A haplotype of the CYP4F2 gene is associated with cerebral infarction in Japanese men

Suggestive evidence of CYP4F2 gene polymorphisms with HAPE susceptibility in the Chinese Han population

High altitude pulmonary edema (HAPE) is a common respiratory disease in the high altitude area, which is rapid and harmful. We firstly conducted a case-control study to assess the potential association of CYP4F2 gene polymorphisms with HAPE susceptibility in the Chinese Han population. The study recruited 238 patients with HAPE and 230 healthy controls in Northwest China. Genomic DNA was extracted from blood samples, and gene polymorphisms were detected using the Agena MassARRAY platform. Odds ratios (ORs), 95% confidence intervals (95% CIs), and P-value were used to evaluate the relationship between HAPE risk and CYP4F2 gene polymorphisms. Multi-factor dimension reduction (MDR) was used to assess the optimal interaction of CYP4F2 gene polymorphisms on HAPE risk. We found rs3093193 was shown to reduce the risk of HAPE (OR = 0.70, 95% CI = 0.52-0.93, P = 0.014), while rs12459936 was increased the susceptibility to HAPE (OR = 2.08, 95% CI = 1.33-3.26, P = 0.001). Age stratified analysis revealed that rs3093193 and rs12459936 were correlated with HAPE risk in people at age > 32 years old, and rs3093193 and rs3093110 were correlated with the HAPE risk in people at age ≤ 32 years old. Gender stratification analysis was found that rs3093193, rs12459936, and rs3093110 were all related to HAPE risk in males. A combination of rs12459936 and rs3093110 was the best multi-loci model with the highest testing accuracy. Our study is the first to provide the association between CYP4F2 gene polymorphisms and HAPE risk in the Chinese Han population.

20-HETE-promoted cerebral blood flow autoregulation is associated with enhanced pericyte contractility

We previously reported that deficiency in 20-HETE or CYP4A impaired the myogenic response and autoregulation of cerebral blood flow (CBF) in rats. The present study demonstrated that CYP4A was coexpressed with alpha-smooth muscle actin (α-SMA) in vascular smooth muscle cells (VSMCs) and most pericytes along parenchymal arteries (PAs) isolated from SD rats. Cell contractile capabilities of cerebral VSMCs and pericytes were reduced with a 20-HETE synthesis inhibitor, HET0016, but restored with 20-HETE analog WIT003. Similarly, intact myogenic responses of the middle cerebral artery and PA of SD rats decreased with HET0016 and were rescued by WIT003. The myogenic response of the PA was abolished in SS and was restored in SS.BN5 and SS.Cyp4a1 rats. HET0016 enhanced CBF and impaired its autoregulation in the surface and deep cortex of SD rats. These results demonstrate that 20-HETE has a direct effect on cerebral mural cell contractility that may play an essential role in controlling cerebral vascular function.

The correlation between CYP4F2 variants and chronic obstructive pulmonary disease risk in Hainan Han population

Background

Chronic obstructive pulmonary disease (COPD) is a complex pulmonary disease. Cytochrome P450 family 4 subfamily F member 2 (CYP4F2) belongs to cytochrome P450 superfamily of enzymes responsible for metabolism, its single nucleotide polymorphisms (SNPs) were reported to be involved in metabolism in the development of many diseases. The study aimed to assess the relation between CYP4F2 SNPs and COPD risk in the Hainan Han population.

Method

We genotyped five SNPs in CYP4F2 in 313 cases and 508 controls by Agena MassARRAY assay. The association between CYP4F2 SNPs and COPD risk were assessed by χ² test and genetic models. Besides, logistic regression analysis was introduced into the calculation for odds ratio (OR) and 95% confidence intervals (CIs).

Results

Allele model analysis indicated that rs3093203 A was significantly correlated with an increased risk of COPD. Also, rs3093193 G and rs3093110 G were associated with a reduced COPD risk. In the genetic models, we found that rs3093203 was related to an increased COPD risk, while rs3093193 and rs3093110 were related to a reduced risk of COPD. After gender stratification, rs3093203, rs3093193 and rs3093110 showed the association with COPD risk in males. With smoking stratification, rs3093144 was significantly associated with an increased risk of COPD in smokers. CYP4F2 SNPs were significantly associated with COPD risk.

Conclusions

Our findings illustrated potential associations between CYP4F2 polymorphisms and COPD risk. However, large-scale and well-designed studies are needed to determine conclusively the association between the CYP4F2 SNPs and COPD risk.

