Immunohistochemical distribution of Ki67 in epidermis of thick glabrous skin of human digits.

Abstract

The glabrous skin on the flexor sides of hands and feet, compared to other integument regions, has thicker epidermis and more complex pattern of epidermal ridges, wherefore in microscopy is denominated as thick skin. The epidermis of this skin type has individually unique and permanent superficial patterns, called dermatoglyphics, which are maintained byregenerative potential of deep epidermal rete ridges,that interdigitate with adjacent dermis. Using light microscopy, we analyzed cadavericbig toes thick skin samples, described histology of deep epidermal ridges (intermediate, limiting, and transverse), andquantitatively evidenced their pattern of proliferation by immunohistochemicalassessment of Ki67. Immunohistochemical distribution of Ki67 was confined to basal and suprabasal layers, with pattern of distribution specific for intermediate, limiting and transverse ridges that gradually transform within epidermal height. Deep epidermal ridges, interdigitating with dermal papillae, participate in construction of intricate epidermal base, whose possible role in epidermal regeneration was also discussed. Having a prominent morphology, thistype of epidermisoffers the best morphological insight in complexities of skin organization, and its understanding could challenge and improve currently accepted models of epidermal organization.