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Yamoune S, Müller JP, Langmia IM, Scholl C, Stingl JC. Uncoupling of Cytochrome P450 2B6 and stimulation of reactive oxygen species production in pharmacogenomic alleles affected by interethnic variability. Biochim Biophys Acta Gen Subj 2024; 1868:130595. [PMID: 38467309 DOI: 10.1016/j.bbagen.2024.130595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/13/2024]
Abstract
Cytochrome P450 mediated substrate metabolism is generally characterized by the formation of reactive intermediates. In vitro and in vivo reaction uncoupling, results in the accumulation and dissociation of reactive intermediates, leading to increased ROS formation. The susceptibility towards uncoupling and altered metabolic activity is partly modulated by pharmacogenomic alleles resulting in amino acid substitutions. A large variability in the prevalence of these alleles has been demonstrated in CYP2B6, with some being predominantly unique to African populations. The aim of this study is to characterize the uncoupling potential of recombinant CYP2B6*1, CYP2B6*6 and CYP2B6*34 metabolism of specific substrates. Therefore, functional effects of these alterations on enzyme activity were determined by quantification of bupropion, efavirenz and ketamine biotransformation using HPLC-MS/MS. Determination of H2O2 levels was performed by the AmplexRed/horseradish peroxidase assay. Our studies of the amino acid substitutions Q172H, K262R and R487S revealed an exclusive use of the peroxide shunt for the metabolism of bupropion and ketamine by CYP2B6*K262R. Ketamine was also identified as a trigger for the peroxide shunt in CYP2B6*1 and all variants. Concurrently, ketamine acted as an uncoupler for all enzymes. We further showed that the expressed CYP2B6*34 allele results in the highest H2O2 formation. We therefore conclude that the reaction uncoupling and peroxide shunt are directly linked and can be substrate specifically induced with K262R carriers being most likely to use the peroxide shunt and R487S carrier being most prone to reaction uncoupling. This elucidates the functional diversity of pharmacogenomics in drug metabolism and safety.
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Affiliation(s)
- Sabrina Yamoune
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Germany; Research Division, Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany.
| | - Julian Peter Müller
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Germany
| | | | - Catharina Scholl
- Research Division, Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
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Abdullahi ST, Soyinka JO, Olagunju A, Bolarinwa RA, Olarewaju OJ, Bakare‐Odunola MT, Winterberg M, Tarning J, Owen A, Khoo S. CYP2B6*6 Genotype Specific Differences in Artemether-Lumefantrine Disposition in Healthy Volunteers. J Clin Pharmacol 2020; 60:351-360. [PMID: 31549442 PMCID: PMC7028104 DOI: 10.1002/jcph.1527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/03/2019] [Indexed: 12/30/2022]
Abstract
Cytochrome P450 2B6 (CYP2B6) is involved in the metabolism of the antimalarial drugs artemether and lumefantrine. Here we investigated the effect of CYP2B6*6 on the plasma pharmacokinetics of artemether, lumefantrine, and their metabolites in healthy volunteers. Thirty healthy and previously genotyped adult volunteers-15 noncarriers (CYP2B6*1/*1) and 15 homozygote carriers (CYP2B6*6/*6)-selected from a cohort of 150 subjects from the Ilorin metropolitan area were administered the complete 3-day course of artemether and lumefantrine (80 and 480 mg twice daily, respectively). Intensive pharmacokinetic sampling was conducted at different time points before and after the last dose. Plasma concentrations of artemether, lumefantrine, dihydroartemisinin, and desbutyllumefantrine were quantified using validated liquid chromatography-mass spectrometric methods. Pharmacokinetic parameters were evaluated using noncompartmental analysis. Artemether clearance of CYP2B6*6/*6 volunteers was nonsignificantly lower by 26% (ratios of geometric mean [90% CI]; 0.74 [0.52-1.05]), and total exposure (the area under the plasma concentration-time curve from time 0 to infinity [AUC0-∞ ]) was greater by 35% (1.35 [0.95-1.93]) when compared with those of *1/*1 volunteers. Similarly, assuming complete bioconversion from artemether, the dihydroartemisinin AUC0-∞ was 22% lower. On the contrary, artemether-to-dihydroartemisinin AUC0-∞ ratio was 73% significantly higher (1.73 [1.27-2.37]). Comparison of lumefantrine exposure and lumefantrine-to-desbutyllumefantrine metabolic ratio of *6/*6 with corresponding data from *1/*1 volunteers showed no differences. The increased artemether-to-dihydroartemisinin metabolic ratio of *6/*6 volunteers is unlikely to result in differences in artemether-lumefantrine efficacy and treatment outcomes. This is the first study in humans to associate CYP2B6*6 genotype with artemether disposition.
