Accuracy of an internationally validated genetic-guided warfarin dosing algorithm compared to a clinical algorithm in an Arab population.

PURPOSE: To identify the impact of CYP2C9*2, *3, VKORC1-1639 G>A and CYP4F2*3 on warfarin dose in an Arab population. To compare the accuracy of a clinical warfarin dosing (CWD) versus genetic warfarin dosing algorithms (GWD) during warfarin initiation. METHODS: A cohort of Arab patients newly starting on warfarin had their dose calculated using CWD published in www.warfarindosing.org and were followed for 1 month. Each patient provided a saliva sample. DNA was extracted, purified and genotyped for VKORC-1639 G>A, CYP2C9*2, CYP2C9*3 and CYP4F2*3. After reaching warfarin maintenance dose, the dose was recalculated using the GWD and median absolute error (MAE) and the percentage of warfarin doses within 20% of the actual dose were calculated and compared for the two algorithms. RESULTS: The study enrolled 130 patients from 12 Arabian countries. Compared to those with wild type, carriers of reduced function alleles in CYP2C9 required significantly lower median (IQR) warfarin weekly dose [24.5 (15.3) vs. 35 (29.8) mg/week, p=0.006]. With regards to VKORC, patients with AA genotype had a significantly lower median (IQR) weekly warfarin dose compared to AG and GG [21(10.5) vs 29.4 (21), p<0.001 for AA vs AG, p<0.001 for AA vs GG]. The MAE (IQR) for the weekly dose of the GWD was significantly lower compared to CWD [8.1 (10.5) vs 12.4 (12.6) (p<0.001)]. CONCLUSION: CYP2C9 and VKORC1 variants are important determinants of warfarin dose in the Arab population. The use of the genetic and clinical factors led to better warfarin dose estimation when compared to clinical factors alone.

Targeting estrogen mediated CYP4F2/CYP4F11-20-HETE metabolic disorder decelerates tumorigenesis in ER+ breast cancer.

Purpose: As the most common subset of breast cancer (BC), estrogen receptor positive (ER+) BC accounting for 80% of cases, has become a global public health concern. The female hormone estrogen (E2) unequivocally drives ER + breast malignancies. The reasons that estrogen affects BC development has long been considered, yet further study remains to be conducted of the molecular events in the E2-estrogen receptor α (ERα) signaling pathway in ER + BC progression, especially lipid metabolism, so providing more options for tailored and individualized therapy. Our aim is to find out new targets and clinical biomarkers for ER + breast cancer treatment from the perspective of lipid metabolism. Methods: Lipid metabolomics profiling was used to examine the membrane phospholipid stimulated by E2. Clinical BC samples were used to assess the association of CYP4F2, CYP4F11 expression with clinicopathological characteristics and patient outcomes. Some inhibitors of main enzymes in AA metabolism were used combined with E2 to assess roles of CYP4F2/CYP4F11 in the progression of ER + BC. CYP4F2, CYP4F11 overexpression and knockdown BC cell lines were employed to examine the effects of CYP4F2, CYP4F11 on cellular proliferation, apoptosis and tumor growth. Western blotting, qPCR, Immunohistochemical staining and flow cytometry were also conducted to determine the underlying mechanisms related to CYP4F2, CYP4F11 function. Results: The activation of the CYP450 signaling pathway in arachidonic acid metabolism contributed to ER + BC tumorigenesis. In ER + BC, CYP4F2 and CYP4F11 overexpression induced by E2 could promote cancer cell proliferation and resistance to apoptosis by producing the metabolite 20-HETE and activating the antiapoptotic protein Bcl-2. CYP4F2 and CYP4F11 elevation correlates with poorer overall survival and disease-free survival in ER + BC patients. Conclusion: CYP4F2, CYP4F11 and their metabolite 20-HETE could serve as effective prognostic markers and attractive therapeutic targets for novel anticancer drug development about ER + BC.

One Rare Warfarin Resistance Case and Possible Mechanism Exploration.

