Author(s): Kubin T, Ando H, Scholz D, Bramlage P, Kostin S,
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Abstract We investigated the paracrine effect of cardiac microvascular endothelial cells (MVEC) on cultured adult rat cardiomyocytes (ARC). ARC were exposed for 8 days to serum-free medium (CM) conditioned by MVEC. Controls were grown in FCS or FCS-free medium. Protein synthesis of CM-stimulated ARC increased twofold versus 5\% FCS-stimulated cells until day 8. Seventy-nine percent of CM-treated myocytes survived, whereas only twenty-four percent of FCS-free ARC retained viability. The phenotype of myocytes exposed to CM was different from control. Analysis by confocal laser microscopy of CM-stimulated myocytes showed actin staining throughout the whole cell body up to the peripheral extensions, with concomitant appearance of myomesin in a cross-striated pattern. The reexpression of fetal alpha-smooth muscle actin determined immunohistochemically and by Western blot increased from day 6 in CM-treated cells, whereas ARC grown in up to 20\% serum were negative. These effects could not be mimicked by any of the other cardioactive substances tested here, indicating a novel trophic factor in CM.
This article was published in Am J Physiol
and referenced in Journal of Clinical & Experimental Cardiology