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Affiliation(s)
- Sa'ad T. Abdullahi
- Department of Pharmaceutical ChemistryObafemi Awolowo UniversityIle‐IfeNigeria
- Department of Pharmaceutical & Medicinal ChemistryUniversity of IlorinIlorinNigeria
| | - Julius O. Soyinka
- Department of Pharmaceutical ChemistryObafemi Awolowo UniversityIle‐IfeNigeria
| | - Adeniyi Olagunju
- Department of Pharmaceutical ChemistryObafemi Awolowo UniversityIle‐IfeNigeria
- Department of Molecular & Clinical PharmacologyUniversity of LiverpoolLiverpoolUK
| | - Rahman A. Bolarinwa
- Department of HaematologyObafemi Awolowo University Teaching Hospitals ComplexIle‐IfeNigeria
| | - Olusola J. Olarewaju
- Department of HaematologyObafemi Awolowo University Teaching Hospitals ComplexIle‐IfeNigeria
| | | | - Markus Winterberg
- Mahidol‐Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global HealthUniversity of OxfordOxfordUK
| | - Joel Tarning
- Mahidol‐Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global HealthUniversity of OxfordOxfordUK
| | - Andrew Owen
- Department of Molecular & Clinical PharmacologyUniversity of LiverpoolLiverpoolUK
| | - Saye Khoo
- Department of Molecular & Clinical PharmacologyUniversity of LiverpoolLiverpoolUK
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Zahari Z, Lee CS, Ibrahim MA, Musa N, Mohd Yasin MA, Lee YY, Tan SC, Mohamad N, Ismail R. Relationship between CYP2B6*6 and cold pressor pain sensitivity in opioid dependent patients on methadone maintenance therapy (MMT). Drug Alcohol Depend 2016; 165:143-50. [PMID: 27289271 DOI: 10.1016/j.drugalcdep.2016.05.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/22/2016] [Accepted: 05/30/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND CYP2B6 polymorphisms contribute to inter-individual variations in pharmacokinetics of methadone. Increased pain sensitivity is frequently reported by opioid dependent patients on methadone maintenance therapy (MMT). It is possible, therefore, that genetic polymorphisms in CYP2B6, which affects the metabolism of methadone, influence pain sensitivity among patients on MMT. This study investigated CYP2B6 polymorphisms and pain sensitivity in this group. METHODS The cold pressor pain responses of 148 opioid dependent patients receiving MMT were evaluated using the cold pressor test (CPT). DNA was extracted from whole blood and subjected to polymerase chain reaction (PCR)-genotyping. RESULTS Of the 148 subjects, 77 (52.0%) were carriers of CYP2B6*6 allele. CYP2B6*6 allele carriers had shorter cold pain threshold and pain tolerance times than non-carriers of CYP2B6*6 allele (21.05s vs 33.69s, p=0.036 and 27.15s vs 44.51s, p=0.020, respectively). Pain intensity scores of the CYP2B6*6 allele carriers was 67.55, whereas that of the CYP2B6*6 allele non-carriers was 64.86 (p=0.352). CONCLUSION Our study indicates that the CYP2B6*6 allele is associated with a lower pain threshold and lower pain tolerance among males with opioid dependence on MMT. The CYP2B6*6 allele may provide a mechanistic explanation for clinical observations of heightened pain sensitivity among opioid dependent patients receiving MMT.
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Affiliation(s)
- Zalina Zahari
- Department of Pharmacy, Hospital Universiti Sains Malaysia, Kelantan, Malaysia; Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia.
| | - Chee Siong Lee
- Department of Emergency Medicine, School of Medical Sciences, Universiti Sains Malaysia (USM), Kelantan, Malaysia
| | - Muslih Abdulkarim Ibrahim
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia; Department of Pharmacology and Toxicology, College of Pharmacy, Hawler Medical University, Hawler, Iraq
| | - Nurfadhlina Musa
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia
| | - Mohd Azhar Mohd Yasin
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia; Department of Psychiatry, School of Medical Sciences, Universiti Sains Malaysia (USM), Kelantan, Malaysia
| | - Yeong Yeh Lee
- School of Medical Sciences, Universiti Sains Malaysia (USM), Kelantan, Malaysia
| | - Soo Choon Tan
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia
| | - Nasir Mohamad
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia; Faculty of Medicine & Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Rusli Ismail
- Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kelantan, Malaysia; Centre of Excellence for Research in AIDS (CERiA), University of Malaya, Kuala Lumpur, Malaysia
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