Conflicting Roles of 20-HETE in Hypertension and Stroke

Hypertension is the most common modifiable risk factor for stroke, and understanding the underlying mechanisms of hypertension and hypertension-related stroke is crucial. 20-hydroxy-5, 8, 11, 14-eicosatetraenoic acid (20-HETE), which plays an important role in vasoconstriction, autoregulation, endothelial dysfunction, angiogenesis, inflammation, and blood-brain barrier integrity, has been linked to hypertension and stroke. 20-HETE can promote hypertension by potentiating the vascular response to vasoconstrictors; it also can reduce blood pressure by inhibition of sodium transport in the kidney. The production of 20-HETE is elevated after the onset of both ischemic and hemorrhagic strokes; on the other hand, subjects with genetic variants in CYP4F2 and CYP4A11 that reduce 20-HETE production are more susceptible to stroke. This review summarizes recent genetic variants in CYP4F2, and CYP4A11 influencing 20-HETE production and discusses the role of 20-HETE in hypertension and the susceptibility to the onset, progression, and prognosis of ischemic and hemorrhagic strokes.

The impact of CYP2C19*2, CYP4F2*3, and clinical factors on platelet aggregation, CYP4F2 enzyme activity, and 20-hydroxyeicosatetraenoic acid concentration in patients treated with dual antiplatelet therapy

: The aim of the current study was to evaluate the impact of CYP2C192 (rs4244285), CYP4F23 (rs2108622), and nongenetic factors on platelet aggregation and to investigate the mechanism of CYP4F2's effect on platelet aggregation in the patients treated with dual antiplatelet therapy. A total of 146 patients were included in this study. Ticagrelor or clopidogrel were administered in a loading dose of 180 mg and 600 mg, respectively, in combination with aspirin (300 mg). Blood samples for analysis were taken the next morning after antiplatelet therapy induction. Clopidogrel users with the CYP2C1912 variant had higher platelet aggregation values (median 43, range 30-54%) compared with 11 wild-type carriers (median 33, range 15-77%; P = 0.009). Carriers of the CYP4F213 variant had higher platelet aggregation values than carriers of the 33 variant (median 34, range 8-70% vs. median 24.5, range 10-47%, P = 0.016, respectively). Higher CYP4F2 concentrations were detected in clopidogrel users than in ticagrelor users (median 3.6, range 1.6-22.0 ng/ml vs. median 2.3, range 1.6-27.2 ng/ml, P = 0.056, respectively) and in carriers of the CYP4F213 variant compared with carriers of the 11 variant (median 4.3, range 1.6-27.2 ng/ml vs. median 2.4, range 1.6-22.0 ng/ml, P = 0.009, respectively). No correlation between plasma 20-hydroxyeicosatetraenoic acid and CYP4F2 enzyme concentrations were detected (r = -0.045, P = 0.587). Our results proved that CYP2C192 might significantly affect antiplatelet function of clopidogrel. Plasma CYP4F2 concentrations were significantly lower in ticagrelor users than in clopidogrel users.

20-HETE in the regulation of vascular and cardiac function

20-HETE, the ω-hydroxylation product of arachidonic acid catalyzed by enzymes of the cytochrome P450 (CYP) 4A and 4F gene families, is a bioactive lipid mediator with potent effects on the vasculature including stimulation of smooth muscle cell contractility, migration and proliferation as well as activation of endothelial cell dysfunction and inflammation. Clinical studies have shown elevated levels of plasma and urinary 20-HETE in human diseases and conditions such as hypertension, obesity and metabolic syndrome, myocardial infarction, stroke, and chronic kidney diseases. Studies of polymorphic associations also suggest an important role for 20-HETE in hypertension, stroke and myocardial infarction. Animal models of increased 20-HETE production are hypertensive and are more susceptible to cardiovascular injury. The current review summarizes recent findings that focus on the role of 20-HETE in the regulation of vascular and cardiac function and its contribution to the pathology of vascular and cardiac diseases.

Association of Optic Neuritis with CYP4F2 Gene Single Nucleotide Polymorphism and IL-17A Concentration

Background

The aetiology and pathophysiology of optic neuritis (ON) is not absolutely clear but genetic and inflammatory factors may be also involved in its development. The aim of the present study was to determine the influence of single nucleotide polymorphism (SNP) of CYP4F2 (rs1558139) and serum levels of IL-17A on ON development.

Materials and Methods

Forty patients with ON and 164 control subjects were evaluated. Patients were divided by gender, also ON patients were divided into two subgroups: ON with and without multiple sclerosis (MS). CYP4F2 rs1558139 was genotyped using real-time PCR. Serum IL-17A levels were measured using ELISA IL-17A kits.

Results

We found that A/A genotype of CYP4F2 rs1558139 was statistically significantly more frequent in men with ON and MS than in women: 57.1% versus 0%, p = 0.009. Also, allele A was statistically significantly more frequent in men with ON and MS than in women: 71.4% versus 37.5%, p = 0.044. Serum levels of IL-17A were higher in ON group than in control group: (median, IQR): 20.55 pg/ml, 30.66 pg/ml versus 8.97 pg/ml, 6.24 pg/ml, p < 0.001.

