The common functional polymorphism -50G>T of the CYP2J2 gene is not associated with ischemic coronary and cerebrovascular events in an urban-based sample of Swedes

CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control

Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.

Association between CYP4A11 and EPHX2 genetic polymorphisms and chronic kidney disease progression in hypertensive patients

BACKGROUND

There are evidence indicating that some metabolites of arachidonic acid produced by cytochromes P450 (CYP) and epoxide hydroxylase (EPHX2), such as hydroxyeicosatetraenoic acids (HETEs), epoxyeicosatrienoic acids (EETs) or dihydroxyeicosatrienoic acids (DHETEs), play an important role in blood pressure regulation and they could contribute to the development of hypertension (HT) and kidney damage. Therefore, the main aim of the study was to evaluate whether the genetic polymorphisms of CYP2C8, CYP2C9, CYP2J2, CYP4F2, CYP4F11 and EPHX2, responsible for the formation of HETEs, EETs and DHETEs, are related to the progression of impaired renal function in a group of patients with hypertension.

METHODS

151HT patients from a hospital nephrology service were included in the study. Additionally, a group of 87 normotensive subjects were involved in the study as control group. For HT patients, a general biochemistry analysis, estimated glomerular filtration rate and genotyping for different CYPs and EPHX2 variant alleles was performed.

RESULTS

CYP4A11 rs3890011, rs9332982 and EPHX2 rs41507953 polymorphisms, according to the dominant model, presented a high risk of impaired kidney function, with odds ratios (OR) of 2.07 (1.00-4.32; P=0.049) 3.02 (1.11-8.23; P=0.030) and 3.59 (1.37-9.41; P=0.009), respectively, and the EPHX2 rs1042032 polymorphism a greater risk according to the recessive model (OR=6.23; 95% CI=1.50-25.95; P=0.007). However, no significant differences in allele frequencies between HT patients and in normotensive subjects for any of the SNP analysed. In addition, the patients with diagnosis of dyslipidemia (n=90) presented higher frequencies of EPHX2 K55R (rs41507953) and *35A>G (rs1042032) variants than patients without dyslipidemia, 4% vs. 14% (P=0.005) and 16 vs. 27% (P=0.02), respectively.

CONCLUSIONS

In this study has been found higher odds of impaired renal function progression associated with rs3890011 and rs9332982 (CYP4A11) and rs41507953 and rs1042032 (EPHX2) polymorphisms, which may serve as biomarkers for improve clinical interventions aimed at avoiding or delaying, in chronic kidney disease patients, progress to end-stage kidney disease needing dialysis or kidney transplant.

Crosstalk between adenosine receptors and CYP450-derived oxylipins in the modulation of cardiovascular, including coronary reactive hyperemic response

