After 13 days of culture, a multistratified epidermis has been reconstructed in vitro and consists of a basal layer, several prickle cell and granular layers and a horny layer (1).
After cDNA array analysis, the EpiSkin model shows stronger expression of epidermal differentiation markers than is shown by monolayer cultures. An overexpression of genes coding for keratin K1, loricrin, filaggrin, corneodesmosin, CLSP and caspase 14 has been demonstrated (2).

An SDS-PAGE analysis of keratin expressed in the EpiSkin model shows the presence of two pairs of predominant keratins in normal human epidermis: the 1/10 and 5/14 pairs. The 2/11 pair, a minor component of the normal epidermis is detected in smaller quantities (3).

The different lipid classes in normal human epidermis are present in the EpiSkin model: phospholipids, cholesterol sulphate and neutral lipids, triglycerides, free fatty acids and several types of ceramides (sphingolipids).