Dynamic Single Cell Imaging of Coronary Microvascular Dysfunction in the Failing Heart

尽管在心脏病的临床诊断和治疗方面取得了数十年的进展，但心脏病的流行率仍在上升。 心力衰竭在全球老龄化人口中的比例。从历史上看，许多焦点一直集中在动脉粥样硬化，急性 心肌梗塞和大血管冠状动脉疾病的治疗。然而，相对而言， 机械水平的巨大网络的小动脉，毛细血管和静脉在心脏以外的大 冠状动脉，冠状动脉微循环，越来越多的证据表明， 微循环对包括心力衰竭在内的各种形式的心脏病的影响。体外实验，组织学 分析和计算建模提供了关于冠状动脉微循环如何 在衰竭的心脏中调节和重塑，但先前的研究无法直接评估复合物 在体内细胞水平上的心脏微循环生理学。活体光学显微镜正被用于 神经科学和肿瘤生物学来破译体内动态血管生理学，但这些技术 由于收缩运动造成的严重成像限制，我们 最近开创了活体成像方法， 在跳动的心脏中进行显微镜检查。在这项工作的基础上，本提案力求调查 应用活体显微镜定量绘制冠状动脉血流图评价冠状动脉微血管功能障碍 在心脏病动物模型中，微循环下降到毛细血管水平。将在小鼠中进行研究 比较健康对照组、运动引起的生理性肥大模型 以及在导致病理性肥大和心力衰竭的压力超负荷模型中。此外该 将研究微血管周细胞作为毛细血管血流的主要调节剂的特殊作用。 活体共聚焦和双光子显微镜，多路复用荧光报告和细胞特异性光遗传学 将使用各种方法记录和操纵微血管血流，并将异常血流模式与 心肌细胞代谢、炎症反应和纤维化。这项工作将导致新的理解 微循环病理生理学在衰竭的心脏在单细胞水平和有前途的新见解 临床治疗学

Despite decades of advances in clinical diagnosis and treatment of heart disease, there is a rising epidemic of heart failure in an aging population worldwide. Historically, much focus has been on atherosclerosis, acute myocardial infarction, and treatment of large vessel coronary disease. However, relatively little is known at a mechanistic level about the vast network of small arteries, capillaries and veins in the heart beyond the large coronary arteries, the coronary microcirculation, and increasing evidence links dysfunction of the microcirculation to various forms of heart disease including heart failure. In vitro experiments, histologic analysis, and computational modeling have provided insight about how the coronary microcirculation is regulated and remodels in the failing heart, but prior studies have been unable to directly evaluate the complex microcirculatory physiology of the heart at the cellular level in vivo. Intravital optical microscopy is being used in the neurosciences and tumor biology to decipher dynamic vascular physiology in vivo, but these techniques have not been applicable in the heart due to severe imaging limitations imposed by contractile motion. We have recently pioneered intravital imaging methods to perform motion-artifact free, cellular resolution microscopy in the beating heart. Building on this work, this proposal seeks to investigate mechanisms of coronary microvascular dysfunction by utilizing intravital microscopy to quantitatively map flow in the coronary microcirculation down to the capillary level in animal models of heart disease. Studies will be performed in mice comparing microcirculatory function in healthy controls, in a model of physiologic hypertrophy due to exercise, and in a model of pressure overload leading to pathologic hypertrophy and heart failure. In addition, the specific role of microvascular pericytes will be investigated as a master regulator of capillary blood flow. Intravital confocal and two-photon microscopy, multiplexed fluorescent reporters, and cell-specific optogenetics approaches will be used to record and manipulate microvascular flow, and to correlate abnormal flow patterns with cardiomyocyte metabolism, inflammatory response, and fibrosis. This work will lead to new understanding of microcirculatory pathophysiology in the failing heart at the single cell level and promising new insights for clinical therapeutics.