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CYP2C19 high activity

Elena Puris, Markku Pasanen, Mikko Gynther, Merja R Häkkinen, Jussi Pihlajamäki, Tapani Keränen, Paavo Honkakoski, Hannu Raunio, Aleksanteri Petsalo
Cocktail phenotyping using specific probe drugs for cytochrome P450 (CYP) enzymes provides information on the real-time activity of multiple CYPs. We investigated different sample preparation techniques and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with simple protein precipitation for the analysis of nine CYP probe drugs and their metabolites in human serum and urine. Specific CYP probe drugs (melatonin, CYP1A2; nicotine, CYP2A6; bupropion, CYP2B6; repaglinide, CYP2C8; losartan, CYP2C9; omeprazole, CYP2C19 and CYP3A4; dextromethorphan, CYP2D6; chlorzoxazone, CYP2E; midazolam, CYP3A4) and their main metabolites, with the exception of 3'-hydroxyrepaglinide, were quantified in human serum and urine using the developed LC-MS/MS method...
October 12, 2016: Analytical and Bioanalytical Chemistry
Allison B Chambliss, Molly Resnick, Athena K Petrides, William A Clarke, Mark A Marzinke
BACKGROUND: Current methods for the detection of single nucleotide polymorphisms (SNPs) associated with aberrant drug-metabolizing enzyme function are hindered by long turnaround times and specialized techniques and instrumentation. In this study, we describe the development and validation of a high-resolution melting (HRM) curve assay for the rapid screening of variant genotypes for targeted genetic polymorphisms in the cytochrome P450 enzymes CYP2C9, CYP2C19, and CYP3A5. METHODS: Sequence-specific primers were custom-designed to flank nine SNPs within the genetic regions of aforementioned drug metabolizing enzymes...
October 12, 2016: Clinical Chemistry and Laboratory Medicine: CCLM
Pui Shen Lau, Kenny Voon Gah Leong, Chin Eng Ong, Amelia Nathania Hui Min Dong, Yan Pan
Cytochrome P450 (CYP) 2C19 is essential for the metabolism of clinically used drugs including omeprazole, proguanil, and S-mephenytoin. This hepatic enzyme exhibits genetic polymorphism with inter-individual variability in catalytic activity. This study aimed to characterise the functional consequences of CYP2C19*23 (271 G>C, 991 A>G) and CYP2C19*24 (991 A>G, 1004 G>A) in vitro. Mutations in CYP2C19 cDNA were introduced by site-directed mutagenesis, and the CYP2C19 wild type (WT) as well as variants proteins were subsequently expressed using Escherichia coli cells...
August 30, 2016: Biochemical Genetics
S Samant, X L Jiang, L A Peletier, A R Shuldiner, R B Horenstein, J P Lewis, L J Lesko, S Schmidt
High interindividual variability in clinical outcomes following clopidogrel's standard dosing regimen continues to be a challenge even two decades after its approval. CYP2C19 polymorphisms, obesity, older age, diabetes, and drug-drug interactions have been identified as risk factors for adverse events and treatment failure. We conducted a mechanism-based pharmacokinetic/pharmacodynamic analysis, where we integrated knowledge on in vitro enzyme kinetic, physiological, genetic, and demographic information to characterize changes in platelet reactivity from baseline following clopidogrel antiplatelet therapy...
August 24, 2016: Clinical Pharmacology and Therapeutics
Xiaojing Tang, Lele Ge, Zhongjian Chen, Sisi Kong, Wenhui Liu, Yingchun Xu, Su Zeng, Shuqing Chen
Hepatocellular carcinoma (HCC), one of the most dangerous malignancies with an increasing incidence and a high mortality rate, represents a major international health problem. HCC progression is known to involve genome-wide alteration of epigenetic modifications, leading to aberrant gene expression patterns. The activity of CYP2C19, an important member of the cytochrome P450 superfamily, was reported to be compromised in HCC, but the underlying mechanism remains unclear. To understand whether epigenetic modification in HCC is associated with a change in CYP2C19 activity, we evaluated the expression levels of CYP2C19 and its transcription factors by quantitative real-time polymerase chain reaction using mRNA extracted from both primary hepatocytes and paired tumor versus nontumor liver tissues of patients infected with hepatitis B virus (HBV)...