One 59-year-old female patient with deep venous thrombosis (DVT) and pulmonary embolism (PE) was treated with 6 mg warfarin once daily as an anticoagulant. Before taking warfarin, her international normalized ratio (INR) was 0.98. Two days after warfarin treatment, her INR did not change from baseline. Due to the high severity of the PE, the patient needed to reach her target range (INR goal = 2.5, range = 2~3) rapidly, so the dose of warfarin was increased from 6 mg daily to 27 mg daily. However, the patient's INR did not improve with the dose escalation, still maintaining an INR of 0.97-0.98. We drew a blood sample half an hour before administering 27 mg warfarin and detected single nucleotide polymorphism for the following genes, which were identified to be relevant with warfarin resistance: CYP2C9 rs1799853, rs1057910, VKORC1 rs9923231, rs61742245, rs7200749, rs55894764, CYP4F2 rs2108622, and GGCX rs2592551. The trough plasma concentration of warfarin was 196.2 ng/mL after 2 days of warfarin administration with 27 mg QD, which was much lower than the therapeutic drug concentration ranges of warfarin (500-3,000 ng/mL). The genotype results demonstrate that the CYP4F2gene has rs2108622 mutation which can explain some aspect of warfarin resistance. Further investigations are necessary to fully characterize other pharmacogenomics or pharmacodynamics determinants of warfarin dose-response in Chinese.

Genetic Variants of CYP4F2 Associated with Ischemic Stroke Susceptibility in the Han Population from Southern China.

Background: The pathophysiological mechanism of ischemic stroke is complex. Traditional risk factors cannot fully or only partially explain the occurrence and development of IS. Genetic factors are getting more and more attention. Our study aimed to explore the association between CYP4F2 gene polymorphism and susceptibility to IS. Methods: A total of 1322 volunteers were enrolled to perform an association analysis through SNPStats online software. Using FPRP (false-positive report probability) to detect whether the result is a noteworthy finding. The interaction of SNP-SNP in IS risk was assessed by multi-factor dimensionality reduction. Statistical analysis of this study was mainly completed by SPSS 22.0 software. Results: Mutant allele "A" (OR = 1.24) and genotype "AA" (OR = 1.49) or "GA" (OR = 1.26) of CYP4F2-rs2108622 are risk genetic factors for IS. Rs2108622 is significantly associated with an increased risk of IS among subjects who are females, aging >60 years old, with BMI ≥24 kg/m2, and smoking or drinking volunteers. CYP4F2-rs3093106 and -rs3093105 are associated with susceptibility to IS among smoking, drinking subjects, or IS patients complicated with hypertension. Conclusion: CYP4F2-rs2108622, -rs3093106, and -rs3093105 are associated with an increased risk of IS.

Computational analysis of missense variant CYP4F2*3 (V433M) in association with human CYP4F2 dysfunction: a functional and structural impact.

BACKGROUND: Cytochrome P450 4F2 (CYP4F2) enzyme is a member of the CYP4 family responsible for the metabolism of fatty acids, therapeutic drugs, and signaling molecules such as arachidonic acid, tocopherols, and vitamin K. Several reports have demonstrated that the missense variant CYP4F2*3 (V433M) causes decreased activity of CYP4F2 and inter-individual variations in warfarin dose in different ethnic groups. However, the molecular pathogenicity mechanism of missense V433M in CYP4F2 at the atomic level has not yet been completely elucidated. METHODS AND RESULTS: In the current study, we evaluated the effect of the V433M substitution on CYP4F2 using 14 different bioinformatics tools. Further molecular dynamics (MD) simulations were performed to assess the impact of the V433M mutation on the CYP4F2 protein structure, stability, and dynamics. In addition, molecular docking was used to illustrate the effect of V433M on its interaction with vitamin K1. Based on our results, the CYP4F2*3 variant was a damaging amino acid substitution with a destabilizing nature. The simulation results showed that missense V433M affects the dynamics and stability of CYP4F2 by reducing its compactness and stability, which means that it tends to change the overall structural conformation and flexibility of CYP4F2. The docking results showed that the CYP4F2*3 variant decreased the binding affinity between vitamin K1 and CYP4F2, which reduced the activity of CYP4F2*3 compared to native CYP4F2. CONCLUSIONS: This study determined the molecular pathogenicity mechanism of the CYP4F2*3 variant on the human CYP4F2 protein and provided new information for understanding the structure-function relationship of CYP4F2 and other CYP4 enzymes. These findings will aid in the development of effective drugs and treatment options.

Evaluation of a warfarin dosing algorithm including CYP2C9, VKORC1, and CYP4F2 polymorphisms and non-genetic determinants for the Iranian population.

