High-Speed, Depth-Resolved Images of Cardiac physiology

心脏生理学的高速、深度分辨图像

• 批准号: 6795352
• 负责人: Guy Salama
• 金额: $ 42.52万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6795352
• 关键词: action potentials; arrhythmia; bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical equipment development; calcium flux; computer program /software; computer system design /evaluation; confocal scanning microscopy; fluorescent dye /probe; guinea pigs; heart cell; heart electrical activity; heart function; heart imaging /visualization /scanning; image processing; laboratory rabbit; myocardium; optics; reagent /indicator

DESCRIPTION (provided by applicant): The long-term goal of this Bioengineering Research Partnership (BRP) is to develop a High-Speed, Depth-Resolved Imager (HSDRI) to map electrical activity or intracellular free Ca 2+ transients inside the myocardium of perfused hearts. The partnership consists of 3 groups. Dr. Guy Salama (PI at the University of Pittsburgh) will administer the BRP, develop the instrument and apply the new technology to problems in cardiac electrophysiology, that remain unresolved due to a lack of 3-D information. Drs. Alan Waggoner (at Carnegie-Mellon University, Director of the Center for Light Microscope Imaging and Biotechnology (CLMIB)) and Lauren Ernst will develop optical probes (voltage-sensitive and Ca2+ indicator dyes) with long excitation and emission wavelengths to improve tissue penetration and reduce light scattering from the myocardium. Dr. Fred Lanni (at CLMIB) will provide the theoretical and engineering expertise to develop and refine the HSDRI. The 3 groups will work in parallel. Aim 1 (Salama and Lanni, years 1-5): Two approaches will be developed and tested to obtain the best possible HSDRI system. (a) A system based on a Ronchi line grating to focus dark and bright bands in a focal plane 2-5 mm deep in ventricular tissue. Fluorescence images from the tissue will be taken (at 3k frames/s) during shifts of bright and dark bands of light excitation by 1/3 period. Images will be processed on-line to eliminate light emanating above and below the plane of focus to obtain depth-resolved images, at 1k frames/s. (b) A standard Nipkow spinning disk confocal imager will be modified for large fields-of-view (3x3 mm 2)and high frame rates. Aim 2 (years 1-5): Drs. Waggoner and Ernst will synthesize new longer wavelength fluorescent dyes to monitor action potentials (APs) or cytosolic free Ca2+(Cai) and Dr. Salama will test, analyze the spectral characteristics and response characteristics of the new probes in heart muscle. Aim 3 (Salama, Choi and Lanni years 1-5): Software will be developed to drive the HSDRI, analyze APs and Ca-i transients and map electrical activity in 3-D. Depth-resolved maps of activation, repolarization and AP durations will be used to investigate 2 topics in cardiac electrophysiology, where measurements in 3-D are essential to elucidate fundamental concepts. A) We will investigate the factors that modify electrical coupling (time-delay or block) between Purkinje fibers (P), Transitional (T) and Ventricular (V) cells to elucidate the role of PV junctions in the initiation and maintenance of arrhythmias. APs will be mapped in 3-D to resolve PV delays during antegrade and retrograde conduction, normoxic and ischemic in paced and during arrhythmias. B) Impulse propagation across the atrio-ventricular node (AVN) has been difficult to trace because of the complex 3-D structure of the node and the small region of compact cells. Activation maps of the AVN in 3-D will help us answer basic questions regarding the precise inputs to the node (fast and slow pathways), mechanisms of AVN reentry, Wenckebach periodicity and Wolf-Parkinson syndrome. Fast, depth-resolved images of voltage and Ca 2+are a powerful new tool that will have a wide range of applications in cardiac electrophysiology and can be extended to neuronal networks and other organ systems. We focus here on the heart because therein lie salient problems that are ready to be addressed by this new technology. However, the wide range of possible applications may lead to the commercialization of this new technology.

描述（由申请人提供）：该生物工程研究合作伙伴关系 (BRP) 的长期目标是开发高速深度分辨成像仪 (HSDRI)，以绘制心肌内的电活动或细胞内游离 Ca 2+ 瞬变图。灌注的心。该伙伴关系由 3 个小组组成。 Guy Salama 博士（匹兹堡大学 PI）将管理 BRP、开发该仪器并将新技术应用于心脏电生理学问题，这些问题由于缺乏 3D 信息而仍未得到解决。博士。 Alan Wagoner（卡内基梅隆大学，光学显微镜成像和生物技术中心 (CLMIB) 主任）和 Lauren Ernst 将开发具有长激发和发射波长的光学探针（电压敏感和 Ca2+ 指示剂染料），以改善组织穿透和减少心肌的光散射。 Fred Lanni 博士（CLMIB）将提供理论和工程专业知识来开发和完善 HSDRI。 3个小组将并行工作。目标 1（Salama 和 Lanni，1-5 年）：将开发和测试两种方法以获得最佳的 HSDRI 系统。 (a) 基于 Ronchi 线光栅的系统，用于将暗带和亮带聚焦在心室组织中 2-5 毫米深的焦平面上。在光激发的亮带和暗带移动 1/3 周期期间，将拍摄组织的荧光图像（以 3k 帧/秒）。图像将被在线处理，以消除焦点平面上方和下方发出的光线，从而以 1k 帧/秒的速度获得深度分辨图像。 (b) 标准 Nipkow 转盘共焦成像仪将进行修改，以实现大视场 (3x3 mm 2) 和高帧速率。目标 2（1-5 年）：Drs. Wagoner 和 Ernst 将合成新的较长波长荧光染料来监测动作电位 (AP) 或胞质游离 Ca2+(Cai)，Salama 博士将测试、分析新探针在心肌中的光谱特性和响应特性。目标 3（Salama、Choi 和 Lanni 1-5 年级）：将开发软件来驱动 HSDRI、分析 AP 和 Ca-i 瞬变并绘制 3D 电活动图。激活、复极和 AP 持续时间的深度解析图将用于研究心脏电生理学的 2 个主题，其中 3D 测量对于阐明基本概念至关重要。 A) 我们将研究改变浦肯野纤维 (P)、移行细胞 (T) 和心室 (V) 细胞之间电耦合（延时或阻滞）的因素，以阐明 PV 接头在心律失常的引发和维持中的作用。 AP 将以 3D 形式绘制，以解决顺行和逆行传导、正常含氧量和缺血性起搏以及心律失常期间的 PV 延迟。 B) 由于房室结 (AVN) 的 3D 结构复杂且致密细胞区域较小，因此很难追踪房室结 (AVN) 上的脉冲传播。 3D AVN 激活图将帮助我们回答有关节点精确输入（快和慢路径）、AVN 折返机制、Wenckebach 周期性和 Wolf-Parkinson 综合征的基本问题。电压和 Ca 2+ 的快速、深度分辨图像是一种强大的新工具，将在心脏电生理学中具有广泛的应用，并可扩展到神经网络和其他器官系统。我们在这里关注心脏，因为其中存在着可以通过这项新技术解决的突出问题。然而，广泛的可能应用可能会导致这项新技术的商业化。