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Publication - Professor Mark Cannell

    Species differences in the morphology of T-tubule openings in cardiomyocytes

    Citation

    Rog-Zielinska, E, Kong, CHT, Zgierski-Johnston, CM, Verkade, P, Mantell, J, Cannell, M & Kohl, P, 2018, ‘Species differences in the morphology of T-tubule openings in cardiomyocytes’. EP-Europace.

    Abstract

    Aims: The ultrastructure of ventricular cardiomyocyte T-tubule connections with the outer cell surface has been reported to be different between mice and rabbits. In mice, T-tubules form convoluted narrow spaces filled with electron-dense matter that impedes diffusion between T-tubular lumen and bulk extracellular space. Here, we explore whether T-tubule mouths are also restricted in rat (another murine model used frequently for cardiac research) and whether pig and human T-tubule mouths are also generally restricted as is the case for mouse.

    Methods: We used chemically-fixed tissue and high-pressure frozen cells to compare T-tubule mouth architecture in rats, mice, and rabbits using transmission electron microscopy and 3D electron tomography.

    Results: We find that rat T-tubular mouth architecture is more similar to that of rabbits than mice, lacking the marked tortuosity and electron-dense ground substance that obstructs access to deeper portions of the T-tubular system in mice. Pilot observations in larger mammals (pig, human) suggest that mouse may be the least representative animal model of T-tubule connectivity with the outer cell surface in larger mammals.

    Conclusion: Rat T-tubular system architecture appears to be more similar in size and topology to other mammals than mice. T-tubular mouth topology may contribute to differences in experimental model behaviour, underscoring the problems of appropriate model selection for research into cell and tissue functions.

    Full details in the University publications repository