An organ which can be grown: Episkin

AN ORGAN WHICH CAN BE GROWN

	An Episkin^TM kit The Episkin^TM bio-engineering center near Gerland.		EPISKIN^TM A validated model - Safety studies - Efficacy tests - Next generations A validated model The model developed by E. Tinnois and marketed in the form of a kit by the Imedex Company under the name of Episkin was bought by L'Oral in April 1997. It consists of a dermal support formed from collagens. Keratinocytes, deposited on the support, divide for three days in the culture medium., then differentiate in the air exposed culture. At the end, the epidermis consists of a mitotic layer, a mucous Malphigian layer and a functional horny layer. In March 1998, an in vitro validation study of cutaneous corrosion linked to 60 chemical products, based on the viability of cells, carried out by ECVAM (Europe Center for the Validation of Alternative Methods) showed that EPISKIN allows good discrimination between chemical products with different physical properties and different corrosive potential. While a long way from the cosmetic context, this study has opened the door to other development studies concerning the safety of products applied to the skin, thanks to Episkin^TM. The Episkin^TM kit is currently marketed in the form of 12 well plates. These kits are manufactured in L'Oral's 2,200 m² cutaneous bio-engineering centre, at Gerland, in the suburbs of Lyons. During its first year of activity, 12,480 kits were produced, but the capacity allows for rapid growth. This kit is used to evaluate products in vitro Each of the 12 wells corresponds to an epidermal unit. Formulae to be tested are directly applied topically to the surface of the sample or in the culture medium. Analysis of results is made by measurements in the culture fluid at the bottom of each well, by cellular viability measurements and by histological sections of each "epidermis". Several studies have already shown the validity of the model.
			Safety studies Increase in defence mechanism markers and cellular damage markers synthesis reflectes, *in vivo, cutaneous irritation. In vitro, irritation can be assessed through the measurement of cellular viability and those marker concentrations. EPISKIN was shown to be highly reproductible in a study carried out, on a series of cosmetic products, by 3 different industrial laboratories. This kit allows to test, in situ*, the effects of substances applied to a human skin, without using human volunteers, and to select the safest ones.
			Efficacy tests Vitamin C applied to Episkin^TM increases production of essential lipids, the ceramides, in the horny layer. This shows that Episkin^TM is a model where cellular metabolism is active. Moreover, the protective effect of vitamin C against damage induced by UVA radiation has also been demonstrated. This vitamin therefore globally improves the barrier role of the epidermis. Retinol based formulations have been studied on EPISKIN^TM in order to determine the best tolerated concentration which is most active on the proliferation of epidermal keratinocytes.
			Next generations EPISKIN^TM is a first generation model of the epidermis. More complex second and third generation epidermal models already exist in the laboratory, containing cells responsible for colour (melanocyte) or cutaneous immunity (Langerhans cells). The introduction, e.g. of Langerhans cells into an epidermal model by L'Oral teams is a big step towards the evaluation of contact allergy phenomena.