Development and organization of human stratum corneum after birth: electron microscopy isotropy score and immunocytochemical corneocyte labelling as epidermal maturation's markers in infancy

• Published in: British journal of dermatology (1951) Vol. 171; no. 5; pp. 978 - 986
• Main Authors: Fluhr, J.W., Lachmann, N., Baudouin, C., Msika, P., Darlenski, R., De Belilovsky, C., Bossert, J., Colomb, E., Burdin, B., Haftek, M.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.11.2014; Wiley-Blackwell; Oxford University Press
• Subjects: Adult; Age; Aging - physiology; Anisotropy; Biological and medical sciences; Biomarkers - metabolism; Birth; Cell surface; Child, Preschool; Dermatology; Desmosomes - ultrastructure; Epidermis - cytology; Epidermis - growth & development; Epidermis - ultrastructure; Humans; Immunohistochemistry; Infant; Infant, Newborn; Infants; Labeling; Medical sciences; Microscopy; Microscopy, Electron, Scanning; Neonates; Scanning electron microscopy; Skin; Stratum corneum; Structure-function relationships; Young Adult; Human; Ripening; Anatomic pathology; Stratum corneum; Organization; Dermatology; Development; Biological marker; Epidermis; Infant; Electron microscopy; Birth
• ISSN: 0007-0963; 1365-2133
• DOI: 10.1111/bjd.12880

Summary Background There is growing evidence for the ongoing structural and functional adaptation of the skin after birth. Objectives The aim of this study was the definition of scanning electron microscopy markers of skin maturation in different age groups (birth to adulthood). We propose a semiquantitative score to analyse the maturation of the skin surface and a complementary evaluation of the distribution of corneodesmosin and corneodesmosomes. Material and methods An electron microscopy isotropy (E.M.I.) score was performed in six age‐groups to include fullterm neonates, babies, children and adults. The distribution of corneodesmosome remnants was analysed by corneodesmosin distribution with immunocytochemical corneocyte labelling. Results The E.M.I. score showed the highest anisotropy in neonates. The youngest groups displayed irregular and thick cell clusters composed of poorly individualized cells. In the older groups, the distribution of superficial corneocytes was more regular. The cells evenly covered the surface and displayed easily visualized single cell outlines. The distribution of immune‐labelled corneodesmosome remnants and the corneocyte projected area showed a correlation between age and structural maturation. The observed evolution indicated a poorly controlled process of corneocyte desquamation in infants and confirmed the relative immaturity of the epidermal barrier up to 1–2 years after birth under basal conditions. Conclusion Our study is the first attempt at semiquantitative evaluation of the micromorphology maturation of the epidermal surface at the ultrastructural level. The E.M.I. score and the associated pattern of corneodesmosome breakdown may be used as markers of the stratum corneum maturation. What's already known about this topic? Human epidermis, although assuring competent barrier function under basal conditions, undergoes structural and functional adaptation after birth during infancy. Earlier studies about the structural adaptation of the outermost skin layers during infancy and childhood are lacking What does this study add? Our results demonstrate the maturation of the epidermal surface micromorphology at the ultrastructural level A semiquantitative method is proposed and validated to evaluate the skin surface isotropy in scanning electron microscopy studies of skin surface, i.e. E.M.I. score