title: Detection of metabolic activation leading to drug-induced phospholipidosis in rat hepatocyte spheroids.
abstract: Drug-induced phospholipidosis (PLD) is one of the adverse reactions to treatment with cationic amphiphilic drugs. Recently, simple and reliable evaluation methods for PLD have been reported. However, the predictive power of these methods for in vivo PLD induction is insufficient in some cases. To accurately predict PLD, we focused on drug metabolism and used three-dimensional cultures of hepatocytes known as spheroids. Here we used the fluorescent phospholipid dye N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (NBD-PE) to detect PLD induction. After 48 hr exposure to 20 µM amiodarone and amitriptyline, PLD inducers, NBD-PE fluorescence in the spheroids was significantly higher than that in the control. In contrast, 1 mM acetaminophen, as a negative control, did not increase fluorescence. Furthermore, the combination of NBD-PE fluorescence and LysoTracker Red fluorescence and the accumulation of intrinsic phospholipids reflected PLD induction in spheroids. To evaluate metabolic activation, we assessed PLD induction by loratadine. NBD-PE fluorescence intensity was significantly increased by 50 µM loratadine treatment. However, the fluorescence was markedly decreased by co-treatment with 500 µM 1-aminobenzotriazole, a broad cytochrome P450 inhibitor. The formation of desloratadine, a metabolite of loratadine, was observed in spheroids after treatment with loratadine alone. These results showed that metabolic activation is the key factor in PLD induction by treatment with loratadine. We demonstrated that rat primary hepatocyte spheroid culture is a useful model for evaluating drug-induced PLD induction mediated by metabolic activation of the drug using the fluorescence probe technique.
authors.affiliation: Graduate School of Biomedical and Health Sciences, Hiroshima University.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takagi
authors.forename: Seigo
authors.initials: S
authors.lastname: Sanoh
authors.forename: Masataka
authors.initials: M
authors.lastname: Santoh
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ejiri
authors.forename: Yaichiro
authors.initials: Y
authors.lastname: Kotake
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohta
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005456:Fluorescent Dyes; D022781:Hepatocytes / Q000166:cytology*; D017336:Loratadine / Q000494:pharmacology; D010714:Phosphatidylethanolamines; D010743:Phospholipids / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D018874:Spheroids, Cellular / Q000378:metabolism*; D013501:Surface-Active Agents / Q000009:adverse effects
chemical_list: D005456:Fluorescent Dyes; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D013501:Surface-Active Agents; C042077:N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine; D017336:Loratadine; D003577:Cytochrome P-450 Enzyme System