Adenosine is a ubiquitous endogenous nucleoside or autacoid that affects the cardiovascular system through the activation of four G-protein coupled receptors: adenosine A₁ receptor (A₁AR), adenosine A_2A receptor (A_2AAR), adenosine A_2B receptor (A_2BAR), and adenosine A₃ receptor (A₃AR). With the rapid generation of this nucleoside from cellular metabolism and the widespread distribution of its four G-protein coupled receptors in almost all organs and tissues of the body, this autacoid induces multiple physiological as well as pathological effects, not only regulating the cardiovascular system but also the central nervous system, peripheral vascular system, and immune system. Mounting evidence shows the role of CYP450-enzymes in cardiovascular physiology and pathology, and the genetic polymorphisms in CYP450s can increase susceptibility to cardiovascular diseases (CVDs). One of the most important physiological roles of CYP450-epoxygenases (CYP450-2C & CYP2J2) is the metabolism of arachidonic acid (AA) and linoleic acid (LA) into epoxyeicosatrienoic acids (EETs) and epoxyoctadecaenoic acid (EpOMEs) which generally involve in vasodilation. Like an increase in coronary reactive hyperemia (CRH), an increase in anti-inflammation, and cardioprotective effects. Moreover, the genetic polymorphisms in CYP450-epoxygenases will change the beneficial cardiovascular effects of metabolites or oxylipins into detrimental effects. The soluble epoxide hydrolase (sEH) is another crucial enzyme ubiquitously expressed in all living organisms and almost all organs and tissues. However, in contrast to CYP450-epoxygenases, sEH converts EETs into dihydroxyeicosatrienoic acid (DHETs), EpOMEs into dihydroxyoctadecaenoic acid (DiHOMEs), and others and reverses the beneficial effects of epoxy-fatty acids leading to vasoconstriction, reducing CRH, increase in pro-inflammation, increase in pro-thrombotic and become less cardioprotective. Therefore, polymorphisms in the sEH gene (Ephx2) cause the enzyme to become overactive, making it more vulnerable to CVDs, including hypertension. Besides the sEH, ω-hydroxylases (CYP450-4A11 & CYP450-4F2) derived metabolites from AA, ω terminal-hydroxyeicosatetraenoic acids (19-, 20-HETE), lipoxygenase-derived mid-chain hydroxyeicosatetraenoic acids (5-, 11-, 12-, 15-HETEs), and the cyclooxygenase-derived prostanoids (prostaglandins: PGD₂, PGF_2α; thromboxane: Txs, oxylipins) are involved in vasoconstriction, hypertension, reduction in CRH, pro-inflammation and cardiac toxicity. Interestingly, the interactions of adenosine receptors (A_2AAR, A₁AR) with CYP450-epoxygenases, ω-hydroxylases, sEH, and their derived metabolites or oxygenated polyunsaturated fatty acids (PUFAs or oxylipins) is shown in the regulation of the cardiovascular functions. In addition, much evidence demonstrates polymorphisms in CYP450-epoxygenases, ω-hydroxylases, and sEH genes (Ephx2) and adenosine receptor genes (ADORA1 & ADORA2) in the human population with the susceptibility to CVDs, including hypertension. CVDs are the number one cause of death globally, coronary artery disease (CAD) was the leading cause of death in the US in 2019, and hypertension is one of the most potent causes of CVDs. This review summarizes the articles related to the crosstalk between adenosine receptors and CYP450-derived oxylipins in vascular, including the CRH response in regular salt-diet fed and high salt-diet fed mice with the correlation of heart perfusate/plasma oxylipins. By using A_2AAR^-/-, A₁AR^-/-, eNOS^-/-, sEH^-/- or Ephx2^-/-, vascular sEH-overexpressed (Tie2-sEH Tr), vascular CYP2J2-overexpressed (Tie2-CYP2J2 Tr), and wild-type (WT) mice. This review article also summarizes the role of pro-and anti-inflammatory oxylipins in cardiovascular function/dysfunction in mice and humans. Therefore, more studies are needed better to understand the crosstalk between the adenosine receptors and eicosanoids to develop diagnostic and therapeutic tools by using plasma oxylipins profiles in CVDs, including hypertensive cases in the future.

Plasma epoxyeicosatrienoic acids and diabetes-related cardiovascular disease: The cardiovascular health study

Background

Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid that may impact atherosclerosis, and animal experimental studies suggest EETs protect cardiac function. Plasma EETs are mostly esterified to phospholipids and part of an active pool. To address the limited information about EETs and CVD in humans, we conducted a prospective study of total plasma EETs (free + esterified) and diabetes-related CVD in the Cardiovascular Health Study (CHS).

Methods

We measured 4 EET species and their metabolites, dihydroxyepoxyeicosatrienoic acids (DHETs), in plasma samples from 892 CHS participants with type 2 diabetes. We determined the association of EETs and DHETs with incident myocardial infarction (MI) and ischemic stroke using Cox regression.

Findings

During follow-up (median 7.5 years), we identified 150 MI and 134 ischemic strokes. In primary, multivariable analyses, elevated levels of each EET species were associated with non-significant lower risk of incident MI (for example, hazard ratio for 1 SD higher 14,15-EET: 0.86, 95% CI: 0.72–1.02; p=0.08). The EETs-MI associations became significant in analyses further adjusted for DHETs (hazard ratio for 1 SD higher 14,15-EET adjusted for 14,15-DHET: 0.76, 95% CI: 0.63–0.91; p=0.004). Elevated EET levels were associated with higher risk of ischemic stroke in primary but not secondary analyses. Three DHET species were associated with higher risk of ischemic stroke in all analyses.

