Inter-donor variability of phase I/phase II metabolism of three reference drugs in cryopreserved primary human hepatocytes in suspension and monolayer. (June 2016)

• Record Type: Journal Article
• Authors: den Braver-Sewradj, Shalenie P.; den Braver, Michiel W.; Vermeulen, Nico P.E.; Commandeur, Jan N.M.; Richert, Lysiane; Vos, J. Chris
• Is Part Of: Toxicology in vitro. Volume 33(2016)
• Page Start: 71
• Page End: 79
• Publication Date: 2016-06
• Subjects: 4′-OH DF 4′-hydroxy diclofenac -- 5-OH DF 5-hydroxy diclofenac -- 7-HC 7-hydroxycoumarin -- APAP acetaminophen -- CYP cytochrome P450 -- DMEM Dulbecco's modified Eagle's medium -- DF diclofenac -- OH-TC hydroxy tolcapone -- TC tolcapone -- GST glutathione-S-transferase -- PBS phosphate-buffered saline -- SULT sulfotransferase -- UGT UDP glucuronosyltransferase; Cryopreserved hepatocytes -- Cytochrome P450 -- Sulfotransferase -- UDP glucuronosyltransferase -- DILI; Toxicity testing -- In vitro -- Periodicals; Toxicology -- Periodicals; 615.9
• DOI: 10.1016/j.tiv.2016.02.013
• Languages: English
• ISSNs: 0887-2333

Abstract

Abstract: Cytochrome P450s (CYPs), UDP-glucuronosyltransferases (UGTs) and sulfotransferases (SULTs) are the most important enzymes for metabolic clearance. Characterization of phase I and phase II metabolism of a given drug in cellular models is therefore important for an adequate interpretation of the role of drug metabolism in toxicity. We investigated phase I (CYP) and phase II (UGT and SULT) metabolism of three drugs related to drug-induced liver injury (DILI), namely acetaminophen (APAP), diclofenac (DF) and tolcapone (TC), in cryopreserved primary human hepatocytes from 5 donors in suspension and monolayer. The general phase II substrate 7-hydroxycoumarin (7-HC) was included for comparison. Our results show that the decrease in CYP, UGT and SULT activity after plating is substrate dependent. As a consequence the phase I/phase II metabolism ratio is significantly affected, with a shift in monolayer towards phase I metabolism for TC and towards phase II metabolism for APAP and DF. Inter-donor variability in drug metabolism is significant, especially in sulfation of 7-HC or APAP. As CYP, UGT and SULT metabolism may lead to bioactivation and/or detoxification of drugs, a changed ratio in phase I/phase II metabolism may have important consequences for metabolism-related toxicity. Highlights: First comparison of phase I and phase II metabolism in cryopreserved human hepatocytes in suspension and monolayer Comparison of 7-HC metabolism as general UGT and SULT substrate with phase II metabolism of three DILI drugs Ratio of phase I/phase II metabolism of drugs is different in suspension and monolayer and donor-dependent. SULT-activity shows a high inter-donor variability, dependence on culture conditions, as well as on test substrate.