SODIUM TRANSPORT IN DISEASES CARDIOMYOCYTES--A NMR STUDY

疾病心肌细胞中的钠转运——核磁共振研究

• 批准号: 2219208
• 负责人: MARY D OSBAKKEN
• 金额: $ 23.21万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2219208
• 关键词: bioenergetics; diabetes mellitus; disease /disorder model; glycolysis; hyperlipidemia; hypertension; isolation perfusion; laboratory rat; nuclear magnetic resonance spectroscopy; ouabain; oxidative phosphorylation; sodium potassium exchanging ATPase

To define biochemical function in hearts cells, we have developed an isolated cardiomyocyte model which can be used in conjunction with NMR spectroscopy to continuously probe the interaction between real time metabolism and ion transport. We have done initial studies using P NMR to monitor energetic metabolites in conjunction with Na NMR to monitor sodium transport. Preliminary data suggest that discrete source and/or location (membrane vs cytoplasm) of cellular energy are critical to the maintenance of myocyte Na- gradients and that there are differences in this function in different models of disease (spontaneous hypertension (SH), diabetes mellitus (DM) and chronic hyperlipidemia (HPL) compared to controls. We proposed to further explore these mechanism by using inhibitors of Na transport (Na, K-ATPase inhibitors, such as ouabain), and specific inhibitors of energetics (2-deoxyglucose or iodoacetate to block glycolysis, oligomycin to block oxidative phosphorylation, and dinitrophenol to uncouple oxidative phosphorylation) alone and combined. Specific questions are: 1) What proportion of Na transport is supported by glycolytic versus oxidative processes, during normoxia or ischemia? 2) How are Na transport and bioenergetics correlates of these altered by disease states? 3) Are altered Na transporter processes the basis of specific pathophysiologic events? 4) Can Na ad P NMR be used to define these processes? To further use this model to investigate clinically relevant problems, additional studies will be done to evaluate the role of the myocyte (as opposed to endothelial, smooth muscle, and white blood cells) in preconditioning protection against the effect of prolonged ischemia. It is hypothesized that prolonged maintenance of Na,K, transport function is intrinsically involved in the preconditioning protection. Smaller increases in Nai during prolonged ischemia stabilized the membrane potential and decrease Na+ and Ca2+ exchange, thereby decreasing Ca2+ overload. Further, it is hypothesized that the protective effect is also related to maintenance of glycolytic function during and after prolonged ischemia. Both of these processes will be monitored with combined Na and P NMR. The goal of this project are two: 1) to demonstrate that specific abnormalities in Na transport are important determinants of cardiac pathophysiology; 2) to explore the use of NMR techniques as a diagnostic tool to evaluate pathophysiological processes with an "eye" to adapt these techniques for clinical use. These studies will allow delineation of the mechanisms and energetics of Na transport which will allow characterization of disease processes. Myocytes from controls rats and animal models of cardiovascular disease (DM, SH, HPL) will be studied under baseline conditions and during inhibition of specific transport and metabolic processes.

为了定义心脏细胞的生化功能，我们开发了一种 可与 NMR 结合使用的分离心肌细胞模型 光谱学连续探测实时之间的相互作用 新陈代谢和离子运输。 我们已经使用 P NMR 进行了初步研究 与 Na NMR 结合监测高能代谢物 钠运输。 初步数据表明离散源和/或 细胞能量的位置（膜与细胞质）对于 心肌细胞 Na 梯度的维持，并且存在差异 这种功能在不同的疾病模型（自发性高血压 (SH)、糖尿病(DM)和慢性高脂血症(HPL)比较 来控制。 我们建议通过使用进一步探索这些机制 Na转运抑制剂（Na、K-ATP酶抑制剂，例如哇巴因）， 和能量学的特异性抑制剂（2-脱氧葡萄糖或碘乙酸盐） 阻断糖酵解，寡霉素阻断氧化磷酸化，以及 二硝基苯酚单独或组合解偶联氧化磷酸化）。 具体问题是：1）支持Na运输的比例是多少 在常氧或缺血期间，通过糖酵解与氧化过程？ 2) Na 转运和生物能学相关性如何改变 疾病状态？ 3) 改变Na转运过程的基础 具体的病理生理事件？ 4) Na和P NMR可以用来定义 这些过程？ 为了进一步使用该模型来研究临床相关问题， 将进行额外的研究来评估肌细胞的作用（如 与内皮细胞、平滑肌细胞和白细胞相反） 预处理可防止长时间缺血的影响。 它 假设长期维持 Na、K 运输功能 本质上参与预处理保护。 较小 长时间缺血期间 Nai 的增加稳定了膜 电位并减少 Na+ 和 Ca2+ 交换，从而减少 Ca2+ 超载。 此外，据推测，保护作用也 与长时间服用期间和之后糖酵解功能的维持有关 缺血。 这两个过程都将通过 Na 和 核磁共振氢谱。 该项目的目标有两个：1）展示具体的 钠转运异常是心脏疾病的重要决定因素 病理生理学； 2) 探索使用核磁共振技术作为诊断 用“眼睛”来评估病理生理过程的工具来适应 这些技术可供临床使用。 这些研究将有助于描述其机制和能量学 Na 运输将允许描述疾病过程。 来自对照大鼠和心血管疾病动物模型的肌细胞 （DM、SH、HPL）将在基线条件下和期间进行研究 抑制特定的运输和代谢过程。