Conclusion

The higher IL-17A levels were found to be associated with ON, while allele A at rs1558139 was associated only with ON with MS in male patients.

Cytochrome P450 family 4 subfamily F member 2 (CYP4F2) rs1558139, rs2108622 polymorphisms and susceptibility to several cardiovascular and cerebrovascular diseases

Background

Inconsistent conclusions have been reported for the genetic relationship between CYP4F2 (Cytochrome P450 Family 4 Subfamily F Member 2) polymorphisms and the susceptibility to cardiovascular and cerebrovascular diseases.

Methods

We performed a meta-analysis to assess the potential role of rs1558139 C/T and rs2108622 G/A polymorphisms of CYP4F2 in the risks of cardiovascular and cerebrovascular diseases. The retrieval of four databases, including PubMed, Web of Science (WOS), China National Knowledge Infrastructure (CNKI) and WANFANG DATA, was conducted. Mantel-Haenszel statistics for association test, Cochran’s Q statistic, sensitivity analysis for heterogeneity assessment, and Begg’s/Egger’s tests for publication bias evaluation were performed under allele, homozygote, heterozygote, dominant, and recessive models, respectively.

Results

A total of 597 articles were initially obtained by database searching, and twenty eligible articles were finally included. For rs1558139, a decreased risk of cardiovascular and cerebrovascular diseases was observed in the overall meta-analysis and in “hypertension”, “population-based” and “male” subgroups under models of T vs. C, CT vs. CC, and CT + TT vs. CC [all P values in association tests < 0.05, odds ratio (OR) < 1]. For rs2108622, a decreased coronary artery disease (CAD) risk was observed in the subgroup meta-analysis based on disease type under all genetic models (all P values in association tests < 0.05, OR< 1). Begg’s/Egger’s tests excluded the potential publication bias, while sensitivity analysis data supported the stability of the above results.

Conclusion

C/T genotype of CYP4AF2 rs1558139 may be linked to the decreased risk of hypertension in the male patients of Asian populations, while CYP4F2 rs2108622 is likely associated with reduced susceptibility to CAD.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0763-y) contains supplementary material, which is available to authorized users.

Clinical Implications of 20-Hydroxyeicosatetraenoic Acid in the Kidney, Liver, Lung and Brain: An Emerging Therapeutic Target

Cytochrome P450-mediated metabolism of arachidonic acid (AA) is an important pathway for the formation of eicosanoids. The ω-hydroxylation of AA generates significant levels of 20-hydroxyeicosatetraenoic acid (20-HETE) in various tissues. In the current review, we discussed the role of 20-HETE in the kidney, liver, lung, and brain during physiological and pathophysiological states. Moreover, we discussed the role of 20-HETE in tumor formation, metabolic syndrome and diabetes. In the kidney, 20-HETE is involved in modulation of preglomerular vascular tone and tubular ion transport. Furthermore, 20-HETE is involved in renal ischemia/reperfusion (I/R) injury and polycystic kidney diseases. The role of 20-HETE in the liver is not clearly understood although it represents 50%-75% of liver CYP-dependent AA metabolism, and it is associated with liver cirrhotic ascites. In the respiratory system, 20-HETE plays a role in pulmonary cell survival, pulmonary vascular tone and tone of the airways. As for the brain, 20-HETE is involved in cerebral I/R injury. Moreover, 20-HETE has angiogenic and mitogenic properties and thus helps in tumor promotion. Several inhibitors and inducers of the synthesis of 20-HETE as well as 20-HETE analogues and antagonists are recently available and could be promising therapeutic options for the treatment of many disease states in the future.

Molecular mechanisms and cell signaling of 20-hydroxyeicosatetraenoic acid in vascular pathophysiology

Cytochrome P450s enzymes catalyze the metabolism of arachidonic acid to epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid and hydroxyeicosatetraeonic acid (HETEs). 20-HETE is a vasoconstrictor that depolarizes vascular smooth muscle cells by blocking K+ channels. EETs serve as endothelial derived hyperpolarizing factors. Inhibition of the formation of 20-HETE impairs the myogenic response and autoregulation of renal and cerebral blood flow. Changes in the formation of EETs and 20-HETE have been reported in hypertension and drugs that target these pathways alter blood pressure in animal models. Sequence variants in CYP4A11 and CYP4F2 that produce 20-HETE, UDP-glucuronosyl transferase involved in the biotransformation of 20-HETE and soluble epoxide hydrolase that inactivates EETs are associated with hypertension in human studies. 20-HETE contributes to the regulation of vascular hypertrophy, restenosis, angiogenesis and inflammation. It also promotes endothelial dysfunction and contributes to cerebral vasospasm and ischemia-reperfusion injury in the brain, kidney and heart. This review will focus on the role of 20-HETE in vascular dysfunction, inflammation, ischemic and hemorrhagic stroke and cardiac and renal ischemia reperfusion injury.

