Freshly isolated mitochondria from failing human hearts exhibit preserved respiratory function

Andrea M. Cordero-Reyes, Anisha A. Gupte, Keith A. Youker, Matthias Loebe, Willa A. Hsueh, Guillermo Torre-Amione, Heinrich Taegtmeyer, Dale J. Hamilton

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

In heart failure mitochondrial dysfunction is thought to be responsible for energy depletion and contractile dysfunction. The difficulties in procuring fresh left ventricular (LV) myocardium from humans for assessment of mitochondrial function have resulted in the reliance on surrogate markers of mitochondrial function and limited our understanding of cardiac energetics. We isolated mitochondria from fresh LV wall tissue of patients with heart failure and reduced systolic function undergoing heart transplant or left ventricular assist device placement, and compared their function to mitochondria isolated from the non-failing LV (NFLV) wall tissue with normal systolic function from patients with pulmonary hypertension undergoing heart-lung transplant. We performed detailed mitochondrial functional analyses using 4 substrates: glutamate-malate (GM), pyruvate-malate (PM) palmitoyl carnitine-malate (PC) and succinate. NFLV mitochondria showed preserved respiratory control ratios and electron chain integrity with only few differences for the 4 substrates. In contrast, HF mitochondria had greater respiration with GM, PM and PC substrates and higher electron chain capacity for PM than for PC. Surprisingly, HF mitochondria had greater respiratory control ratios and lower ADP-independent state 4 rates than NFLV mitochondria for GM, PM and PC substrates demonstrating that HF mitochondria are capable of coupled respiration ex vivo. Gene expression studies revealed decreased expression of key genes in pathways for oxidation of both fatty acids and glucose. Our results suggest that mitochondria from the failing LV myocardium are capable of tightly coupled respiration when isolated and supplied with ample substrates. Thus energy starvation in the failing heart may be the result of dysregulation of metabolic pathways, impaired substrate supply or reduced mitochondrial number but not the result of reduced mitochondrial electron transport capacity.

Original languageEnglish (US)
Pages (from-to)98-105
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume68
DOIs
StatePublished - Mar 1 2014
Externally publishedYes

Keywords

  • Electron transport chain
  • Human heart failure
  • Mitochondrial function
  • Oxidative phosphorylation

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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  • Cite this

    Cordero-Reyes, A. M., Gupte, A. A., Youker, K. A., Loebe, M., Hsueh, W. A., Torre-Amione, G., Taegtmeyer, H., & Hamilton, D. J. (2014). Freshly isolated mitochondria from failing human hearts exhibit preserved respiratory function. Journal of Molecular and Cellular Cardiology, 68, 98-105. https://doi.org/10.1016/j.yjmcc.2013.12.029