Abstract
We report here a novel experimental system, cryopreserved MetMax human hepatocytes (MMHHs), for in vitro drug metabolism studies. MMHHs consist of cofactor-supplemented permeabilized cryopreserved human hepatocytes. The use procedures for MMHHs are significantly simplified from that for conventional cryopreserved human hepatocytes (CCHHs): 1) storage at -80°C instead of in liquid nitrogen and 2) usage directly after thawing without centrifugation and microscopic evaluation of cell density and viability and cell density adjustment. In this study, we compared MMHHs and CCHHs in CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2D6, CYP2E1, CYP3A4, CYP2J2, monoamine oxidase A, aldehyde oxidase, flavin-containing monooxygenase, UDP-glucuronyl transferase, SULT, N-acetyltransferase 1, and acetaminophen glutathione (GSH) conjugation activities based on liquid chromatography-tandem mass spectrometry quantification of substrate metabolism. MMHHs were prepared from CCHHs consisting of hepatocytes pooled from 10 individual donors. The drug metabolizing enzyme activities of both CCHHs and MMHHs were cell concentration and time dependent, with specific activities of MMHHs ranging from 27.2% (carboxylesterase 2) to 234.2% (acetaminophen GSH conjugation) of that for CCHHs. As observed in CCHHs, sequential oxidation and conjugation was observed in MMHHs for coumarin, 7-ethoxycoumarin, and acetaminophen. 7-Hydroxycoumarin conjugation results showed that metabolic pathways in MMHHs could be selected via the choice of cofactors, with glucuronidation but not sulfation observed in the presence of UDP-glucuronic acid and not 3-phosphoadenosine-5-phosphosulfate, and vice versa. Results with noncytotoxic and cytotoxic concentrations of acetaminophen showed that drug metabolism was compromised in CCHHs but not in MMHHs. Our results suggest that the MMHHs system represents a convenient and robust in vitro experimental system for the evaluation of drug metabolism.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Drug metabolism and disposition: the biological fate of chemicals
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