Interaction Between CYP4F2 rs2108622 and CPY4A11 rs9333025 Variants Is Significantly Correlated with Susceptibility to Ischemic Stroke and 20-Hydroxyeicosatetraenoic Acid Level

AIMS

To investigate the association of four variants of two CYP ω-hydroxylase genes and 20-hydroxyeicosatetraenoic acid (HETE) levels with ischemic stroke (IS) and whether gene-gene interactions between these genes increase the risk of IS.

METHODS

Three hundred ninety-six patients with IS and 378 controls were genotyped for rs2269231, rs9333025, rs2108622, and rs3093135. Gene-gene interactions were analyzed using generalized multifactor dimensionality reduction (GMDR) methods. The 20-HETE levels was measured in 218 IS patients and 126 controls.

RESULTS

The frequency of the GG genotype of rs9333025 was significantly higher in IS patients than in controls (p < 0.001). The GMDR analysis showed a significant gene-gene interaction between rs9333025 and rs2108622 (p = 0.0116). This gene-gene interaction predicted a significantly higher risk of IS in individuals carrying the genotypes of rs9333025 GG and rs2108622 GG (odds ratio = 1.92, 95% confidence interval = 1.12-4.26, p = 0.007). The plasma levels of 20-HETE were significantly higher in IS patients than in controls, and IS patients carrying the genotype combination of rs9333025 GG and rs2108622 GG had higher 20-HETE levels than IS patients with other combinations of the two variants.

CONCLUSION

CYP4A1l rs9333025 GG and CYP4F2 rs2108622 GG two-loci interaction significantly increases the risk for IS and an elevated 20-HETE level.

Cerebral Hypoperfusion in Hereditary Coproporphyria (HCP): A Single Photon Emission Computed Tomography (SPECT) Study

Background: Hereditary Coproporphyria (HCP) is characterized by abdominal pain, neurologic symptoms and psychiatric disorders, even if it might remain asymptomatic. The pathophysiology of both neurologic and psychiatric symptoms is not fully understood. Therefore, aiming to evaluate a possible role of brain blood flow disorders, we have retrospectively investigated cerebral perfusion patterns in Single Photon Emission Computed Tomography (SPECT) studies in HCP patients.

Materials & Methods: We retrospectively evaluated the medical records of patients diagnosed as being affected by HCP. A total of seven HCP patients had been submitted to brain perfusion SPECT study with 99mTc-Exametazime (hexamethylpropyleneamine oxime, HMPAO) or with its functionally equivalent 99mTc-Bicisate (ECD or Neurolite) according with common procedures. In 3 patients the scintigraphic study had been repeated for a second time after the first evaluation at 3, 10 and 20 months, respectively. All the studied subjects had been also submitted to an electromyographic and a Magnetic Resonance Imaging (MRI) study of the brain.

Results: Mild to moderate perfusion defects were detected in temporal lobes (all 7 patients), frontal lobes (6 patients) and parietal lobes (4 patients). Occipital lobe, basal ganglia and cerebellar involvement were never observed. In the three subjects in which SPECT study was repeated, some recovery of hypo-perfused areas and appearance of new perfusion defects in other brain regions have been found. In all patients electromyography resulted normal and MRI detected few unspecific gliotic lesions only in one patient.

Discussion & Conclusions: Since perfusion abnormalities were usually mild to moderate, this can probably explain the normal pattern observed at MRI studies. Compared to MRI, SPECT with 99mTc showed higher sensitivity in HCP patients. Changes observed in HCP patients who had more than one study suggest that transient perfusion defects might be due to a brain artery spasm possibly leading to psychiatric and neurologic symptomatology, as already observed in patients affected by acute intermittent porphyria. This observation, if confirmed by other well designed studies aiming to demonstrate a direct link between artery spasm, perfusion defects and related symptoms could lead to improvements in HCP treatments.

Cytochrome 4A11 Genetic Polymorphisms Increase Susceptibility to Ischemic Stroke and Associate with Atherothrombotic Events After Stroke in Chinese

To evaluate the associations between four single-nucleotide polymorphisms (SNPs) in CYP4A11 and CYP4F2 and ischemic stroke (IS), and between these variants and atherothrombotic events after stroke. IS patients (n=396) and controls (n=378) were genotyped for two CYP4A11 SNPs (rs2269231 and rs9333025) and two CYP4F2 SNPs (rs2108622 and rs3093135). Patients were followed up for 12 months after the stroke for the atherothrombotic events. The frequency of the rs9333025 GG genotype was significantly higher in IS patients than in controls. Logistic regression analysis showed that the presence of rs9333025 GG in patients was associated with significantly higher risk of IS. Cox regression analysis revealed that the rs9333025 GG genotype was an independent risk factor for atherothrombotic events after stroke. The rs9333025 GG genotype increases patients' susceptibility to IS and is associated with high frequencies of atherothrombotic events in stroke patients.

