[Extracellular matrix dependence of the cardiomyocyte contractile apparatus organization]

In the process of cardiomyocyte culturing, their contractile apparatus undergoes reorganization involving the convertation of typical myofibrils into non-muscle type structures and subsequent restoration of the initial organization. The causes and mechanisms of the rearrangements described are unknown. In this study, we have shown that cultivation of cardiomyocytes on the individual extracellular matrix proteins, as well as on the matrix produced either by cardiac fibroblasts or by similar cardiomyocyte, reduses the time when the contractile apparatus is in a rearranged state, whereas soluble factors of the conditioned culture do not affect obviously these rearrangements. Using method of extracellular matrix isolation adapted for cardiomyocytes, we have shown that cardiomyocytes in culture produce their own extracellular matrix, which differs from the extracellular matrix of cardiac fibroblasts and varies with the culturing time.