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ENHANCED GLYCOLYSIS FOR HYPOTHERMIC HEART PRESERVATION

增强糖酵解以保护低温心脏

基本信息

批准号：
6650874
负责人：
Sufan Chien
金额：
$ 36.81万
依托单位：
UNIVERSITY OF LOUISVILLE
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-09-01 至 2006-07-31
项目状态：
已结题

项目摘要

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.

该项目的最终目标是开发一种安全和长期保存器官的有效技术。这样做的具体目的是研究是在低温心脏期间增强糖酵解能量的产生储藏室。尽管经过了三十多年的广泛研究，安全保存时间因为心仍然很短促。这是两个主要缺陷的结果： 1)心脏在缺血期间的关键能量需求是大部分被忽视，2)几乎没有人注意到这样一个事实是糖酵解中的许多限速因子，因此，使用单一的化学物质可能并不有效。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。这一目标通过使用糖酵解中间体，1，6-二磷酸果糖(FDP)，绕过两个消耗ATP的步骤，通过添加AMP前体促进ATP的重新合成，并通过使用胰岛素来减少乳酸的产生。他们有证据表明将FDP添加到Euro-Collins或St.Thomas解决方案中可以显著提高低温保存大鼠和兔心脏，且FDP可通过以剂量依赖的方式影响细胞膜。尽管FDP已被用于组织缺血的效果令人印象深刻，它还没有用于心脏保存，而对其作用机制的研究也令人惊讶地肤浅和稀少。该假设将使用三种不同的方法进行评估：1)在常温和常温下常氧低氧下的心肌细胞低温，2)低温保存兔心脏，3)兔和狗的心脏移植。心肌细胞功能，FDP摄取和代谢，丙酮酸脱氢酶(PDH)活性、丙酮酸和乳酸的产生在心肌细胞培养中将检查细胞膜和线粒体的完整性。机械性能、组织生化完整性、酶释放、腺嘌呤核苷酸生产和消费，丙酮酸和乳酸生产，以及心脏保存过程中的组织学变化将被量化。这个项目将极大地提高我们对缺血和组织的了解保护，并提供一种机制，可以显著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并潜在起到有效的作用缺血时的组织保护剂，不仅在心脏保护和心脏停搏液，但也在其他缺血情况下，如休克，中风，冠心病和体外循环。