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Miksys S, McDonald C, Baghai Wadji F, Gonzalez FJ, Tyndale RF. Human CYP2D6 varies across the estrous cycle in brains of transgenic mice altering drug response. Prog Neuropsychopharmacol Biol Psychiatry 2024; 135:111108. [PMID: 39069248 PMCID: PMC11402587 DOI: 10.1016/j.pnpbp.2024.111108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/17/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Cytochrome P450 (CYP) 2Ds are drug metabolizing enzymes found in brain and liver which metabolize numerous centrally acting drugs. Inhibition and induction of CYP2D-mediated metabolism in rodent brain alters brain drug and metabolite concentrations and resulting drug response. In female rats, brain CYP2D metabolism varies across the estrous cycle and with exogenous estrogen, changing brain drug concentrations and response. In this study harmine-induced hypothermia was lower in humanized CYP2D6 transgenic female mice during estrus compared to diestrus. Pretreatment into the cerebral ventricles with propranolol, a selective irreversible inhibitor of human CYP2D6 in brain, increased hypothermia in estrus but not in diestrus. In vivo enzyme activity was higher in brains of transgenic mice in estrus compared to diestrus and was lower after pretreatment with inhibitor in estrus, but not in diestrus. Hepatic activity and plasma harmine concentrations were unaffected by either estrous phase or inhibition of brain CYP2D6. In wild-type female mice, harmine-induced hypothermia was unaffected by either estrous phase or inhibitor pretreatment. Male mice were used as positive controls, where pretreatment with inhibitor increased harmine-induced hypothermia in transgenic but not wild-type, mice. This study provides evidence for female hormone cycle-based regulation of drug metabolism by human CYP2D6 in brain and resulting drug response. This suggests that brain CYP2D6 metabolism may vary, for example, during the menstrual cycle, pregnancy, or menopause, or while taking oral contraceptives or hormone therapy. This variation could contribute to individual differences in response to centrally acting CYP2D6-substrate drugs by altering local brain drug and/or metabolite concentrations.
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Affiliation(s)
- Sharon Miksys
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
| | - Claire McDonald
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
| | - Fariba Baghai Wadji
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
| | - Frank J Gonzalez
- Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Rachel F Tyndale
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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Bassi M, Bilel S, Tirri M, Corli G, Di Rosa F, Gregori A, Alkilany AM, Rachid O, Roda E, Zauli G, Locatelli CA, Marti M. Pharmaco-toxicological effects of the novel tryptamine hallucinogen 5-MeO-MiPT on motor, sensorimotor, physiological, and cardiorespiratory parameters in mice-from a human poisoning case to the preclinical evidence. Psychopharmacology (Berl) 2024; 241:489-511. [PMID: 38214743 PMCID: PMC10884077 DOI: 10.1007/s00213-024-06526-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/01/2024] [Indexed: 01/13/2024]
Abstract
RATIONALE The 5-methoxy-N-methyl-N-isopropyltryptamine (5-MeO-MiPT, known online as "Moxy") is a new psychedelic tryptamine first identified on Italian national territory in 2014. Its hallucinogen effects are broadly well-known; however, only few information is available regarding its pharmaco-toxicological effects. OBJECTIVES Following the seizure of this new psychoactive substances by the Arm of Carabinieri and the occurrence of a human intoxication case, in the current study we had the aim to characterize the in vivo acute effects of systemic administration of 5-MeO-MiPT (0.01-30 mg/kg i.p.) on sensorimotor (visual, acoustic, and overall tactile) responses, thermoregulation, and stimulated motor activity (drag and accelerod test) in CD-1 male mice. We also evaluated variation on sensory gating (PPI, prepulse inhibition; 0.01-10 mg/kg i.p.) and on cardiorespiratory parameters (MouseOx and BP-2000; 30 mg/kg i.p.). Lastly, we investigated the in silico ADMET (absorption, distribution, metabolism, excretion, toxicity) profile of 5-MeO-MiPT compared to 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) and N,N-dimethyltryptamine (DMT). RESULTS This study demonstrates that 5-MeO-MiPT dose-dependently inhibits sensorimotor and PPI responses and, at high doses, induces impairment of the stimulated motor activity and cardiorespiratory changes in mice. In silico prediction shows that the 5-MeO-MiPT toxicokinetic profile shares similarities with 5-MeO-DIPT and DMT and highlights a cytochrome risk associated with this compound. CONCLUSIONS Consumption of 5-MeO-MiPT can affect the ability to perform activities and pose a risk to human health status, as the correspondence between the effects induced in mice and the symptoms occurred in the intoxication case suggests. However, our findings suggest that 5-MeO-MiPT should not be excluded from research in the psychiatric therapy field.
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Grants
- Effects of NPS: development of a multicentre research for the information enhancement of the Early Warning System Anti-Drug Policies Department, Presidency of the Council of Ministers, Italy
- Implementation of the identification Anti-Drug Policies Department, Presidency of the Council of Ministers, Italy
- study of the effects of NPS: Development of a multicentric research to strengthen the database of the National Monitoring Centre for Drug Addiction Anti-Drug Policies Department, Presidency of the Council of Ministers, Italy
- the Early Warning System Anti-Drug Policies Department, Presidency of the Council of Ministers, Italy
- FAR 2021 Università degli Studi di Ferrara
- FAR 2022 Università degli Studi di Ferrara
- Anti-Drug Policies Department, Presidency of the Council of Ministers, Italy
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Affiliation(s)
- Marta Bassi
- Department of Translational Medicine, Section of Legal Medicine and LTTA Centre, University of Ferrara, Via Fossato Di Mortara 70, 44121, Ferrara, Italy
| | - Sabrine Bilel
- Department of Translational Medicine, Section of Legal Medicine and LTTA Centre, University of Ferrara, Via Fossato Di Mortara 70, 44121, Ferrara, Italy
| | - Micaela Tirri
- Department of Translational Medicine, Section of Legal Medicine and LTTA Centre, University of Ferrara, Via Fossato Di Mortara 70, 44121, Ferrara, Italy
| | - Giorgia Corli
- Department of Translational Medicine, Section of Legal Medicine and LTTA Centre, University of Ferrara, Via Fossato Di Mortara 70, 44121, Ferrara, Italy
| | - Fabiana Di Rosa
- Department of Scientific Investigation (RIS), Carabinieri, 00191, Rome, Italy
| | - Adolfo Gregori
- Department of Scientific Investigation (RIS), Carabinieri, 00191, Rome, Italy
| | - Alaaldin M Alkilany
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Ousama Rachid
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Elisa Roda
- Laboratory of Clinical & Experimental Toxicology, Pavia Poison Centre, National Toxicology Information Centre, Toxicology Unit, Istituti Clinici Scientifici Maugeri, IRCCS, Pavia, Italy
| | - Giorgio Zauli
- Research Department, King Khaled Eye Specialistic Hospital, Riyadh, Saudi Arabia
| | - Carlo Alessandro Locatelli
- Laboratory of Clinical & Experimental Toxicology, Pavia Poison Centre, National Toxicology Information Centre, Toxicology Unit, Istituti Clinici Scientifici Maugeri, IRCCS, Pavia, Italy
| | - Matteo Marti
- Department of Translational Medicine, Section of Legal Medicine and LTTA Centre, University of Ferrara, Via Fossato Di Mortara 70, 44121, Ferrara, Italy.
- Department of Anti-Drug Policies, Collaborative Center for the Italian National Early Warning System, Presidency of the Council of Ministers, Ferrara, Italy.
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Thamilselvan M, Mather C, Wang Y, Foo JC, Aitchison KJ. Haplotype phasing of CYP2D6: an allelic ratio method using Agena MassARRAY data. Transl Psychiatry 2024; 14:91. [PMID: 38346976 PMCID: PMC10861455 DOI: 10.1038/s41398-024-02809-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 01/18/2024] [Accepted: 01/29/2024] [Indexed: 02/15/2024] Open
Abstract
Pharmacogenomics aims to use the genetic information of an individual to personalize drug prescribing. There is evidence that pharmacogenomic testing before prescription may prevent adverse drug reactions, increase efficacy, and reduce cost of treatment. CYP2D6 is a key pharmacogene of relevance to multiple therapeutic areas. Indeed, there are prescribing guidelines available for medications based on CYP2D6 enzyme activity as deduced from CYP2D6 genetic data. The Agena MassARRAY system is a cost-effective method of detecting genetic variation that has been clinically applied to other genes. However, its clinical application to CYP2D6 has to date been limited by weaknesses such as the inability to determine which haplotype was present in more than one copy for individuals with more than two copies of the CYP2D6 gene. We report application of a new protocol for CYP2D6 haplotype phasing of data generated from the Agena MassARRAY system. For samples with more than two copies of the CYP2D6 gene for which the prior consensus data specified which one was present in more than one copy, our protocol was able to conduct CYP2D6 haplotype phasing resulting in 100% concordance with the prior data. In addition, for three reference samples known to have more than two copies of CYP2D6 but for which the exact number of CYP2D6 genes was unknown, our protocol was able to resolve the number for two out of the three of these, and estimate the likely number for the third. Finally, we demonstrate that our method is applicable to CYP2D6 hybrid tandem configurations.
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Affiliation(s)
- Megana Thamilselvan
- University of Alberta, College of Natural and Applied Sciences, Department of Biological Sciences, Edmonton, Canada
| | - Cheryl Mather
- University of Alberta, College of Health Sciences, Department of Laboratory Medicine and Pathology, Edmonton, Canada
- Alberta Precision Laboratories, Edmonton, Canada
| | - Yabing Wang
- University of Alberta, College of Health Sciences, Department of Psychiatry, Edmonton, Canada
| | - Jerome C Foo
- University of Alberta, College of Health Sciences, Department of Psychiatry, Edmonton, Canada
| | - Katherine J Aitchison
- University of Alberta, College of Health Sciences, Department of Psychiatry, Edmonton, Canada.
