A comparative study into the ultrastructure changes of atrial myocytes, pulmonary vein sleeve cells and ventricular myocytes during ageing

Masoud, Said R.; McDonald, Fraser; Bootman, Martin D. and Rietdorf, Katja (2014). A comparative study into the ultrastructure changes of atrial myocytes, pulmonary vein sleeve cells and ventricular myocytes during ageing. In: Calcium Signalling: The Next Generation, 9-10 Oct 2014, London, UK.

URL: http://www.biochemistry.org/

Abstract

Atrial fibrillation (AF) is the most common form of a cardiac arrhythmia, with age being a significant risk factor. One of the mechanisms causing AF is structural remodelling in both atrial myocytes and pulmonary vein sleeve cells (PVCs). We conducted an electron microscopic (EM) study to compare the ultrastructural changes in PVCs, atrial and ventricular myocytes in 3 and 24 month-old mice. EM images of PVCs from 24 month-old mice showed an increased number of mitochondria, which had disorganised cristae and were significantly enlarged (1.08 ± 0.1 μm² vs. 0.65 ± 0.03 μm², 24 vs. 3 month, respectively, P = 0.0004, unpaired t-test, n = 3 animals per age group). Preliminary observations suggest an increase in mitochondrial number and size in ventricular myocytes from 24 month-old mice (1.57 ± 0.15 vs. 1.27 ± 0.12 μm², 24 vs. 3 month, respectively), whereas there were no obvious morphological changes in mitochondria within atrial myocytes (0.58 ± 0.05 vs. 0.59 ± 0.07 μm² , 24 vs. 3 month, respectively). Due to a low n-number at the time of abstract submission, no statistics could be performed for the mitochondrial size in atrial and ventricular myocytes. These results show ageassociated structural changes in PVCs and ventricular myocytes although we can’t be sure if the changes presented here contribute to the development of AF.

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