October 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
N A Helsby
The study of pharmacogenetic variants in populations which reside in Oceania has been mainly focused on CYP2C19 and CYP2D6. Statements about the high prevalence of CYP2C19 no function genotype in "Pacific Islanders" can be found in the literature. This review article summarizes the published information about these pharmacogenes in this geographical region and highlights the differences observed between Melanesian and Polynesian populations. It is not appropriate to combine the prevalence data of pharmacogenetic variants, particularly CYP2C19, across this region...
June 15, 2016: British Journal of Clinical Pharmacology
Ying-Lu Cui, Fang Xu, Rongling Wu
The CYP2C subfamily is of particular importance in the metabolism of drugs, food toxins, and procarcinogens. Like other P450 subfamilies, 2C enzymes share a high sequence identity, but significantly contribute in different ways to hepatic capacity to metabolize drugs. They often metabolize the same substrate to more than one product with different catalytic sites. Because it is challenging to characterize experimentally, much still remains unknown about the reason for why the substrate regioselectivity of these closely related subfamily members is different...
June 29, 2016: Physical Chemistry Chemical Physics: PCCP
Mahmoud Fahmi Elsebai, Khaled Abass, Jukka Hakkola, Ahmed Rezk Atawia, Mohamed A Farag
Infection by hepatitis C virus (HCV) and its subsequent complications are a major cause of mortality worldwide. The water extract of the wild Egyptian artichoke (WEA) (Cynara cardunculus L. var. sylvestris (Lam.) Fiori) leaves is a freely available herbal product that is used for treatment of HCV-infection complications such as jaundice and ascites. The purpose of this study was to evaluate whether WEA exhibits activity against HCV, identify bioactive chemicals in its extract and to tentatively examine the potential inhibitory interactions of WEA with human drug-metabolizing enzymes...
July 13, 2016: Food & Function
T C Leunissen, S M O Peeters Weem, R T Urbanus, H M den Ruijter, F L Moll, F W Asselbergs, G J de Borst
OBJECTIVE: Restenosis and stent thrombosis after endovascular intervention in patients with peripheral arterial disease (PAD) can potentially be tackled by more intensive antiplatelet therapy, such as dual antiplatelet therapy (DAPT) consisting of aspirin and P2Y12 inhibitor. Despite clopidogrel treatment, some patients still display high platelet reactivity (HCPR). Tailored antiplatelet therapy, based on platelet reactivity testing, might overcome HCPR. However, more data are warranted regarding the proportion of patients with HCPR in the PAD population, different platelet reactivity tests, their correlation, and the optimal timing for these tests as a stepping stone for a future trial investigating the potential benefit of tailored antiplatelet therapy in PAD patients...
August 2016: European Journal of Vascular and Endovascular Surgery
A Ormeci, Z Emrence, B Baran, O M Soyer, S Gokturk, S Evirgen, F Akyuz, C Karaca, F Besisik, S Kaymakoglu, D Ustek, K Demir
Proton pump inhibitors (PPI) metabolism and pharmacokinetics are regulated by cytochrome P450 enzymes in the liver. Cytochrome P450 2C19 (CYP2C19) polymorphism plays an import role in the metabolism of PPIs. The three possible genotypes for CYP2C19 each has a distinct effect on the pharmacodynamics of PPIs. Homozygote extensive metabolizers (HomEM) are the most frequent genotype and have two wild-types (non-mutant) (*1/*1) alleles. HomEM is associated with increased enzyme activity, which increases the rate of PPI metabolism...