Interpretation

Findings from this prospective study complement the extensive studies in animal models showing EETs protect cardiac function and provide new information in humans. Replication is needed to confirm the associations.

Funding

US National Institutes of Health.

Cardiomyocyte-specific CYP2J2 and its therapeutic implications

INTRODUCTION

Cytochrome P450s (CYPs) are a superfamily of monooxygenases with diverse biological roles. CYP2J2 is an isozyme highly expressed in the heart where it metabolizes endogenous substrates such as N-3/N-6 polyunsaturated fatty acids (PUFA) to produce lipid mediators involved in homeostasis and cardioprotective responses. Expanding our knowledge of the role CYP2J2 has within the heart is important for understanding its impact on cardiac health and disease.

AREAS COVERED

The objective of this review was to assess the state of knowledge regarding cardiac CYP2J2. A literature search was conducted using PubMed-MEDLINE (from 2022 and earlier) to evaluate relevant studies regarding CYP2J2 mediated cardioprotection, small molecule modulators, effects of CYP2J2 substrates toward biologically relevant effects and implications of CYP2J2 polymorphisms and sexual dimorphism in the heart.

EXPERT OPINION

Cardiac CYP2J2-mediated metabolism of endogenous and exogenous substrates have been shown to impact cardiac function. Identifying individual factors, like sex and age, that affect CYP2J2 require further elucidation to better understand CYP2J2's clinical relevance. Resolving the biological targets and activities of CYP2J2-derived PUFA metabolites will be necessary to safely target CYP2J2 and design novel analogues. Targeting CYP2J2 for therapeutic aims offers a potential novel approach to regulating cardiac homeostasis, drug metabolism and cardioprotection.

CYP2J2 Molecular Recognition: A New Axis for Therapeutic Design

Cytochrome P450 (CYP) epoxygenases are a special subset of heme-containing CYP enzymes capable of performing the epoxidation of polyunsaturated fatty acids (PUFA) and the metabolism of xenobiotics. This dual functionality positions epoxygenases along a metabolic crossroad. Therefore, structure-function studies are critical for understanding their role in bioactive oxy-lipid synthesis, drug-PUFA interactions, and for designing therapeutics that directly target the epoxygenases. To better exploit CYP epoxygenases as therapeutic targets, there is a need for improved understanding of epoxygenase structure-function. Of the characterized epoxygenases, human CYP2J2 stands out as a potential target because of its role in cardiovascular physiology. In this review, the early research on the discovery and activity of epoxygenases is contextualized to more recent advances in CYP epoxygenase enzymology with respect to PUFA and drug metabolism. Additionally, this review employs CYP2J2 epoxygenase as a model system to highlight both the seminal works and recent advances in epoxygenase enzymology. Herein we cover CYP2J2's interactions with PUFAs and xenobiotics, its tissue-specific physiological roles in diseased states, and its structural features that enable epoxygenase function. Additionally, the enumeration of research on CYP2J2 identifies the future needs for the molecular characterization of CYP2J2 to enable a new axis of therapeutic design.

Cyp2j5-Gene Deletion Affects on Acetylcholine and Adenosine-Induced Relaxation in Mice: Role of Angiotensin-II and CYP-Epoxygenase Inhibitor