- University of Alberta, Neuroscience and Mental Health Institute, Edmonton, Canada.
- University of Alberta, College of Health Sciences, Department of Medical Genetics, Edmonton, Canada.
- Northern Ontario School of Medicine, Thunder Bay, Canada.
- University of Alberta, Women and Children's Health Research Institute, Edmonton, Canada.
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Yaowaluk T, Senanarong V, Limwongse C, Boonprasert R, Bunditvorapoom D, Kaewsutthi S, Kijsanayotin P. Association study identifies genetic determinants and non-genetic factors on steady-state plasma and therapeutic outcome of galantamine in mixed dementia. Eur J Clin Pharmacol 2022; 78:1249-1259. [PMID: 35633386 DOI: 10.1007/s00228-022-03322-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 04/15/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE This study aimed to evaluate the influence of genetic polymorphisms of drug-metabolizing enzyme genes, transporter gene, pathological gene (APOE), and non-genetic factors on therapeutic outcomes as well as steady-state plasma concentrations (Cpss) of galantamine in Thai patients with mixed dementia. METHODS Fifty-one Thai patients with mixed dementia who received galantamine for at least 6 months were recruited. CYP2D6, CYP3A5, and ABCB1 polymorphisms were detected by TaqMan® Genotyping Assay. UGT1A1 and APOE polymorphism was detected by direct Sanger sequencing technique and restriction fragment length polymorphism technique. Cpss of galantamine was measured by ultra-performance liquid chromatography. Associations of genetic and non-genetic factors with Cpss and clinical outcomes (change in cognitive function as measured by the Thai Mental State Examination (ΔTMSE) scores) were determined by using univariate and multivariate analysis. RESULTS The multivariate regression model revealed that patients who carried one or more detrimental allelic variant (CYP2D6, CYP3A5, and UGT1A1) showed a tendency toward a higher galantamine adjusted Cpss (B = 34.559, 95% CI = 0.741-68.377, p value = 0.045). Logistic regression analysis also revealed CYP2D6*10 carriers were significantly associated with higher ΔTMSE (B = 5.227, 95% CI = 2.395-8.060, p value = 0.001). UGT1A1 mutant alleles and non-genetic factors including concomitant use of statin drugs and higher education level can attenuate therapeutic outcomes of galantamine. CONCLUSION Pharmacokinetic-related genes including CYP2D6*10 and UGT1A1 mutant alleles were significantly associated with galantamine adjusted Cpss and cognitive function. Determination of Cpss and genotype could be an adjunct examination to provide further explanation in interindividual variability of galantamine therapeutic outcome.
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Affiliation(s)
- Thitipon Yaowaluk
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Phayathai Rd, Pathumwan, Bangkok, 10330, Thailand
| | - Vorapun Senanarong
- Division of Neurology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chanin Limwongse
- Division of Medical Genetics, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Rasda Boonprasert
- Clinical Toxicology Laboratory, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Duangkamon Bunditvorapoom
- Division of Medical Genetics, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Supannee Kaewsutthi
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pornpimol Kijsanayotin
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Phayathai Rd, Pathumwan, Bangkok, 10330, Thailand.
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Kutuk MO, Tufan AE, Topal Z, Acikbas U, Guler G, Karakas B, Basaga H, Kilicaslan F, Altintas E, Aka Y, Kutuk O. CYP450 2D6 and 2C19 genotypes in ADHD: not related with treatment resistance but with over-representation of 2C19 ultra-metabolizers. Drug Metab Pers Ther 2022; 37:261-269. [PMID: 35218180 DOI: 10.1515/dmpt-2021-0163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 01/03/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Cytochrome P450 (CYP450) is a major enzyme system involved in drug metabolism as well as regulation of brain function. Although individual variability in CYP enzymes have been studied in terms of personality traits and treatment effects, no study up to now evaluated CYP polymorphisms in children with attention deficit/hyperactivity disorder (ADHD). We aimed to define the genetic profiles of CYP2D6 and CYP2C19 relevant alleles in children with ADHD according to treatment status and compare the frequencies according to past results. METHODS Three hundred and seventeen patients with ADHD-Combined Presentation were enrolled; symptom severity was evaluated by parents and clinicians while adverse effects of previous treatments were evaluated with parent and child reports. Reverse blotting on strip assays was used for genotyping and descriptive and bivariate analyses were conducted. A p-value was set at 0.05 (two-tailed). RESULTS Children were divided into treatment-naïve (n=194, 61.2%) and treatment-resistant (n=123, 38.8%) groups. Within the whole sample PM, EM and UM status according to 2D6 were 3.8% (n=12), 94.3% (n=299) and 21.9% (n=6); respectively. PM, IM, EM and UM status according to 2C19 were 2.5% (n=8), 19.8% (n=63), 48.6% (n=154) and 29.0% (n=92), respectively. No relationship with treatment resistance, comorbidity or gender could be found. Importantly, CYP2C19 UMs were significantly more frequent in ADHD patients compared to previous studies in the general population. CONCLUSIONS CYPs may be a rewarding avenue of research to elucidate the etiology and treatment of patients with ADHD.
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Affiliation(s)
- Meryem Ozlem Kutuk
- Department of Child and Adolescent Psychiatry, Baskent University School of Medicine, Adana Dr. Turgut Noyan Medical and Research Center, Adana, Turkey
| | - Ali Evren Tufan
- Department of Child and Adolescent Psychiatry, Abant Izzet Baysal University, School of Medicine, Bolu, Turkey
| | - Zehra Topal
- Department of Child and Adolescent Psychiatry, Gaziantep University, Gaziantep, Turkey
| | | | - Gulen Guler
- Department of Child and Adolescent Psychiatry, Mersin University School of Medicine, Mersin, Turkey
| | - Bahriye Karakas
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey
| | - Huveyda Basaga
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey
| | - Fethiye Kilicaslan
- Department of Child and Adolescent Psychiatry, Harran University, Sanliurfa, Turkey
| | - Ebru Altintas
- Department of Psychiatry, Baskent University, Dr. Turgut Noyan Medical and Research Center, Adana, Turkey
| | - Yeliz Aka
- Department of Immunology, Baskent University School of Medicine, Adana Dr. Turgut Noyan Medical and Research Center, Adana, Turkey
| | - Ozgur Kutuk
- Department of Immunology, Baskent University School of Medicine, Adana Dr. Turgut Noyan Medical and Research Center, Adana, Turkey
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Russell LE, Zhou Y, Almousa AA, Sodhi JK, Nwabufo CK, Lauschke VM. Pharmacogenomics in the era of next generation sequencing - from byte to bedside. Drug Metab Rev 2021; 53:253-278. [PMID: 33820459 DOI: 10.1080/03602532.2021.1909613] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pharmacogenetic research has resulted in the identification of a multitude of genetic variants that impact drug response or toxicity. These polymorphisms are mostly common and have been included as actionable information in the labels of numerous drugs. In addition to common variants, recent advances in Next Generation Sequencing (NGS) technologies have resulted in the identification of a plethora of rare and population-specific pharmacogenetic variations with unclear functional consequences that are not accessible by conventional forward genetics strategies. In this review, we discuss how comprehensive sequencing information can be translated into personalized pharmacogenomic advice in the age of NGS. Specifically, we provide an update of the functional impacts of rare pharmacogenetic variability and how this information can be leveraged to improve pharmacogenetic guidance. Furthermore, we critically discuss the current status of implementation of pharmacogenetic testing across drug development and layers of care. We identify major gaps and provide perspectives on how these can be minimized to optimize the utilization of NGS data for personalized clinical decision-support.
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Affiliation(s)
| | - Yitian Zhou
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ahmed A Almousa
- Department of Pharmacy, London Health Sciences Center, Victoria Hospital, London, ON, Canada
| | - Jasleen K Sodhi
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California San Francisco, San Francisco, CA, USA.,Department of Drug Metabolism and Pharmacokinetics, Plexxikon, Inc., Berkeley, CA, USA
| | | | - Volker M Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Just KS, Dormann H, Freitag M, Schurig M, Böhme M, Steffens M, Scholl C, Seufferlein T, Graeff I, Schwab M, Stingl JC. CYP2D6 in the Brain: Potential Impact on Adverse Drug Reactions in the Central Nervous System-Results From the ADRED Study. Front Pharmacol 2021; 12:624104. [PMID: 34025403 PMCID: PMC8138470 DOI: 10.3389/fphar.2021.624104] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/19/2021] [Indexed: 12/15/2022] Open
Abstract
Cytochrome P450 (CYP) 2D6 is a polymorphic enzyme expressed in the central nervous system (CNS), important in drug metabolism and with a potentially constitutive role in CNS function such as vigilance. This study aimed to analyze variability in CYP2D6 activity linked to vigilance-related adverse drug reactions (ADRs) in the CNS. A dataset of N = 2939 ADR cases of the prospective multicenter observational trial in emergency departments (EDs) (ADRED; trial registration: DRKS-ID: DRKS00008979) was analyzed. Dizziness as the most frequent reported CNS ADR symptom (12.7% of patients, n = 372) related to vigilance was chosen as the outcome. The association of dizziness with CYP2D6 activity markers was analyzed. The number of CYP2D6 substrates taken, a CYP2D6 saturation score (no, moderate, and strong saturation), a CYP2D6 saturation/inhibition score (no, weak, moderate, and strong), and composed CYP2D6 activity using a genotyped subsample (n = 740) calculating additive effects of genotype and CYP2D6 saturation by drug exposure were used as CYP2D6 activity markers. Effects were compared to other frequent nonvigilance-related CNS ADR symptoms (syncope and headache). Secondary analyses were conducted to control for other ADR symptoms frequently associated with dizziness (syncope, nausea, and falls). The majority of all patients (64.5%, n = 1895) took at least one drug metabolized by CYP2D6. Around a third took a CNS drug (32.5%, n = 955). The chance to present with drug-related dizziness to the ED increased with each CYP2D6 substrate taken by OR 1.11 [1.01–1.23]. Presenting with drug-related dizziness was more likely with CYP2D6 saturation and saturation/inhibition (both OR 1.27 [1.00–1.60]). The composed CYP2D6 activity was positively associated with dizziness (p = 0.028), while poorer activity affected patients more often with dizziness as an ADR. In contrast, nonvigilance-related ADR symptoms such as syncope and nausea were not consistently significantly associated with CYP2D6 activity markers. This study shows an association between the number of CYP2D6 substrates, the predicted CYP2D6 activity, and the occurrence of dizziness as a CNS ADR symptom. As dizziness is a vigilance-related CNS symptom, patients with low CYP2D6 activity might be more vulnerable to drug-related dizziness. This study underlines the need for understanding individual drug metabolism activity and individual risks for ADRs.
