In Vitro Three-dimensional Skin Tissue Constructs

Human skin provides fortification against peripheral threats which may compromise the integrity and health of the human body. Its presence as the largest human organ forms a protective barrier making it an effective first line of defence against pathogenic, chemical and physical damage. Tissue engineering technology has enabled the development of in vitro three-dimensional (3D) organotypic skin cultures in order to understand the skin's physiology and architecture. This advancement has enabled the use of 3D skin model platforms to study skin diseases and conditions as well as facilitate drug discovery, clinical research and cosmetic product development.In this study, an in vitro three-dimensional human skin model was constructed and characterised with epidermal and dermal layers analogous to normal skin. The differentiation of keratinocyte cells in the epidermis gave rise to the basal, spinal, granular and corneal layers. Keratinocyte cell culture in high calcium media resulted In the upregulation of genes associated with differentiation stages including keratin 1 (KRTl) and keratin 10 (KRTIO), in contrast to the low calcium media cultures. Involucrin (INV) a gene associated with keratinocyte differentiation was not upregulated, and showed similar expression levels in both media cultures, suggesting an absence of late/terminal differentiation. Alkaline phosphatase activity (ALP) was assessed to determine if it was influenced following the induction of keratinocyte differentiation. ALP activity was shown to be elevated in keratinocyte cells following culture in high calcium media after 14 days. Keratinocyte differentiation is a crucial and complex process to replenish lost, differentiated upper epidermal layers and new methods to evaluate this differentiation process are needed.