BACKGROUND: The response to warfarin, as an oral anticoagulant agent, varies widely among patients from different ethnic groups. In this study, we tried to ascertain and determine the relationship between non-genetic factors and genetic polymorphisms with warfarin therapy; we then proposed a new warfarin dosing prediction algorithm for the estimation of drug sensitivity and resistance in the Iranian population. METHODS: Overall, 200 warfarin-treated patients with stable doses were recruited, the demographic and clinical characteristics were documented, and genotyping was done using a sequencing assay. RESULTS: The outcomes of our investigation showed that the genetic polymorphisms of VKORC1(-1639 G > A), CYP2C9*3, CYP2C9*2, amiodarone use, and increasing age were found to be related to a significantly lower mean daily warfarin dose. In contrast, the CYP4F2*3 variant and increased body surface area were linked with an increased dose of warfarin in the Iranians. Our descriptive model could describe 56.5% of the variability in response to warfarin. This population-specific dosing model performed slightly better than other previously published warfarin algorithms for our patient's series. Furthermore, our findings provided the suggestion that incorporating the CYP4F2*3 variant into the dosing algorithm could result in a more precise calculation of warfarin dose requirements in the Iranian population. CONCLUSIONS: We proposed and validated a population-specific dosing algorithm based on genetic and non-genetic determinants for Iranian patients and evaluated its performance. Accordingly, by using this newly developed algorithm, prescribers could make more informed decisions regarding the treatment of Iranian patients with warfarin.

CYP4F2 is a human-specific determinant of circulating N-acyl amino acid levels.

N-acyl amino acids are a large family of circulating lipid metabolites that modulate energy expenditure and fat mass in rodents. However, little is known about the regulation and potential cardiometabolic functions of N-acyl amino acids in humans. Here, we analyze the cardiometabolic phenotype associations and genomic associations of four plasma N-acyl amino acids (N-oleoyl-leucine, N-oleoyl-phenylalanine, N-oleoyl-serine, and N-oleoyl-glycine) in 2351 individuals from the Jackson Heart Study. We find that plasma levels of specific N-acyl amino acids are associated with cardiometabolic disease endpoints independent of free amino acid plasma levels and in patterns according to the amino acid head group. By integrating whole genome sequencing data with N-acyl amino acid levels, we identify that the genetic determinants of N-acyl amino acid levels also cluster according to the amino acid head group. Furthermore, we identify the CYP4F2 locus as a genetic determinant of plasma N-oleoyl-leucine and N-oleoyl-phenylalanine levels in human plasma. In experimental studies, we demonstrate that CYP4F2-mediated hydroxylation of N-oleoyl-leucine and N-oleoyl-phenylalanine results in metabolic diversification and production of many previously unknown lipid metabolites with varying characteristics of the fatty acid tail group, including several that structurally resemble fatty acid hydroxy fatty acids. These studies provide a structural framework for understanding the regulation and disease associations of N-acyl amino acids in humans and identify that the diversity of this lipid signaling family can be significantly expanded through CYP4F-mediated ω-hydroxylation.

Genetic polymorphisms in CYP4F2 may be associated with lung cancer risk among females and no-smoking Chinese population.

Background: Our study aimed to explore the potential association of CYP4F2 gene polymorphisms with lung cancer (LC) risk. Methods: The five variants in CYP4F2 were genotyped using Agena MassARRAY in 507 cases and 505 controls. Genetic models and haplotypes based on logistic regression analysis were used to evaluate the potential association between CYP4F2 polymorphisms and LC susceptibility. Results: This study observed that rs12459936 was linked to an increased risk of LC in no-smoking participants (allele: OR = 1.38, p = 0.035; homozygote: OR = 2.00, p = 0.035; additive: OR = 1.40, p = 0.034) and females (allele: OR = 1.64, p = 0.002; homozygote: OR = 2.57, p = 0.006; heterozygous: OR = 2.56, p = 0.001; dominant: OR = 2.56, p < 0.002; additive: OR = 1.67, p = 0.002). Adversely, there was a significantly decreased LC risk for rs3093110 in no-smoking participants (heterozygous: OR = 0.56, p = 0.027; dominant: OR = 0.58, p = 0.035), rs3093193 (allele: OR = 0.66, p = 0.016; homozygote: OR = 0.33, p = 0.011; recessive: OR = 0.38, p = 0.021; additive: OR = 0.64, p = 0.014), rs3093144 (recessive: OR = 0.20, p = 0.045), and rs3093110 (allele: OR = 0.54, p = 0.010; heterozygous: OR = 0.50, p = 0.014; dominant: OR = 0.49, p = 0.010; additive: OR = 0.54, p = 0.011) in females. Conclusions: The study demonstrated that CYP4F2 variants were associated with LC susceptibility, with evidence suggesting that this connection may be affected by gender and smoking status.

