An interdisciplinary approach involving the National Institute of Optics of the CNR, the European Laboratory of Non-Linear Spectroscopy, the Institute of Experimental Cardiovascular Medicine of the University of Freiburg and the Center for Electron Microscopy at the University of Colorado Boulder (USA) has made possible the discovery of a new system of assisted diffusion within cardiac cells.
Combining expertise in cardiac physiology, optical and electron microscopy present in the National Institute of Optics of the Italian National Research Council (CNR-Ino), in the European Laboratory of Non-Linear Spectroscopy (Lens), in the Institute of Experimental Cardiovascular Medicine at the University of Freiburg (Germany) and in the Center for Electron Microscopy at the University of Colorado Boulder (USA) a mechanism of assisted diffusion within heart cells has been discovered and it has been demonstrated how this mechanism is essential to maintain a proper ionic balance within heart muscle cells. The work is published in the journal Circulation Research.
“The cells of our heart contain a dense network of micro-tubes called the tubular network, which in addition to propagating electrical signals make the extra-cellular solution reach the innermost regions of the cell. However, the diffusion of solution within this network is very slow, raising many questions about how the right concentration of ions is maintained during the continuous exchanges with the intra-cellular space,” explains Marina Scardigli of Lens.
“Our study shows that the mechanical activity of cardiac cells assists the exchange of contents within this network, compressing them rhythmically with each heartbeat. This pushes used contents out of the tubes (just like we do with toothpaste), which after cellular relaxation is replaced with fresh solution, sucking extra-cellular solution into them,” continues Leonardo Sacconi of CNR-Ino and University of Freiburg. “In essence, heart muscle cells ventilate their tube system just as insects do in their tracheal breathing systems. Until now, it was thought that the maintenance of tubule contents occurred only by passive diffusion. The beauty of this assisted diffusion is that as the demand increases, the number of ventilation cycles also increases – so it’s a self-controlling system.”
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Source: Italian National Research Council CNR