1Universitätsklinikum Carl Gustav Carus an der TU Dresden Institut für Pharmakologie und Toxikologie Dresden, Deutschland; 2Medizinische Fakultät Carl Gustav Carus der TU Dresden Institut für Pharmakologie und Toxikologie Dresden, Deutschland; 3Centre for Biotechnology and Biomedicine, Biochemical Cell Technology, Leipzig University Leipzig, Deutschland; 4Sciospec Scientific Instruments GmbH Bennewitz, Deutschland
Keywords:
high-density microelectrode array, re-entry, Brugada syndrome, atrial fibrillation, induced pluripotent stem cell-derived atrial cardiomyocytes, propranolol, flecainide
Abstract
Recently, we developed a novel large-area high-density microelectrode array system (HD-MEA), which contains 512 electrodes distributed over an area of 95.3 mm2. HD-MEA utilizes the label-free MEA technology to non-invasively detect field potential signals for a long time period. Thus, the HD-MEA overcomes the limitations of voltage-sensitive fluorescent sensors for optical mapping of electrophysiological activity, such as dye-induced toxicity and photobleaching, low signal-to-noise ratio, and the time delay between the voltage change and change of the fluorescence signal. We further integrated four independent stimulation electrodes into the HD-MEA to allow consistent pacing of the cultures and to avoid the use of external commercial pacers, which was associated with inconsistent electrode positions leading to cell damage and altered pacing intensity. Atrial fibrillation (AF) is being increasingly reported in patients with Brugada syndrome (BrS); however, the underlying mechanism and BrS-specific anti-AF pharmacotherapy have been rarely studied and tested. Here, we investigated the atrial re-entry and tested anti-AF drugs, using induced pluripotent stem cell (iPSC)-derived atrial cardiomyocytes (aCMs) from two BrS patients (BrS-aCMs) carrying a heterozygous SCN5A mutation p.S1812X. Sodium current recording with automated patch clamp revealed more than 50% reduction in INa in BrS-aCMs compared to control aCMs (Ctrl-aCMs) derived from 3 independent iPSC lines generated from 3 healthy donors. Using our integrated stimulation module, we established a burst-pacing protocol to model re-entry in aCM cultures on HD-MEA. Our studies revealed that BrS-aCM cultures were more susceptible to burst pacing-induced re-entry, showing long-lasting reentry patterns, as illustrated by magnitude and phase mapping using our custom software. Moreover, the rate-controlling class II anti-arrhythmic agent propranolol reduced rotation frequency by 39% in BrS-aCM cultures. The rhythm-controlling class I anti-arrhythmic agent flecainide reduced rotation frequency by 42% in BrS-aCM cultures. However, all BrS-aCM cultures still exhibited re-entry rhythm 10 min after flecainide perfusion. Taken together, the novel HD-MEA with integrated stimulation electrodes shows great potential for studying human re-entry arrhythmias in vitro and for testing the efficacy of anti-arrhythmic drugs in patient-specific aCM models.