Insights into the binding mechanism between α-TOH and CYP4F2: A homology modeling, molecular docking, and molecular dynamics simulation study.

α-Tocopherol (α-TOH) is a potent antioxidant. The concentrations of α-TOH in plasma are closely related to human health. α-TOH can be regulated by the metabolism of cytochrome P450 4F2 (CYP4F2). However, the atomic-level basis for this regulation process remains elusive. Here, we successfully constructed the structure of CYP4F2 by homology modeling and obtained the α-TOH-CYP4F2 complex models using molecular docking. Three parallel 500 ns molecular dynamics simulations were performed on each complex model to investigate the details of the interaction between α-TOH and CYP4F2. MM-GBSA method combined with principal component analysis shows that 8 key residues establish a hydrophobic cavity stabilizing α-TOH in the pocket of CYP4F2 and S423 forms an important hydrogen bond with α-TOH anchoring α-TOH in the favorable position for ω-hydroxylation. Based on our simulation results and the experimental facts, we designed mutation simulation experiments to clarify the important role of two key residues (S423 and V433) in the binding of α-TOH with CYP4F2. The results show that the mutations directly or indirectly change the binding mode of α-TOH and decrease its binding affinity with CYP4F2, which is unfavorable for ω-hydroxylation. Our results could enrich the information on structure-function relationships of CYP4F2 and provide valuable insights into the regulatory mechanism of CYP4F2 on the metabolism of α-TOH.

The frequency of cytochrome 4F2 rs2108622 genetic variant and its effects on the lipid profile and complications of type II diabetes among a sample of patients in Jordan: A pilot study.

BACKGROUND: Cytochrome 4F2 (CYP4F2) is a major arachidonic acid-metabolizing enzyme which produces 20-Hydroxyeicosatetraenoic acid (20-HETE). It is found that 20-HETE is involved in the pathophysiology of many diseases, including diabetes mellitus. The genetic variants of CYP4F2 can affect its enzymatic activity as well as the 20-HETE production. AIMS: Our aim with this paper was to find out the genotype frequency of CYP4F2 rs2108622 C>T, the major functional variant in the CYP4F2 gene, among a sample of type II diabetes (TIIDM) and its effects on diabetes complications and lipid profile. METHODS: The CYP4F2 rs2108622 variant was genotyped among 90 healthy volunteers and 90 TIIDM patients that attending the University of Jordan Hospital, using the DNA Sanger sequencing method. The data of lipid profile and diabetes complications were obtained from the electronic records available in the hospital. RESULTS: We found that the frequency of CYP4F2 rs2108622C>T variant is significantly (P = 0.02) lower among TIIDM patients in comparison to healthy subjects using both co-dominant and dominant genotyping models. In addition, the CYP4F2 rs2108622 T/T genotype was significantly (P = 0.02) more frequent among TIIDM patients with retinopathy complications (OR=4.36, CI: 1.32-14.37). Lastly, the CYP4F2 rs2108622C>T variant was not associated (P > 0.05) with the glycaemic and lipid profile of patients. CONCLUSIONS: It can be concluded from this study that the frequency of CYP4F2 rs2108622 T/T genotype is lower among TIIDM, but this genotype is associated with an increased risk of retinopathy complications in patients of Jordanian origin. Further studies with a larger sample size are needed to validate the findings of this study.

Diversity of pharmacogenomic variants affecting warfarin metabolism in Sri Lankans.