May 2016: European Review for Medical and Pharmacological Sciences
Neville F Ford
The major metabolic pathway of clopidogrel is conversion to the carboxylic acid by an esterase (CES1), forming clopidogrelic acid (SR26334) that is inactive. There is agreement on the structure of the active metabolite, however there are differing views as to the mechanism of its formation. Sanofi studied the conversion of clopidogrel to the active metabolite using human liver microsomes. It was concluded that 2-oxo-clopidogrel was formed via CYP3A oxidation. From a subsequent in vitro study by Sankyo of the metabolism of clopidogrel using recombinant DNA CYPs it was concluded that CYP2C19 was the major oxidative pathway...
May 16, 2016: Journal of Clinical Pharmacology
Andrew G S Warrilow, Josie E Parker, Claire L Price, W David Nes, Edward P Garvey, William J Hoekstra, Robert J Schotzinger, Diane E Kelly, Steven L Kelly
Cryptococcosis is a life-threatening disease often associated with HIV infection. Three Cryptococcus species CYP51 enzymes were purified and catalyzed the 14α-demethylation of lanosterol, eburicol, and obtusifoliol. The investigational agent VT-1129 bound tightly to all three CYP51 proteins (dissociation constant [Kd] range, 14 to 25 nM) with affinities similar to those of fluconazole, voriconazole, itraconazole, clotrimazole, and ketoconazole (Kd range, 4 to 52 nM), whereas VT-1129 bound weakly to human CYP51 (Kd, 4...
August 2016: Antimicrobial Agents and Chemotherapy
Gail D Anderson, Lingtak-Neander Chan
Tobacco smoke contains a large number of compounds in the form of metals, volatile gases and insoluble particles, as well as nicotine, a highly addictive alkaloid. Marijuana is the most widely used illicit drug of abuse in the world, with a significant increase in the USA due to the increasing number of states that allow medical and recreational use. Of the over 70 phytocannabinoids in marijuana, Δ(9)-tetrahydrocannabinol (Δ(9)THC), cannabidiol (CBD) and cannibinol are the three main constituents. Both marijuana and tobacco smoking induce cytochrome P450 (CYP) 1A2 through activation of the aromatic hydrocarbon receptor, and the induction effect between the two products is additive...
April 22, 2016: Clinical Pharmacokinetics
Krystina Parker, Willy Aasebø, Tore Haslemo, Knut Stavem
BACKGROUND: Elderly patients on haemodialysis have a high prevalence of polypharmacy and are at risk of drug-related complications. More than 80 % of all prescribed drugs are metabolized by the cytochrome P450 (CYP) enzyme system. The aims of this study were to describe the prevalence of polymorphism in three CYP isoenzymes and the relationship between CYP polymorphism and prescribed drugs. METHODS: Fifty-one elderly haemodialysis patients aged ≥65 years were included...
2016: SpringerPlus
Jonathan Q Tran, Ahmed A Othman, Paul Wolstencroft, Jacob Elkins
AIMS: To characterize the potential effect of daclizumab high-yield process (DAC HYP), a monoclonal antibody that blocks the high-affinity interleukin-2 receptors for treatment of multiple sclerosis, on activity of cytochrome P450 (CYP) enzymes. METHODS: Twenty patients with multiple sclerosis received an oral cocktail of probe substrates of CYP1A2 (caffeine 200 mg), CYP2C9 (warfarin 10 mg/vitamin K 10 mg), CYP2C19 (omeprazole 40 mg), CYP2D6 (dextromethorphan 30 mg) and CYP3A (midazolam 5 mg) on two sequential occasions: 7 days before and 7 days after subcutaneous administration of DAC HYP 150 mg every 4 weeks for three doses...
