Soluble epoxide hydrolase inhibition and gene deletion are protective against myocardial ischemia-reperfusion injury in vivo

Abstract

to dihydroxyeicosatrienoic acids. EETs are formed from arachidonic acid during myocardial ischemia and play a protective role against ischemic cell death. Deletion of sEH has been shown to be protective against myocardial ischemia in the isolated heart preparation. We tested the hypothesis that sEH inactivation by targeted gene deletion or pharmacological inhibition reduces infarct size (I) after regional myocardial ischemia-reperfusion injury in vivo. Male C57BL‫6گ‬J wildtype or sEH knockout mice were subjected to 40 min of left coronary artery (LCA) occlusion and 2 h of reperfusion. Wild-type mice were injected intraperitoneally with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester (AUDA-BE), a sEH inhibitor, 30 min before LCA occlusion or during ischemia 10 min before reperfusion. 14,15-EET, the main substrate for sEH, was administered intravenously 15 min before LCA occlusion or during ischemia 5 min before reperfusion. The EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (EEZE) was given intravenously 15 min before reperfusion. Area at risk (AAR) and I were assessed using fluorescent microspheres and triphenyltetrazolium chloride, and I was expressed as I/AAR. I was significantly reduced in animals treated with AUDA-BE or 14,15-EET, independent of the time of administration. The cardioprotective effect of AUDA-BE was abolished by the EET antagonist 14,15-EEZE. Immunohistochemistry revealed abundant sEH protein expression in left ventricular tissue. Strategies to increase 14,15-EET, including sEH inactivation, may represent a novel therapeutic approach for cardioprotection against myocardial ischemia-reperfusion injury.14,15-epoxyeicosatrienoic acids; 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester THE P-450 EPOXYGENASE PATHWAY metabolizes arachidonic acid into four biologically active eicosanoids, referred to as epoxyeicosatrienoic acids (5,6-, 8,9-, 11,12-, and 14,15-EET) (10). EETs play an important role in regulating tissue perfusion in both cardiac and extracardiac organs. The actions of EETs are terminated by conversion to dihydroxyeicosatrienoic acids (DHETs) by epoxide hydrolases (11). Two major epoxide hydrolases are found in mammalian tissues, the microsomal (mEH) and soluble epoxide hydrolases (sEH) (2). However, sEH is the primary enzyme involved in the in vivo metabolism of EETs (19). In addition to their vascular effects, EETs exhibit a cardioprotective effect, which has been linked to activation of the reperfusion injury salvage kinase pathway (18) and mediated in part through activation of the phosphatidylinositol 3-kinase/Akt pathway and the mitochondrial ATP-sensitive K ϩ channels (5, 15). Augmenting endogenously released EETs by inhibiting the converting enzyme sEH represents an attractive strategy to increase ischemic tolerance. Our laboratory has recently used this strategy to show that pharmacological inhibition (20) and gene deletion (21) are protective against experimental stroke in vivo. Similarly, using the isolated heart preparation, Seubert et al. (16) demonstrat...

Cardiotonic Pill Reduces Myocardial Ischemia-Reperfusion Injury via Increasing EET Concentrations in Rats

“…For example, CYP2J2 transgenic mice exhibited not only increased EET biosynthesis in coronary arteries, but also improved postischemic recovery of left ventricular function after myocardial I/R (Seubert et al, 2004). sEH inhibition through gene deletion or pharmacological suppression was protective against MIRI in mice (Motoki et al, 2008). Administration of exogenous 14,15-EET was found to reduce MIRI in rats and dogs (Nithipatikom et al, 2006; , 2007).…”

“…Furthermore, although CYP2J2 and CYP2C both generate cardioprotective EETs from AA, studies have demonstrated that CYP2C also produces detrimental reactive oxygen species (ROS) (Fleming et al, 2001). In animal models, effective protection against MIRI has been shown by increasing EET concentrations through direct administration of EETs, upregulating the expression of AA epoxygenases using transgenic technology, or inhibiting the activity of sEH (Seubert et al, 2004;Motoki et al, 2008;Batchu et al, 2011;Oni-Orisan et al, 2014); decreasing 20-HETE generation through CYP4A/4F inhibition (Nithipatikom et al, 2004); and depressing ROS formation via CYP2C inhibition (Granville et al, 2004). AA-metabolizing P450 enzymes are thus considered to be therapeutic targets for MIRI and other CVDs.…”

Heart failure–induced activation of phospholipase iPLA2γ generates hydroxyeicosatetraenoic acids opening the mitochondrial permeability transition pore

“…For example, EETs and a soluble epoxide hydrolase inhibitor have been demonstrated to reduce infract size during I/R and improve cardiac function by preventing cardiac fibrosis (20,41,42). In contrast, cardiac overexpression of 12/15-LOX was reported to result in systolic dysfunction, inflammation, cardiac fibrosis, and macrophage infiltration (43,44).…”

“…For example, increased levels of 14,15-epoxyeicosatrienoic acid (14, in murine myocardium produced by either overexpression of the cytochrome P450 enzyme CYP2J3 or by genetic knock-out of soluble epoxide hydrolase resulted in decreased mPTP opening probability, improved preservation of mitochondrial membrane potential (⌬ mt ), and attenuated damage after ischemia/reperfusion (17,20,21). The diverse effects of prostaglandin E 2 (PGE 2 ), a cyclooxygenase-2 product, on cardiac function have been documented, which include the reduction of cardiac ischemia/reperfusion injury and a contribution to myocardial hypertrophy via prostaglandin E 2 receptor signaling (22,23).…”

Factor XI contributes to myocardial ischemia-reperfusion injury in mice

“…We used an established murine model of nonthrombotic acute MI, 21,22 with minor modifications. Male C57BL/6 mice (17-20 weeks) were intubated and ventilated under isoflurane anesthesia, the jugular vein was catheterized, and body temperature was maintained at 37°C.…”