Aims: To describe the diversity of pharmacogenomic variants affecting warfarin metabolism in Sri Lankans. Materials & methods: Genotype data were filtered out from an anonymized database of 400 Sri Lankans, and minor allele frequencies (MAF) were calculated. Variants of CYP2C9, VKORC1 and CYP4F2 genes were studied. Results: Overall, CYP2C9*2 and CYP2C9*3 alleles had MAFs of 2.25% (95% CI: 0.80-3.70) and 10.38% (95% CI: 7.50-13.50), respectively. CYP2C9*11 and CYP2C9*14 alleles had MAFs of 0.13% (95% CI: 0-0.74) and 2.50% (95% CI: 0.97-4.03), respectively. MAFs of VKORC1 variants rs7294, rs9934438, rs8050894 and rs2884737 were 47.25% (95% CI: 42.36-52.14), 10.13% (95% CI: 7.28-13.22), 9.88% (95% CI: 7.06-12.94) and 4.88% (95% CI: 2.86-7.14), respectively. MAF of CYP4F2 variant rs2108622 was 45.63% (95% CI: 40.87-50.63). Conclusion: Compared with other populations, the frequencies of some studied variants were significantly different in Sri Lankans, and these are likely to account for variability in warfarin dosage requirements.

Pleiotropic Effects of Ticagrelor: Influence on CYP4F2 Gene and Protein Expression in HUVEC and HepG2, and Escherichia coli Bacterial Survival.

Background: Antiplatelet drugs, such as ticagrelor, which target platelet P2Y12 receptors, are used for prevention of ischemic heart disease. Ticagrelor is also known to have pleiotropic effects of unknown mechanisms. Ticagrelor could influence the expression of molecules involved in resolution of inflammation. This study aimed to investigate if ticagrelor could change the expression of CYP4F2 and its encoded protein concentration and, additionally, to determine ticagrelor possible antibacterial activity against gram-negative bacteria. Methods: CYP4F2 expression was determined in HUVEC and HepG2 cell lines by qPCR. CYP4F2 protein concentration was determined by ELISA. Antibiotic susceptibility testing was performed using a disc diffusion method. Results: Ticagrelor was observed to reduce the expression of CYP4F2 in HUVEC and HepG2 cell lines. It also reduced CYP4F2 protein levels in HUVEC cells. Ticagrelor had no bactericidal activity against gram-negative third generation cephalosporin resistant E. coli. Conclusion: Ticagrelor reduced CYP4F2 protein concentration in HUVEC, and CYP4F2 expression in HUVEC and HepG2 cells, but had no effect on third-generation cephalosporin-resistant E. coli strains.

Warfarin dosing strategies evolution and its progress in the era of precision medicine, a narrative review.

Background For decades, vitamin K antagonists and specifically warfarin, have been the sole agents used orally to manage thromboembolic conditions, including stroke and venous thromboembolism (VTE). Several factors lead to warfarin dose variability, including genetic and non-genetic factors which made warfarin management challenging especially at the initiation phase. To overcome the challenges with warfarin dosing at initiation, strategies other than conventional or fixed dosing were introduced and explored. Aim In this narrative review, we aim to discuss and critique the different dosing strategies for warfarin at initiation with more focus on genotype-guided warfarin dosing and the most recent supporting evidence for and against its use. Method Medline database was searched from 1965 to July 2021. Articles addressing different warfarin dosing methods were screened for inclusion. Results A number of methods exist for warfarin initiation. Studies comparing different dosing methods for initiation yielded conflicting outcomes due to differences in study design, population studied, comparator, and outcomes measured. Conclusions Looking at the big picture, the use of genetic dosing for warfarin initiation can lead to better outcomes. Whether these better outcomes are clinically or economically beneficial remains controversial.

Exploring the Interactome of Cytochrome P450 2E1 in Human Liver Microsomes with Chemical Crosslinking Mass Spectrometry.

