title: An epidermal equivalent assay for identification and ranking potency of contact sensitizers.
abstract: The purpose of this study was to explore the possibility of combining the epidermal equivalent (EE) potency assay with the assay which assesses release of interleukin-18 (IL-18) to provide a single test for identification and classification of skin sensitizing chemicals, including chemicals of low water solubility or stability. A protocol was developed using different 3D-epidermal models including in house VUMC model, epiCS® (previously EST1000™), MatTek EpiDerm™ and SkinEthic™ RHE and also the impact of different vehicles (acetone:olive oil 4:1, 1% DMSO, ethanol, water) was investigated. Following topical exposure for 24h to 17 contact allergens and 13 non-sensitizers a robust increase in IL-18 release was observed only after exposure to contact allergens. A putative prediction model is proposed from data obtained from two laboratories yielding 95% accuracy. Correlating the in vitro EE sensitizer potency data, which assesses the chemical concentration which results in 50% cytotoxicity (EE-EC50) with human and animal data showed a superior correlation with human DSA05 (μg/cm(2)) data (Spearman r=0.8500; P value (two-tailed)=0.0061) compared to LLNA data (Spearman r=0.5968; P value (two-tailed)=0.0542). DSA05=induction dose per skin area that produces a positive response in 5% of the tested population Also a good correlation was observed for release of IL-18 (SI-2) into culture supernatants with human DSA05 data (Spearman r=0.8333; P value (two-tailed)=0.0154). This easily transferable human in vitro assay appears to be very promising, but additional testing of a larger chemical set with the different EE models is required to fully evaluate the utility of this assay and to establish a definitive prediction model.
authors.affiliation: Department of Dermatology, VU University Medical Centre, Dept of Oral Cell Biology, ACTA, Amsterdam, The Netherlands. Electronic address: S.Gibbs@VUMC.nl.
authors.forename: Susan
authors.initials: S
authors.lastname: Gibbs
authors.forename: Emanuela
authors.initials: E
authors.lastname: Corsini
authors.forename: Sander W
authors.initials: SW
authors.lastname: Spiekstra
authors.forename: Valentina
authors.initials: V
authors.lastname: Galbiati
authors.forename: Horst W
authors.initials: HW
authors.lastname: Fuchs
authors.forename: George
authors.initials: G
authors.lastname: Degeorge
authors.forename: Matthew
authors.initials: M
authors.lastname: Troese
authors.forename: Patrick
authors.initials: P
authors.lastname: Hayden
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.forename: Erwin
authors.initials: E
authors.lastname: Roggen
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000633:toxicity*; D001681:Biological Assay; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D004797:Enzyme-Linked Immunosorbent Assay; D004817:Epidermis / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D020382:Interleukin-18 / Q000276:immunology / Q000378:metabolism*; D018448:Models, Immunological; D011237:Predictive Value of Tests; D023422:Skin Irritancy Tests
chemical_list: D000485:Allergens; D020382:Interleukin-18
keywords: 2-mercaptobenzothiazole; 4-nitrobenzyl bromide; C-OH; CA; DMF; DMSO; DNCB; DSA(05) (μg/cm(2)); DiSFeB; Dipartimento di Scienze Farmacologiche e Biomolecolari; EE; EUG; Epidermal equivalent; GLC; GXL; HBA; IL-18; In vitro; Irritant; LAC; MBT; NBB; PHL; PPD; Potency; RES; SDS; Sensitizer; VU University Medical Centre; VUMC; cinnamaldehyde; cinnamic alcohol; dimethylformamide; dimethylsulfoxide; dinitrochlorobenzene; epidermal equivalent; eugenol; glycerol; glyoxal; hydroxybenzoic acid; induction dose per skin area (DSA) that produces a positive response in 5% of the tested population; interleukin-18; lactic acid; p-phenylendiamine; phenol; resorcinol; sodium dodecyl sulphate