Previously, we showed vascular endothelial overexpression of human-CYP2J2 enhances coronary reactive hyperemia in Tie2-CYP2J2 Tr mice, and eNOS^−/− mice had overexpression of CYP2J-epoxygenase with adenosine A_2A receptor-induced enhance relaxation, but we did not see the response in CYP2J-epoxygenase knockout mice. Therefore, we hypothesized that Cyp2j5-gene deletion affects acetylcholine- and 5'-N-ethylcarboxamidoadenosine (NECA) (adenosine)-induced relaxation and their response is partially inhibited by angiotensin-II (Ang-II) in mice. Acetylcholine (Ach)-induced response was tested with N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH, CYP-epoxygenase inhibitor; 10⁻⁵M) and Ang-II (10⁻⁶M). In Cyp2j5^−/− mice, ACh-induced relaxation was different from C57Bl/6 mice, at 10⁻⁵ M (76.1 ± 3.3 vs. 58.3 ± 5.2, P < 0.05). However, ACh-induced relaxation was not blocked by MS-PPOH in Cyp2j5^−/−: 58.5 ± 5.0%, P > 0.05, but blocked in C57Bl/6: 52.3 ± 7.5%, P < 0.05, and Ang-II reduces ACh-induced relaxation in both Cyp2j5^−/− and C57Bl/6 mice (38.8 ± 3.9% and 45.9 ± 7.8, P <0.05). In addition, NECA-induced response was tested with Ang-II. In Cyp2j5^−/− mice, NECA-induced response was not different from C57Bl/6 mice at 10⁻⁵M (23.1 ± 2.1 vs. 21.1 ± 3.8, P > 0.05). However, NECA-induced response was reduced by Ang-II in both Cyp2j5^−/− and C57Bl/6 mice (−10.8 ± 2.3% and 3.2 ± 2.7, P < 0.05). Data suggest that ACh-induced relaxation in Cyp2j5^−/− mice depends on nitric oxide (NO) but not CYP-epoxygenases, and the NECA-induced different response in male vs. female Cyp2j5^−/− mice when Ang-II treated.

Association of CYP2J2 polymorphism with susceptibility to psoriasis in Turkish population: a case-control study

BACKGROUND

Cytochrome P450 2J2 is mostly expressed in extrahepatic tissues; it metabolizes arachidonic acid to epoxyeicosatrienoic acids, with various cardio protective and anti-inflammatory effects. CYP2J2 polymorphism has been identified as a risk factor for cardiovascular diseases, but its association with psoriasis remains unknown.

OBJECTIVE

To evaluate CYP2J2 polymorphism as a risk factor for psoriasis in the Turkish population.

METHODS

There were 94 patients with psoriasis and 100 age- and sex-matched healthy controls included in the study. Detailed demographic and clinical characteristics were recorded, and Psoriasis Area and Severity Index (PASI) scores were calculated for psoriasis patients. Venous blood samples were collected from all the participants and CYP2J2 50G>T (rs890293) polymorphism was analyzed using polymerase chain reaction (PCR).

RESULTS

Both T allele and TT+GT genotype frequencies were increased in psoriasis vulgaris patients compared to the control group (p=0.024 and p=0.029 respectively, OR=2.82, 95% CI: 1.11-7.15) No association between CYP2J2 polymorphism and clinical features of psoriasis was identified.

STUDY LIMITATIONS

A limited number of patients were included in the study.

CONCLUSION

CYP2J2 50G>T (rs890293) polymorphism was associated with an increased risk for PsV in the Turkish population.

Ephx2-gene deletion affects acetylcholine-induced relaxation in angiotensin-II infused mice: role of nitric oxide and CYP-epoxygenases

Previously, we showed that adenosine A_2A receptor induces relaxation independent of NO in soluble epoxide hydrolase-null mice (Nayeem et al. in Am J Physiol Regul Integr Comp Physiol 304:R23-R32, 2013). Currently, we hypothesize that Ephx2-gene deletion affects acetylcholine (Ach)-induced relaxation which is independent of A_2AAR but dependent on NO and CYP-epoxygenases. Ephx2^-/- aortas showed a lack of sEH (97.1%, P < 0.05) but an increase in microsomal epoxide hydrolase (mEH, 37%, P < 0.05) proteins compared to C57Bl/6 mice, and no change in CYP2C29 and CYP2J protein (P > 0.05). Ach-induced response was tested with nitro-L-arginine methyl ester (L-NAME) NO-inhibitor; 10^-4 M), N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH) (CYP-epoxygenase inhibitor; 10^-5 M), 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE, an epoxyeicosatrienoic acid-antagonist; 10^-5 M), SCH-58261 (A_2AAR-antagonist; 10^-6 M), and angiotensin-II (Ang-II, 10^-6 M). In Ephx2^-/- mice, Ach-induced relaxation was not different from C57Bl/6 mice except at 10^-5 M (92.75 ± 2.41 vs. 76.12 ± 3.34, P < 0.05). However, Ach-induced relaxation was inhibited with L-NAME (Ephx2^-/-: 23.74 ± 3.76% and C57Bl/6: 11.61 ± 2.82%), MS-PPOH (Ephx2^-/-: 48.16 ± 6.53% and C57Bl/6: 52.27 ± 7.47%), and 14,15-EEZE (Ephx2^-/-: 44.29 ± 8.33% and C57Bl/6: 39.27 ± 7.47%) vs. non-treated (P < 0.05). But, it did not block with SCH-58261 (Ephx2^-/-: 68.75 ± 11.41% and C57Bl/6: 66.26 ± 9.43%, P > 0.05) vs. non-treated (P > 0.05). Interestingly, Ang-II attenuates less relaxation in Ehx2^-/- vs. C57Bl/6 mice (58.80 ± 7.81% vs. 45.92 ± 7.76, P < 0.05). Our data suggest that Ach-induced relaxation in Ephx2^-/- mice depends on NO and CYP-epoxygenases but not on A_2A AR, and Ephx2-gene deletion attenuates less Ach-induced relaxation in Ang-II-infused mice.

