Rishi Arora1, Gary L Aistrup2, Stephen Supple2, Caleb Frank2, Jasleen Singh2, Shannon Tai2, Anne Zhao2, Laura Chicos2, William Marszalec2, Ang Guo3, Long-Sheng Song3, J Andrew Wasserstrom2. 1. Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois,. Electronic address: r-arora@northwestern.edu. 2. Division of Cardiology, Department of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois. 3. Division of Cardiology, University of Iowa School of Medicine, Iowa City, Iowa.
Abstract
BACKGROUND: The peculiarities of transverse tubule (T-tubule) morphology and distribution in the atrium-and how they contribute to excitation-contraction coupling-are just beginning to be understood. OBJECTIVES: The objectives of this study were to determine T-tubule density in the intact, live right and left atria in a large animal and to determine intraregional differences in T-tubule organization within each atrium. METHODS: Using confocal microscopy, T-tubules were imaged in both atria in intact, Langendorf-perfused normal dog hearts loaded with di-4-ANEPPS. T-tubules were imaged in large populations of myocytes from the endocardial surface of each atrium. Computerized data analysis was performed using a new MatLab (Mathworks, Natick, MA) routine, AutoTT. RESULTS: There was a large percentage of myocytes that had no T-tubules in both atria with a higher percentage in the right atrium (25.1%) than in the left atrium (12.5%) (P < .02). The density of transverse and longitudinal T-tubule elements was low in cells that did contain T-tubules, but there were no significant differences in density between the left atrial appendage, the pulmonary vein-posterior left atrium, the right atrial appendage, and the right atrial free wall. In contrast, there were significant differences in sarcomere spacing and cell width between different regions of the atria. CONCLUSION: There is a sparse T-tubule network in atrial myocytes throughout both dog atria, with significant numbers of myocytes in both atria-the right atrium more so than the left atrium-having no T-tubules at all. These regional differences in T-tubule distribution, along with differences in cell width and sarcomere spacing, may have implications for the emergence of substrate for atrial fibrillation.
BACKGROUND: The peculiarities of transverse tubule (T-tubule) morphology and distribution in the atrium-and how they contribute to excitation-contraction coupling-are just beginning to be understood. OBJECTIVES: The objectives of this study were to determine T-tubule density in the intact, live right and left atria in a large animal and to determine intraregional differences in T-tubule organization within each atrium. METHODS: Using confocal microscopy, T-tubules were imaged in both atria in intact, Langendorf-perfused normal dog hearts loaded with di-4-ANEPPS. T-tubules were imaged in large populations of myocytes from the endocardial surface of each atrium. Computerized data analysis was performed using a new MatLab (Mathworks, Natick, MA) routine, AutoTT. RESULTS: There was a large percentage of myocytes that had no T-tubules in both atria with a higher percentage in the right atrium (25.1%) than in the left atrium (12.5%) (P < .02). The density of transverse and longitudinal T-tubule elements was low in cells that did contain T-tubules, but there were no significant differences in density between the left atrial appendage, the pulmonary vein-posterior left atrium, the right atrial appendage, and the right atrial free wall. In contrast, there were significant differences in sarcomere spacing and cell width between different regions of the atria. CONCLUSION: There is a sparse T-tubule network in atrial myocytes throughout both dog atria, with significant numbers of myocytes in both atria-the right atrium more so than the left atrium-having no T-tubules at all. These regional differences in T-tubule distribution, along with differences in cell width and sarcomere spacing, may have implications for the emergence of substrate for atrial fibrillation.
Authors: Sunil Kapur; Gary L Aistrup; Rohan Sharma; James E Kelly; Rishi Arora; Jiabo Zheng; Mitra Veramasuneni; Alan H Kadish; C William Balke; J Andrew Wasserstrom Journal: Am J Physiol Heart Circ Physiol Date: 2010-10-01 Impact factor: 4.733
Authors: Long-Sheng Song; Silvia Guatimosim; Leticia Gómez-Viquez; Eric A Sobie; Andrew Ziman; Hali Hartmann; W J Lederer Journal: Ann N Y Acad Sci Date: 2005-06 Impact factor: 5.691
Authors: Ioannis Smyrnias; Waltraud Mair; Dagmar Harzheim; Simon A Walker; H Llewelyn Roderick; Martin D Bootman Journal: Cell Calcium Date: 2010-01-27 Impact factor: 6.817
Authors: Michael Frisk; Jussi T Koivumäki; Per A Norseng; Mary M Maleckar; Ole M Sejersted; William E Louch Journal: Am J Physiol Heart Circ Physiol Date: 2014-06-20 Impact factor: 4.733
Authors: Ilse Lenaerts; Virginie Bito; Frank R Heinzel; Ronald B Driesen; Patricia Holemans; Jan D'hooge; Hein Heidbüchel; Karin R Sipido; Rik Willems Journal: Circ Res Date: 2009-09-17 Impact factor: 17.367
Authors: Niels Voigt; Jordi Heijman; Qiongling Wang; David Y Chiang; Na Li; Matthias Karck; Xander H T Wehrens; Stanley Nattel; Dobromir Dobrev Journal: Circulation Date: 2013-11-18 Impact factor: 29.690
Authors: Dylan F Colli; S Ryan Blood; Aparna C Sankarankutty; Frank B Sachse; Michael Frisk; William E Louch; Peter M Kekenes-Huskey Journal: Biophys J Date: 2019-03-22 Impact factor: 4.033
Authors: Georg Gussak; William Marszalec; Shin Yoo; Rishi Modi; Caitlin O'Callaghan; Gary L Aistrup; Jonathan M Cordeiro; Robert Goodrow; Giedrius Kanaporis; Lothar A Blatter; Yohannes Shiferaw; Rishi Arora; Junlan Zhou; Amy R Burrell; J Andrew Wasserstrom Journal: Circ Arrhythm Electrophysiol Date: 2020-05-20
Authors: Georg Gussak; Anna Pfenniger; Lisa Wren; Mehul Gilani; Wenwei Zhang; Shin Yoo; David A Johnson; Amy Burrell; Brandon Benefield; Gabriel Knight; Bradley P Knight; Rod Passman; Jeffrey J Goldberger; Gary Aistrup; J Andrew Wasserstrom; Yohannes Shiferaw; Rishi Arora Journal: JCI Insight Date: 2019-10-17