Is stunning an important component of preconditioning?

Anna Cargnoni, Claudio Ceconi, Palmira Bernocchi, Evasio Pasini, Salvatore Curello, Roberto Ferrari

Research output: Contribution to journalArticle

Abstract

We tested the hypothesis that stunning following a brief period of ischaemia is a component of cardioprotection afforded by preconditioning in an in vitro model of global normothermic ischaemia. Isolated Langendorff-perfused rat hearts, after 120-150 min of aerobic perfusion, were divided into four groups. Groups 1 and 2 constituted the aerobic and ischaemic controls. The other hearts were preconditioned by two 2-min ischaemia/reperfusion cycles. Two ischaemic preconditioning protocols were used, the only difference being prolongation of the reperfusion cycle from 5 (group 3) to 20 min (group 4) before the onset of severe ischaemic insult. Mechanical function, energetic metabolism and the rate of enzyme release were followed throughout. In group 3, myocardial function remained significantly downregulated before the onset of severe ischaemia. This resulted in cardiac protection as evidenced by enhanced recovery of systolic pressure (37.7 ± 3.6 v 61.9 ± 5.7 mmHg for groups 2 and 3, respectively; P <0.02), reduced rise in diastolic pressure (55.8 ± 5.9 v 34.3 ± 5.2 mmHg; P <0.02), reduced creatine kinase (CK) release (957.3 ± 175.7 v 541.5 ± 85.9 mU/min/gww; P <0.05) and higher contents of high-energy phosphate at the end of ischaemia [3.6 ± 0.3 v 25.3 ± 2.9 μmol/gdw for creatine phosphate (CP), P <0.001] as well as after reperfusion (16.8 ± 2.4 v 31.4 ± 1.8 for CP, P <0.01, and 3.9 ± 0.5 v 6.2 ± 0.8 μmol/gdw for ATP, P <0.05). When severe ischaemia was started only after complete recovery of mechanical function (group 4), no protection was observed. Our data suggest that a decrease in mechanical function or stunning occurring after the short period of ischaemia causes ATP sparing and constitutes an additional mechanism of preconditioning cardioprotection in vitro.

Original languageEnglish
Pages (from-to)2323-2331
Number of pages9
JournalJournal of Molecular and Cellular Cardiology
Volume28
Issue number12
DOIs
Publication statusPublished - Dec 1996

Keywords

  • Isolated heart
  • Preconditioning
  • Stunning

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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