An ex vivo human skin model for studying skin barrier repair

In the studies described in this study, we introduce a novel ex vivo human skin barrier repair model. To develop this, we removed the upper layer of the skin, the stratum corneum (SC) by a reproducible cyanoacrylate stripping technique. After stripping the explants, they were cultured in vitro to allow the regeneration of the SC. We selected two culture temperatures 32 degrees C and 37 degrees C and a period of either 4 or 8days. After 8days of culture, the explant generated SC at a similar thickness compared to native human SC. At 37 degrees C, the early and late epidermal differentiation programmes were executed comparably to native human skin with the exception of the barrier protein involucrin. At 32 degrees C, early differentiation was delayed, but the terminal differentiation proteins were expressed as in stripped explants cultured at 37 degrees C. Regarding the barrier properties, the SC lateral lipid organization was mainly hexagonal in the regenerated SC, whereas the lipids in native human SC adopt a more dense orthorhombic organization. In addition, the ceramide levels were higher in the cultured explants at 32 degrees C and 37 degrees C than in native human SC. In conclusion, we selected the stripped ex vivo skin model cultured at 37 degrees C as a candidate model to study skin barrier repair because epidermal and SC characteristics mimic more closely the native human skin than the ex vivo skin model cultured at 32 degrees C. Potentially, this model can be used for testing formulations for skin barrier repair.