Cytochrome P450 eicosanoids in hypertension and renal disease

PURPOSE OF REVIEW

Cytochrome (CYP) P450 metabolites of arachidonic acid, 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) contribute to the regulation of renal tubular and vascular function. This review highlights the results of the recent genetic studies in humans and rodent models, indicating that these eicosanoids participate in the control of blood pressure (BP), chronic kidney disease (CKD), renal ischemia-reperfusion injury (IRI) and polycystic kidney disease (PKD).

RECENT FINDINGS

Endogenous 20-HETE has been reported to play an essential role in the myogenic and tubuloglomerular feedback responses in the afferent arteriole, and a deficiency of 20-HETE contributes to the development of hypertension and renal injury in Dahl S rats. Mutations in CYP4A11 and CYP4F2 have been linked to elevated BP in humans. EETs have been shown to regulate epithelial sodium channel in the collecting duct, lower BP and have renoprotective properties. 20-HETE also opposes the development of CKD and IRI, and may play a role in PKD.

SUMMARY

These studies indicate that CYP P450 metabolites of arachidonic acid play an important role in the control of BP, CKD, AKI and PKD. Drugs targeting these pathways could be useful in the treatment of IRI and CKD.

Urinary CYP eicosanoid excretion correlates with glomerular filtration in African-Americans with chronic kidney disease

Previous studies have indicated that cytochrome P450 (CYP) metabolites of arachidonic acid (AA), i.e., 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs), play an important role in the regulation of renal tubular and vascular function. The present study for the first time profiled HETEs and epoxygenase derived dihydroxyeicosatetraenoic acid diHETEs levels in spot urines and plasma in 262 African American patients from the University of Mississippi Chronic Kidney Disease Clinic and 31 African American controls. Significant correlations in eGFR and urinary 20-HETE/creatinine and 19-HETE/creatinine levels were observed. The eGFR increased by 17.47 [p=0.001] and 60.68 [(p=0.005]ml/min/for each ng/mg increase in 20-HETE and 19-HETE levels, respectively. Similar significant positive associations were found between the other urinary eicosanoids and eGFR and also with 19-HETE/urine creatinine concentration and proteinuria. We found that approximately 80% of plasma HETEs and 30% diHETEs were glucuronidated and the fractional excretion of 20-HETE was less than 1%. These results suggest that there is a significant hepatic source of urinary 20-HETE glucuronide and EETs with extensive renal biotransformation to metabolites which may play a role in the pathogenesis of CKD.

The role of 20-HETE in androgen-mediated hypertension

Androgen plays an important role in blood pressure regulation. Epidemiological studies have shown that men have a higher prevalence for developing hypertension than aged-matched, premenopausal women. Interestingly, postmenopausal women and women with polycystic ovary syndrome, both of which have increased endogenous androgen production, have elevated risks for hypertension suggesting that androgen may contribute to its development. Studies from our laboratory and others have provided substantial evidence that 20-hydroxyeicosatetraenoic acid (20-HETE) mediates the hypertension seen in rodents treated with androgen. 20-HETE is the cytochrome P450 (CYP)-derived ω-hydroxylated metabolite of arachidonic acid. 20-HETE plays a complex role in blood pressure regulation. In the kidney tubules, 20-HETE decreases blood pressure by promoting natriuresis, while in the microvasculature it has a pressor effect. In the microcirculation, 20-HETE participates in the regulation of vascular tone by sensitizing the smooth muscle cells to constrictor stimuli and contributes to myogenic, mitogenic and angiogenic responses. In addition, 20-HETE acts on the endothelium to promote endothelial dysfunction and endothelial activation. Recently, we have demonstrated that 20-HETE induces endothelial ACE thus setting forth a potential feed forward mechanism through activation of the renin-angiotensin-aldosterone system. In this review, we will discuss the pro-hypertensive effects of 20-HETE and its role in androgen-induced vascular dysfunction and hypertension.

A Promoter polymorphism (rs17222919, -1316T/G) of ALOX5AP is associated with intracerebral hemorrhage in Korean population

To investigate whether single nucleotide polymorphisms (SNPs) of eicosanoid biosynthesis genes are associated with intracerebral hemorrhage (ICH) and ischemic stroke (IS), seven SNPs in the coding or promoter regions were selected: ALOX12 (rs434473, Asn322Ser), ALOX5 (rs2228064, Thr90Thr), ALOX5AP (rs17222919, -1316T/G), PTGES (rs7872802, -404A/G), PTGIS (rs5628, Leu256Leu), PTGS1 (rs3842788, Gln41Gln) and PTGS2 (rs5275, 3'UTR). A total of 398 control subjects and 196 stroke patients (79 ICH and 117 IS) were genotyped by direct sequencing. The rs17222919 SNP was associated with ICH in codominant 1 (P=0.008), dominant (P=0.003) and log-additive (P=0.004) models. Allele frequencies of rs17222919 were different between ICH and controls (P=0.007). However, the seven tested SNPs were not associated with clinical phenotypes (NIHSS, MBI and CRPS) in ICH and IS. These results suggest that the promoter SNP rs17222919 of ALOX5AP may be associated with the development of ICH in Korean population.