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Affiliation(s)
- Katja S Just
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Aachen, Germany
| | - Harald Dormann
- Central Emergency Department, Hospital Fürth, Fürth, Germany
| | - Mathias Freitag
- Department of Geriatric Medicine, University Hospital of RWTH Aachen, Aachen, Germany
| | - Marlen Schurig
- Research Department, Federal Institute of Drugs and Medical Devices, Bonn, Germany
| | - Miriam Böhme
- Research Department, Federal Institute of Drugs and Medical Devices, Bonn, Germany
| | - Michael Steffens
- Research Department, Federal Institute of Drugs and Medical Devices, Bonn, Germany
| | - Catharina Scholl
- Research Department, Federal Institute of Drugs and Medical Devices, Bonn, Germany
| | - Thomas Seufferlein
- Internal Medicine Emergency Department, Ulm University Medical Centre, Ulm, Germany
| | - Ingo Graeff
- Interdisciplinary Emergency Department (INZ), University Hospital of Bonn, Bonn, Germany
| | - Matthias Schwab
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany.,Department of Clinical Pharmacology, University of Tuebingen, Tuebingen, Germany.,Department of Pharmacy and Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Julia C Stingl
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Aachen, Germany
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Influence of cytochrome P450 2D6 polymorphism on hippocampal white matter and treatment response in schizophrenia. NPJ SCHIZOPHRENIA 2021; 7:5. [PMID: 33514751 PMCID: PMC7846743 DOI: 10.1038/s41537-020-00134-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/12/2020] [Indexed: 12/16/2022]
Abstract
Cytochrome P450 2D6 (CYP2D6) is expressed at high levels in the brain and plays a considerable role in the biotransformation and neurotransmission of dopamine. This raises the question of whether CYP2D6 variations and its impact on the brain can confer susceptibility to schizophrenia. We investigated the possible links among the CYP2D6 genotype, white matter (WM) integrity of the hippocampus, and the treatment response to antipsychotic drugs in Korean patients with schizophrenia (n = 106). Brain magnetic resonance imaging and genotyping for CYP2D6 were conducted at baseline. The severity of clinical symptoms and the treatment response were assessed using the Positive and Negative Syndrome Scale (PANSS). After genotyping, 43 participants were classified as intermediate metabolizers (IM), and the remainder (n = 63) were classified as extensive metabolizers (EM). IM participants showed significantly higher fractional anisotropy (FA) values in the right hippocampus compared to EM participants. Radial diffusivity (RD) values were significantly lower in the overlapping region of the right hippocampus in the IM group than in the EM group. After 4 weeks of antipsychotic treatment, the EM group showed more improvements in positive symptoms than the IM group. FAs and RDs in the CYP2D6-associated hippocampal WM region were significantly correlated with a reduction in the positive symptom subscale of the PANSS. Greater improvements in positive symptoms were negatively associated with FAs, and positively associated with RDs in the right hippocampal region. The findings suggest that CYP26D-associated hippocampal WM alterations could be a possible endophenotype for schizophrenia that accounts for individual differences in clinical features and treatment responses.
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Abstract
The regulation of brain cytochrome P450 enzymes (CYPs) is different compared with respective hepatic enzymes. This may result from anatomical bases and physiological functions of the two organs. The brain is composed of a variety of functional structures built of different interconnected cell types endowed with specific receptors that receive various neuronal signals from other brain regions. Those signals activate transcription factors or alter functioning of enzyme proteins. Moreover, the blood-brain barrier (BBB) does not allow free penetration of all substances from the periphery into the brain. Differences in neurotransmitter signaling, availability to endogenous and exogenous active substances, and levels of transcription factors between neuronal and hepatic cells lead to differentiated expression and susceptibility to the regulation of CYP genes in the brain and liver. Herein, we briefly describe the CYP enzymes of CYP1-3 families, their distribution in the brain, and discuss brain-specific regulation of CYP genes. In parallel, a comparison to liver CYP regulation is presented. CYP enzymes play an essential role in maintaining the levels of bioactive molecules within normal ranges. These enzymes modulate the metabolism of endogenous neurochemicals, such as neurosteroids, dopamine, serotonin, melatonin, anandamide, and exogenous substances, including psychotropics, drugs of abuse, neurotoxins, and carcinogens. The role of these enzymes is not restricted to xenobiotic-induced neurotoxicity, but they are also involved in brain physiology. Therefore, it is crucial to recognize the function and regulation of CYP enzymes in the brain to build a foundation for future medicine and neuroprotection and for personalized treatment of brain diseases.
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Affiliation(s)
- Wojciech Kuban
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Władysława Anna Daniel
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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Stocco MR, Tolledo C, Wadji FB, Gonzalez FJ, Miksys S, Tyndale RF. Human CYP2D6 in the Brain Is Protective Against Harmine-Induced Neurotoxicity: Evidence from Humanized CYP2D6 Transgenic Mice. Mol Neurobiol 2020; 57:4608-4621. [PMID: 32761352 PMCID: PMC8865091 DOI: 10.1007/s12035-020-02050-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/28/2020] [Indexed: 10/25/2022]
Abstract
CYP2D6 metabolically inactivates several neurotoxins, including beta-carbolines, which are implicated in neurodegenerative diseases. Variation in CYP2D6 within the brain may alter local inactivation of neurotoxic beta-carbolines, thereby influencing neurotoxicity. The beta-carboline harmine, which induces hypothermia and tremor, is metabolized by CYP2D6 to the non-hypothermic/non-tremorgenic harmol. Transgenic mice (TG), expressing human CYP2D6 in addition to their endogenous mouse CYP2D, experience less harmine-induced hypothermia and tremor compared with wild-type mice (WT). We first sought to elucidate the role of CYP2D in general within the brain in harmine-induced hypothermia and tremor severity. A 4-h intracerebroventricular (ICV) pretreatment with the CYP2D inhibitor propranolol increased harmine-induced hypothermia and tremor in TG and increased harmine-induced hypothermia in WT. We next sought to specifically demonstrate that human CYP2D6 expressed in TG brain altered harmine response severity. A 24-h ICV propranolol pretreatment, which selectively and irreversibly inhibits human CYP2D6 in TG brain, increased harmine-induced hypothermia. This 24-h pretreatment had no impact on harmine response in WT, as propranolol is not an irreversible inhibitor of mouse CYP2D in the brain, thus confirming no off-target effects of ICV propranolol pretreatment. Human CYP2D6 activity in TG brain was sufficient in vivo to mitigate harmine-induced neurotoxicity. These findings suggest that human CYP2D6 in the brain is protective against beta-carboline-induced neurotoxicity and that the extensive interindividual variability in CYP2D6 expression in human brain may contribute to variation in susceptibility to certain neurotoxin-associated neurodegenerative disorders.
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Affiliation(s)
- Marlaina R Stocco
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Cole Tolledo
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Fariba Baghai Wadji
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sharon Miksys
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
- Department of Psychiatry, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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11
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Viviani R, Messina I, Bosch JE, Dommes L, Paul A, Schneider KL, Scholl C, Stingl JC. Effects of genetic variability of CYP2D6 on neural substrates of sustained attention during on-task activity. Transl Psychiatry 2020; 10:338. [PMID: 33024081 PMCID: PMC7539151 DOI: 10.1038/s41398-020-01020-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/01/2020] [Accepted: 08/05/2020] [Indexed: 12/25/2022] Open
Abstract
The polymorphic drug-metabolizing enzyme CYP2D6, which is responsible for the metabolism of most psychoactive compounds, is expressed not only in the liver, but also in the brain. The effects of its marked genetic polymorphism on the individual capacity to metabolize drugs are well known, but its role in metabolism of neural substrates affecting behavior personality or cognition, suggested by its CNS expression, is a long-standing unresolved issue. To verify earlier findings suggesting a potential effect on attentional processes, we collected functional imaging data, while N = 415 participants performed a simple task in which the reward for correct responses varied. CYP2D6 allelic variants predicting higher levels of enzymatic activity level were positively associated with cortical activity in occipito-parietal areas as well as in a right lateralized network known to be activated by spatial attentional tasks. Reward-related modulation of activity in cortical areas was more pronounced in poor metabolizers. In conjunction with effects on reaction times, our findings provide evidence for reduced cognitive efficiency in rapid metabolizers compared to poor metabolizers in on-task attentional processes manifested through differential recruitment of a specific neural substrate.
