Induction of Cytochrome P450 Enzymes in Cultured Precision-Cut Human Liver Slices

Edwards, Robert J.; Price, Roger J.; Watts, Patricia; Renwick, A.B.; Tredger, J. Michael; Boobis, Alan R.; Lake, Brian G.

doi:10.1124/dmd.31.3.282

Cited by 80 publications

(51 citation statements)

References 30 publications

(64 reference statements)

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“…The induction within the brain is striking as CYP2D6 is considered uninducible in the liver by drugs and xenobiotics that readily induce other CYPs (e.g. phenobarbital) (Rae et al, 2001;Edwards et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Induction of the drug metabolizing enzyme CYP2D in monkey brain by chronic nicotine treatment

et al. 2008

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Cytochrome P450 (CYP) 2D6, an enzyme found in the liver and the brain, is involved in the metabolism of numerous centrally acting drugs (e.g. antidepressants, neuroleptics, opiates), endogenous neurochemicals (e.g. catecholamines) and in the inactivation of neurotoxins (e.g. pesticides, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)). Although CYP2D6 is essentially an uninducible enzyme in the liver, we show that smokers have higher CYP2D6 in the brain, especially in the basal ganglia. In order to determine whether nicotine, a component of cigarette smoke, could increase brain CYP2D, African Green monkeys were treated chronically with nicotine (0.05 mg/kg for 2 days, then 0.15 mg/kg for 2 days followed by 0.3 mg/kg for 18 days s.c., b.i.d.). Monkeys treated with nicotine showed significant induction of CYP2D in brain when compared to saline-treated animals as detected by western blotting and immunocytochemistry. No changes in liver CYP2D were observed in nicotine-treated monkeys. Induction was observed in various brain regions including those affected in Parkinson's disease (PD) such as substantia nigra (3-fold, p = 0.01), putamen (2.1-fold, p = 0.001) and brainstem (2.4-fold, p = 0.001), with the caudate nucleus approaching significance (1.6-fold, p = 0.07).Immunocytochemistry revealed that the expression of CYP2D in both saline-and nicotine-treated monkeys is cell-specific particularly in the cerebellum, frontal cortex and hippocampus. These results suggest that monkey brain expresses CYP2D, which is induced in specific cells and brain regions upon chronic nicotine treatment. Smokers, or those using nicotine treatment, may have higher levels of brain CYP2D6 that may result in altered localized CNS drug metabolism and inactivation of neurotoxins.

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Section: Discussionmentioning

confidence: 99%

Induction of the drug metabolizing enzyme CYP2D in monkey brain by chronic nicotine treatment

et al. 2008

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“…The use of these recombinant enzymes provides an effective way to further confirm results obtained for the apparent metabolic pathways using microsomes [29]. However, the rationale for performing the CYP reaction phenotyping for an investigational drug is viable only if CYPs are a major contributor in the overall clearance (>30%) [8,30].…”

Section: Cdna-expressed Recombinant Human Cyp Activitymentioning

confidence: 99%

“…Although microsomes continue to be the first-line screening model for high throughput assays, the number of publications in the last 5 years citing metabolism in hepatocytes has increased by approximately 30% [13], partially due to commercial availability of the cryopreserved cells. Preparation of hepatocytes has been reported in detail by Soars et al [32], while Edwards et al [30] and Lake et al [33] have reported on the preparation of precision-cut human liver slices.…”

Section: Hepatocytes and Liver Slicesmentioning

confidence: 99%

The Conduct of Drug Metabolism Studies Considered Good Practice (II): In Vitro Experiments