Peripheral and central augmentation indexes in relation to the CYP4F2 polymorphisms in Chinese

OBJECTIVE

Cytochrome (CYP) 4F2 isoform is a key metabolizing enzyme for the renal 20-hydroxyeicosatetraenoic acid (20-HETE), which, as an endogenous vasoconstrictor, may influence properties of the peripheral muscular arteries and arterioles. We, therefore, investigated the CYP4F2 polymorphisms in relation to arterial wave reflections, as measured by augmentation indexes (AIx) in Chinese.

METHODS

We performed arterial measurements by SphygmoCor and genotyped three CYP4F2 polymorphisms (V433M, rs3093089, and rs3093098) by PCR-restriction fragment length polymorphism in 1421 participants enrolled in the JingNing Population study. A replication study for the V433M polymorphism was performed in 924 Chinese recruited from a workplace setting. Urinary 20-HETE concentration was determined by ELISA in a randomly selected subsample of 318 JingNing individuals.

RESULTS

In spite of the fact that genetic associations were not significant (P ≥ 0.12) in all JingNing participants, there was significant (Pint ≤ 0.02) interaction of the V433M polymorphism with sex and pulse rate in relation to peripheral and central AIx. M433 allele carriers, compared with V433V homozygotes, had significantly greater peripheral (+5.0%, P = 0.0002) and central AIx (+3.2%, P = 0.001) in 693 men. The corresponding values were +2.7% (P = 0.04) and +1.9% (P = 0.04) in 490 individuals of the top tertile of pulse rate (≥ 76 beats/min), and were +4.0% (P = 0.02) and +3.3% (P = 0.02) in 315 replication participants with a pulse rate at least 76 beats/min. Urinary 20-HETE concentration was significantly higher (P = 0.002) in M433M (2.06 ng/ml) and V433M (1.13 ng/ml) individuals than in V433V homozygotes (0.98 ng/ml).

CONCLUSION

The CYP4F2 V433M polymorphism is associated with the size of arterial wave reflections in male Chinese, or individuals with a faster pulse rate.

Association of 1347 G/A cytochrome P450 4F2 (CYP4F2) gene variant with hypertension and stroke

Genetic variants of cytochrome P450 4F2 (CYP4F2) gene have been suggested to be risk factors for hypertension, cardiovascular diseases and stroke. In the present case-control study we investigated the association of 1347 G/A polymorphism (rs2108622) in the 11th exon region of CYP4F2 gene with hypertension, ischemic stroke and stroke subtypes classified according to TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. Five hundred and seven stroke patients (hypertensives: normotensives = 279:228) and four hundred and eighty seven, age and sex matched controls (males: females = 356:131) (hypertensives: normotensives = 148:339) were involved in the study. The genotypes were determined by PCR-RFLP technique. Genotypes were confirmed by subjecting the PCR products to sequencing. Significant difference was observed in the genotypic distribution and allelic frequency between the stroke patients and healthy controls. AA genotype and A allele associated significantly with stroke and hypertension [P = 0.009; OR = 1.59 (95% CI = 1.119-2.283) and P = 0.010; OR = 1.26 (95% CI = 1.056-1.502); P = 0.01; OR = 1.58 (95% CI = 1.11-2.272) and P = 0.010; OR = 1.25(95% CI = 1.054-1.504) respectively]. A stepwise logistic regression analysis confirmed these findings. To establish that this polymorphism is associated with stroke independent of hypertension; we compared stroke patients without hypertension with normotensive controls. Significant difference was observed in genotypic distribution and allelic frequency between the two groups (P = 0.001 and 0.002 respectively). Evaluating the association of this polymorphism with stroke subtypes we found significant associations with cardioembolic stroke (P < 0.001). In conclusion our study suggests that 1347A allele of CYP4F2 gene is an important risk factor for hypertension and ischemic stroke.