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Affiliation(s)
- Roberto Viviani
- grid.5771.40000 0001 2151 8122Institute of Psychology, University of Innsbruck, Innsbruck, Austria ,grid.6582.90000 0004 1936 9748Department of Psychiatry and Psychotherapy Clinic III, University of Ulm, Ulm, Germany
| | - Irene Messina
- grid.6582.90000 0004 1936 9748Department of Psychiatry and Psychotherapy Clinic III, University of Ulm, Ulm, Germany ,grid.466190.cUniversitas Mercatorum, Rome, Italy
| | - Julia E. Bosch
- grid.6582.90000 0004 1936 9748Department of Psychiatry and Psychotherapy Clinic III, University of Ulm, Ulm, Germany
| | - Lisa Dommes
- grid.6582.90000 0004 1936 9748Department of Psychiatry and Psychotherapy Clinic III, University of Ulm, Ulm, Germany
| | - Anna Paul
- grid.414802.b0000 0000 9599 0422Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Katharina L. Schneider
- grid.414802.b0000 0000 9599 0422Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Catharina Scholl
- grid.414802.b0000 0000 9599 0422Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Julia C. Stingl
- grid.412301.50000 0000 8653 1507Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Aachen, Germany
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12
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Tolledo C, Stocco MR, Miksys S, Gonzalez FJ, Tyndale RF. Human CYP2D6 Is Functional in Brain In Vivo: Evidence from Humanized CYP2D6 Transgenic Mice. Mol Neurobiol 2020; 57:2509-2520. [PMID: 32189192 DOI: 10.1007/s12035-020-01896-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/02/2020] [Indexed: 01/08/2023]
Abstract
CYP2D metabolizes many drugs that act within the brain, and variable expression of CYP2D in the brain may alter local drug and metabolite levels sufficiently to affect behavioral responses. Transgenic mice that express human CYP2D6 (TG) were compared to wild type mice (WT). Following selective inhibition of human CYP2D6 in TG brain, we demonstrated in vivo that human CYP2D6 in the brain was sufficient to alter a drug-induced behavioral response. After a 4-h pre-treatment with intracerebroventricular (i.c.v.) propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo, but not in vitro, was reduced in WT brain. After a 24-h pre-treatment with i.c.v. propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo and in vitro was not changed in WT brain. These results indicate that i.c.v. propranolol irreversibly inhibited human CYP2D6 in TG brain but not mouse CYP2D in TG and WT brain. Pre-treatments with propranolol did not change liver CYP2D activity in vivo or in vitro. Furthermore, 24-h pre-treatment with i.c.v. propranolol resulted in a significant decrease of the haloperidol-induced catalepsy response in TG, but not in WT, without changing serum haloperidol levels in either mouse line. These studies reveal a new tool to selectively and irreversibly inhibit human CYP2D6 in TG brain and indicate that human CYP2D6 has a functional role within the brain sufficient to impact the central nervous system response from peripherally administered drugs.
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Affiliation(s)
- Cole Tolledo
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Marlaina R Stocco
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Sharon Miksys
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada. .,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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13
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Yaowaluk T, Senanarong V, Limwongse C, Boonprasert R, Kijsanayotin P. Influence of CYP2D6, CYP3A5, ABCB1, APOE polymorphisms and nongenetic factors on donepezil treatment in patients with Alzheimer's disease and vascular dementia. Pharmgenomics Pers Med 2019; 12:209-224. [PMID: 31564952 PMCID: PMC6732559 DOI: 10.2147/pgpm.s211259] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 07/16/2019] [Indexed: 01/15/2023] Open
Abstract
PURPOSE This study aims to evaluate the influence of genetic polymorphisms of CYP2D6, CYP3A5, ABCB1, and APOE genes and nongenetic factors on steady-state plasma concentrations (Cpss) of donepezil and therapeutic outcomes in Thai patients with Alzheimer's disease (AD) and vascular dementia (VAD). PATIENTS AND METHODS Eighty-five dementia patients who received donepezil for at least six months were recruited. CYP2D6, CYP3A5, ABCB1, and APOE polymorphisms were genotyped. Cpss of donepezil was measured. Association of genetic and non-genetic factors with Cpss and clinical outcomes of donepezil (cognitive function as measured by the Thai Mental State Examination score; TMSE) were determined by using univariate and multivariate analysis. RESULTS Both univariate and multiple linear regression analysis indicated that only CYP2D6*10 allele was associated with higher Cpss (p-value =0.029 and B =0.478, p-value =0.032, respectively) that might influence the clinical outcomes of donepezil. ie, TMSE (p-value =0.010 and B =4.527, p-value =0.001) and ΔTMSE (p-value =0.023 and B =4.107, p-value =0.002), especially in patients with AD. Interestingly, concomitant use of memantine was found to be associated with increased Cpss of donepezil (p-value =0.007 and B =0.511, p-value =0.014). Whereas, co-medication with antidepressant drugs attenuated clinical responses in patients with AD (TMSE: B =-2.719, p-value =0.013 and ΔTMSE: B =-2.348, p-value =0.028). Age was a significant predictor of donepezil response in VAD patients. No significant association of CYP3A5*3, ABCB1 3435C>T or ABCB1 1236C>T, and APOE ε4 genotypes with Cpss or clinical outcomes of donepezil was found in this study. CONCLUSION Our results suggests that CYP2D6*10 strongly influences Cpss and there is a trend toward better outcomes of donepezil in patients with AD. Nongenetic factors including concomitant drugs treatment might alter Cpss of donepezil or clinical outcomes.
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Affiliation(s)
- Thitipon Yaowaluk
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Vorapun Senanarong
- Division of Neurology, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chanin Limwongse
- Division of Medical Genetics, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Rasda Boonprasert
- Clinical Toxicology Laboratory, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pornpimol Kijsanayotin
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
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14
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Haduch A, Rysz M, Papp M, Daniel WA. The activity of brain and liver cytochrome P450 2D (CYP2D) is differently affected by antidepressants in the chronic mild stress (CMS) model of depression in the rat. Biochem Pharmacol 2018; 156:398-405. [PMID: 30195732 DOI: 10.1016/j.bcp.2018.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/05/2018] [Indexed: 12/21/2022]
Abstract
The effect of two second-generation antidepressants escitalopram and venlafaxine on the activity of brain and liver cytochrome P450 2D (CYP2D) involved in the metabolism of psychotropics and neurotransmitters was determined in the chronic mild stress (CMS) model of depression. Escitalopram or venlafaxine (10 mg/kg ip/day each) were administered to control and CMS rats for 5 weeks. The activity of CYP2D was studied by measurement of the rate of bufuralol 1'-hydroxylation in microsomes derived from the liver or different brain structures. The obtained results indicate that CMS and the studied antidepressants had different effects on the CYP2D activity depending on the location of the enzyme. In the brain, CMS produced an increase in the CYP2D activity in the hippocampus. Chronic escitalopram or venlafaxine had no effect on the CYP2D activity in the brain of nonstressed rats, however, the antidepressants increased the enzyme activity in the frontal cortex, hypothalamus and cerebellum of stressed animals. In the liver, CMS did not affect the CYP2D activity, while chronic escitalopram or venlafaxine significantly decreased the CYP2D activity and protein level in nonstressed and stressed rats. We conclude that: 1) CMS stimulates the CYP2D activity in the hippocampus and triggers the stimulatory effect of antidepressants on CYP2D in other brain structures; 2) the local brain metabolism of CYP2D substrates (neurosteroids, neurotransmitters, psychotropics) may be enhanced by CMS and/or antidepressants; 3) in contrast to the brain, the liver metabolism of CYP2D substrates may be slower during long-term treatment with escitalopram or venlafaxine.
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Affiliation(s)
- Anna Haduch
- Department of Pharmacokinetics and Drug Metabolism, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Marta Rysz
- Department of Pharmacokinetics and Drug Metabolism, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Mariusz Papp
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
| | - Władysława A Daniel
- Department of Pharmacokinetics and Drug Metabolism, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland.
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15
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Boland M, Stirnberg R, Pracht ED, Kramme J, Viviani R, Stingl J, Stöcker T. Accelerated 3D-GRASE imaging improves quantitative multiple post labeling delay arterial spin labeling. Magn Reson Med 2018; 80:2475-2484. [PMID: 29770492 DOI: 10.1002/mrm.27226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 11/08/2022]
Abstract
PURPOSE To investigate the impact of accelerated, single-shot 3D-GRASE acquisition on quantitative arterial spin labeling (ASL) with multiple and single post-labeling delay (PLD) in terms of perfusion-weighted SNR per unit scan time (TSNRPW ) and quantification accuracy. METHODS Five subjects were scanned on a 3T MRI scanner using the pseudo-continuous arterial spin labeling (PCASL) technique with a 3D-GRASE imaging sequence capable of parallel imaging acceleration. A 3-inversion pulse background suppression was simulated and implemented in the sequence. Three time-matched single PLD measurements, a segmented one without acceleration, 1 with conventional GRAPPA, and 1 with CAIPIRINHA sampling, were used to compare TSNRPW . Three time-matched multiple PLD measurements with the identical imaging parameters were additionally evaluated (no acceleration vs. CAIPIRINHA sampling vs. CAIPIRINHA sampling with doubled number of PLDs). Cerebral blood flow and arterial transit time fit uncertainties were compared and used as a quality measure. RESULTS The single PLD measurements show an 11% TSNRPW increase using CAIPIRINHA sampling instead of GRAPPA sampling, while the non-accelerated scan exhibits 35% higher TSNRPW compared to the GRAPPA scan. However, taking advantage of the increased number of averages for multiple PLD acquisitions, a 14%/16% (gray matter) and 34%/36% (white matter) reduction of CBF fit uncertainty is observed with CAIPIRINHA sampling (6 PLDs/12 PLDs) compared to no acceleration. CONCLUSION Accelerated single-shot 3D-GRASE with PCASL allows for smaller quantification uncertainties than time-matched segmented acquisitions. Corresponding single-shot acquisitions with acceptable blurring and no intra-volume motion render state-of-the-art ASL methods in a clinically feasible time possible.
