title: In Silico Modeling for the Prediction of Dose and Pathway-Related Adverse Effects in Humans From In Vitro Repeated-Dose Studies.
abstract: Long-term repeated-dose toxicity is mainly assessed in animals despite poor concordance of animal data with human toxicity. Nowadays advanced human in vitro systems, eg, metabolically competent HepaRG cells, are used for toxicity screening. Extrapolation of in vitro toxicity to in vivo effects is possible by reverse dosimetry using pharmacokinetic modeling. We assessed long-term repeated-dose toxicity of bosentan and valproic acid (VPA) in HepaRG cells under serum-free conditions. Upon 28-day exposure, the EC50 values for bosentan and VPA decreased by 21- and 33-fold, respectively. Using EC(10) as lowest threshold of toxicity in vitro, we estimated the oral equivalent doses for both test compounds using a simplified pharmacokinetic model for the extrapolation of in vitro toxicity to in vivo effect. The model predicts that bosentan is safe at the considered dose under the assumed conditions upon 4 weeks exposure. For VPA, hepatotoxicity is predicted for 4% and 47% of the virtual population at the maximum recommended daily dose after 3 and 4 weeks of exposure, respectively. We also investigated the changes in the central carbon metabolism of HepaRG cells exposed to orally bioavailable concentrations of both drugs. These concentrations are below the 28-day EC(10) and induce significant changes especially in glucose metabolism and urea production. These metabolic changes may have a pronounced impact in susceptible patients such as those with compromised liver function and urea cycle deficiency leading to idiosyncratic toxicity. We show that the combination of modeling based on in vitro repeated-dose data and metabolic changes allows the prediction of human relevant in vivo toxicity with mechanistic insights.
authors.affiliation: *Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Klein
authors.affiliation: IRCCS - Instituto di Ricerche Farmacologiche "Mario Negri," 20156 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Maggioni
authors.affiliation: Insilico Biotechnology AG, 70563 Stuttgart, Germany, and.
authors.forename: Joachim
authors.initials: J
authors.lastname: Bucher
authors.affiliation: *Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mueller
authors.affiliation: Insilico Biotechnology AG, 70563 Stuttgart, Germany, and.
authors.forename: Jens
authors.initials: J
authors.lastname: Niklas
authors.affiliation: Biopredic International, 35760 Saint-Grégoire, France.
authors.forename: Valery
authors.initials: V
authors.lastname: Shevchenko
authors.affiliation: Insilico Biotechnology AG, 70563 Stuttgart, Germany, and.
authors.forename: Klaus
authors.initials: K
authors.lastname: Mauch
authors.affiliation: *Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Heinzle
authors.affiliation: *Biochemical Engineering, Saarland University, 66123 Saarbruecken, Germany, fozia.noor@mx.uni-saarland.de.
authors.forename: Fozia
authors.initials: F
authors.lastname: Noor
mesh_terms: D000077300:Bosentan; D045744:Cell Line, Tumor; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology*; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D006801:Humans; D013449:Sulfonamides / Q000009:adverse effects; D018675:Toxicity Tests / Q000379:methods*; D014635:Valproic Acid / Q000009:adverse effects
chemical_list: D013449:Sulfonamides; D014635:Valproic Acid; D000077300:Bosentan
keywords: Bosentan; HepaRG; IVIVE; VPA; oral equivalent dose; reverse dosimetry;  metabolic pathway;  repeated-dose toxicity