Anchored skin equivalent cultured in vitro: a new tool for percutaneous absorption studies

Authors: Michel, MartineAuger, François A.Germain, Lucie
Abstract: Dear Editor: The recent awareness that skin plays many important roles, such as a physical and immunological semi-permeable membrane which protects the whole body surface from water loss and selectively controls the rate of molecule penetration in the circulatory system, has fostered a keen interest in percutaneous absorption studies. The development of transdermal therapeutic system has concretely shown that skin bioabsorption properties are of major interest in the pharmaceutical industry (7). Moreover, in the field of toxicology, potentially harmful compounds that come in contact with the body surface must be tested. Different models have been designed to evaluate this important biological skin function using fresh or frozen skin (7,10,12,18). A major drawback of these models is the constant need of a human or animal skin supply which may lead to technical and ethical problems. Human cadaver skin is not easily available for most investigators. Moreover, an important and unavoidable variability in the skin absorption properties has been observed between samples from different individuals (21). Therefore, the present study was undertaken to set up an in vitro cultured skin equivalent for percutaneous absorption studies which could remedy these drawbacks. Recent progress in cell and tissue culture lead to the production of skin equivalents composed of a keratinocyte layer growing on a dermal equivalent. Various dermal equivalents have been proposed upon which keratinocytes can be seeded (1,15,19,20). These epidermal cells will remain in an undifferentiated state when the three-dimensional culture is kept immersed in the culture medium. However, an improved epidermal cell differentiation, characterized by the formation of the stratum corneum, is obtained when these skin equivalents were cultured at the air-liquid interface (13). In order to produce a skin equivalent suitable for the measurement of in vitro percutaneous absorption, we have adapted our previous design described for dermal equivalent anchorage (8) to the culture of skin equivalent. This technique allows these skin equivalents to be easily mounted on Franz diffusion cells. In the present study, human keratinocytes and dermal fibroblasts were isolated from normal adult skin specimens removed during plastic surgery and cultured as previously described (2,6,16). Dermal equivalents were prepared according to the method of Bell (1), with some modifications as described by Rompr~ et at. (17). The collagen/fibroblasts mixture was poured into a petri dish (35 mm in diameter) containing a ring of filter paper, accordingly to the method developed by L5pez Valle et at. (8), to prevent the collagen lattice contraction. In the present study, this anchorage was not glued to the bottom of the dish, to facilitate the subsequent technical manipulations of the skin equivalent. After keratinocyte addition, such a system led to the production of a skin equivalent presenting a constant surface area (Fig. 1). These skin equivalents, when raised at the air-liquid interface using conventional systems i.e. deposition
Document Type: Lettre à l'éditeur
Issue Date: 1 November 1993
Open Access Date: Restricted access
Document version: VoR
This document was published in: In Vitro Cellular & Developmental Biology - Animal, Vol. 29 (11), 834–837 (1993)
Tissue Culture Association
Alternative version: 10.1007/BF02631358
Collection:Autres articles publiés

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