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Affiliation(s)
- Markus Boland
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | | | | | - Johanna Kramme
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Roberto Viviani
- Institute of Psychology, University of Innsbruck, Innsbruck, Austria.,Psychiatry and Psychotherapy Clinic III, University of Ulm, Ulm, Germany
| | - Julia Stingl
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Tony Stöcker
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department for Physics and Astronomy, University of Bonn, Bonn, Germany
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16
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Vendelbo MH, Gormsen LC, Jessen N. Imaging in Pharmacogenetics. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2018; 83:95-107. [PMID: 29801585 DOI: 10.1016/bs.apha.2018.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An increasing collection of imaging technologies makes it possible to differentiate treatment responders from nonresponders based on genetic variation. This chapter will review some of the imaging technologies currently available in nuclear medicine to visualize drug absorption, distribution, metabolism, and elimination. Some of the commonly used techniques to detect radiation-emitting compounds are the two-dimensional scintigraphy and the three-dimensional single-photon emission computed tomography (SPECT) which both detect photons using a gamma camera, and the three-dimensional positron emission tomography (PET), which detect the decay of positron-emitting radionuclides. Current examples include visualization of functional effects of genetic variants, and these provide proof of concept for imaging in pharmacogenetics as a tool to improve efficacy and safety of drugs.
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Affiliation(s)
- Mikkel H Vendelbo
- Aarhus University Hospital, Aarhus, Denmark; Aarhus University, Aarhus, Denmark
| | | | - Niels Jessen
- Aarhus University Hospital, Aarhus, Denmark; Aarhus University, Aarhus, Denmark.
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17
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Napolitano G, Stingl JC, Schmid M, Viviani R. Predicting CYP2D6 phenotype from resting brain perfusion images by gradient boosting. Psychiatry Res Neuroimaging 2017; 259:16-24. [PMID: 27918912 DOI: 10.1016/j.pscychresns.2016.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/13/2016] [Accepted: 11/21/2016] [Indexed: 01/21/2023]
Abstract
The cytochrome P450 enzyme 2D6 is involved in the metabolism of 20% of all commonly used drugs, including many psychotropic drugs and CNS-active substances. CYP2D6 is among the CYP enzymes with the highest expression levels in the brain, suggesting a role in the local brain metabolism of psychotropic drugs and the existence of endogenous substrates. The genetic polymorphism of CYP2D6, which causes individual differences in activity levels of the enzyme, has also been characterized functionally in human brain imaging studies. Here we explore the feasibility of predicting CYP2D6 phenotype using component-wise gradient boosting on fMRI resting brain perfusion images. The images belonged to subjects showing a range of genetic CYP2D6 variants. We achieved sensitivity and specificity values between 85% and 87% for the classification of ultrarapid metabolisers, and between 71% and 79% for poor metabolisers. An extension of the boosting algorithm, developed to improve the clinical plausibility of the inherently sparse models, produced enhanced models in agreement with the results of previous studies, showing some brain regions as positively associated with genotypic variation, most prominently in the prefrontal white matter and the corpus callosum. With further development, such a probabilistic method might constitute a valuable, non-invasive alternative to actual genotyping.
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Affiliation(s)
- Giulio Napolitano
- Institute of Medical Biometry, Informatics and Epidemiology (IMBIE), University Hospital Bonn, Germany.
| | - Julia C Stingl
- Federal Institute for drugs and medical devices, Research division, Centre for Translational Medicine and University Bonn Medical School, Bonn, Germany
| | - Matthias Schmid
- Institute of Medical Biometry, Informatics and Epidemiology (IMBIE), University Hospital Bonn, Germany
| | - Roberto Viviani
- Institute of Psychology, University of Innsbruck, Austria, and Psychiatry and Psychotherapy Clinic, University of Ulm, Germany
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18
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Pan X, Ning M, Jeong H. Transcriptional Regulation of CYP2D6 Expression. Drug Metab Dispos 2016; 45:42-48. [PMID: 27698228 DOI: 10.1124/dmd.116.072249] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/29/2016] [Indexed: 01/04/2023] Open
Abstract
CYP2D6-mediated drug metabolism exhibits large interindividual variability. Although genetic variations in the CYP2D6 gene are well known contributors to the variability, the sources of CYP2D6 variability in individuals of the same genotype remain unexplained. Accumulating data indicate that transcriptional regulation of CYP2D6 may account for part of CYP2D6 variability. Yet, our understanding of factors governing transcriptional regulation of CYP2D6 is limited. Recently, mechanistic studies of increased CYP2D6-mediated drug metabolism in pregnancy revealed two transcription factors, small heterodimer partner (SHP) and Krüppel-like factor 9, as a transcriptional repressor and an activator, respectively, of CYP2D6. Chemicals that increase SHP expression (e.g., retinoids and activators of farnesoid X receptor) were shown to downregulate CYP2D6 expression in the humanized mice as well as in human hepatocytes. This review summarizes the series of studies on the transcriptional regulation of CYP2D6 expression, potentially providing a basis to better understand the large interindividual variability in CYP2D6-mediated drug metabolism.
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Affiliation(s)
- Xian Pan
- Department of Biopharmaceutical Sciences (X.P., M.N., H.J.), and Department of Pharmacy Practice (H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Miaoran Ning
- Department of Biopharmaceutical Sciences (X.P., M.N., H.J.), and Department of Pharmacy Practice (H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Hyunyoung Jeong
- Department of Biopharmaceutical Sciences (X.P., M.N., H.J.), and Department of Pharmacy Practice (H.J.), College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
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19
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Toselli F, Dodd PR, Gillam EMJ. Emerging roles for brain drug-metabolizing cytochrome P450 enzymes in neuropsychiatric conditions and responses to drugs. Drug Metab Rev 2016; 48:379-404. [DOI: 10.1080/03602532.2016.1221960] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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20
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Pietarinen P, Tornio A, Niemi M. High Frequency ofCYP2D6Ultrarapid Metabolizer Genotype in the Finnish Population. Basic Clin Pharmacol Toxicol 2016; 119:291-6. [DOI: 10.1111/bcpt.12590] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 03/17/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Paavo Pietarinen
- Department of Clinical Pharmacology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Aleksi Tornio
- Department of Clinical Pharmacology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
| | - Mikko Niemi
- Department of Clinical Pharmacology; University of Helsinki and Helsinki University Hospital; Helsinki Finland
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21
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Stingl J, Viviani R. Polymorphism in CYP2D6 and CYP2C19, members of the cytochrome P450 mixed-function oxidase system, in the metabolism of psychotropic drugs. J Intern Med 2015; 277:167-177. [PMID: 25297512 DOI: 10.1111/joim.12317] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Numerous studies in the field of psychopharmacological treatment have investigated the possible contribution of genetic variability between individuals to differences in drug efficacy and safety, motivated by the wide individual variation in treatment response. Genomewide analyses have been conducted in several large-scale studies on antidepressant drug response. However, no consistent findings have emerged from these studies. In a recent meta-analysis of genomewide data from the three studies capturing common variation for association with symptomatic improvement and remission revealed the absence of any strong genetic association and failed to replicate results of individual studies in the pooled data. However, there are good reasons to consider the possible importance of pharmacogenetic variants separately. These variants explain a large portion of the manifold variability in individual drug metabolism. More than 20 psychotropic drugs have now been relabelled by the FDA adding information on polymorphic drug metabolism and therapeutic recommendations. Furthermore, dose recommendations for polymorphisms in drug metabolizing enzymes, first and foremost CYP2D6 and CYP2C19, have been issued with the advice to reduce the dosage in poor metabolizers to 50% or less (in eight cases), or to choose an alternative treatment. Beside the well-described role in hepatic drug metabolism, these enzymes are also expressed in the brain and play a role in biotransformation of endogenous substrates. These polymorphisms may therefore modulate brain metabolism and affect the function of the neural substrates of cognition and emotion.
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Affiliation(s)
- J Stingl
- Center for Translational Medicine, University of Bonn Medical School, Bonn, Germany
| | - R Viviani
- Department of Psychiatry and Psychotherapy III, University of Ulm, Ulm, Germany
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22
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Ning M, Koh KH, Pan X, Jeong H. Hepatocyte nuclear factor (HNF) 4α transactivation of cytochrome P450 (Cyp) 2d40 promoter is enhanced during pregnancy in mice. Biochem Pharmacol 2015; 94:46-52. [PMID: 25598084 DOI: 10.1016/j.bcp.2015.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/08/2015] [Accepted: 01/08/2015] [Indexed: 12/12/2022]
Abstract
We have recently reported that transactivation of cytochrome P450 (CYP) 2D6 promoter by hepatocyte nuclear factor (HNF) 4α is enhanced during pregnancy, and this is triggered in part by altered expression of small heterodimer partner (SHP) and Krüppel-like factor 9 (KLF9). The objective of this study is to determine whether this is conserved for mouse endogenous Cyp2d gene(s). Among the eight Cyp2d homologs of mouse we examined, only Cyp2d40 expression was found induced (by 6-fold) at term pregnancy as compared to pre-pregnancy level. In mice where hepatic Hnf4α was knocked-down, the pregnancy-mediated increase in Cyp2d40 expression was abrogated. Results from transient transfection, promoter reporter assays, and electrophoretic mobility shift assays indicated that HNF4α transactivates Cyp2d40 promoter via direct binding to -117/-105 of the gene. Chromatin immunoprecipitation assay showed a 2.3-fold increase in HNF4α recruitment to Cyp2d40 promoter during pregnancy. Results from mice treated with an SHP inducer (i.e., GW4064) and HepG2 cells co-transfected with KLF9 suggest that neither SHP nor KLF9 is involved in the increased HNF4α transactivation of Cyp2d40 promoter during pregnancy. Together, our results indicate that while the underlying molecular mechanism is different from that for CYP2D6, Cyp2d40 is induced during pregnancy through enhanced transactivation by HNF4α.
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Affiliation(s)
- Miaoran Ning
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood St. (MC 865), Chicago, IL 60612, USA.
| | - Kwi Hye Koh
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood St. (MC 886), Chicago, IL 60612, USA.
| | - Xian Pan
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood St. (MC 865), Chicago, IL 60612, USA.
| | - Hyunyoung Jeong
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood St. (MC 865), Chicago, IL 60612, USA; Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood St. (MC 886), Chicago, IL 60612, USA.
