Nano-imaging of the beating mouse heart in vivo: Importance of sarcomere dynamics, as opposed to sarcomere length per se, in the regulation of cardiac function.
Nano-imaging of the beating mouse heart in vivo: Importance of sarcomere dynamics, as opposed to sarcomere length per se, in the regulation of cardiac function.
复制标题
DOI：
10.1085/jgp.201511484
复制
发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Fukuda N
中科院分区：
文献类型：
--
作者：
Kobirumaki-Shimozawa F;Oyama K;Shimozawa T;Mizuno A;Ohki T;Terui T;Minamisawa S;Ishiwata S;Fukuda N
差异万岁！在心脏收缩中，肌节长度的减少而不是长度本身决定了收缩力。心肌细胞中的肌节收缩是哺乳动物心脏泵功能的基础。虽然心肌肌节在循环系统中起着关键作用，但由于技术上的困难，在生理条件下，心肌肌节长度（SL）的变化还没有在体内直接测量。在这项研究中，我们开发了一个高速（每秒100帧），高分辨率（20纳米）的成像系统，在活的小鼠心肌肌节。使用该系统，我们进行了三维分析，在心动周期中的左心室肌细胞肌节动力学，同时与心电图和左心室压力测量。我们发现：（a）SL的工作范围位于静息分布的短端;（B）左室发展压与SL在舒张期和收缩期之间的变化呈正相关。目前的研究结果提供了第一个直接的证据，肌节动力学和心室泵功能在心脏生理学的紧密耦合。
¡Vive la différence! In cardiac contraction, the reduction in sarcomere length—rather than length itself—determines contractile force. Sarcomeric contraction in cardiomyocytes serves as the basis for the heart’s pump functions in mammals. Although it plays a critical role in the circulatory system, myocardial sarcomere length (SL) change has not been directly measured in vivo under physiological conditions because of technical difficulties. In this study, we developed a high speed (100–frames per second), high resolution (20-nm) imaging system for myocardial sarcomeres in living mice. Using this system, we conducted three-dimensional analysis of sarcomere dynamics in left ventricular myocytes during the cardiac cycle, simultaneously with electrocardiogram and left ventricular pressure measurements. We found that (a) the working range of SL was on the shorter end of the resting distribution, and (b) the left ventricular–developed pressure was positively correlated with the SL change between diastole and systole. The present findings provide the first direct evidence for the tight coupling of sarcomere dynamics and ventricular pump functions in the physiology of the heart.