20-hydroxyeicosatetraeonic acid: a new target for the treatment of hypertension

Arachidonic acid is metabolized by enzymes of the CYP4A and 4F families to 20-hydroxyeicosatetraeonic acid (20-HETE), which plays an important role in the regulation of renal function, vascular tone, and the long-term control of arterial pressure. In the vasculature, 20-HETE is a potent vasoconstrictor, and upregulation of the production of this compound contributes to the elevation in oxidative stress and endothelial dysfunction and the increase in peripheral vascular resistance associated with some forms of hypertension. In kidney, 20-HETE inhibits Na transport in the proximal tubule and thick ascending loop of Henle, and deficiencies in the renal formation of 20-HETE contributes to sodium retention and development of some salt-sensitive forms of hypertension. 20-HETE also has renoprotective actions and opposes the effects of transforming growth factor β to promote proteinuria and renal end organ damage in hypertension. Several new inhibitors of the synthesis of 20-HETE and 20-HETE agonists and antagonists have recently been developed. These compounds along with peroxisome proliferator-activated receptor-α agonists that induce the renal formation of 20-HETE seem to have promise as antihypertensive agents. This review summarizes the rationale for the development of drugs that target the 20-HETE pathway for the treatment of hypertension and associated cardiovascular complications.

Cytochrome P450 eicosanoids and cerebral vascular function

The eicosanoids 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs), which are generated from the metabolism of arachidonic acid by cytochrome P450 (CYP) enzymes, possess a wide array of biological actions, including the regulation of blood flow to organs. 20-HETE and EETs are generated in various cell types in the brain and cerebral blood vessels, and contribute significantly to cerebral blood flow autoregulation and the coupling of regional brain blood flow to neuronal activity (neurovascular coupling). Investigations are beginning to unravel the molecular and cellular mechanisms by which these CYP eicosanoids regulate cerebral vascular function and the changes that occur in pathological states. Intriguingly, 20-HETE and the soluble epoxide hydrolase (sEH) enzyme that regulates EET levels have been explored as molecular therapeutic targets for cerebral vascular diseases. Inhibition of 20-HETE, or increasing EET levels by inhibiting the sEH enzyme, decreases cerebral damage following stroke. The improved outcome following cerebral ischaemia is a consequence of improving cerebral vascular structure or function and protecting neurons from cell death. Thus, the CYP eicosanoids are key regulators of cerebral vascular function and novel therapeutic targets for cardiovascular diseases and neurological disorders.

Genistein, resveratrol, and 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside induce cytochrome P450 4F2 expression through an AMP-activated protein kinase-dependent pathway

Activators of AMP-activated protein kinase (AMPK) increase the expression of the human microsomal fatty acid ω-hydroxylase CYP4F2. A 24-h treatment of either primary human hepatocytes or the human hepatoma cell line HepG2 with 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), which is converted to 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranosyl 5'-monophosphate, an activator of AMPK, caused an average 2.5- or 7-fold increase, respectively, of CYP4F2 mRNA expression but not of CYP4A11 or CYP4F3, CYP4F11, and CYP4F12 mRNA. Activation of CYP4F2 expression by AICAR was significantly reduced in HepG2 cells by an AMPK inhibitor, 6-[4-(2-piperidin-1-yl-ethoxy)-phenyl)]-3-pyridin-4-yl-pyrrazolo[1,5-a]-pyrimidine (compound C) or by transfection with small interfering RNAs for AMPKα isoforms α1 and α2. A 2.5-fold increase in CYP4F2 mRNA expression was observed upon treatment of HepG2 cells with 6,7-dihydro-4-hydroxy-3-(2'-hydroxy[1,1'-biphenyl]-4-yl)-6-oxo-thieno[2,3-b]pyridine-5-carbonitrile (A-769662), a direct activator for AMPK. In addition, the indirect activators of AMPK, genistein and resveratrol increased CYP4F2 mRNA expression in HepG2 cells. Pretreatment with compound C or 1,2-dihydro-3H-naphtho[2,1-b]pyran-3-one (splitomicin), an inhibitor of the NAD(+) activated deacetylase SIRT1, only partially blocked activation of CYP4F2 expression by resveratrol, suggesting that a SIRT1/AMPK-independent pathway also contributes to increased CYP4F2 expression. Compound C greatly diminished genistein activation of CYP4F2 expression. 7H-benz[de]benzimidazo[2,1-a]isoquinoline-7-one-3-carboxylic acid acetate (STO-609), a calmodulin kinase kinase (CaMKK) inhibitor, reduced the level of expression of CYP4F2 elicited by genistein, suggesting that CaMKK activation contributed to AMPK activation by genistein. Transient transfection studies in HepG2 cells with reporter constructs containing the CYP4F2 proximal promoter demonstrated that AICAR, genistein, and resveratrol stimulated transcription of the reporter gene. These results suggest that activation of AMPK by cellular stress and endocrine or pharmacologic stimulation is likely to activate CYP4F2 gene expression.

CYP4F2 gene V433M polymorphism is associated with ischemic stroke in the male Northern Chinese Han population

BACKGROUND

CYP4F2 is a member of the cytochrome P450 enzymes and is responsible for metabolizing arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE); 20-HETE plays a role in the regulation of vascular tone in the cerebral, coronary, and renal circulation. The present study aimed to evaluate whether or not the CYP4F2 gene polymorphism V433M (rs2108622) is involved in ischemic stroke in the Northern Chinese Han population.