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Anna Haduch A, Bromek E, Daniel WA. Role of brain cytochrome P450 (CYP2D) in the metabolism of monoaminergic neurotransmitters. Pharmacol Rep 2014; 65:1519-28. [PMID: 24553000 DOI: 10.1016/s1734-1140(13)71513-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/24/2013] [Indexed: 01/25/2023]
Abstract
This article focuses on recent research on the cytochrome P450 2D (CYP2D) catalyzed synthesis of the monoaminergic neurotransmitters dopamine and serotonin in the brain and on the influence of psychotropic drugs on the activity of brain CYP2D. Recent in vitro and in vivo studies performed in rodents indicate that dopamine and serotonin may be formed in the brain via alternative CYP2D-mediated pathways, i.e., tyramine hydroxylation and 5-methoxytryptamine O-demethylation, respectively. The contribution of these alternative pathways to the total synthesis of brain neurotransmitters may be higher in humans and may be significantly increased under specific conditions, such as tyrosine hydroxylase and amino acid decarboxylase or tryptophan hydroxylase deficiency. These alternative pathways of neurotransmitter synthesis may also become more efficient when the CYP2D enzyme is mutated or activated by inducers (e.g., alcohol, nicotine, psychotropics), which may be of importance in some neurodegenerative or psychiatric diseases. In addition to the previously observed influence of antidepressants and neuroleptics on CYP2D in the liver, the investigated drugs also produce an effect on CYP2D in the brain. However, their effect on brain CYP2D is different than that in the liver and is structure-dependent. The observed psychotropic drug-brain CYP2D interactions may be important for the metabolism of endogenous neuroactive substrates (e.g., monoaminergic neurotransmitters, neurosteroids) and for the local biotransformation of drugs. The results are discussed with regard to the contribution of CYP2D to the total synthesis of neurotransmitters in the brain in vivo as well as the possible significance of these alternative pathways in specific physiological and pathological conditions and in the pharmacological actions of psychotropic drugs.
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Affiliation(s)
- Anna Anna Haduch
- Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, PL 31-343 Kraków, Poland.
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24
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Koh KH, Pan X, Zhang W, McLachlan A, Urrutia R, Jeong H. Krüppel-like factor 9 promotes hepatic cytochrome P450 2D6 expression during pregnancy in CYP2D6-humanized mice. Mol Pharmacol 2014; 86:727-35. [PMID: 25217496 DOI: 10.1124/mol.114.093666] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 2D6 (CYP2D6), a major drug-metabolizing enzyme, is responsible for metabolism of approximately 25% of marketed drugs. Clinical evidence indicates that metabolism of CYP2D6 substrates is increased during pregnancy, but the underlying mechanisms remain unclear. To identify transcription factors potentially responsible for CYP2D6 induction during pregnancy, a panel of genes differentially expressed in the livers of pregnant versus nonpregnant CYP2D6-humanized (tg-CYP2D6) mice was compiled via microarray experiments followed by real-time quantitative reverse-transcription polymerase chain reaction(qRT-PCR) verification. As a result, seven transcription factors-activating transcription factor 5 (ATF5), early growth response 1 (EGR1), forkhead box protein A3 (FOXA3), JUNB, Krüppel-like factor 9 (KLF9), KLF10, and REV-ERBα-were found to be up-regulated in liver during pregnancy. Results from transient transfection and promoter reporter gene assays indicate that KLF9 itself is a weak transactivator of CYP2D6 promoter but significantly enhances CYP2D6 promoter transactivation by hepatocyte nuclear factor 4 (HNF4α), a known transcriptional activator of CYP2D6 expression. The results from deletion and mutation analysis of CYP2D6 promoter activity identified a KLF9 putative binding motif at -22/-14 region to be critical in the potentiation of HNF4α-induced transactivation of CYP2D6. Electrophoretic mobility shift assays revealed a direct binding of KLF9 to the putative KLF binding motif. Results from chromatin immunoprecipitation assay showed increased recruitment of KLF9 to CYP2D6 promoter in the livers of tg-CYP2D6 mice during pregnancy. Taken together, our data suggest that increased KLF9 expression is in part responsible for CYP2D6 induction during pregnancy via the potentiation of HNF4α transactivation of CYP2D6.
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Affiliation(s)
- Kwi Hye Koh
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
| | - Xian Pan
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
| | - Wei Zhang
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
| | - Alan McLachlan
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
| | - Raul Urrutia
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
| | - Hyunyoung Jeong
- Department of Pharmacy Practice (K.H.K., H.J.), Department of Biopharmaceutical Sciences (X.P., H.J.), College of Pharmacy, and Department of Pediatrics (W.Z.) and Department of Microbiology and Immunology (A.M.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois; and Laboratory of Epigenetics and Chromatin Dynamics, and Departments of Biology and Molecular Biology, Epigenomics Translational Program, Mayo Clinic Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota (R.U.)
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Haertter S. Recent examples on the clinical relevance of the CYP2D6 polymorphism and endogenous functionality of CYP2D6. ACTA ACUST UNITED AC 2014; 28:209-16. [PMID: 24088607 DOI: 10.1515/dmdi-2013-0032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/22/2013] [Indexed: 11/15/2022]
Abstract
The cytochrome P450 2D6 (CYP2D6) belongs to a group of CYPs considered of utmost importance in the metabolism of xenobiotics. Despite being of only minor abundance in the liver, it is involved in the clearance of >25% of marketed drugs. Accordingly, CYP2D6 can be very efficiently inhibited by a couple of commonly used drugs such as some antidepressants, although induction by any drug has not been observed thus far. CYP2D6 was also one of the first enzymes for which a highly polymorphic expression could be shown leading to a widespread range of functionality, from a complete lack of a functional enzyme to overexpression due to multiplication of active alleles. A clear relationship between the CYP2D6 genotype and adverse events during treatment with CNS-active drugs such as codeine, antidepressants, or antipsychotics could be demonstrated. More recently, some new aspects emerged about the potential endogenous function of CYP2D6 in terms of behavior and brain disorders.
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Leeder JS, Gaedigk A. CYP2D6 and pharmacogenomics: where does future research need to focus? Part 2: clinical aspects. Pharmacogenomics 2014; 15:1055-8. [DOI: 10.2217/pgs.14.27] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- J Steven Leeder
- Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Department of Pediatrics, Children’s Mercy Kansas City & University of Missouri-Kansas City, 2401 Gillham Rd, Kansas City, MO 64108, USA
| | - Andrea Gaedigk
- Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Department of Pediatrics, Children’s Mercy Kansas City & University of Missouri-Kansas City, 2401 Gillham Rd, Kansas City, MO 64108, USA
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27
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Miller RT, Miksys S, Hoffmann E, Tyndale RF. Ethanol self-administration and nicotine treatment increase brain levels of CYP2D in African green monkeys. Br J Pharmacol 2014; 171:3077-88. [PMID: 24611668 PMCID: PMC4055207 DOI: 10.1111/bph.12652] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/31/2014] [Accepted: 02/09/2014] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE CYP2D6 metabolizes many centrally acting drugs, neurotoxins and endogenous neurochemicals, and differences in brain levels of CYP2D have been associated with brain function and drug response. Alcohol consumers and smokers have higher levels of CYP2D6 in brain, but not liver, suggesting ethanol and/or nicotine may induce human brain CYP2D6. We investigated the independent and combined effects of chronic ethanol self-administration and nicotine treatment on CYP2D expression in African green monkeys. EXPERIMENTAL APPROACH Forty monkeys were randomized into control, ethanol-only, nicotine-only and ethanol + nicotine groups. Two groups voluntarily self-administered 10% ethanol in sucrose solution for 4 h·day(-1) , whereas two groups consumed sucrose solution on the same schedule. Two groups received daily s.c. injections of 0.5 mg·kg(-1) nicotine in saline bid, whereas two groups were injected with saline on the same schedule. KEY RESULTS Both nicotine and ethanol dose-dependently increased CYP2D in brain; brain mRNA was unaffected, and neither drug altered hepatic CYP2D protein or mRNA. The combination of ethanol and nicotine increased brain CYP2D protein levels to a greater extent than either drug alone (1.2-2.2-fold, P < 0.05 among the eight brain regions assessed). Immunohistochemistry revealed the induction of brain CYP2D protein within specific cell types and regions in the treatment groups. CONCLUSIONS AND IMPLICATIONS Ethanol and nicotine increase brain CYP2D protein levels in monkeys, in a region and treatment-specific manner, suggesting that CNS drug responses, neurodegeneration and personality may be affected among people who consume alcohol and/or nicotine.
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Affiliation(s)
- R T Miller
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health and Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
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28
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Peñas-LLedó EM, LLerena A. CYP2D6 variation, behaviour and psychopathology: implications for pharmacogenomics-guided clinical trials. Br J Clin Pharmacol 2014; 77:673-83. [PMID: 24033670 PMCID: PMC3971983 DOI: 10.1111/bcp.12227] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 08/11/2013] [Indexed: 12/16/2022] Open
Abstract
Individual and population differences in polymorphic cytochrome P450 enzyme function have been known for decades. The biological significance of these differences has now been deciphered with regard to drug metabolism, action and toxicity as well as disposition of endogenous substrates, including neuroactive compounds. While the cytochrome P450 enzymes occur abundantly in the liver, they are expressed in most tissues of the body, albeit in varying amounts, including the brain. The latter location of cytochrome P450s is highly pertinent for susceptibility to neuropsychiatric diseases, not to mention local drug metabolism at the site of psychotropic drug action in the brain. In the current era of personality medicine with companion theranostics (i.e. the fusion of therapeutics with diagnostics), this article underscores that such versatile biological roles of cytochrome P450s offer multiple points of entry for personalized medicine and rational therapeutics. We focus our discussion on CYP2D6, one of the most intensively researched drug and endogenous compound metabolism pathways, with a view to relevance for, and optimization of, pharmacogenomic-guided clinical trials. Working on the premise that CYP2D6 is related to human behaviour and certain personality traits such as serotonin and dopamine system function, we further suggest that the motivation of healthy volunteers to participate in clinical trials may in part be influenced by an under- or over-representation of certain CYP2D6 metabolic groups.
