Glucocorticoid Programming of the Peripheral Vasculature

意义：我们将评估胎儿糖皮质激素（GC）暴露对正常个体发育成熟和终生外周血管的影响。NIH建议产前CG可加速胎肺成熟。GC暴露可增加绵羊外周血管收缩和胎儿血压。胎儿接触GC后即刻和终生外周血管效应的信息有限。我们在胎儿和成人的初步数据表明，并改变外周血管功能后，母体GC管理。我们提出了内皮素（ET）受体，ET受体A和ET受体B，一氧化氮（NO）和低氧血症的生理挑战的具体假设。我们有两个具体的假设，母亲给药地塞米松（DM）对这些终点的影响：1）一个单一的48小时DM过程开始于103天的妊娠（dGA，0.68妊娠-27周人类妊娠当量）改变胎儿外周血管反应; 3）从103 dGA开始的一个48小时的DM过程导致在3岁的成年生活中持续改变的外周血管反应。方法：长期仪器胎羊允许最强大的组合，从整个动物的基因功能的最先进的技术，以评估胎儿的影响和寿命规划在纵向时间和组织特异性的方式。我们将进行体内胎儿和成年羊的研究开始103 dGA，以确定胎儿和成人的区域血流使用微球和流量探针的产前GC编程的机制。将使用阻力血管丝肌造影术在体外研究血管反应性。我们将评估ET和NO在这些外周血管功能改变中的作用。我们将研究DM的影响后，一个单一的48小时课程。将在胎儿期和3岁时对动物进行研究。这种多学科的方法利用独特的基础设施动物，生理和生化实验室环境与体内，体外生理和分子工具，在基因，细胞和整个动物水平上研究关键的候选系统。研究者已经研究胎羊38年了。纽约大学的调查人员是一个综合小组，他们一起从康奈尔大学过渡过来。我们提供的证据表明：1）产前DM暴露改变了胎儿血管对ET和NO的反应和基因功能，2）导致3岁时血管反应的改变。在这次重新提交中，我们试图解决IRG的问题，并通过增加RT-PCR鉴定关键基因（与我们的假设和其他潜在候选基因相关的基因）的变化来加强工作，并根据胎儿性别改进我们对潜在差异的方法。

Significance: We will evaluate normal ontogenic maturation and lifetime peripheral vascular effects of fetal glucocorticoid (GC) exposure. NIH recommends antenatal CG to accelerate fetal lung maturation. GC exposure increases peripheral vasoconstriction and fetal BP in sheep. Information on immediate and lifetime peripheral vascular effects of fetal GC exposure is limited. Our preliminary data in both fetus and adult demonstrate and altered peripheral vascular function after maternal GC administration. We propose specific hypotheses for endothelin (ET) receptors, ET receptor A and ET receptor B, nitric oxide (NO) and the physiological challenge of hypoxemia. We have two specific hypotheses for effects of maternal administration of dexamethasone (DM) on each of these end-points: 1) a single 48h DM course beginning 103 days gestation (dGA, 0.68 gestation -27 wks human gestation equivalent) alters fetal peripheral vascular responses; 3) a single 48h DM course beginning 103 dGA results in persistent altered peripheral vascular responses in adult life at three years of age. Approach: Chronically instrumented fetal sheep permit the most powerful combination of state-of-the-art techniques from whole animal to gene function to assess both fetal effects and lifetime programming in both a longitudinal time and tissue specific manner. We will conduct in vivo fetal and adult sheep studies beginning 103 dGA to determine mechanisms of prenatal GC programming on fetal and adult regional blood flows using microspheres and flow probes. Vascular reactivity will be studied in vitro using resistance vessel wire myography. We will evaluate the role of ET and NO in these altered peripheral vascular functions. We will study DM effects following a single 48h course. Animals will be studied in both fetal life and at 3 years of age. This multidisciplinary approach utilizes a unique infrastructural animal, physiological and biochemical laboratory environment with both in vivo, and in vitro physiological and molecular tools to study critical candidate systems at gene, cellular and whole animal levels. The investigator has worked with fetal sheep 38 years. The NYU investigators are an integrated group that has made the transition from Cornell together. We provide evidence that 1) prenatal DM exposure alters fetal vascular responses to ET and NO and gene function, 2) results in altered vascular responses at 3 years of age. In this resubmission we have tried to address the IRG concerns and strengthen the work by addition of RT-PCR identification of changes in critical genes (both those related to our hypotheses and other potential candidates) and improved our approach to potential differences according to fetal sex.