Aiming to elucidate the system-wide effects of the alcohol-induced increase in the content of cytochrome P450 2E1 (CYP2E1) on drug metabolism, we explored the array of its protein-protein interactions (interactome) in human liver microsomes (HLM) with chemical crosslinking mass spectrometry (CXMS). Our strategy employs membrane incorporation of purified CYP2E1 modified with photoreactive crosslinkers benzophenone-4-maleimide and 4-(N-succinimidylcarboxy)benzophenone. Exposure of bait-incorporated HLM samples to light was followed by isolating the His-tagged bait protein and its crosslinked aggregates on Ni-NTA agarose. Analyzing the individual bands of SDS-PAGE slabs of thereby isolated protein with the toolset of untargeted proteomics, we detected the crosslinked dimeric and trimeric complexes of CYP2E1 with other drug-metabolizing enzymes. Among the most extensively crosslinked partners of CYP2E1 are the cytochromes P450 2A6, 2C8, 3A4, 4A11, and 4F2, UDP-glucuronosyltransferases (UGTs) 1A and 2B, fatty aldehyde dehydrogenase (ALDH3A2), epoxide hydrolase 1 (EPHX1), disulfide oxidase 1α (ERO1L), and ribophorin II (RPN2). These results demonstrate the exploratory power of the proposed CXMS strategy and corroborate the concept of tight functional integration in the human drug-metabolizing ensemble through protein-protein interactions of the constituting enzymes.

Blood direct PCR: impact of CYP2C19 and CYP4F2 variants for bleeding prediction in ST-elevation myocardial infarction patients with ticagrelor.

Aims: The goals of this study were to develop a new technique that could pave the way for a quicker determination of CYP4F2 rs3093135 and CYP2C19 rs4244285 variants directly from a patient's blood and to attempt to apply this technique in clinical practice. Patients & methods: The study included 144 consecutive patients admitted with ST elevation myocardial infarction. A blood-direct PCR and real-time PCR were used to detect variants of interest. Results & conclusion: Patients with bleeding events had the CYP2C19 GG (*1*1) variant more frequently than patients without bleeding events. The CYP4F2 TT variant was more frequently detected in patients with bleeding events 3 months after hospitalization.

Ticagrelor is one of the main antiplatelet drugs used for prevention of coronary blood clots after interventional procedures in patients with acute coronary syndromes. It has previously been shown that gene variants of CYP2C19 and CYP4F2 may affect antiplatelet therapy. This paper reports a novel instrument and the results of genetic tests obtained using this instrument. Our instrument can detect variants of the genes associated with ticagrelor antiplatelet therapy in only 40 min. These findings might facilitate individualized treatment with ticagrelor of patients with ST-elevation myocardial infarction.

Change in plasma α-tocopherol associations with attenuated pulmonary function decline and with CYP4F2 missense variation.

BACKGROUND: Vitamin E (vitE) is hypothesized to attenuate age-related decline in pulmonary function. OBJECTIVES: We investigated the association between change in plasma vitE (∆vitE) and pulmonary function decline [forced expiratory volume in the first second (FEV1)] and examined genetic and nongenetic factors associated with ∆vitE. METHODS: We studied 1144 men randomly assigned to vitE in SELECT (Selenium and Vitamin E Cancer Prevention Trial). ∆vitE was the difference between baseline and year 3 vitE concentrations measured with GC-MS. FEV1 was measured longitudinally by spirometry. We genotyped 555 men (vitE-only arm) using the Illumina Expanded Multi-Ethnic Genotyping Array (MEGAex). We used mixed-effects linear regression modeling to examine the ∆vitE-FEV1 association. RESULTS: Higher ∆vitE was associated with lower baseline α-tocopherol (α-TOH), higher baseline γ-tocopherol, higher baseline free cholesterol, European ancestry (as opposed to African) (all P < 0.05), and the minor allele of a missense variant in cytochrome P450 family 4 subfamily F member 2 (CYP4F2) (rs2108622-T; 2.4 µmol/L higher ∆vitE, SE: 0.8 µmol/L; P = 0.0032). Higher ∆vitE was associated with attenuated FEV1 decline, with stronger effects in adherent participants (≥80% of supplements consumed): a statistically significant ∆vitE × time interaction (P = 0.014) indicated that a 1-unit increase in ∆vitE was associated with a 2.2-mL/y attenuation in FEV1 decline (SE: 0.9 mL/y). The effect size for 1 SD higher ∆vitE (+4 µmol/mmol free-cholesterol-adjusted α-TOH) was roughly one-quarter of the effect of 1 y of aging, but in the opposite direction. The ∆vitE-FEV1 association was similar in never smokers (2.4-mL/y attenuated FEV1 decline, SE: 1.0 mL/y; P = 0.017, n = 364), and current smokers (2.8-mL/y, SE: 1.6 mL/y; P = 0.079, n = 214), but there was little to no effect in former smokers (-0.64-mL/y, SE: 0.9 mL/y; P = 0.45, n = 564). CONCLUSIONS: Greater response to vitE supplementation was associated with attenuated FEV1 decline. The response to supplementation differed by rs2108622 such that individuals with the C allele, compared with the T allele, may need a higher dietary intake to reach the same plasma vitE concentration.

