OXIDANTS, ENERGY AND PULMONARY VASCULAR DEVELOPMENT

（改编自申请摘要）由于 高氧暴露可能会对肺产生重要的负面影响， 新生儿的生长、发育和功能，如 支气管肺发育不良的肺部的可能性 常压高氧严重抑制能量代谢， 这是一个相当有争议的问题。但近期 三羧酸循环关键酶乌头酸酶的鉴定 作为被高氧快速有效抑制的靶点， 这种损害的一个例子可能对 肺的生长和功能。据推测， 三羧酸循环的关键酶乌头酸酶是高氧的关键 抑制能量（ATP）产生的事件，因此，肺 早产新生儿的细胞生长和功能。一氧化氮也可以 在这一过程中发挥了重要作用。此外，建议 这个过程可能会被夸大的过早，由于缺乏 重要的肺抗氧化防御。此外，有人建议， 抑制乌头酸酶失活或增强 其重新激活或通过其 替代机制，将恢复肺细胞的生长和功能。测试 这些假设，肺泡上皮细胞从妊娠晚期胎鼠 在基质上生长，并且在一些研究中，在存在下共培养， 活的基质细胞在漂浮的过滤器上，或胎儿肺外植体， 利用。 高氧和强氧对乌头酸酶的抑制作用 特异性抑制剂氟柠檬酸对能量产生、生长、细胞工作 如表面活性蛋白表达和脂质产生，以及表达 上皮源性生长因子在肺血管中的关键作用 血管内皮生长因子（VEGF）等生长因子都将被 评估。核磁共振和其他分析生化 技术将被用于实时确定能量， 持续暴露于高氧期间的中间代谢物，或 氟柠檬酸。在牛胎肺血管内皮细胞中， 乌头酸酶抑制对细胞能量状态、生长和生长- 将评估相关功能（VEGF受体的表达）。此外，本发明还 血管壁、平滑肌和其他细胞类型的敏感性 和成纤维细胞，能量受损和生长抑制，由于 将比较乌头酸酶抑制。根据这些研究，抗氧化剂 可能降低高氧引起的乌头酸酶失活的干预措施，或 增加其再激活，将评价潜在的姑息治疗 方面的影响.通过新的方法，这些研究将提供新的 关于高氧损害能量的机制的信息 在肺中的代谢和改变肺血管生长， 发展 此外，还可以因此开发姑息疗法。

(Adapted from the application's abstract) Impaired energy metabolism due to hyperoxic exposure may have important negative consequences for lung growth, development and function in the newborn such as the poorly developed, scarred lungs of bronchopulmonary dysplasia. The possibility that energy metabolism is seriously inhibited by normobaric hyperoxia has been an issue of considerable controversy. However, the recent identification of the critical tricarboxylic acid cycle enzyme aconitase as a target which is rapidly and potently inhibited by hyperoxia provides one example of such an impairment which may have devastating effects on lung growth and function. It is hypothesized that inactivation of the critical tricarboxylic acid cycle enzyme aconitase by hyperoxia is a key event which inhibits energy (ATP) production, and , consequently, lung cell growth and function in the premature newborn. Nitric oxide also could play a contributory role in this process. Further, it is proposed that this process may be exaggerated in the premature due to a deficiency of important lung antioxidant defenses. In addition, it is suggested that interventions which either inhibit aconitase inactivation or potentiate its re-activation or which facilitate energy production through its alternative mechanism, will restore lung cell growth and function. To test these hypothesis, alveolar epithelial cells from late gestation fetal rat grown on matrix, and, in some studies, co-cultured in the presence of living matrix cells on floating filters, or fetal lung explants, will be utilized. The effects of inhibition of aconitase both by hyperoxia and by the potent specific inhibitor fluorocitrate on energy production, growth, cell work such as surfactant protein expression and lipid production, and expression of epithelium-derived growth factors critical in pulmonary vascular development such as vascular endothelial growth factor (VEGF) all will be assessed. Nuclear magnetic resonance and other analytical biochemical techniques will be used to make real-time determinations of energy and intermediary metabolites during ongoing exposure to hyperoxia or flurocitrate. In bovine fetal pulmonary vascular endothelial cells, the effect of aconitase inhibition on cell energy status, growth, and growth- related function (expression of VEGF receptors) will be assessed. Further, the sensitivity of other cell types of the vascular wall, smooth muscle and fibroblast, to energy impairment and growth inhibition due to aconitase inhibition will be compared. Based on these studies, antioxidant interventions which may decrease aconitase inactivation by hyperoxia, or increase it re-activation, will be evaluated for potential palliative effects. Through novel approaches, these studies will provide new information about the mechanisms by which hyperoxia impairs energy metabolism in the lung and alters pulmonary vascular growth and development. In addition, palliative therapies could be developed as a result.