ENHANCED GLYCOLYSIS FOR HYPOTHERMIC HEART PRESERVATION

该项目的最终目标是开发一种安全， 长期保存器官的有效技术。其具体目的是 研究是在低温心脏期间增强糖酵解能量产生 存储. 尽管经过三十多年的广泛研究，安全保存时间 因为心脏仍然很短。这是两个主要缺陷的结果： 1)在局部缺血期间心脏的临界能量需求 大多数被忽视，2）很少注意到， 是糖酵解中的许多限速因素，因此， 单一化学品可能无效。 研究人员提出了一种改善心脏保护的新方法。他们的 一般的假设是低温心脏保存时间可以延长 通过提高糖酵解能量的产生。这一目标是通过使用 糖酵解中间体，果糖-1，6-二磷酸（FDP），以绕过两个 ATP消耗步骤，通过添加AMP前体促进ATP再合成， 以及通过使用胰岛素来减少乳酸盐的产生。他们有证据表明 将FDP添加到Euro-Collins或St.托马斯溶液中可以显著提高 FDP可通过大鼠和家兔心脏低温保存， 细胞膜以剂量依赖的方式。虽然FDP已用于组织 缺血具有令人印象深刻的结果，但它尚未用于心脏保存， 而对其作用机制的研究却令人惊讶地肤浅和缺乏。 该假设将使用三种不同的方法进行评估： 心肌细胞在常氧和缺氧在常温和 低温，2）在低温兔心脏保存中，和3）在兔和 犬心脏移植心肌细胞功能，FDP摄取和代谢， 丙酮酸脱氢酶（PDH）活性，丙酮酸和乳酸产生，和 在心肌细胞培养物中检查膜和线粒体的完整性。 机械性能、组织生化完整性、酶释放、腺嘌呤 核苷酸的产生和消耗，丙酮酸和乳酸的产生，以及 将在心脏保存中量化组织学变化。 这个项目将大大提高我们对缺血和组织的理解 保护，并提供一种机制，可以显着增加心脏 移植保存时间。这些糖酵解调节剂可能 产生协同效应， 缺血期间的组织保护剂，不仅用于心脏保存， 心脏停搏液，而且在其它缺血性病症，如休克，中风， 冠心病和心肺转流术。

The ultimate goal of this project is to develop a safe and effective technique for long-term organ preservation. The specific aim of this study is to enhance glycolytic energy production during hypothermic heart storage. Despite more than three decades of extensive research, safe preservation times for the heart remain very short. This is the result of two major deficiencies: 1) the critical energy requirement for the heart during ischemia has been mostly ignored, and 2) little attention has been paid to the fact that there are many rate-limiting factors in glycolysis, and, therefore, the use of a single chemical may not be effective. The investigators propose a new approach for improving heart protection. Their general hypothesis is that hypothermic heart preservation times can be extended by enhancing glycolytic energy production. This goal is achieved by using a glycolytic intermediate, fructose-1,6-diphosphate (FDP), to bypass two ATP-consuming steps, by adding AMP precursors to facilitate ATP re-synthesis, and by using insulin to reduce lactate production. They have evidence that adding FDP to Euro-Collins or St. Thomas solution can substantially enhance hypothermic heart preservation in rats and rabbits, and that FDP can cross the cell membrane in a dose-dependent fashion. Although FDP has been used in tissue ischemia with impressive results, it has not been used in heart preservation, and studies on its mechanism of action are surprisingly superficial and scarce. The hypothesis will be evaluated using three different approaches: 1) in cardiomyocytes in normoxia and hypoxia at normal temperature and during hypothermia, 2) in hypothermic rabbit heart preservation, and 3) in rabbit and dog heart transplantation. Cardiomyocyte function, FDP uptake and metabolism, pyruvate dehydrogenase (PDH) activity, pyruvate and lactate production, and membrane and mitochondrial integrity will be examined in cardiomyocyte culture. Mechanical performance, tissue biochemical integrity, enzyme release, adenine nucleotide production and consumption, pyruvate and lactate production, and histological changes will be quantified in heart preservation. This project will greatly enhance our understanding of ischemia and tissue protection, and provide a mechanism that could significantly increase heart preservation times for transplantation. These glycolytic modulators might produce a synergistic effect and serve potentially as effective tissue-protective agents during ischemia, not only in heart preservation and cardioplegia, but also in other ischemic conditions, such as shock, stroke, coronary heart disease, and cardiopulmonary bypass.