In vitro inhibitory effects of components from Salvia miltiorrhiza on catalytic activity of three human Arachidonic acid ω-hydroxylases.

CYP4 enzymes are involved in the metabolism of xenobiotics and endogenous molecules. 20-Hydroxyeicosatetraenoic acid (20-HETE), the arachidonic acid (AA) ω-hydroxylation metabolite catalyzed by CYP4A/4F enzymes, is implicated in various biological functions. The goal of this investigation is to examine the inhibitory effects of components from Salvia miltiorrhiza(Danshen) on AA ω-hydroxylation using recombinant CYP4A11, CYP4F2, CYP4F3B, and microsomal systems. Tanshinone IIA had noncompetitive inhibition on CYP4F3B (Ki = 4.98 µM). Cryptotanshinone (Ki = 6.87 µM) and tanshinone I (Ki = 0.42 µM) had mixed-type inhibition on CYP4A11. Dihydrotanshinone I had mixed-type inhibition on CYP4A11 (Ki = 0.09 µM), and noncompetitive inhibition on CYP4F2 (Ki = 4.25 µM) and CYP4F3B (Ki = 3.08 µM). Salvianolic acid A had competitive inhibition on CYP4A11 (Ki = 19.37 µM), and noncompetitive inhibition on CYP4F2 (Ki = 15.28 µM) and CYP4F3B (Ki = 6.45 µM). Salvianolic acid C had noncompetitive inhibition on CYP4F2 (Ki = 5.70 µM) and CYP4F3B (Ki = 18.64 µM). In human kidney, human liver or rat heart microsomes, 20-HETE formation was significantly inhibited (P < 0.05) by dihydrotanshinone I (5 and 20 µM) and salvianolic acid A (20 and 50 µM). Given that low plasma concentrations of Danshen components after oral administration, Danshen preparations may not play pharmacological roles by inhibiting AA ω-hydroxylases; however, as Danshen components may reach high concentration in human intestine, drugs that have an important pre-systemic metabolism by these CYP4A/4F enzymes should avoid being co-administered with Danshen preparations.

Genetics Variants in the Epoxygenase Pathway of Arachidonic Metabolism Are Associated with Eicosanoids Levels and the Risk of Diabetic Nephropathy.

Genes in the epoxygenase pathway of arachidonic acid metabolism leading to vasoactive eicosanoids, mainly 20-hydroxyeicosatetraenoic (20-HETE) and epoxyeicosatrienoic (EETs) acids, have been related to glucose-induced renal damage in preclinical reports. We genotyped 1088 diabetic kidney disease (DKD) patients and controls for seven polymorphisms in five genes (CYP2C8, CYP2J2, CYP4F2, CYP4A11, and EPHX2) along this metabolic route and evaluated their effect on DKD risk, clinical outcomes, and the plasma/urine levels of eicosanoids measured by LC/MS/MS and immunoenzymatic assays. The CYP4F2 433M variant allele was associated with lower incidence of DKD (OR = 0.65 (0.48-0.90), p = 0.008), whilst the CYP2C8*3/*3 genotype was related to increased risk (OR = 3.21 (1.05-9.87), p = 0.036). Patients carrying the 433M allele also showed lower eGFR [median and interquartile range vs. wildtype carriers: 30.8 (19.8) and 33.0 (23.2) mL/min/1.73 m2, p = 0.037). Finally, the 433VM/MM variant genotypes were associated with lower urinary levels of 20-HETE compared with 433VV (3.14 (0.86) vs. 8.45 (3.69) ng/mg Creatinine, p = 0.024). Our results indicate that the CYP4F2 V433M polymorphism, by decreasing 20-HETE levels, may play an important role in DKD.

Pharmacogenetic determinants of warfarin in the Indian population.