A comprehensive study revealed SNP-SNP interactions and a sex-dependent relationship between polymorphisms of the CYP2J2 gene and hypertension risk

This study investigated whether common polymorphisms of cytochrome P450 2J2 (CYP2J2), a major enzyme that controls the biosynthesis of vasoactive epoxyeicosatrienoic acids, are collectively involved in the molecular basis of essential hypertension (EH). A total of 2314 unrelated Russian subjects from the Kursk (discovery sample: 913 EH patients and 645 controls) and Belgorod (replication sample: 345 EH patients and 411 controls) regions were recruited for this study. Eight single nucleotide polymorphisms (SNPs), including rs890293, rs11572182, rs10493270, rs1155002, rs2280275, rs7515289, rs11572325, and rs10889162, of CYP2J2 were genotyped using the MassARRAY 4 system and TaqMan-based assays. Significant associations were identified among the SNPs rs890293 (OR = 2.17, 95%CI 1.30-3.65), rs2280275 (OR = 1.59, 95%CI 1.10-2.37) and rs11572325 (OR = 1.89, 95%CI 1.22-2.95) and the risk of EH in females from the Kursk population. Sixteen CYP2J2 genotype combinations only showed significant associations with EH risk only in females. A common haplotype, T-T-G-C-C-C-T-A, increased the risk of EH in females. The bioinformatic analysis enabled identification of the SNPs that possess regulatory potential and/or are located within the binding sites for multiple transcription factors that play roles in the pathways involved in hypertension pathogenesis. Moreover, the polymorphisms rs890293, rs2280275, and rs11572325 were found to be significantly associated with hypertension risk in the Belgorod population. In conclusion, the rs2280275 and rs11572325 SNPs of CYP2J2 may be considered novel genetic markers of hypertension, at least in Russian women. However, sex-specific associations between CYP2J2 gene polymorphisms and hypertension require further investigation to clarify the specific genetic and/or environmental factors that are responsible for the increased disease susceptibility of women compared to that of men.

Regulation of CYP2J2 and EET Levels in Cardiac Disease and Diabetes

Cytochrome P450 2J2 (CYP2J2) is a known arachidonic acid (AA) epoxygenase that mediates the formation of four bioactive regioisomers of cis-epoxyeicosatrienoic acids (EETs). Although its expression in the liver is low, CYP2J2 is mainly observed in extrahepatic tissues, including the small intestine, pancreas, lung, and heart. Changes in CYP2J2 levels or activity by xenobiotics, disease states, or polymorphisms are proposed to lead to various organ dysfunctions. Several studies have investigated the regulation of CYP2J2 and EET formation in various cell lines and have demonstrated that such regulation is tissue-dependent. In addition, studies linking CYP2J2 polymorphisms to the risk of developing cardiovascular disease (CVD) yielded contradictory results. This review will focus on the mechanisms of regulation of CYP2J2 by inducers, inhibitors, and oxidative stress modeling certain disease states in various cell lines and tissues. The implication of CYP2J2 expression, polymorphisms, activity and, as a result, EET levels in the pathophysiology of diabetes and CVD will also be discussed.

