NUTRITIONAL REGULATION OF CULTURED ANALOGS OF HUMAN SKIN

Applications for a valid analogue of human skin include treatment of f ull-thickness skin wounds, alternatives to animals for safety testing of consumer products, and investigations of skin biology and pathology . In vitro models of cultured skin have been developed from combinatio ns of cultured human keratinocytes and fibroblasts, and biopolymer sub strates, but none has yet demonstrated regeneration of functional epid ermal barrier. Formation of epidermal barrier in cultured skin depends greatly on the nutritional composition of incubation media to regulat e proliferation and differentiation of keratinocytes into corneocytes and barrier lipids of stratum corneum. To simulate wound healing by ke ratinocytes, culture media should promote rapid proliferation early in the incubation period, followed by reduced proliferation and stimulat ion of synthesis of corneocytes and barrier lipids. Although functiona l epidermal barrier has not yet been produced in vitro, transplantatio n of cultured skin to animals and humans has demonstrated that true ep idermal barrier can be generated by cultured epithelium. Understanding of the regulatory factors that promote stratum corneum formation has great potential for the generation of true epidermal barrier in vitro. Standardization and validation of analogues of human skin for therape utic and diagnostic purposes will lead to meaningful advances in publi c health and safety.