的急性变化(PBF)是外科手术修复许多先天性心脏病不可或缺的一部分。在单脑室解剖和生理学的患者中，术后流向肺和身体的血流平衡通常由各自血管床的阻力决定。事实上，术后血管阻力的动态变化可能会导致显著的发病率和死亡率，我们的许多治疗方法都集中在改变肺血管阻力，试图优化心输出量，同时保持足够的肺流量，以确保足够的全身氧合。在我们最初的项目中，我们描述了在先天性心脏病继发于羔羊的PBF增加的模型中，一氧化氮(NO)和内皮素-1(ET-1)信号的新的慢性变化和相互作用。我们最近已经证明，NO和ET-1也可能通过超氧化物依赖的机制相互强烈地相互调节，这些相互作用介导了胎儿PBF急性变化后血管张力的动态变化。根据我们的初步数据，我们假设在手术引起的PBF改变后，NO-ET-1的相互作用立即介导了肺血管阻力的动态变化。特别是，我们假设手术后PBF通过ETa受体信号通路，超氧化物介导的NO活性降低，ET-L诱导的血管收缩极限增加。在这一更新的应用中，我们将利用生理学、生化、细胞和分子的综合方法来研究这一假说及其在3个拟议目标中的作用机制。在目标1中，我们计划间接研究PBF和压力的变化对临床相关的整个动物模型中NO和ET-1基因表达和活性的影响，以及潜在的发育差异。在目标2中，我们将利用全动物模型、平滑肌细胞培养和内皮/平滑肌细胞共培养来研究NO/ET-1相互作用在调节PBF和压力变化中的作用，活性氧在这些相互作用中的潜在作用，以及潜在的发育差异。在目标3中，我们将利用全动物模型、内皮细胞培养和共培养来确定压力和流量在这一过程中的独立影响。更好地了解这些机制可能会改进围手术期的治疗策略，降低发病率和死亡率。

DESCRIPTION (provided by applicant): Acute changes in pulmonary blood flow (PBF) are an integral part of surgical repair of many congenital heart defects. In patients with single ventricle anatomy and physiology, the post-operative balance of blood flow to the lungs and body is often dictated by the resistances of the respective vascular beds. In fact, post-operatively the dynamic changes in vascular resistance can lead to significant morbidity and mortality, and much of our therapies are focused on altering pulmonary vascular resistance in attempt to optimize cardiac output while maintaining enough pulmonary flow to ensure adequate systemic oxygenation. In our initial project, we characterized novel chronic alterations and interactions in nitric oxide (NO) and endothelin-1 (ET-1) signaling during a model of increased PBF secondary to congenital heart disease in the lamb. We have recently demonstrated that NO and ET-1 may also acutely co-regulate each other, via a superoxide-dependent mechanism, and that these interactions mediate dynamic changes in vascular tone following acute changes in fetal PBF. Based on our preliminary data, we hypothesize that NO-ET-1 interactions mediate the dynamic changes in pulmonary vascular resistance immediately following surgically induced changes in PBF. In particular, we hypothesize that via ETA receptor signaling, superoxide-mediated decreases in NO activity and increased ET-l-induced vasoconstriction limit increases in PBF following surgery. In this renewal application, we will utilize an integrated physiologic, biochemical, cellular, and molecular approach to investigate this hypothesis and its mechanisms in 3 proposed Aims. In Aim 1, we plan to indirectly investigate the effect of changes in PBF and pressure on NO and ET-1 gene expression and activity in clinically relevant whole animal models, and potential developmental differences. In Aim 2, we will utilize whole animal models, smooth muscle cell cultures, and endothelial/smooth muscle cell co-cultures to investigate the effects of NO/ET-1 interactions in regulating changes in PBF and pressure, the potential role of reactive oxygen species in these interactions, and potential developmental differences. In Aim 3, we will utilize whole animal models, endothelial cell cultures, and co-cultures to determine the independent effects of pressure vs. flow in this process. A better understanding of these mechanisms may improve perioperative treatment strategies and reduce morbidity and mortality.