title: Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase I).
abstract: We have developed a new in vitro skin irritation test based on an open source reconstructed epidermis (OS-REp) with openly accessible protocols for tissue production and test performance. Due to structural, mechanistic and procedural similarity, a blinded catch-up validation study for skin irritation according to OECD Performance Standards (PS) was conducted in three laboratories to promote regulatory acceptance, with OS-REp models produced at a single production site only. While overall sensitivity and predictive capacity met the PS requirements, overall specificity was only 57%. A thorough analysis of the test results led to the assumption that some of the false-positive classifications could have been evoked by volatile skin-irritating chemicals tested in the same culture plate as the non-irritants falsely predicted as irritants. With GC/MS and biological approaches the cross-contamination effect was confirmed and the experimental set-up adapted accordingly. Retesting of the affected chemicals with the improved experimental set-up and otherwise identical protocol resulted in correct classifications as non-irritants. Taking these re-test results into account, 93% overall sensitivity, 70% specificity and 82% accuracy was achieved, which is in accordance with the OECD PS. A sufficient reliability of the method was indicated by a within-laboratory-reproducibility of 85-95% and a between-laboratory-reproducibility of 90%.
authors.affiliation: Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, Germany. Electronic address: karsten.mewes@henkel.com.
authors.forename: K R
authors.initials: KR
authors.lastname: Mewes
authors.affiliation: Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Fischer
authors.affiliation: Goethe-University, Medical School, Department of Dermatology, Venereology and Allergology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
authors.forename: N N
authors.initials: NN
authors.lastname: Zöller
authors.affiliation: Goethe-University, Medical School, Department of Dermatology, Venereology and Allergology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Laubach
authors.affiliation: Goethe-University, Medical School, Department of Dermatology, Venereology and Allergology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bernd
authors.affiliation: VITO NV Flemish Institute for Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Jacobs
authors.affiliation: VITO NV Flemish Institute for Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: van Rompay
authors.affiliation: Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Liebsch
authors.affiliation: Bundesinstitut für Risikobewertung (BfR), Max-Dohrn-Straße 8-10, 10589 Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Pirow
authors.affiliation: Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Petersohn
mesh_terms: D000826:Animal Testing Alternatives; D004817:Epidermis / Q000033:anatomy & histology / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D007509:Irritants / Q000633:toxicity*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D023422:Skin Irritancy Tests
chemical_list: D007509:Irritants
keywords: Catch-up validation study; Cross-contamination; OECD performance standards; Open source concept; Reconstructed human epidermis; Skin irritation test