An optimized inexpensive emollient mixture improves barrier repair in murine skin

Background/Objective: Maintenance of epidermal permeability barrier homeostasis is the most crucial cutaneous function, as it allows life in a terrestrial environment. Defective epidermal permeability barrier results not only in excessive water loss, but also in the induction of cutaneous inflammation and an increased risk of infections. Together, these abnormalities could help explain the increased risk of death in premature and low birth weight infants whose skin is functionally compromised. Improvement of permeability barrier function by topical barrier repair therapies could become a valuable approach not only to reduce neonatal mortality, but also to prevent/treat dermatoses, accompanied by barrier abnormalities at all ages, and to prevent microbial pathogen colonization/invasion. Yet, most current barrier enhancing products are not optimal, and too expensive to allow their use in the developing countries. Methods: we optimized the ratio of several inexpensive ingredients, previously shown to be effective individually for barrier homeostasis. The effects of this mixture on epidermal functions barrier function, skin surface pH and stratum corneum hydration, on murine skin were assessed using respective probe connected to an MPA5 skin physiology monitor. Epidermal differentiation and antimicrobial peptide expression were assessed by immnuohistochemical staining. Changes in lamellar body formation and secretion were evaluated with an electron microscope. Results: Although barrier function, skin surface pH and stratum corneum hydration remained unchanged under basal conditions, our results show that pretreatment of normal murine skin with this optimized mixture improves permeability barrier homeostasis, indicating by an acceleration of barrier recovery, and enhances expression of antimicrobial peptides. The barrier-enhancing effects and antimicrobial activities of this optimized mixture could be attributed at least in part to a parallel stimulation of epidermal differentiation. Conclusion: Since the individual ingredients in this mixture are inexpensive, this optimized mixture shows promise as a means of reducing neonatal mortality in low-income settings, but it also could be more widely used to prevent skin disorders associated with permeability and antimicrobial barrier abnormalities. Copyright (C) 2015, Taiwanese Dermatological Association. Published by Elsevier Taiwan LLC. All rights reserved.