Meta-analysis of the association of the CYP2J2 G-50T polymorphism with coronary artery disease

The association of the CYP2J2 G-50T polymorphism with coronary artery disease has been explored, but the results remain controversial. Thus, a meta-analysis was conducted to provide a comprehensive estimate of this association. We selected ten articles encompassing 12 independent case-control studies with 7063 cases and 10,453 controls for this meta-analysis. Overall, we found significant associations between the CYP2J2 G-50T polymorphism and coronary artery disease risk in three genetic models (allele model: odds ratio (OR) = 1.19, 95% confidence interval (CI) = 1.05–1.34; homozygote model: OR = 2.25, 95% CI = 1.27–4.01; recessive model: OR = 2.17, 95% CI = 1.22–3.86). In these three genetic models, a significant association was observed in Caucasians but not in Asians when the data were stratified by ethnicity. However, no significant associations were found between the CYP2J2 polymorphism G-50T and coronary artery disease risk in heterozygote model and dominant model. In conclusion, our meta-analysis suggested that the CYP2J2 G-50T polymorphism was associated with coronary artery disease risk in the allele, homozygote and recessive models in Caucasians.

Effect of Cytochrome P450 Metabolites of Arachidonic Acid in Nephrology

Thirty-five years ago, a third pathway for the metabolism of arachidonic acid by cytochrome P450 enzymes emerged. Subsequent work revealed that 20-hydroxyeicosatetraenoic and epoxyeicosatrienoic acids formed by these pathways have essential roles in the regulation of renal tubular and vascular function. Sequence variants in the genes that produce 20-hydroxyeicosatetraenoic acid are associated with hypertension in humans, whereas the evidence supporting a role for variants in the genes that alter levels of epoxyeicosatrienoic acids is less convincing. Studies in animal models suggest that changes in the production of cytochrome P450 eicosanoids alter BP. However, the mechanisms involved remain controversial, especially for 20-hydroxyeicosatetraenoic acid, which has both vasoconstrictive and natriuretic actions. Epoxyeicosatrienoic acids are vasodilators with anti-inflammatory properties that oppose the development of hypertension and CKD; 20-hydroxyeicosatetraenoic acid levels are elevated after renal ischemia and may protect against injury. Levels of this eicosanoid are also elevated in polycystic kidney disease and may contribute to cyst formation. Our review summarizes the emerging evidence that cytochrome P450 eicosanoids have a role in the pathogenesis of hypertension, polycystic kidney disease, AKI, and CKD.

Association of CYP2J2 gene polymorphisms with ischemic stroke and stroke subtypes in Chinese population

BACKGROUND AND PURPOSE

Ischemic stroke (IS) is the main cause of mortality and disability among the old people in China and is a multifactorial disease influenced by many factors including genetic factors like the allele for CYP 2J2. It has been demonstrated that CYP2J2 polymorphisms alter the transcriptional activity. However, studies on the association between CYP2J2-50G/T polymorphism and IS have reported conflicting results. Thus, our study aimed to examine the association between 4 variants in the CYP2J2 gene and the risk of IS and its subtypes, in the Chinese population.

MATERIALS AND METHODS

In this study, genotyping was performed by using polymerase chain reaction (PCR) sequencing for 202 IS patients and 206 age- and sex-matched controls. Odds ratios (ORs) and confidence interval (CI) were estimated by multivariate logistic regression and PCR results were confirmed by DNA sequencing. A meta-analysis was conducted to evaluate the association of CYP2J2-50G>T polymorphism with the risk of IS in Chinese population by calculating pooled OR.

RESULTS

We found this polymorphism was significantly associated with IS (17.82% vs. 10.68%, P = 0.039). Multiple logistic regression analysis revealed that GT genotype was associated with a significantly high risk of IS (OR = 2.32, 95% CI: 1.21-4.45, P = 0. 011) after adjustment for other confounding factors such as hypertension, diabetes, heart disease, smoking habit, family history, triglyceride and low-density lipoprotein levels. We also found a significant association of GT genotype with small artery occlusion (SAA) (P < 0.05; OR = 2.22; 95% CI: 1.043-4.72). Meta-analysis results also showed that the GT genotype carriers had a negative effect on the risk of IS in Chinese population with overall OR of 1.40 (95% CI: 1.06-1.84).