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Affiliation(s)
- Eva M Peñas-LLedó
- CICAB Clinical Research Centre, Extremadura University Hospital and Medical SchoolBadajoz
| | - Adrián LLerena
- CICAB Clinical Research Centre, Extremadura University Hospital and Medical SchoolBadajoz
- CIBERSAM, ISCIIIMadrid, Spain
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29
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Viviani R, Lehmann ML, Stingl JC. Use of magnetic resonance imaging in pharmacogenomics. Br J Clin Pharmacol 2014; 77:684-94. [PMID: 23802603 PMCID: PMC3971984 DOI: 10.1111/bcp.12197] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 06/18/2013] [Indexed: 01/11/2023] Open
Abstract
Because of the large variation in the response to psychoactive medication, many studies have attempted to uncover genetic factors that determine response. While considerable knowledge exists on the large effects of genetic polymorphisms on pharmacokinetics and plasma concentrations of drugs, effects of the concentration at the target site and pharmacodynamic effects on brain functions in disease are much less known. This article reviews the role of magnetic resonance imaging (MRI) to visualize response to medication in brain behaviour circuits in vivo in humans and assess the influence of pharmacogenetic factors. Two types of studies have been used to characterize effects of medication and genetic variation. In task-related activation studies the focus is on changes in the activity of a neural circuit associated with a specific psychological process. The second type of study investigates resting state perfusion. These studies provide an assessment of vascular changes associated with bioavailability of drugs in the brain, but may also assess changes in neural activity after binding of centrally active agents. Task-related pharmacogenetic studies of cognitive function have characterized the effects in the prefrontal cortex of genetic polymorphisms of dopamine receptors (DRD2), metabolic enzymes (COMT) and in the post-synaptic signalling cascade under the administration of dopamine agonists and antagonists. In contrast, pharmacogenetic imaging with resting state perfusion is still in its infancy. However, the quantitative nature of perfusion imaging, its non-invasive character and its repeatability might be crucial assets in visualizing the effects of medication in vivo in man during therapy.
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Affiliation(s)
- Roberto Viviani
- Department of Psychiatry and Psychotherapy III, University of Ulm, Ulm, Germany; Institute of Psychology, University of Innsbruck, Innsbruck, Austria
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30
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Abstract
Cytochrome P450 enzymes (CYPs) metabolize many drugs that act on the central nervous system (CNS), such as antidepressants and antipsychotics; drugs of abuse; endogenous neurochemicals, such as serotonin and dopamine; neurotoxins; and carcinogens. This takes place primarily in the liver, but metabolism can also occur in extrahepatic organs, including the brain. This is important for CNS-acting drugs, as variation in brain CYP-mediated metabolism may be a contributing factor when plasma levels do not predict drug response. This review summarizes the characterization of CYPs in the brain, using examples from the CYP2 subfamily, and discusses sources of variation in brain CYP levels and metabolism. Some recent experiments are described that demonstrate how changes in brain CYP metabolism can influence drug response, toxicity and drug-induced behaviours. Advancing knowledge of brain CYP-mediated metabolism may help us understand why patients respond differently to drugs used in psychiatry and predict risk for psychiatric disorders, including neurodegenerative diseases and substance abuse.
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Affiliation(s)
| | - Rachel F. Tyndale
- Correspondence to: R.F. Tyndale, Department of Pharmacology and Toxicology, 1 King’s College Circle, Toronto ON M5S 1A8;
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31
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Influence of CYP2D6 and CYP2C19 gene variants on antidepressant response in obsessive-compulsive disorder. THE PHARMACOGENOMICS JOURNAL 2013; 14:176-81. [PMID: 23545896 DOI: 10.1038/tpj.2013.12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/29/2013] [Accepted: 02/04/2013] [Indexed: 12/31/2022]
Abstract
Numerous studies have reported on pharmacogenetics of antidepressant response in depression. In contrast, little is known of response predictors in obsessive-compulsive disorder (OCD), a disorder with among the lowest proportion of responders to medication (40-60%). Our study is the largest investigation to date (N=184) of treatment response and side effects to antidepressants in OCD based on metabolizer status for CYP2D6 and CYP2C19. We observed significantly more failed medication trials in CYP2D6 non-extensive compared with extensive metabolizers (P=0.007). CYP2D6 metabolizer status was associated with side effects to venlafaxine (P=0.022). There were nonsignificant trends for association of CYP2D6 metabolizer status with response to fluoxetine (P=0.056) and of CYP2C19 metabolizer status with response to sertraline (P=0.064). Our study is the first to indicate that CYP genes may have a role in antidepressant response in OCD. More research is required for a future clinical application of genetic testing, which could lead to improved treatment outcomes.
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Genetic variability of drug-metabolizing enzymes: the dual impact on psychiatric therapy and regulation of brain function. Mol Psychiatry 2013; 18:273-87. [PMID: 22565785 DOI: 10.1038/mp.2012.42] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Polymorphic drug-metabolizing enzymes (DMEs) are responsible for the metabolism of the majority of psychotropic drugs. By explaining a large portion of variability in individual drug metabolism, pharmacogenetics offers a diagnostic tool in the burgeoning era of personalized medicine. This review updates existing evidence on the influence of pharmacogenetic variants on drug exposure and discusses the rationale for genetic testing in the clinical context. Dose adjustments based on pharmacogenetic knowledge are the first step to translate pharmacogenetics into clinical practice. However, also clinical factors, such as the consequences on toxicity and therapeutic failure, must be considered to provide clinical recommendations and assess the cost-effectiveness of pharmacogenetic treatment strategies. DME polymorphisms are relevant not only for clinical pharmacology and practice but also for research in psychiatry and neuroscience. Several DMEs, above all the cytochrome P (CYP) enzymes, are expressed in the brain, where they may contribute to the local biochemical homeostasis. Of particular interest is the possibility of DMEs playing a physiological role through their action on endogenous substrates, which may underlie the reported associations between genetic polymorphisms and cognitive function, personality and vulnerability to mental disorders. Neuroimaging studies have recently presented evidence of an effect of the CYP2D6 polymorphism on basic brain function. This review summarizes evidence on the effect of DME polymorphisms on brain function that adds to the well-known effects of DME polymorphisms on pharmacokinetics in explaining the range of phenotypes that are relevant to psychiatric practice.
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Sim SC, Kacevska M, Ingelman-Sundberg M. Pharmacogenomics of drug-metabolizing enzymes: a recent update on clinical implications and endogenous effects. THE PHARMACOGENOMICS JOURNAL 2012; 13:1-11. [PMID: 23089672 DOI: 10.1038/tpj.2012.45] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Interindividual differences in drug disposition are important causes for adverse drug reactions and lack of drug response. The majority of phase I and phase II drug-metabolizing enzymes (DMEs) are polymorphic and constitute essential factors for the outcome of drug therapy. Recently, both genome-wide association (GWA) studies with a focus on drug response, as well as more targeted studies of genes encoding DMEs have revealed in-depth information and provided additional information for variation in drug metabolism and drug response, resulting in increased knowledge that aids drug development and clinical practice. In addition, an increasing number of meta-analyses have been published based on several original and often conflicting pharmacogenetic studies. Here, we review data regarding the pharmacogenomics of DMEs, with particular emphasis on novelties. We conclude that recent studies have emphasized the importance of CYP2C19 polymorphism for the effects of clopidogrel, whereas the CYP2C9 polymorphism appears to have a role in anticoagulant treatment, although inferior to VKORC1. Furthermore, the analgesic and side effects of codeine in relation to CYP2D6 polymorphism are supported and the influence of CYP2D6 genotype on breast cancer recurrence during tamoxifen treatment appears relevant as based on three large studies. The influence of CYP2D6 polymorphism on the effect of antidepressants in a clinical setting is yet without any firm evidence, and the relation between CYP2D6 ultrarapid metabolizers and suicide behavior warrants further studies. There is evidence for the influence of CYP3A5 polymorphism on tacrolimus dose, although the influence on response is less studied. Recent large GWA studies support a link between CYP1A2 polymorphism and blood pressure as well as coffee consumption, and between CYP2A6 polymorphism and cigarette consumption, which in turn appears to influence the lung cancer incidence. Regarding phase II enzyme polymorphism, the anticancer treatment with mercaptopurines and irinotecan is still considered important in relation to the polymorphism of TPMT and UGT1A1, respectively. There is a need for further clarification of the clinical importance and use of all these findings, but the recent research in the field that encompasses larger studies and a whole genome perspective, improves the possibilities be able to make firm and cost-effective recommendations for drug treatment in the future.
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Affiliation(s)
- S C Sim
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Joffe H, Deckersbach T, Lin NU, Makris N, Skaar TC, Rauch SL, Dougherty DD, Hall JE. Metabolic activity in the insular cortex and hypothalamus predicts hot flashes: an FDG-PET study. J Clin Endocrinol Metab 2012; 97:3207-15. [PMID: 22723326 PMCID: PMC3791433 DOI: 10.1210/jc.2012-1413] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Hot flashes are a common side effect of adjuvant endocrine therapies (AET; leuprolide, tamoxifen, aromatase inhibitors) that reduce quality of life and treatment adherence in breast cancer patients. Because hot flashes affect only some women, preexisting neurobiological traits might predispose to their development. Previous studies have implicated the insula during the perception of hot flashes and the hypothalamus in thermoregulatory dysfunction. OBJECTIVE The aim of the study was to understand whether neurobiological factors predict hot flashes. DESIGN [18F]-Fluorodeoxyglucose (FDG) positron emission tomography (PET) brain scans coregistered with structural magnetic resonance imaging were used to determine whether metabolic activity in the insula and hypothalamic thermoregulatory and estrogen-feedback regions measured before and in response to AET predict hot flashes. Findings were correlated with CYP2D6 genotype because of CYP2D6 polymorphism associations with tamoxifen-induced hot flashes. OUTCOME MEASURES We measured regional cerebral metabolic rate of glucose uptake (rCMRglu) in the insula and hypothalamus on FDG-PET. RESULTS Of 18 women without hot flashes who began AET, new-onset hot flashes were reported by 10 (55.6%) and were detected objectively in nine (50%) participants. Prior to the use of all AET, rCMRglu in the insula (P ≤ 0.01) and hypothalamic thermoregulatory (P = 0.045) and estrogen-feedback (P = 0.007) regions was lower in women who reported developing hot flashes. In response to AET, rCMRglu was further reduced in the insula in women developing hot flashes (P ≤ 0.02). Insular and hypothalamic rCMRglu levels were lower in intermediate than extensive CYP2D6 metabolizers. CONCLUSIONS Trait neurobiological characteristics predict hot flashes. Genetic variability in CYP2D6 may underlie the neurobiological predisposition to hot flashes induced by AET.
