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Cardiovasc Res. 2005 Feb 15;65(3):719-27.

Erythropoietin prevents the acute myocardial inflammatory response induced by ischemia/reperfusion via induction of AP-1.

Author information

1
Vascular Cell Biology Laboratory, Lawson Health Research Institute, University of Western Ontario, London, ON, Canada N6A 4G5.

Abstract

OBJECTIVE:

Erythropoietin (EPO) prevents the myocardial dysfunction induced by ischemia/reperfusion (I/R). Since I/R-induced myocardial dysfunction is associated with an acute inflammatory response, we assessed the anti-inflammatory properties of EPO using in vitro and in vivo models of I/R.

METHODS:

Isolated cardiac myocytes were exposed to anoxia/reoxygenation (A/R; the in vitro counterpart to I/R). Hearts were challenged with I/R in situ.

RESULTS:

In vitro, A/R increased myocyte oxidant stress and converted the myocytes to a proinflammatory phenotype (these myocytes induced PMN transendothelial migration). Pretreatment of the myocytes with EPO prevented the A/R-induced proinflammatory effects. EPO increased myocyte (1) nuclear translocation of AP-1 (c-fos/c-jun), (2) eNOS, but not iNOS, protein expression, and (3) NO production. An AP-1 "decoy" oligonucleotide prevented the induction of eNOS by EPO and reversed the beneficial effect of EPO. An inhibitor of phosphatidylinostol 3 (PI3)-kinase prevented the nuclear translocation of AP-1 induced by EPO. In vivo, in wild type mice, I/R induced an increase in myocardial MPO activity (indicative of PMN infiltration); an effect prevented by pretreatment of the mice with EPO. This anti-inflammatory effect of EPO was not observed in cardiac specific c-fos(-/-) mice.

CONCLUSIONS:

Collectively, these findings indicate that EPO can ameliorate the myocardial inflammatory response in both in vitro and in vivo models of I/R. This beneficial effect of EPO is mediated by eNOS-derived NO via a PI3-kinase-dependent activation of AP-1.

PMID:
15664399
DOI:
10.1016/j.cardiores.2004.11.019
[Indexed for MEDLINE]

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