CONCLUSION

The findings of the present study suggested that polymorphism in -50G/T position of CYP2J2 gene might be a risk factor for IS in Chinese population. Further large prospective studies were required to confirm these findings.

Beneficial effects of ω-3 PUFA in children on cardiovascular risk factors during childhood and adolescence

Omega-3 polyunsatured fatty acids (ω-3 PUFA) are essential nutrients mainly derived from fish and seafood but present also in vegetables such as nuts and seed-oils. Some epidemiological and clinical studies indicate a protection of ω-3 FA against cardiovascular disease and a favourable effect on cardiovascular risk factors control in adults. The evidences of their effects in children and adolescents are scanty but a possible beneficial role, especially for insulin sensitivity and blood pressure control, has been proposed. In this review we want to focus especially on the evidences, which could justify the assumption of ω-3 in children and adolescents, and to underline the aspects which need further investigation. Mechanisms through which ω-3 FA act are manifolds and still a matter of investigation: beside their interaction with ion channel and their influence on plasma membrane fluidity, probably the main effect is acting as competitor for cytochrome P-450 (CYP) with respect to ω-6 FA. Thus, they can modulate the biosynthesis of eicosanoids and other lipid mediators, which likely exert a protective action. Another suggestive hypothesis is that their beneficial effect is not dependent only on the intake of ω-3 FA, but also on the complex interaction between different nutrients including ω-3 and other FAs with polymorphisms in genes involved in ω-3 FA modulation. This complex interaction has seldom been explored in children and adolescents. Further studies are needed to investigate all these points in order to find a better collocation of ω-3 FA on the available armamentarium for preventive, possibly individualized, medicine.

Cytochrome P450 2J2: distribution, function, regulation, genetic polymorphisms and clinical significance

Cytochrome P450 2J2 (CYP2J2) is an enzyme mainly found in human extrahepatic tissues, with predominant expression in the cardiovascular systems and lower levels in the intestine, kidney, lung, pancreas, brain, liver, etc. During the past 15 years, CYP2J2 has attracted much attention for its epoxygenase activity in arachidonic acid (AA) metabolism. It converts AA to four epoxyeicosatrienoic acids (EETs) that have various biological effects, especially in the cardiovascular systems. In recent publications, CYP2J2 is shown highly expressed in various human tumor cells, and its EET metabolites are demonstrated to implicate in the pathologic development of human cancers. CYP2J2 is also a human CYP that involved in phase I xenobiotics metabolism. Antihistamine drugs and many other compounds were identified as the substrates of CYP2J2, and studies have demonstrated that these substrates have a broad structural diversity. CYP2J2 is found not readily induced by known P450 inducers; however, its expression could be regulated in some pathological conditions, might through the activator protein-1(AP-1), the AP-1-like element and microRNA let-7b. Several genetic mutations in the CYP2J2 gene have been identified in humans, and some of them have been shown to have potential associations with some diseases. With the increasing awareness of its roles in cancer disease and drug metabolism, studies about CYP2J2 are still going on, and various inhibitors of CYP2J2 have been determined. Further studies are needed to delineate the roles of CYP2J2 in disease pathology, drug development and clinical practice.

Roles of the epoxygenase CYP2J2 in the endothelium

Cytochrome p450 (CYP)2J2 is an epoxygenase enzyme that metabolises arachidonic acid to epoxyeicosatrienoic acids (EETs). EETs are inactivated by soluble epoxide hydrolase (sEH), which converts them in to their corresponding dihydroxyeicosatrienoic acids (DHETs). CYP2J2 is highly expressed in cardiovascular tissue including the heart and vascular endothelial cells. CYP2J2 and the EETs it produces have been shown to have a diverse range of effects on the vasculature, including the regulation of inflammation, vascular tone, cellular proliferation, angiogenesis, and metabolism. This review will examine these established and emerging roles of CYP2J2 in the biology of vascular endothelial cells.

