Optical Mapping of Cardiac Electromechanics.
Optical Mapping of Cardiac Electromechanics.
复制标题
心脏机电的光学测绘。
DOI：
10.1016/j.bpj.2016.04.052
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发表时间：
2016
影响因子：
3.4
通讯作者：
Efimov,IgorR
中科院分区：
文献类型：
--
作者：
Kay,MatthewW;Efimov,IgorR
心脏生物物理学依赖于三个基本支柱：能量产生、电激发和机械功。心脏代谢、生物电和生物力学的研究在降低复杂性的各个层次上都非常富有成效，尤其是在组织、细胞和分子水平上。心脏的三个生物物理支柱协同工作，不能孤立地完全理解。然而，现有的实验方法是有限的，限制了我们同时研究它们的能力。我们经常被实验现实所迫，以降低心脏系统的复杂性，每次研究一个组件。荧光报告分子的光学图谱是当今心脏生物物理学研究的基石，因为它提供了有关跨膜电位、细胞内钙、线粒体内膜电位、NADH和其他关键生理参数的有价值信息（1）。许多代谢、生物电和生物力学机制汇聚在一起，为心脏的工作功能提供了基础，心脏将氧气和营养物质输送到整个身体。离体灌注心脏是研究心脏代谢、生物电和生物力学的宝贵准备材料（2，3）。然而，应用光学标测来研究灌注心脏中的心脏力学是有限的，因为荧光的记录需要抑制收缩以防止由跳动的心脏的运动引起的伪影。显然，这使得心脏力学的评估是不可能的。此外，在生物电研究中，心脏收缩通常通过阻断肌动球蛋白ATP酶而受到抑制，这会使心肌耗氧量降低四倍（4）。这种耗氧量的急剧减少显著减缓了代谢动力学，并改变了依赖于代谢率的细胞过程。在缺血和再灌注的光学标测研究中，这是一个特别重要的问题（5，6）。心脏研究界充分认识到光学标测的局限性，但开发新的光学标测技术，为正常收缩的心脏提供无伪影标测，一直是一个挑战。显然，光学标测的技术发展以心脏生物物理学的三个基本支柱的同时成像为目标。最近的进展包括动作电位的光学映射，同时增加RV应变（7），以及使用结构光在心动周期期间高速测量心外膜变形（8）。结构光成像提供三维心外膜变形的高空间和时间分辨率测量：
Cardiac biophysics rests on three fundamental pillars: energy production, electrical excitation, and mechanical work. Studies of cardiac metabolism, bioelectricity, and biomechanics have been very productive at all levels of reduced complexity, but especially at the levels of tissue, cell, and molecule. The three cardiac biophysical pillars work in concert and cannot be fully understood in isolation. However, available experimental methods are limited, restricting our ability to study them simultaneously. We are often forced by experimental reality to reduce the complexity of the cardiac system to study one component at a time. Optical mapping of fluorescence reporters is a cornerstone of presentday cardiac biophysics research, because it provides valuable information about transmembrane potential, intracellular calcium, mitochondrial inner membrane potential, NADH, and other critical physiological parameters (1). A multitude of metabolic, bioelectric, and biomechanical mechanisms converge to provide a foundation for the function of the working heart, which delivers oxygen and nutrients to the entire body. Excised perfused hearts are valuable preparations for studying cardiac metabolism, bioelectricity, and biomechanics (2, 3). Yet the application of optical mapping to study cardiac mechanics in perfused hearts is limited, because recordings of fluorescence require the suppression of contraction to prevent artifacts caused by the motion of a beating heart. Obviously, this makes the assessment of cardiac mechanics impossible. Furthermore, cardiac contraction is often suppressed in bioelectric studies by blocking the actomyosin ATPase, which drops myocardial oxygen consumption fourfold (4). This dramatic reduction in oxygen consumption significantly slows metabolic kinetics and alters cellular processes that depend upon metabolic rate. This is a particularly important issue in optical mapping studies of ischemia and reperfusion (5, 6).The limitations of optical mapping are well recognized by the cardiac research community, but the development of new optical mapping technologies that provide for artifact-free mapping of normally contracting hearts has been challenging. Clearly, the technical evolution of optical mapping progresses with a goal of simultaneous imaging of the three fundamental pillars of cardiac biophysics. Examples of recent progress include optical mapping of action potentials, while increasing RV strain (7), and highspeed measurements of epicardial deformation during the cardiac cycle using structured light (8). Structured light imaging provides high spatial and temporal resolution measurements of epicardial deformation in three dimensions: a requirement for accurate