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Affiliation(s)
- Hadine Joffe
- Center for Women's Mental Health, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston Massachusetts 02114, USA.
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35
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Müller DJ, Brandl EJ, Hwang R, Tiwari AK, Sturgess JE, Zai CC, Lieberman JA, Kennedy JL, Richter MA. The AmpliChip® CYP450 test and response to treatment in schizophrenia and obsessive compulsive disorder: a pilot study and focus on cases with abnormal CYP2D6 drug metabolism. Genet Test Mol Biomarkers 2012; 16:897-903. [PMID: 22775532 DOI: 10.1089/gtmb.2011.0327] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIM Genetic factors can result in variance in drug metabolism enzyme function, which is one major mechanism impacting on interindividual variability in response and side effects. We therefore performed a pilot study to investigate genetic variants in the drug metabolizing enzymes CYP2D6 and CYP2C19. METHODS We evaluated 35 schizophrenic and 39 obsessive compulsive disorder (OCD) patients treated with various antipsychotics and antidepressants. Patients were assessed for treatment response and side effects. Genotyping for CYP2D6 and CYP2C19 was performed using the AmpliChip(®). Statistical analysis was performed using analysis of variance and Fisher's exact test. Cases of poor metabolizers (PMs) or ultrarapid metabolizers (UMs) were examined in further detail to assess medication outcomes. RESULTS Statistical analysis identified no overall significant association of CYP2D6 metabolizer status with treatment response or occurrence of side effects. Nonetheless, case reports of PM and UM individuals indicated lack of response and/or occurrence of side effects in most of these patients. A secondary analysis comparing OCD subjects with impaired 2D6 function to extensive metabolizers was significant (p=0.021). CONCLUSION Although not conclusive, there was some association between CYP2D6 impaired metabolic status and medication response. Our case reports suggest a potential clinical benefit of CYP genotyping for specific patients. Further validation of CYP2D6 and CYP2C19 testing in prospective, randomized trials is warranted.
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Affiliation(s)
- Daniel J Müller
- Pharmacogenetics Research Clinic, Neurogenetics Section, Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada.
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Brandl EJ, Müller DJ, Richter MA. Pharmacogenetics of obsessive-compulsive disorders. Pharmacogenomics 2012; 13:71-81. [PMID: 22176623 DOI: 10.2217/pgs.11.133] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Genetic factors have been shown to influence occurrence and severity of several psychiatric disorders and also to modulate outcome to drug treatment. Obsessive-compulsive disorder (OCD) is a severe psychiatric condition with clear genetic roots; there is also some evidence to suggest that genetic factors may impact on response to drug treatment. Typically between 40 and 60% of patients are deemed nonresponders to antidepressant medication and clinical factors have only been modestly correlated with treatment response. Thus, identification of biological factors which may relate to treatment response could be extremely valuable in improving clinical outcome. In this article, we briefly review previous work regarding clinical and demographical factors associated with drug response in OCD, then focus on recent findings regarding candidate genes which may influence drug response, including those in the serotonin system, brain-derived neurotrophic factor and the glutamate transporter gene. The cytochrome system may also be highly relevant to drug response. Thus far, relatively few studies regarding the pharmacogenetics of OCD have been published, and therefore further investigation with functional analyses and consideration of environmental factors are warranted to facilitate clinical use of pharmacogenetic findings in the future.
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Affiliation(s)
- Eva J Brandl
- Neurogenetics Section, Centre for Addiction & Mental Health & University of Toronto, Toronto, ON, Canada
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Stingl JC, Esslinger C, Tost H, Bilek E, Kirsch P, Ohmle B, Viviani R, Walter H, Rietschel M, Meyer-Lindenberg A. Genetic variation in CYP2D6 impacts neural activation during cognitive tasks in humans. Neuroimage 2012; 59:2818-23. [DOI: 10.1016/j.neuroimage.2011.07.052] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/11/2011] [Accepted: 07/18/2011] [Indexed: 02/03/2023] Open
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Ferguson CS, Tyndale RF. Cytochrome P450 enzymes in the brain: emerging evidence of biological significance. Trends Pharmacol Sci 2011; 32:708-14. [PMID: 21975165 DOI: 10.1016/j.tips.2011.08.005] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/25/2011] [Accepted: 08/29/2011] [Indexed: 10/17/2022]
Abstract
Cytochrome P450 (CYP) enzymes are responsible for the metabolism of many exogenous and endogenous compounds. CYPs are abundant in the liver and are also expressed in many extra-hepatic tissues including the brain. Although total CYP levels in the brain are much lower than in the liver, brain CYPs are concentrated near drug targets in specific regions and cell types, and can potentially have a considerable impact on local metabolism. Individual differences in brain CYP metabolism, due to inducers, inhibitors or genetic variation, can influence sensitivity and response to centrally acting drugs. Brain CYPs may also play a role in modulating brain activity, behavior, susceptibility to central nervous system diseases and treatment outcomes. This review highlights recent progress that has been made in understanding the functional significance of CYPs in the brain.
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Affiliation(s)
- Charmaine S Ferguson
- Centre for Addiction and Mental Health and Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON, Canada
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Bromek E, Haduch A, Gołembiowska K, Daniel WA. Cytochrome P450 mediates dopamine formation in the brain in vivo. J Neurochem 2011; 118:806-15. [PMID: 21651557 DOI: 10.1111/j.1471-4159.2011.07339.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cytochrome P450-mediated synthesis of dopamine from tyramine has been shown in vitro. The aim of the present study was to demonstrate the ability of rat cytochrome P450 (CYP) 2D to synthesize dopamine from tyramine in the brain in vivo. We employed two experimental models using reserpinized rats with a blockade of the classical pathway of dopamine synthesis from tyrosine. Model A estimated dopamine production from endogenous tyramine in brain structures in vivo (ex vivo measurement of a tissue dopamine level), while Model B measured extracellular dopamine produced from exogenous tyramine (an in vivo microdialysis). In Model A, quinine (a CYP2D inhibitor) given intraperitoneally caused a significant decrease in dopamine level in the striatum and nucleus accumbens and tended to fall in the substantia nigra and frontal cortex. In Model B, an increase in extracellular dopamine level was observed after tyramine given intrastructurally (the striatum). After joint administration of tyramine and quinine, the amount of the dopamine formed was significantly lower compared to the group receiving tyramine only. The results of the two complementary experimental models indicate that the hydroxylation of tyramine to dopamine may take place in rat brain in vivo, and that CYP2D catalyzes this reaction.
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Affiliation(s)
- Ewa Bromek
- Polish Academy of Sciences, Institute of Pharmacology, Kraków, Poland
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Khokhar JY, Tyndale RF. Drug metabolism within the brain changes drug response: selective manipulation of brain CYP2B alters propofol effects. Neuropsychopharmacology 2011; 36:692-700. [PMID: 21107310 PMCID: PMC3055692 DOI: 10.1038/npp.2010.202] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Drug-metabolizing cytochrome P450 (CYPs) enzymes are expressed in the liver, as well as in extrahepatic tissues such as the brain. Here we show for the first time that drug metabolism by a CYP within the brain, illustrated using CYP2B and the anesthetic propofol (2, 6-diisopropylphenol, Diprivan), can meaningfully alter the pharmacological response to a CNS acting drug. CYP2B is expressed in the brains of animals and humans, and this CYP isoform is able to metabolize centrally acting substrates such as propofol, ecstasy, and serotonin. Rats were given intracerebroventricularly (i.c.v.) injections of vehicle, C8-xanthate, or 8-methoxypsoralen (CYP2B mechanism-based inhibitors) and then tested for sleep time following propofol (80 mg/kg intraperitoneally). Both inhibitors significantly increased sleep-time (1.8- to 2-fold) and brain propofol levels, while having no effect on plasma propofol levels. Seven days of nicotine treatment can induce the expression of brain, but not hepatic, CYP2B, and this induction reduced propofol sleep times by 2.5-fold. This reduction was reversed in a dose-dependent manner by i.c.v. injections of inhibitor. Sleep times correlated with brain (r=0.76, P=0.0009), but not plasma (r=0.24, P=0.39) propofol concentrations. Inhibitor treatments increased brain, but not plasma, propofol levels, and had no effect on hepatic enzyme activity. These data indicate that brain CYP2B can metabolize neuroactive substrates (eg, propofol) and can alter their pharmacological response. This has wider implications for localized CYP-mediated metabolism of drugs, neurotransmitters, and neurotoxins within the brain by this highly variable enzyme family and other CYP subfamilies expressed in the brain.
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Affiliation(s)
- Jibran Y Khokhar
- Centre for Addiction and Mental Health (CAMH) and Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Centre for Addiction and Mental Health (CAMH) and Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, Ontario, Canada,Department of Pharmacology and Toxicology, 1 King's College Circle, University of Toronto, Medical Sciences Building, Room 4326, Toronto, Ontario M5S 1A8, Canada, Tel: +1 416 978 6374, Fax: +1 416 978 6395, E-mail:
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