News Column

Researchers' Work from Waseda University Focuses on Cardiology

June 23, 2014

By a News Reporter-Staff News Editor at Cardiovascular Week -- New research on Cardiology is the subject of a report. According to news reporting out of Tokyo, Japan, by NewsRx editors, research stated, "Nanometry is widely used in biological sciences to analyze the movement of molecules or molecular assemblies in cells and in vivo. In cardiac muscle, a change in sarcomere length (SL) by a mere ?100 nm causes a substantial change in contractility, indicating the need for the simultaneous measurement of SL and intracellular Ca(2+) concentration ([Ca(2+)]i) in cardiomyocytes at high spatial and temporal resolution."

Our news journalists obtained a quote from the research from Waseda University, "To accurately analyze the motion of individual sarcomeres with nanometer precision during excitation-contraction coupling, we applied nanometry techniques to primary-cultured rat neonatal cardiomyocytes. First, we developed an experimental system for simultaneous nanoscale analysis of single sarcomere dynamics and [Ca(2+)]i changes via the expression of AcGFP in Z discs. We found that the averaging of the lengths of sarcomeres along the myocyte, a method generally used in today's myocardial research, caused marked underestimation of sarcomere lengthening speed because of the superpositioning of different timings for lengthening between sequentially connected sarcomeres. Then, we found that after treatment with ionomycin, neonatal myocytes exhibited spontaneous sarcomeric oscillations (cell-SPOCs) at partial activation with blockage of sarcoplasmic reticulum functions, and the waveform properties were indistinguishable from those obtained in electric field stimulation. The myosin activator omecamtiv mecarbil markedly enhanced Z-disc displacement during cell-SPOC. Finally, we interpreted the present experimental findings in the framework of our mathematical model of SPOCs."

According to the news editors, the research concluded: "The present experimental system has a broad range of application possibilities for unveiling single sarcomere dynamics during excitation-contraction coupling in cardiomyocytes under various settings."

For more information on this research see: Sarcomere length nanometry in rat neonatal cardiomyocytes expressed with ?-actinin-AcGFP in Z discs. The Journal of General Physiology, 2014;143(4):513-24 (see also Cardiology).

Our news journalists report that additional information may be obtained by contacting S.A. Shintani, Dept. of Pure and Applied Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan. Additional authors for this research include K. Oyama, F. Kobirumaki-Shimozawa, T. Ohki, S. Ishiwata and N. Fukuda.

Keywords for this news article include: Asia, Tokyo, Japan, Cardiology, Cardiomyocyte.

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Source: Cardiovascular Week

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