METHODS

In a case-control study, the participants included 302 (193 males and 109 females) patients with ischemic stroke and 350 (212 males and 138 females) healthy subjects. The V433M polymorphism of the CYP4F2 gene was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) with the restriction enzyme PvuII.

RESULTS

The frequencies of the GG genotype and the G allele were higher in participants with ischemic stroke than in the control group (P=0.018). Multiple logistic regression analysis revealed the significance of the rs2108622 in males after adjustment for confounding factors. No difference was found in all participants and females.

CONCLUSION

The GG genotype and G allele were associated with ischemic stroke in the male Northern Chinese Han population.

Haplotype-based case-control study on human apurinic/apyrimidinic endonuclease 1/redox effector factor-1 gene and essential hypertension

BACKGROUND

Oxidative DNA damage is involved in the pathophysiology of essential hypertension (EH), which is a multifactorial disorder. Apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/REF-1) is an essential endonuclease in the base excision repair pathway of oxidatively damaged DNA, in addition to having reducing properties that promote the binding of redox-sensitive transcription factors. Blood pressure in APE1/REF-1-knockout mice is reported to be significantly higher than in wild-type mice. The aim of this study was to investigate the relationship between EH and the human APE1/REF-1 gene through a haplotype-based case-control study using single-nucleotide polymorphisms (SNPs).

METHODS

We selected five SNPs in the human APE1/REF-1 gene (rs1760944, rs3136814, rs17111967, rs3136817, and rs1130409), and performed case-control studies in 265 EH patients and 266 age-matched normotensive (NT) subjects.

RESULTS

rs17111967 was found to show nonheterogeneity among Japanese subjects. There were no significant differences in the overall distribution of genotypes or alleles for each SNP between EH and NT groups. In the overall distribution of the haplotype-based case-control study constructed based on rs1760944, rs3136817, and rs1130409, the frequency of the G-T-T haplotype was significantly higher in the EH group than in the NT group (2.1% vs. 0.0%, P = 0.001). Multiple logistic regression analysis also revealed significant differences for the G-T-T haplotype, even after adjustment for confounding factors (OR = 8.600, 95% CI: 1.073-68.951, P = 0.043).

CONCLUSIONS

Based on the present results, the G-T-T haplotype appears to be a genetic marker of EH, and the APE1/REF-1 gene appears to be a susceptibility gene for EH.

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.

A haplotype of the CYP4F2 gene associated with myocardial infarction in Japanese men

This study assessed associations between the CYP4F2 gene and myocardial infarction (MI), using a haplotype-based case-control study of 234 MI patients and 248 controls genotyped for 5 single-nucleotide polymorphisms (rs3093105, rs3093135, rs1558139, rs2108622, rs3093200). For men, G allele frequency of rs2108622 and frequency of the T-C-G haplotype were significantly higher, and frequency of the T-C-A haplotype was significantly lower for MI patients than for controls (P=0.006, P=0.001 and P=0.002, respectively).

Cytochrome P450 metabolites of arachidonic acid in the control of renal function

Recent studies indicate that arachidonic acid is primarily metabolized by cytochrome P450 enzymes of the 4A and 2C families in the kidney to 20-hydroxyeicosatetraenoic acid (HETE), epoxyeicosatrienoic acids (EETs) and dihydroxyeicosatrienoic acids. These compounds play central roles in the regulation of renal tubular and vascular function. 20-HETE is produced by renal vascular smooth muscle (VSM) cells and is a potent constrictor that depolarizes VSM cells by blocking the calcium-activated potassium channel. Inhibition of the formation of 20-HETE blocks the myogenic response of isolated renal arterioles in vitro, and autoregulation of renal blood flow and tubuloglomerular feedback responses in vivo. EETs are products formed in the endothelium and are potent dilators that activate the calcium-activated potassium channel in renal VSM. Endothelial-dependent vasodilators stimulate the release of EETs, and these compounds appear to serve as an endothelial-derived hyperpolarizing factor. EETs and 20-HETE are produced in the proximal tubule. There, they regulate sodium/potassium-ATPase activity and serve as second messengers for the natriuretic effects of dopamine, parathyroid hormone and angiotensin II. 20-HETE is also produced in the thick ascending loop of Henle. It regulates sodium-potassium-chloride transport in this nephron segment. The renal production of cytochrome P450 metabolites of arachidonic acid is altered in hypertension, diabetes, toxemia of pregnancy, and hepatorenal syndrome. Given the importance of cytochrome P450 metabolites of arachidonic acid in the control of renal function, it is likely that changes in this system contribute to the abnormalities in renal function that are associated with many of these conditions.