Development of stratum corneum chymotrypsin‐like protease activity and natural moisturizing factors from birth to 4 weeks of age compared with adults3. (22nd July 2016)

• Record Type: Journal Article
• Authors: Chittock, J.; Cooke, A.; Lavender, T.; Brown, K.; Wigley, A.; Victor, S.; Cork, M.J.; Danby, S.G.
• Is Part Of: British journal of dermatology. Volume 175:Number 4(2016)
• Page Start: 713
• Page End: 720
• Publication Date: 2016-07-22
• Subjects: Dermatology -- Periodicals; Skin -- Diseases -- Periodicals; 616.5
• DOI: 10.1111/bjd.14568
• Languages: English
• ISSNs: 0007-0963

Abstract

Summary: Background: From birth, the functional properties of the neonatal epidermal barrier mature whereby the stratum corneum (SC) hydrates and the skin surface acidifies. The identification of a thinner infant SC compared with adults suggests underdeveloped mechanisms underlying differentiation and desquamation. Objectives: To assess the functional properties of the neonatal SC from birth, in conjunction with the quantification of superficial chymotrypsin‐like protease activity [kallikrein‐7 (KLK‐7)] and filaggrin‐derived natural moisturizing factors (NMF). Methods: A total of 115 neonates recruited to the Oil in Baby SkincaRE (OBSeRvE) randomized controlled trial underwent a full evaluation of the SC at birth (< 72 h old) and at 4 weeks of age ( n = 39, no oil control group) using minimally invasive instrumentation and methodology. A cohort of 20 unrelated adults was recruited for comparison. Results: At birth NMF levels correlated with SC hydration ( r = 0·50) and skin‐surface pH ( r = −0·54). From birth to 4 weeks, transepidermal water loss (TEWL), superficial KLK‐7 activity and filaggrin‐derived NMF significantly elevated. Impaired epidermal barrier function at birth (> 75th percentile TEWL) was accompanied by significantly elevated chymotrypsin‐like protease activity and reduced levels of NMF. Conclusions: The biophysical, biological and functional properties of the developing neonatal SC are transitional from birth to 4 weeks of age and differ significantly from adults. The presence of impaired barrier function with elevated protease activity and reduced NMF at birth suggests why certain infants are predisposed to epidermal barrier breakdown and the development of atopic dermatitis. Abstract : What's already known about this topic? From birth the acidification and hydration of the infant stratum corneum to adult levels suggests transitory mechanisms underlying differentiation and desquamation. What does this study add? Superficial chymotrypsin‐like protease activity and natural moisturizing factors (NMF) increase from birth to 4 weeks of age and differ from those of adults. Impaired barrier function at birth is accompanied by elevated protease activity and reduced NMF, highlighting why certain infants are predisposed to epidermal barrier breakdown and the development of atopic dermatitis (AD). What is the translational message? Our data reinforce the need for infant skincare regimens from birth that protect and support normal barrier development. Targeted skincare strategies to ameliorate heightened protease activity and low NMF may be an important preventative measure for neonates at increased risk of developing AD. Linked Comment: Stamatas. Br J Dermatol 2016;175 :670–671 . Plain language summary available online