Esterase Activity and Intracellular Localization in Reconstructed Human Epidermal Cultured Skin Models

BACKGROUND: Reconstructed human epidermal culture skin models have been developed for cosmetic and pharmaceutical research. OBJECTIVE: This study evaluated the total and carboxyl esterase activities (i.e., K(m) and V(max), respectively) and localization in two reconstructed human epidermal culture skin models (LabCyte EPI-MODEL [Japan Tissue Engineering] and EpiDerm [MatTek/Kurabo]). The usefulness of the reconstruction cultured epidermis was also verified by comparison with human and rat epidermis. METHODS: Homogenized epidermal samples were fractioned by centrifugation. p-nitrophenyl acetate and 4-methylumbelliferyl acetate were used as substrates of total esterase and carboxyl esterase, respectively. RESULTS: Total and carboxyl esterase activities were present in the reconstructed human epidermal culture skin models and were localized in the cytosol. Moreover, the activities and localization were the same as those in human and rat epidermis. CONCLUSION: LabCyte EPI-MODEL and EpiDerm are potentially useful for esterase activity prediction in human epidermis.