Identification of 5,6-trans-Epoxyeicosatrienoic Acid in the Phospholipids of Red Blood Cells

Abstract-The aim of the present cross-sectional study was to investigate whether activation of the renin-angiotensin system in renovascular disease affects the cytochrome P450 /-1 hydroxylase (20-hydroxyeicosatetraenoic acid ) and epoxygenase (epoxyeicosatrienoic acids [EETs]) pathways of arachidonic acid metabolism in vivo, each of which interacts with angiotensin II. Plasma concentration and urinary excretion of 20-HETE and EETs and their metabolites, dihydroxyeicosatrienoic acids, were measured in urine and plasma by mass spectrometry in 10 subjects with renovascular disease, 10 with essential hypertension, and 10 healthy normotensive subjects (control subjects), pair-matched for gender and age. Vascular and renal function were evaluated in all of the subjects. Plasma 20-HETE was highest in subjects with renovascular disease (median: 1.20 ng/mL; range: 0.42 to 1.92 ng/mL) compared with subjects with essential hypertension (median: 0.90 ng/mL; range: 0.40 to 2.17 ng/mL) and control subjects (median: 0.45 ng/mL; range: 0.14 to 1.70 ng/mL; PϽ0.05). Plasma 20-HETE significantly correlated with plasma renin activity in renovascular disease (r s ϭ0.67; nϭ10; PϽ0.05). The urinary excretion of 20-HETE was significantly lower in subjects with renovascular disease (median: 12.9 g/g of creatinine; range: 4.4 to 24.9 g/g of creatinine) than in control subjects (median: 31.0 g/g of creatinine; range: 11.9 to 102.8 g/g of creatinine; PϽ0.01) and essential hypertensive subjects (median: 35.9 g/g of creatinine; range: 14.0 to 72.5 g/g of creatinine; PϽ0.05). Total plasma EETs were lowest, as was the ratio of plasma EETs to plasma dihydroxyeicosatrienoic acids, an index of epoxide hydrolase activity, in renovascular disease (ratio: 2.4; range: 1.2 to 6.1) compared with essential hypertension (ratio: 3.4; range: 1.5 to 5.6) and control subjects (ratio: 6.8; range: 1.4 to 18.8; PϽ0.01). In conclusion, circulating levels of 20-HETE are increased and those of EETs are decreased in renovascular disease, whereas the urinary excretion of 20-HETE is reduced. Key Words: eicosanoids Ⅲ 20-HETE Ⅲ EETs Ⅲ DHETs Ⅲ renal artery stenosis Ⅲ hypertension Ⅲ angiotensin II I n the past 2 decades, the view that the cytochrome P450 (CYP) monooxygenase pathway of arachidonic acid (AA) metabolism affects blood pressure and contributes to the development of hypertension is supported by studies in several experimental models. 1,2 However, little information is available on possible contributions of CYP products to essential hypertension (EH) and human renal vascular hypertension. 3 The role of angiotensin II (Ang II) in the development of hypertension and ischemic nephropathy in the experimental model of the 2-kidney 1-clip hypertension is evident, because a fall in renal perfusion pressure triggers renin release. Vasoconstriction, vascular remodeling, glomerulosclerosis, and interstitial matrix deposition implicate an array of mediators that operate downstream from Ang II. 4 CYP monooxygenases are expressed in the renal vasculature and nephron, 5 gen...

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“…Three plasma samples of each group were analyzed by liquid chromatography/mass spectrometry to estimate the EET composition as described. 25 …”

Section: Measurements Of Eicosanoidsmentioning

confidence: 99%

“…25 The ions m/z of 319 and 327 were monitored for endogenous and deuterium (d8)-labeled EETs, the ions m/z of 391 and 397 were monitored for 20-HETE, and the ions m/z of 481 and 489 were monitored for DHETs. The amounts of eicosanoids were calculated from their peak area ratios according to standard curves, respectively.…”

Section: Measurements Of Eicosanoidsmentioning

confidence: 99%

Altered Release of Cytochrome P450 Metabolites of Arachidonic Acid in Renovascular Disease

et al. 2008

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“…whereas, unlike cis-and trans-EETs, it did not inhibit platelet aggregation (Jiang et al, 2004). Red blood cells (RBCs) are reservoirs for both cis-and trans-EETs that can be released by ATP stimulation of erythrocyte P2X 7 receptors (Jiang et al, 2007).…”

