Reconstitution of Human Skin In Vitro Using Readily Available Sources: Novel Studies of Tumor Promotion

The study developed a standardized three-dimensional in vitro model of human skin to assay skin tumor promoters. This model was notable for its replication of human skin characteristics, the ability to seed with "initiated" keratinocytes, and control over the medium's calcium level. It combined methodologies from previous research and did not require actual human skin, making it reproducible in any lab with basic cell culture equipment. The model used human embryonic fibroblasts and rat tail collagen for the dermal equivalent, with keratinocytes from human hair follicles. Stratification was achieved by culturing epidermal cells at the air interface of a serum-free medium, and the model was validated through histological staining, electron microscopy, and immunostaining.