Rapid pacing of embryoid bodies impairs mitochondrial ATP synthesis by a calcium-dependent mechanism-A model of in vitro differentiated cardiomyocytes to study molecular effects of tachycardia

Lorenz Schild, Alicja Bukowska, Andreas Gardemann, Pamela Polczyk, Gerburg Keilhoff, Michael Täger, Samuel C. Dudley, Helmut U. Klein, Andreas Goette, Uwe Lendeckel

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Tachycardia may cause substantial molecular and ultrastructural alterations in cardiac tissue. The underlying pathophysiology has not been fully explored. The purpose of this study was (I) to validate a three-dimensional in vitro pacing model, (II) to examine the effect of rapid pacing on mitochondrial function in intact cells, and (III) to evaluate the involvement of L-type-channel-mediated calcium influx in alterations of mitochondria in cardiomyocytes during rapid pacing. In vitro differentiated cardiomyocytes from P19 cells that formed embryoid bodies were paced for 24 h with 0.6 and 2.0 Hz. Pacing at 2.0 Hz increased mRNA expression and phosphorylation of ERK1/2 and caused cellular hypertrophy, indicated by increased protein/DNA ratio, and oxidative stress measured as loss of cellular thiols. Rapid pacing additionally provoked structural alterations of mitochondria. All these changes are known to occur in vivo during atrial fibrillation. The structural alterations of mitochondria were accompanied by limitation of ATP production as evidenced by decreased endogenous respiration in combination with decreased ATP levels in intact cells. Inhibition of calcium inward current with verapamil protected against hypertrophic response and oxidative stress. Verapamil ameliorated morphological changes and dysfunction of mitochondria. In conclusion, rapid pacing-dependent changes in calcium inward current via L-type channels mediate both oxidative stress and mitochondrial dysfunction. The in vitro pacing model presented here reflects changes occurring during tachycardia and, thus, allows functional analyses of the signaling pathways involved.

Original languageEnglish (US)
Pages (from-to)608-615
Number of pages8
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1762
Issue number6
DOIs
StatePublished - Jun 2006

Bibliographical note

Funding Information:
We thank Katja Mook, Regine Widmayer, Karla Klingenberg, and Cornelia Müller for excellent technical assistance. This work was supported by grants from the “Kultusministerium des Landes Sachsen-Anhalt, Germany” (3517 A/0603M) and by the “Bundesministerium für Bildung und Forschung, Germany” (grant 01ZZ0407 and Kompetenznetz Vorhofflimmern, grant 01GI 0204).

Keywords

  • Arrhythmia
  • Hypertrophy
  • Mitochondria
  • Myocyte
  • Oxidative stress
  • Pacing

Fingerprint

Dive into the research topics of 'Rapid pacing of embryoid bodies impairs mitochondrial ATP synthesis by a calcium-dependent mechanism-A model of in vitro differentiated cardiomyocytes to study molecular effects of tachycardia'. Together they form a unique fingerprint.

Cite this