Characterization of the human ridged and non-ridged skin: a comprehensive histological, histochemical and immunohistochemical analysis

A Vela-Romera,N Prados-Olleta,A Campos,J Chato-Astrain,F Campos,J Aneiros-Fernández,I Garzón,V Carriel,M Alaminos,M A Martín-Piedra

doi:10.1007/s00418-018-1701-x

Abstract

The structure of the human skin is directly dependent on its location and the mechanical forces to which it is subjected. In the present work, we have performed a comprehensive analysis of the human ridged and non-ridged skin to identify the differences and similarities between both skin types. For this purpose, human skin samples were obtained from dorsal hand skin (DHS), palmar hand skin (PHS), dorsal foot skin (DFS) and plantar foot skin (PFS) from the same cadaveric donors. Histological, histochemical and semiquantitative and quantitative immunohistochemical analyses were carried out to evaluate the epidermis, dermis and basement membrane. Results show that the epithelial layer of ridged skin had larger cell number and size than non-ridged skin for most strata. Melanocytes and Langerhans cells were more abundant in non-ridged skin, whereas Merkel cells were preferentially found in ridged skin. The expression pattern of CK5/6 was slightly differed between non-ridged and ridged skin. Involucrin expression was slightly more intense in non-ridged skin than in ridged skin. Collagen was more abundant in foot skin dermis than in hand skin, and in ridged skin as compared to non-ridged skin. Elastic fibers were more abundant in DHS. Biglycan was more abundant in foot skin than in hand skin. No differences were found for blood and lymphatic vessels. The basement membrane laminin was preferentially found in foot skin. These results revealed important differences at the epithelial, dermal and basement membrane levels that could contribute to a better knowledge of the human skin histology.

Highlights

The skin is a complex organ whose functions are tightly related to its histological structure
Histological analysis of skin samples stained with hematoxylin and eosin showed that all skin types consisted of an epidermal layer and a subjacent dermal layer (Fig. 1), but substantial differences existed among the four skin types
Non-ridged dorsal skin of the human hand and foot is characterized by a stratified keratinized epithelium with 8–12 epithelial cell layers below a thin corneous stratum, whilst ridged palmar and plantar skin showed a high number of epithelial layers that ranged between 30 and 60 layers approximately, and a thick corneous stratum

Summary

Introduction

The skin is a complex organ whose functions are tightly related to its histological structure. Histochemistry and Cell Biology (2019) 151:57–73 two types of skin can be found according to its thickness and characteristics: the pressure-resistant ridged skin found in feet soles and hand palms ( called thick, hairless or glabrous skin), and the non-ridged skin found at most of the body surface ( called thin or hairy skin) (Khavkin and Ellis 2011; Kanitakis 2002; Geneser 1986). Both types of skin may be affected by common skin conditions, certain diseases tend to preferentially affect only one type of skin. The loss of palmoplantar skin areas due to trauma, tumors or burns is an important medical challenge (Banis 2001; Uroskie and Colen 2001; Donato et al 2000) that is often treated by transference of free skin grafts from other areas to the palmoplantar area (Engelhardt et al 2011)

Methods

Results

Conclusion