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Infarct-remodelled hearts with limited oxidative capacity boost fatty acid oxidation after conditioning against ischaemia/reperfusion injury


Lou, Phing-How; Zhang, Liyan; Lucchinetti, Eliana; Heck, Markus; Affolter, Andreas; Gandhi, Manoj; Kienesberger, Petra C; Hersberger, Martin; Clanachan, Alexander S; Zaugg, Michael (2013). Infarct-remodelled hearts with limited oxidative capacity boost fatty acid oxidation after conditioning against ischaemia/reperfusion injury. Cardiovascular Research, 97(2):251-261.

Abstract

AIMS: Infarct-remodelled hearts are less amenable to protection against ischaemia/reperfusion. Understanding preservation of energy metabolism in diseased vs. healthy hearts may help to develop anti-ischaemic strategies effective also in jeopardized myocardium.
METHODS AND RESULTS: Isolated infarct-remodelled/sham Sprague-Dawley rat hearts were perfused in the working mode and subjected to 15 min of ischaemia and 30 min of reperfusion. Protection of post-ischaemic ventricular work was achieved by pharmacological conditioning with sevoflurane. Oxidative metabolism was measured by substrate flux in fatty acid and glucose oxidation using [(3)H]palmitate and [(14)C]glucose. Mitochondrial oxygen consumption was measured in saponin-permeabilized left ventricular muscle fibres. Activity assays of citric acid synthase, hydroxyacyl-CoA dehydrogenase, and pyruvate dehydrogenase and mass spectrometry for acylcarnitine profiling were also performed. Six weeks after coronary artery ligation, the hearts exhibited macroscopic and molecular signs of hypertrophy consistent with remodelling and limited respiratory chain and citric acid cycle capacity. Unprotected remodelled hearts showed a marked decline in palmitate oxidation and acetyl-CoA energy production after ischaemia/reperfusion, which normalized in sevoflurane-protected remodelled hearts. Protected remodelled hearts also showed higher β-oxidation flux as determined by increased oxygen consumption with palmitoylcarnitine/malate in isolated fibres and a lower ratio of C16:1+C16OH/C14 carnitine species, indicative of a higher long-chain hydroxyacyl-CoA dehydrogenase activity. Remodelled hearts exhibited higher PPARα-PGC-1α but defective HIF-1α signalling, and conditioning enabled them to mobilize fatty acids from endogenous triglyceride stores, which closely correlated with improved recovery.
CONCLUSIONS: Protected infarct-remodelled hearts secure post-ischaemic energy production by activation of β-oxidation and mobilization of fatty acids from endogenous triglyceride stores.

Abstract

AIMS: Infarct-remodelled hearts are less amenable to protection against ischaemia/reperfusion. Understanding preservation of energy metabolism in diseased vs. healthy hearts may help to develop anti-ischaemic strategies effective also in jeopardized myocardium.
METHODS AND RESULTS: Isolated infarct-remodelled/sham Sprague-Dawley rat hearts were perfused in the working mode and subjected to 15 min of ischaemia and 30 min of reperfusion. Protection of post-ischaemic ventricular work was achieved by pharmacological conditioning with sevoflurane. Oxidative metabolism was measured by substrate flux in fatty acid and glucose oxidation using [(3)H]palmitate and [(14)C]glucose. Mitochondrial oxygen consumption was measured in saponin-permeabilized left ventricular muscle fibres. Activity assays of citric acid synthase, hydroxyacyl-CoA dehydrogenase, and pyruvate dehydrogenase and mass spectrometry for acylcarnitine profiling were also performed. Six weeks after coronary artery ligation, the hearts exhibited macroscopic and molecular signs of hypertrophy consistent with remodelling and limited respiratory chain and citric acid cycle capacity. Unprotected remodelled hearts showed a marked decline in palmitate oxidation and acetyl-CoA energy production after ischaemia/reperfusion, which normalized in sevoflurane-protected remodelled hearts. Protected remodelled hearts also showed higher β-oxidation flux as determined by increased oxygen consumption with palmitoylcarnitine/malate in isolated fibres and a lower ratio of C16:1+C16OH/C14 carnitine species, indicative of a higher long-chain hydroxyacyl-CoA dehydrogenase activity. Remodelled hearts exhibited higher PPARα-PGC-1α but defective HIF-1α signalling, and conditioning enabled them to mobilize fatty acids from endogenous triglyceride stores, which closely correlated with improved recovery.
CONCLUSIONS: Protected infarct-remodelled hearts secure post-ischaemic energy production by activation of β-oxidation and mobilization of fatty acids from endogenous triglyceride stores.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Children's Hospital Zurich > Medical Clinic
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2013
Deposited On:06 Aug 2013 07:12
Last Modified:05 Apr 2016 16:53
Publisher:Oxford University Press
ISSN:0008-6363
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1093/cvr/cvs323
PubMed ID:23097573

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