In-vivo Imaging of Calcium in the Heart

描述（由申请人提供）：钙（Ca2+）振荡是许多重要的细胞过程的基础，使器官功能，包括心脏收缩。Ca2+处理异常伴随大多数类型的心脏病理，并可能导致心室功能障碍和心律失常。该提案旨在开发一种新的成像技术来研究活动物Ca2+瞬态的时空异质性。我们将使用腺相关病毒血清型9 （AAV-9）稳定地将GCaMP2（一种最近开发的遗传编码Ca2+传感分子）传递到活体动物的心脏。然后，光纤探针（光电极）将被用于连续评估开胸和闭胸动物多个跨壁部位的Ca2+浓度。我们将检验在病理状态下Ca2+瞬态的跨壁变化有助于心功能障碍和心律失常的发展的假设。在Specific Aim 1中，将研究左冠状动脉前降支结扎过程中开胸兔缺血-再灌注模型中Ca2+瞬态的急性变化。在Specific Aim 2中，Ca2+瞬态的慢性变化将在起搏性心力衰竭的狗中进行研究。这些在心脏多个部位的原位Ca2+瞬态的时间和空间测量将提供深入了解在缺血和心力衰竭的情况下，异常Ca2+处理导致心功能障碍和心律失常的机制。公共卫生相关性：在美国，心脏病发作和心力衰竭仍然是导致疾病和过早死亡的主要原因。每次心跳时，钙触发收缩，心脏病发作和心力衰竭后，钙的调节是不正常的。在这项提议中，我们将开发一种方法来测量活动物心脏细胞中的钙浓度，并利用这项技术更好地了解钙异常如何导致心力衰竭和猝死。

DESCRIPTION (provided by applicant): Calcium (Ca2+) oscillations underlie many important cellular processes that enable organ function, including contraction in the heart. Abnormalities in Ca2+ handling accompany most types of cardiac pathology, and may contribute to both ventricular dysfunction and arrhythmias. This proposal is aimed at developing a novel imaging technology to study spatial and temporal heterogeneities in Ca2+ transients in living animals. We will use adeno-associated virus serotype 9 (AAV-9) to stably deliver GCaMP2, a recently developed genetically encoded Ca2+-sensing molecule, into the hearts of living animals. Fiber optical probes (optrodes) will then be used to serially assess Ca2+ concentration at multiple transmural sites in both open- and closed-chest animals. We will test the hypothesis that transmural variation in Ca2+ transients during pathological states contributes to the development of cardiac dysfunction and arrhythmias. In Specific Aim 1, acute changes in Ca2+ transients will be studied in an open-chest rabbit model of ischemia-reperfusion during ligation of the left anterior descending coronary artery. In Specific Aim 2, chronic changes in Ca2+ transients will be studied in dogs with pacing-induced heart failure. These temporal and spatial measurements of in-situ Ca2+ transients at multiple sites in the heart will provide insights into the mechanisms by which abnormal Ca2+ handling contributes to cardiac dysfunction and arrhythmias in the setting of ischemia and heart failure. PUBLIC HEALTH RELEVANCE: Heart attacks and heart failure remain leading causes of illness and premature death in the United States. Calcium triggers the contraction during each heart beat, and calcium regulation is abnormal after a heart attack and in heart failure. In this proposal, we will develop a method to measure calcium concentrations in the heart cells of living animals and use this technology to better understand how abnormalities in calcium contribute to heart failure and sudden death.