Corneocytes: relationship between structural and biomechanical properties

Ana S. Évora, Michael J. Adams, Simon A. Johnson, Zhibing Zhang*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

1 Citation (Scopus)
83 Downloads (Pure)

Abstract

Background: Skin is the interface between an organism and the external environment, and hence the stratum corneum (SC) is the first to withstand mechanical insults that, in certain conditions, may lead to integrity loss and the development of pressure ulcers. The SC comprises corneocytes, which are vital elements to its barrier function. These cells are differentiated dead keratinocytes, without organelles, composed of a cornified envelope and a keratin-filled interior, and connected by corneodesmosomes (CDs). Summary: The current review focusses on the relationship between the morphological, structural, and topographical features of corneocytes and their mechanical properties, to understand how they assist the SC in maintaining skin integrity and in responding to mechanical insults. Key Messages: Corneocytes create distinct regions in the SC: the inner SC is characterized by immature cells with a fragile cornified envelope and a uniform distribution of CDs; the upper SC has resilient cornified envelopes and a honeycomb distribution of CDs, with a greater surface area and a smaller thickness than cells from the inner layer. The literature indicates that this upward maturation process is one of the most important steps in the mechanical resistance and barrier function of the SC. The morphology of these cells is dependent on the body site: the surface area in non-exposed skin is about 1,000-1,200 μm2, while for exposed skin, for example, the cheek and forehead, is about 700-800 μm2. Corneocytes are stiff cells compared to other cellular types, for example, the Young's modulus of muscle and fibroblast cells is typically a few kPa, while that of corneocytes is reported to be about hundreds of MPa. Moreover, these skin cells have 2 distinct mechanical regions: the cornified envelope (100-250 MPa) and the keratin matrix (250-500 MPa).

Original languageEnglish
Pages (from-to)146-161
Number of pages16
JournalSkin Pharmacology and Physiology
Volume34
Issue number3
Early online date29 Mar 2021
DOIs
Publication statusPublished - Apr 2021

Bibliographical note

Funding Information:
The work was carried out as part of the project “Skin Tissue Integrity under Shear” (STINTS) that is funded from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 811965.

Publisher Copyright:
© 2021 S. Karger AG. All rights reserved.

Keywords

  • Corneocyte
  • Corneodesmosomes
  • Cornified envelope
  • Mechanical properties
  • Skin
  • Stratum corneum

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Dermatology

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