July 2016: British Journal of Clinical Pharmacology
Adrien Harvey, Anil Modak, Ugo Déry, Mélanie Roy, Stéphane Rinfret, Olivier F Bertrand, Éric Larose, Josep Rodés-Cabau, Gérald Barbeau, Onil Gleeton, Can Manh Nguyen, Guy Proulx, Bernard Noël, Louis Roy, Jean-Michel Paradis, Robert De Larochellière, Jean-Pierre Déry
Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is used for the prevention of cardiovascular events following percutaneous coronary intervention (PCI). These agents increase the risk of gastrointestinal bleeding. To prevent these events, proton pump inhibitors (PPI) are routinely prescribed. It has been reported that with the exception of pantoprazole and dexlanzoprazole, PPIs can impede conversion of clopidogrel by cytochrome P450 2C19 (CYP2C19) to its active metabolite, a critical step required for clopidogrel efficacy...
March 2016: Journal of Breath Research
Matthias Olbrich, Kevin Weigl, Elke Kahler, Katsuhiro Mihara
1. The metabolism of dydrogesterone was investigated in human liver cytosol (HLC) and human liver microsomes (HLM). Enzymes involved in dydrogesterone metabolism were identified and their relative contributions were estimated. 2. Dydrogesterone clearance was clearly higher in HLC compared to HLM. The major active metabolite 20α-dihydrodydrogesterone (20α-DHD) was only produced in HLC. 3. The formation of 20α-DHD by cytosolic aldo-keto reductase 1C (AKR1C) was confirmed with isoenzyme-specific AKR inhibitors...
October 2016: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
Sundeep Dugar, Frank P Hollinger, Dinesh Mahajan, Somdutta Sen, Bilash Kuila, Reena Arora, Yogesh Pawar, Vaibhav Shinde, Mahesh Rahinj, Kamal K Kapoor, Rahul Bhumkar, Santosh Rai, Rakesh Kulkarni
A new class of potent PI3Kα inhibitors is identified based on aryl substituted morpholino-triazine scaffold. The identified compounds showed not only a high level of enzymatic and cellular potency in nanomolar range but also high oral bioavailability. The three lead molecules (based on their in vitro potency) when evaluated further for in vitro metabolic stability as well as pharmacokinetic profile led to the identification of 26, as a candidate for further development. The IC50 and EC50 value of 26 is 60 and 500 nM, respectively, for PI3Kα enzyme inhibitory activity and ovarian cancer (A2780) cell line...
December 10, 2015: ACS Medicinal Chemistry Letters
Yiran Zhai, Lili Wang, Fan Yang, Guo Feng, Shan Feng, Tianyi Cui, Lijun An, Xin He
CONTEXT AND OBJECTIVE: Clopidogrel (CLP) is a prodrug which is widely used as a platelet aggregation inhibitor. Hepatotoxicity is rare but a potentially serious adverse reaction that is associated with CLP. Thiophene in CLP (the thienopyridine derivative) is a group that is easily oxidated by cytochrome P450 enzymes (CYP450s) to generate reactive metabolites (RMs), it may be implicated in the mechanism of CLP-induced hepatotoxicity. CYP2C19 and CYP2B6 are important CYP450s involved in the metabolism and activation of CLP, and the aim of this study is to investigate whether the metabolites of CYP2C19 and CYP2B6 are associated with the CLP-induced liver injury...
October 2016: Drug and Chemical Toxicology
Emre Yucel, Mesut Sancar, Aylin Yucel, Betul Okuyan
INTRODUCTION: Many systematic reviews resulted in claims on drug-drug interactions (DDIs) with proton pump inhibitors (PPIs). Such a large number begs for consensus on the clinical significance of findings. AREAS COVERED: We critically evaluated the safety of PPI use with respect to DDIs with a meta-review of systematic reviews published between 1978 and 2015. We assessed the evidence by their reliability, repeatability, transparency, and objectivity according to the Assessment of Multiple Systematic Reviews (AMSTAR) criteria...
2016: Expert Opinion on Drug Safety
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