mentioning

confidence: 99%

Hydrolysis ofcis- andtrans-Epoxyeicosatrienoic Acids by Rat Red Blood Cells

Jiang¹,

Zhu²,

Mamczur³

et al. 2008

J Pharmacol Exp Ther

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Erythrocytes serve as reservoirs for cis-and trans-epoxyeicosatrienoic acids (EETs). Incubation of rat red blood cells (RBCs)with cis-and trans-EETs produces threo-and erythro-dihydroxyeicosatrienoic acids, respectively. The V max of EET hydrolysis by rat intact RBCs (2.35 Ϯ 0.24 pmol/min/10 8 RBCs for 14,15-trans-EET) decreased by approximately 2 to 3-fold sequentially from 14,15-, 11,12-to 8,9-EETs for both cis-and trans-isomers. The V max of trans-EET hydrolysis by RBCs is approximately 2 to 3 times that of the corresponding cis-EETs. Incubation of EETs with recombinant murine soluble epoxide hydrolase (sEH) yielded the same geometric and regio preferences of EET hydrolysis as with rat intact RBCs. The principal epoxide hydrolase activity for EET hydrolysis (approximately 90%) is present in the erythrocyte cytosol. Western blots of sEH suggested a concentration of sEH protein to be approximately 2 g/mg protein or 0.4 g/10 9 RBCs. The apparent K m values of EETs were between 1 and 2 M, close to the K m for purified sEH as reported. Erythrocyte hydration of cis-and trans-EETs was blocked by sEH inhibitors, 1,3-dicyclohexylurea and 4-[4-(3-adamantan-1-ylureido)cyclohexyloxy]benzoic acid. Erythrocyte sEH activity was inhibited more than 80% by 0.2% bovine serum albumin in the buffer. Preferred hydrolysis of 14,15-EETs and trans-epoxides characterizes sEH activity in RBCs that regulates the hydrolysis and release of cis-and trans-EETs in the circulation. Inhibition of sEH has produced antihypertensive and antiinflammatory effects. Because plasma trans-EETs would increase more than cis-EETs with sEH inhibition, the potential roles of trans-EETs and erythrocyte sEH in terms of circulatory regulation deserve attention.

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“…4) EETs inhabit inflammation responses by decreasing the cytokine-induced endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and to decrease leukocytes adhesion to the vascular wall by inhibiting nuclear factor κB (NF-κB) and IκB kinase [25]; 5) EETs have antithrombotic effects by inhibiting platelet adhesion to endothelial cells, inhibiting platelet aggregation, and enhancing the expression and activity of tissue plasminogen activator [26]; 6) EETs have been suggested to increase the proliferation of various cell types, including vascular smooth muscle cells and endothelial cells demonstrating a potential role of cytochrome P450 eicosanoids to promote vascular remodeling [27]. Recent studies suggest that human CYP2J2 gene is highly polymorphic [28], and it has been proposed that genetic polymorphisms within the gene might contribute to expression and/or activity of the enzyme and affect the metabolism of arachidonic acid, resulting in an altered synthesis of EETs.…”

Section: Cyp2j2 Derivedeets Functionmentioning

confidence: 99%

Single Nucleotide Polymorphism of the CYP2J2 Gene is Associated with Essential Hypertension in Uygur Population in China

Amjad¹

2014

Biochem Anal Biochem

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Background: Human Cytochrome P450 2J2 (CYP2J2) is the major arachidonic acid epoxygenase, which can metabolizes arachidonic acid (AA) to biologically active epoxyeicosatrienoic acids (EETs). The EETs are potent endogenous vasodilators and inhibitors of vascular inflammation. Recently, many evidence from models and human studies suggests that variability of CYP2J2 gene plays a mechanistic role in the development of hypertension. The aim of the present study was to assess the association between the human CYP2J2 gene polymorphism and Essential Hypertension (EH) in a Han and Uygur population in China. Methods:We used two independent case-control studies: a Han population (302 EH patients and 300 control subjects) and a Uygur population (567 EH patients and 215 control subjects). All EH patients and controls were genotyped for the same three single nucleotide polymorphisms (SNPs) (rs890293, rs11572223 and rs2280275) of CYP2J2 gene by a Real-time PCR instrument. Results:In the Uygur population, the distribution of SNP3 (rs2280275) genotypes, alleles and the dominant model (CC vs CT + TT) showed a significant difference between EH and control participants (for genotype: P=0.007; for allele: P=0.001; for dominant model: P=0.002). The significant difference in dominant model was retained after adjustment for covariates (OR: 3.500, 95% confidence interval [CI]: 1.680-7.300, P=0.001). However, all the above differences were not shown in the Han population. Conclusions:The CC genotype of rs2280275 in CYP2J2 gene could be a risk genetic marker of EH and T allele may be a protective genetic marker of EH in Uygur population in China.

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Identification of 5,6-trans-Epoxyeicosatrienoic Acid in the Phospholipids of Red Blood Cells

Cited by 54 publications

References 54 publications

Altered Release of Cytochrome P450 Metabolites of Arachidonic Acid in Renovascular Disease

Altered Release of Cytochrome P450 Metabolites of Arachidonic Acid in Renovascular Disease

Hydrolysis ofcis- andtrans-Epoxyeicosatrienoic Acids by Rat Red Blood Cells

Single Nucleotide Polymorphism of the CYP2J2 Gene is Associated with Essential Hypertension in Uygur Population in China

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