Electrical stimulation of human embryonic stem cells: Cardiac differentiation and the generation of reactive oxygen species
By Serena, Elena; Figallo, Elisa; Tandon, Nina; Cannizzaro, Christopher; Gerecht, Sharon; Elvassore, Nicola & Vunjak-Novakovic, Gordana
Published in Experimental Cell Research
2009
Abstract
Exogenous electric fields have been implied in cardiac differentiation of mouse embryonic stem cells and the generation of reactive oxygen species (ROS). In this work, we explored the effects of electrical field stimulation on ROS generation and cardiogenesis in embryoid bodies (EBs) derived from human embryonic stem cells (hESC, line H13), using a custom-built electrical stimulation bioreactor. Electrical properties of the bioreactor system were characterized by electrochemical impedance spectroscopy (EIS) and analysis of electrical currents. The effects of the electrode material (stainless steel, titanium-nitride-coated titanium, titanium), length of stimulus (1 and 90Â s) and age of EBs at the onset of electrical stimulation (4 and 8Â days) were investigated with respect to ROS generation. The amplitude of the applied electrical field was 1Â V/mm. The highest rate of ROS generation was observed for stainless steel electrodes, for signal duration of 90Â s and for 4-day-old EBs. Notably, comparable ROS generation was achieved by incubation of EBs with 1Â nM H2O2. Cardiac differentiation in these EBs was evidenced by spontaneous contractions, expression of troponin T and its sarcomeric organization. These results imply that electrical stimulation plays a role in cardiac differentiation of hESCs, through mechanisms associated with the intracellular generation of ROS.