Numerous keratinocyte subtypes involved in wound re-epithelialization

The expression of different keratin intermediate filaments has been used to define keratinocyte maturation and different phenotypic subtypes involved in acute wound (AW) healing. Immunohistochemistry with specific anti-keratin monoclonal and polyclonal antibodies was used to examine AW in normal healthy volunteers (n = 16). In all wounds examined, basal keratinocytes and cells at the leading edge of the wound expressed keratins K5 and K14. However, suprabasal cells had a more complex pattern of keratin expression, which was dependent on their position relative to the wound and location within the suprabasal compartment of the epidermis. In general, K10 was expressed in suprabasal keratinocytes at the wound edge, but not in keratinocytes covering the wound center, which expressed K6, K16, and K17 in a complex fashion. Ki67 expression, a marker of cell proliferation, was restricted to basal and immediate suprabasal layers at the wound edge. Keratinocytes populated the wound bed below the scab by migration, which was supported by keratinocyte proliferation in the surrounding epidermis both at and adjacent to the wound edge.