title: Effects of electrical fields on cardiomyocyte differentiation of embryonic stem cells.
abstract: The effects of electromagnetic fields (EMFs) on the differentiation of cardiomyocytes in embryoid bodies derived from pluripotent embryonic stem (ES) cells were investigated. A single direct current (DC) field pulse was applied to 4-day-old embryoid bodies. The electrical field induced a hyperpolarization of the anode-facing side of embryoid bodies and a depolarization at the cathode-facing side. Significant effects of a single electrical field pulse applied for 90 s on cardiomyocyte differentiation were achieved with field strengths of 250 and 500 V/m, which increased both the number of embryoid bodies differentiating beating foci of cardiomyocytes and the size of the beating foci. The 500-V/m electrical field increased intracellular reactive oxygen species (ROS), but not [Ca(2+)](i) and activated nuclear factor kappa B (NF-kappaB). A comparable increase in the number of beating embryoid bodies was achieved by an incubation for 1 h with H(2)O(2) (1-10 nM), indicating that the electrical field effect was transduced via the intracellular generation of ROS. Because the radical scavengers dehydroascorbate and pyrrolidinedithiocarbamate (APDC) and the NF-kappaB antagonist N-tosyl-L-phenylalanine chloromethyl ketone (TPCK) inhibited cardiac differentiation, we assume that ROS and NF-kappaB may play a role in early cardiac development.
authors.affiliation: Department of Neurophysiology, University of Cologne, D-50931 Cologne, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Sauer
authors.forename: G
authors.initials: G
authors.lastname: Rahimi
authors.forename: J
authors.initials: J
authors.lastname: Hescheler
authors.forename: M
authors.initials: M
authors.lastname: Wartenberg
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects*; D002460:Cell Line; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D006321:Heart / Q000196:embryology / Q000502:physiology / Q000528:radiation effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007150:Immunohistochemistry; D007424:Intracellular Fluid / Q000378:metabolism / Q000528:radiation effects; D008564:Membrane Potentials / Q000528:radiation effects; D051379:Mice; D018613:Microscopy, Confocal; D009206:Myocardium / Q000166:cytology*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D000943:Antigens, Differentiation; D016166:Free Radical Scavengers; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002118:Calcium