Jia¹,

Liu²

2007

CDM

249

195

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In vitro drug metabolism studies, which are inexpensive and readily carried out, serve as an adequate screening mechanism to characterize drug metabolites, elucidate their pathways, and make suggestions for further in vivo testing. This publication is a sequel to part I in a series and aims at providing a general framework to guide designs and protocols of the in vitro drug metabolism studies considered good practice in an efficient manner such that it would help researchers avoid common pitfalls and misleading results. The in vitro models include hepatic and non-hepatic microsomes, cDNA-expressed recombinant human CYPs expressed in insect cells or human B lymphoblastoid, chemical P450 inhibitors, S9 fraction, hepatocytes and liver slices. Important conditions for conducting the in vitro drug metabolism studies using these models are stated, including relevant concentrations of enzymes, co-factors, inhibitors and test drugs; time of incubation and sampling in order to establish kinetics of reactions; appropriate control settings, buffer selection and method validation. Separate in vitro data should be logically integrated to explain results from animal and human studies and to provide insights into the nature and consequences of in vivo drug metabolism. This article offers technical information and data and addresses scientific rationales and practical skills related to in vitro evaluation of drug metabolism to meet regulatory requirements for drug development.

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“…toxic, proliferative, degradative) on CYP expression in hepatic tissues we also assessed CYP2D1 as hepatic CYP2D6 is unaltered in smokers and alcohol drinkers and is generally not thought to be an inducible enzyme (Edwards et al, 2003;Mann et al, 2008;Rae et al, 2001;Yue et al, 2008). Linearity and specificity were determined in the same manner as CYP2E1 and CYP2B1/2 (Fig.…”

Section: The Regulation Of Cyp2d1 Following Voluntary Ethanol Intake mentioning

confidence: 99%

Differential induction of ethanol-metabolizing CYP2E1 and nicotine-metabolizing CYP2B1/2 in rat liver by chronic nicotine treatment and voluntary ethanol intake

Yue

Khokhar

Miksys

et al. 2009

European Journal of Pharmacology

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Alcohol and nicotine are frequently co-used and co-abused, and use of both drugs alone can affect hepatic drug metabolism. We investigated the influences of chronic nicotine treatment and voluntary ethanol intake on the induction of rat hepatic cytochrome P450 (CYP) enzymes that metabolize ethanol and nicotine. Rats were trained to voluntarily drink ethanol (6% v/v, 1 h) with nicotine pretreatment for 10 days. Another group of rats were treated with the same nicotine doses alone. Hepatic CYP2E1, CYP2B1/2 and CYP2D1 proteins were assessed by immunoblotting. Nicotine pretreatment (0.4, 0.8 and 1.2 mg/kg) increased voluntary ethanol intake on day 10 by 1.8, 2.0, and 1.4 fold respectively compared to saline pretreatment (P<0.01-0.3). CYP2E1 was increased 1.7, 1.8, and 1.4 fold by the three doses of nicotine alone (P<0.02-0.21); CYP2E1 levels were increased by voluntary ethanol intake alone and a further 2.4, 2.2, and 1.8 fold by 0.4, 0.8, and 1.2 mg/kg nicotine respectively versus saline pretreatment (P<0.002-0.06). CYP2B1/2 proteins were not induced by nicotine alone, but were increased by 2.2-2.5 fold by ethanol drinking (P<0.05). CYP2E1 (r=0.67, P<0.001) and CYP2B1/2 levels (r=0.49, P=0.007) correlated with alcohol consumption on day 10. There was no change in CYP2D1. Chronic nicotine increased voluntary ethanol intake thereby enhancing CYP2E1 and CYP2B1/2 levels. Thus CYPs are regulated not only directly by nicotine and ethanol, but also indirectly via an increase in the ethanol consumption in the presence of nicotine pretreatment. Together this may contribute to the co-abuse of these drugs and alter the metabolism of clinical drugs and endogenous substrates.

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Induction of Cytochrome P450 Enzymes in Cultured Precision-Cut Human Liver Slices

Cited by 80 publications

References 30 publications

Induction of the drug metabolizing enzyme CYP2D in monkey brain by chronic nicotine treatment

Induction of the drug metabolizing enzyme CYP2D in monkey brain by chronic nicotine treatment

The Conduct of Drug Metabolism Studies Considered Good Practice (II): In Vitro Experiments

Differential induction of ethanol-metabolizing CYP2E1 and nicotine-metabolizing CYP2B1/2 in rat liver by chronic nicotine treatment and voluntary ethanol intake

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