Prevalidation trial for a novel in vitro eye irritation test using the reconstructed human cornea-like epithelial model, MCTT HCE™

Here, we report the results of a prevalidation trial for an in vitro eye irritation test (EIT) using the reconstructed human cornea-like epithelium, MCTT HCE™. The optimal cutoff to determine irritation in the prediction model was established at 35% with the receiver operation characteristics(ROC) curve for 126 substances. Within-lab(WL) and between-lab(BL) reproducibility was tested for 20 reference substances by 3 participating laboratories. Viability data described by mean ± SD or ± 1/2 difference between duplicate wells, and scatter plots, demonstrated the WL/BL consistency. WL/BL concordance with the binary decision, whether non-irritant or irritant was estimated to be 85–95% and 95%, respectively. WL/BL reproducibility of viability data was further supported by a strong correlation(ICC, r > 0.9). WL/BL agreement of binary decisions was also examined by Fleiss' Kappa statistics, which showed a strong level of agreement (> 0.78), nevertheless weaker than the reproducibility of the viability. The EIT with MCTT HCE™ exhibited a sensitivity of 82.2% (60/73), a specificity of 81.1% (43/53), and an accuracy of 81.8% (103/126) for 126 reference substances (for liquids; a sensitivity of 100% (47/47), a specificity of 70.6% (24/34), and an accuracy of 87.7% (71/81), and for solids, a sensitivity of 50% (13/26), a specificity of 100% (19/19), and an accuracy of 71.1% (32/45), suggesting that the accuracy is satisfactory but the sensitivity needs improvement, which shall be addressed through correcting the poor sensitivity for solid substances in future full validation trials.