Adenosine A2A receptor modulates vascular response in soluble epoxide hydrolase-null mice through CYP-epoxygenases and PPARγ

The interaction between adenosine and soluble epoxide hydrolase (sEH) in vascular response is not known. Therefore, we hypothesized that lack of sEH in mice enhances adenosine-induced relaxation through A(2A) adenosine receptors (AR) via CYP-epoxygenases and peroxisome proliferator-activated receptor γ (PPARγ). sEH(-/-) showed an increase in A(2A) AR, CYP2J, and PPARγ by 31%, 65%, and 36%, respectively, and a decrease in A(1)AR and PPARα (30% and 27%, respectively) vs. sEH(+/+). 5'-N-ethylcarboxamidoadenosine (NECA, an adenosine receptor agonist), CGS 21680 (A(2A) AR-agonist), and GW 7647 (PPARα-agonist)-induced responses were tested with nitro-l-arginine methyl ester (l-NAME) (NO-inhibitor; 10(-4) M), ZM-241385, SCH-58261 (A(2A) AR-antagonists; 10(-6) M), 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE, an epoxyeicosatrienoic acid-antagonist; 10(-5) M), 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA; 10 μM) or trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB, sEH-inhibitors; 10(-5) M), and T0070907 (PPARγ-antagonist; 10(-7) M). In sEH(-/-) mice, ACh response was not different from sEH(+/+) (P > 0.05), and l-NAME blocked ACh-responses in both sEH(-/-) and sEH(+/+) mice (P < 0.05). NECA (10(-6) M)-induced relaxation was higher in sEH(-/-) (+12.94 ± 3.2%) vs. sEH(+/+) mice (-5.35 ± 5.2%); however, it was blocked by ZM-241385 (-22.42 ± 1.9%) and SCH-58261(-30.04 ± 4.2%). CGS-21680 (10(-6) M)-induced relaxation was higher in sEH(-/-) (+37.4 ± 5.4%) vs. sEH(+/+) (+2.14 ± 2.8%). l-NAME (sEH(-/-), +30.28 ± 4.8%, P > 0.05) did not block CGS-21680-induced response, whereas 14,15-EEZE (-7.1 ± 3.7%, P < 0.05) did. Also, AUDA and t-AUCB did not change CGS-21680-induced response in sEH(-/-) (P > 0.05), but reversed in sEH(+/+) (from +2.14 ± 2.8% to +45.33 ± 4.1%, and +63.37 ± 7.2, respectively). PPARα-agonist did not relax as CGS 21680 (-2.48 ± 1.1 vs. +37.4 ± 5.4%) in sEH(-/-), and PPARγ-antagonist blocked (from +37.4 ± 5.4% to +9.40 ± 3.1) CGS 21680-induced relaxation in sEH(-/-). Our data suggest that adenosine-induced relaxation in sEH(-/-) may depend on the upregulation of A(2A) AR, CYP2J, and PPARγ, and the downregulation of A(1) AR and PPARα.

Effect of cytochrome P450 polymorphism on arachidonic acid metabolism and their impact on cardiovascular diseases

Cardiovascular diseases (CVDs) remain the leading cause of death in the developed countries. Taking into account the mounting evidence about the role of cytochrome P450 (CYP) enzymes in cardiovascular physiology, CYP polymorphisms can be considered one of the major determinants of individual susceptibility to CVDs. One of the important physiological roles of CYP enzymes is the metabolism of arachidonic acid. CYP epoxygenases such as CYP1A2, CYP2C, and CYP2J2 metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs) which generally possess vasodilating, anti-inflammatory, anti-apoptotic, anti-thrombotic, natriuretic, and cardioprotective effects. Therefore, genetic polymorphisms causing lower activity of these enzymes are generally associated with an increased risk of several CVDs such as hypertension and coronary artery disease. EETs are further metabolized by soluble epoxide hydrolase (sEH) to the less biologically active dihydroxyeicosatrienoic acids (DHETs). Therefore, sEH polymorphism has also been shown to affect arachidonic acid metabolism and to be associated with CVDs. On the other hand, CYP omega-hydroxylases such as CYP4A11 and CYP4F2 metabolize arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE) which has both vasoconstricting and natriuretic effects. Genetic polymorphisms causing lower activity of these enzymes are generally associated with higher risk of hypertension. Nevertheless, some studies have denied the association between polymorphisms in the arachidonic acid pathway and CVDs. Therefore, more research is needed to confirm this association and to better understand the pathophysiologic mechanisms behind it.