EPITHELIAL CELL ION TRANSPORT IN PERINATAL LUNGS

描述（改编自申请人的摘要）肺水肿是 急性和慢性呼吸衰竭的常见原因， 出生富含蛋白质的液体由于血管扩张而进入空气空间。 以及尚未发育完全的肺部上皮损伤。的 出生后从空气中清除液体的主要驱动力 进入肺循环的是主动钠转运通过 呼吸上皮既往对胎儿和新生儿肺的研究 提示呼吸道Na-K-ATPase活性异常 气管上皮细胞可能会减缓液体从肺中的清除， 早产目前尚不清楚出生后肺损伤如何影响这些 过程，也不知道这些过程如何运作，以调节肺 人类婴儿或非人类婴儿出生后的液体清除率 灵长类动物该项目的目的是确定 急慢性肺损伤对上皮细胞离子转运的影响 来自早产狒狒的气管和末端气囊，以及 看看这些效应如何影响肺部的液体吸收 流明该项目利用了一种独特的新生儿动物模型， 非人类灵长类动物早产后的肺损伤， 剖腹产，机械通气 直到出生后3周。具体目标集中在中央 假设从空气中吸收液体 发育中的肺是由通过呼吸道的主动Na转运驱动的 道上皮，早产后受损的过程， 机械通气氧疗继发肺损伤 浓缩气体该项目采用补充实验方法， 研究呼吸道上皮细胞离子转运的出生相关变化， 液体运动，以及出生后肺损伤对这些的影响 过程：（1）分离气道和远端肺上皮细胞 从胎儿和新生狒狒身上， 放射性标记离子（86 Rb，36 CJ，22 Na），存在或不存在 离子转运的各种抑制剂;（2）分子技术将 用于测量Na-κ ATP酶的α和B亚基的mRNA， 定量气管和远端肺中的Na-K-ATP酶蛋白丰度 上皮细胞;（3）免疫组织化学和原位杂交将 用于定位呼吸道上的Na-K-ATP酶和Na和Cl通道 有和无出生后肺的胎儿和新生狒狒的上皮 损伤;以及（4）切除的肺将用于测量净产量 （分泌和吸收）的基础下腔液体和 实验条件（有和没有先前的伤害，治疗 在出生前使用糖皮质激素，并用表面活性剂治疗）。这 调查应提供新的洞察力的可能作用 肺上皮功能障碍在肺水肿发病机制中的作用， 常发生在患有急性和慢性呼吸道疾病的新生儿中 痛苦综合症

DESCRIPTION (adapted from the applicants' abstract) Pulmonary edema is a common cause of acute and chronic respiratory failure after premature birth. Protein-rich liquid enters the airspaces as a result of vascular and epithelial injury in lungs that are not yet fully developed. The major driving force for postnatal removal of liquid from the airspaces into the pulmonary circulation is active Na transport across the respiratory epithelium. Previous work with lungs from fetal and newborn rabbits suggested that abnormal Na-K-ATPase activity in the respiratory tract epithelium might slow liquid clearance from the lungs after premature birth. It is unknown how postnatal lung injury affects these processes, nor is it known how these processes operate to regulate lung liquid clearance after birth either in human infants or in non-human primates. The purpose of this project is to determine the effects of acute and chronic lung injury on ion transport in epithelial cells derived from the trachea and terminal air sacs of premature baboons, and to see how these effects influence liquid absorption from the lung lumen. This project takes advantage of a unique animal model of neonatal lung injury after premature birth in non-human primates that are delivered by cesarean section and treated with mechanical ventilation for up to 3 weeks after birth. Specific aims focus on the central hypothesis that absorption of liquid from the airspaces of the developing lung is driven by active Na transport across the respiratory tract epithelium, a process that is impaired after premature birth and subsequent lung injury induced by mechanical ventilation with oxygen enriched gas. The project uses complementary experimental approaches to study birth-related changes in respiratory epithelial ion transport and liquid movement, and the influence of postnatal lung injury on these processes: (1) airway and distal lung epithelial cells will be isolated from fetal and newborn baboons in order to measure fluxes of radiolabeled ions (86Rb, 36CJ, 22Na) in the presence or absence of various inhibitors of ion transport; (2) molecular techniques will be used to measure MRNA for the cc, and B, subunits of Na-KATPase and to quantify Na-K-ATPase protein abundance in tracheal and distal lung epithelial cells; (3) immunohistochemistry and in situ hybridization will be used to localize Na-K-ATPase and Na and Cl channels on respiratory epithelium of fetal and newborn baboons with and without postnatal lung injury; and (4) excised lungs will be used to measure net production (secretion and absorption) of luminal liquid under basal and experimental conditions (with and without preceding injury, treatment with glucocorticoids before birth, and treatment with surfactant). This investigation should provide new insight into the possible role of pulmonary epithelial dysfunction in the pathogenesis of lung edema that often occurs in newborn infants with acute and chronic respiratory distress syndromes.