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This Article Full Text Full Text (PDF) All Versions of this Article: 296/1/H84    most recent 00372.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Burger, D. Articles by Feng, Q. Search for Related Content PubMed PubMed Citation Articles by Burger, D. Articles by Feng, Q.

Role of heme oxygenase-1 in the cardioprotective effects of erythropoietin during myocardial ischemia and reperfusion

Departments of ¹Physiology and Pharmacology and ²Medicine, University of Western Ontario, and ³Centre for Critical Illness Research, Lawson Health Research Institute, London, Ontario, Canada

Submitted 10 April 2008 ; accepted in final form 3 November 2008

We have recently demonstrated that erythropoietin (EPO) protects cardiomyocytes from apoptosis during myocardial ischemia-reperfusion (I/R). The objective of the present study was to investigate the role of heme oxygenase (HO)-1 in the antiapoptotic effects of EPO. Primary cultures of neonatal mouse cardiomyocytes were subjected to anoxia-reoxygenation (A/R). Pretreatment with EPO significantly reduced apoptosis in A/R-treated cells. This reduction in apoptosis was preceded by an increase in the mRNA and protein expression of HO-1. Selective inhibition of HO-1 using chromium mesoporphyrin (CrMP) significantly diminished the ability of EPO to inhibit apoptosis. Cotreatment of EPO with SB-202190, an inhibitor of p38 activation, blocked the EPO-mediated HO-1 expression and antiapoptotic effects, suggesting a p38-dependent mechanism. The in vivo significance of p38 and HO-1 as mediators of EPO's cardioprotection was investigated in mice subjected to myocardial I/R. Pretreatment with EPO decreased infarct size as well as I/R-induced apoptosis in wild-type mice. However, these effects were significantly diminished in HO-1^–/– mice. Furthermore, EPO given during ischemia reduced infarct size in mice subjected to I/R, and this effect was blocked by CrMP treatment in wild-type mice. Moreover, inhibition of p38 diminished the cardioprotective effects of EPO. We conclude that upregulation of HO-1 expression via p38 signaling contributes to EPO-mediated cardioprotection during myocardial I/R.

myocyte; apoptosis; myocardial infarction; p38