BACKGROUND: Several studies optimized the warfarin dose based on CYP2C9*2, CYP2C9*3, VKORC1 -1639 G > A, CYP4F2 V433M. But, the information on the rare variants is lacking. In this study, we have explored the prevalence of common and rare pharmacogenetic determinants of warfarin and determined their damaging nature. METHODS: We have analyzed 2000 healthy adults using the Infinium global screening array (GSA) for 15 pharmacogenetic determinants of warfarin. In addition, we have elucidated the impact of these variants on protein function, stability, dynamics, evolutionary preservation, and ligand binding propensity. RESULTS: The GSA Analysis has revealed that CYP4F2 V433M (MAF: 39.425%), VKORC1 -1639 G > A (MAF: 20.5%), CYP2C9*3 (MAF:9.925%), and CYP2C9*2 (MAF:4.575%) are common, while CYP2C9*14 (MAF: 1.475%), CYP2C9*4 (0.175%), CYP2C9*5 (0.125%), and CYP2C9*11 (0.125%) are rare. Position-specific evolutionary preservation (PSEP) analysis has revealed that CYP2C9*4 is possibly damaging, while CYP2C9*5, CYP2C9*11, and CYP2C9*14 are probably damaging. CYP2C9*4 has high thermolability (-10.14 kcal/mol). Among the rare CYP2C9 variants, CYP2C9*4 and CYP2C9*11 exert destabilizing effects and may have increased molecular flexibility, while CYP2C9*5 and CYP2C9*14 exert stabilizing effects and may have decreased molecular flexibility. DNase I footprint analysis has revealed the loss of the E-box consensus sequence due to VKORC1 -1639 G > A polymorphism. CONCLUSION: CYP2C9*2, CYP2C9*3, VKORC1 -1639 G > A and CYP4F2 V433M are common; CYP2C9*4, CYP2C9*5, CYP2C9*11, and CYP2C9*14 variants are rare in Indian subjects. All the CYP2C9 variants are found to be damaging. DNase I footprint analysis provided the mechanistic rationale for the association of VKORC1 -1639 G > A with warfarin sensitivity.

[The Effect of CYP4 F2 Polymorphism on Initial Warfarin Dose in Patients with Heart Valve Replacement].

OBJECTIVE: To study the effect of cytochrome P-4504F2 ( CYP4 F2) gene polymorphism on the initial dose of warfarin in patients after mechanical heart valve replacement. METHODS: We collected 350 patients receiving warfarin after mechanical heart valve replacement from January 2013 to December 2015 in our hospital. According to the international standardized ratio (INR) ≥2 at the initial stage after surgery, the patients were divided into two groups: INR≥2 group and INR<2 group. We selected the blood samples of all the 350 patients with testing the CYP4 F2 gene type of each patient, and analyzed the effect of CYP4 F2 gene polymorphism on the initial dose of warfarin after mechanical heart valve replacement (the average daily dose during hospitalization of patients 5-10 days after mechanical heart valve replacement). RESULTS: There was no statistical significance in the initial dose of warfarin among patients with different CYP4 F2 genotypes. However, warfarin dose was higher in CYP4 F2 TT genotype than in CYP4 F2 CC carriers ((3.37±0.68) mg vs. (2.94±0.74) mg, P<0.05) in INR≥2 group; In patients with the same genotype, the initial dose of warfarin in the CYP4 F2 CC ((4.02±0.58) mg vs. (2.94±0.74) mg) and CYP4 F2 CT genotypes ((4.15±0.88) mg vs. (3.18±0.82) mg) of INR<2 group was higher than that in INR≥2 group ( P<0.05). Gender, age, body mass index (BMI), comorbidities (hypertension, diabetes mellitus, coronary heart disease, atrial fibrillation), cytopigment P-450 2C9 ( CYP2 C9), CYP4 F2 and vitamin K peroxide-reductase complex 1 ( VKORC1) gene polymorphism and INR compliance were included in multiple linear regression analysis. The regression equation was as follows: warfarin initial dose (mg) =-8.634+0.352×BMI (kg/m 2) +1.102× CYP4 F2 genotype (CC or CT values 1, TT values 2) +2.147× VKORC1 (AA or AG values 1, GG values 2) +1.325×INR ( INR≥2 values 0, INR<2 values 1). The coefficient of determination ( R 2) of regression equation was 0.431 ( P<0.05). CONCLUSION: CYP4 F2 gene polymorphism may affect the initial dose of warfarin in patients after heart valve replacement, and this effect is also affected by body characteristics and other factors.