Journal
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Volume 315, Issue 5, Pages H1148-H1158Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00726.2017
Keywords
epoxyeicosatrienoic acid; heart; hypoxia-inducible factor-1 alpha; ischemia-reperfusion; prolyl hydroxylase 3
Funding
- Czech Science Foundation [15-07544S, 18-03207S, 67985823, 00023001]
- National Institutes of Health [HL-111392, DK-103616]
- Dr. Ralph and Marian Falk Medical Research Trust Bank of America, North America
- Robert A. Welch Foundation [I-0011]
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Epoxyeicosatrienoic acids (EETs) decrease cardiac ischemia-reperfusion injury: however, the mechanism of their protective effect remains elusive. Here, we investigated the cardioprotective action of a novel EET analog, EET-B, in reperfusion and the role of hypoxia-inducible factor (HIF)-1 alpha in such action of EET-B. Adult male rats were subjected to 30 min of left coronary artery occlusion followed by 2 h of reperfusion. Administration of 14,15-EET (2.5 mg/kg) or EET-B (2.5 mg/kg) 5 min before reperfusion reduced infarct size expressed as a percent-age of the area at risk from 64.3 +/- 1.3% in control to 42.6 +/- 1.9% and 46.0 +/- 11.6%, respectively, and their coadministration did not provide any stronger effect. The 14,15-EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (2.5 mg/kg) inhibited the infarct size-limiting effect of EET-B (62.5 +/- 1.1%). Similarly, the HIF-1 alpha inhibitors 2-methoxyestradiol (2.5 mg/kg) and acriflavine (2 mg/kg) completely abolished the cardioprotective effect of EET-B. In a separate set of experiments, the immunoreactivity of HIE-1 alpha and its degrading enzyme prolyl hydroxylase domain protein 3 (PHD3) were analyzed in the ischemic areas and non ischemic septa. At the end of ischemia, the HIF-1 alpha immunogenic signal markedly increased in the ischemic area compared with the septum (10.31 +/- 0.78% vs. 0.34 +/- 0.08%). After 20 min and 2 h of reperfusion, HIF-1 alpha immunoreactivity decreased to 2.40 +/- 0.48% and 1.85 +/- 0.43%, respectively, in the controls. EET-B blunted the decrease of HIF-1 alpha immunoreactivity (7.80 +/- 0.69% and 6.44 +/- 1.37%, respectively) and significantly reduced PHD3 inununogenic signal in ischemic tissue after reperfusion. In conclusion, EET-B provides an infarct size-limiting effect at reperfusion that is mediated by HIF-1 alpha and downregulation of its degrading enzyme PHD3. NEW & NOTEWORTHY The present study shows that EET-B is an effective agonistic 14,15-epoxyeicosatrienoic acid analog, and its administration before reperfusion markedly reduced myocardial infarction in rats. Most importantly, we demonstrate that increased hypoxia-inducible factor-1 alpha levels play a role in cardioprotection mediated by EET-B in reperfusion likely by mechanisms including downregulation of the hypoxia-inducible factor-1 alpha-degrading enzyme prolyl hydroxylase domain protein 3.
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