Overview of in vitro cell culture technologies and pharmaco-toxicological applications

Cutaneous-cell culture technologies have consisted initially of the isolation and maintenance of pure cutaneous cell types. Conventional (two-dimensional cultures) of keratinocytes or fibroblasts have yielded valuable information on the biochemistry and physiology of the epidermis or dermis. Subsequently, the aim of research has been co-culture of the various cell types to reconstitute in vitro the cellular interactions present in vivo. For example, co-culture of keratinocytes and melanocytes allow studies on mechanisms of melanogenesis. At the same time the reconstruction of skin as a tissue-like structure has allowed an improved differentiation of the epidermis and the development of dermatological applications. From a practical point of view, the three-dimensional culture of skin or epidermis is a decisive step in the development of in vitro cutaneous pharmaco-toxicology. Various models are now available with different advantages and limitations according to their composition and their handling. All of them allow the testing of water-insoluble materials including cosmetics and dermatological products, or of physical agents such as UV radiation. In the near future, the refinement of these models by introduction of other cell types such as melanocytes, Langerhans cells or endothelial cells, and improvement of the barrier function of the reconstructed stratum corneum, will permit their use in new fields in alternative methods.