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Objective: Atopic dermatitis (AD) is characterized by compositional and structural changes to the skin at lesional sites. Alteration to the levels and organization of both protein and lipid components are associated with disease status and lead to impaired barrier and hydration. Corneodesmosin (CDSN) and the arrangement and length of the intercellular lipid lamellae (ICLL) are altered in disrupted skin states. The aim of this research was to profile the distribution of CDSN and the ICLL in the stratum corneum (SC) at lesional and non‐lesional sites in AD‐prone skin and to investigate the impact of an eczema calming lotion containing petroleum jelly, fatty acids, and colloidal oatmeal. Methods: An IRB‐approved study was conducted with participants with active AD. From a small subset of participants, tape strips were collected from lesional and non‐lesional sites on the arm, prior to and after twice daily application, over 4 weeks of an eczema calming lotion containing petroleum jelly, fatty acids, and colloidal oatmeal. Fluorescent antibody staining was used to investigate the distribution of CDSN. Transmission electron microscopy (TEM) was used to characterize the ICLL. Results: The distribution/coverage of CDSN was similar between lesional and non‐lesional sites at baseline; application of the lotion resulted in a more defined honeycomb/peripheral distribution. Normalized ICLL (nICLL) was lower in baseline samples from lesional sites relative to non‐lesional sites. Application of the lotion increased this parameter by the end of the study at all sites. Conclusion: The eczema calming lotion containing petroleum jelly, fatty acids and colloidal oatmeal provided changes in corneodesmosomal proteins distribution and ICLL, consistent with improvements in corneocyte maturation and improved barrier function in the skin of individuals with atopic dermatitis. [ABSTRACT FROM AUTHOR]

Objective: Ex vivo skin has been used to study various skin conditions from atopic dermatitis to burn injury. The aim of this research is to identify a more effective barrier improvement strategy and to evaluate topical formulations in replenishing the skin. The skin can create new longer chain fatty acids and ceramides (CERs) from topically applied skin natural fatty acid to help renew the skin's barrier. Methods: An ex vivo skin model damaged by sequential tape stripping of the stratum corneum (SC) was used to investigate the repair of the SC. Confocal laser scanning microscopy was used to assess the SC layers recovered. Ultrastructural analysis was performed using transmission electron microscopy to visualize the lamellar bodies and intercellular lipid lamellae. Results: The data in this study provide the first direct ex vivo evidence comparing different marketed formulations containing three CERs with those containing fatty acids. Free fatty acid (FFA)‐containing formulations, but not CER‐containing formulations, directly applied to the damaged skin, showed an increased number of repaired SC layers and this was reflected at the ultrastructural level by an increased intercellular lipid lamellae length and an increased number of lamellar bodies. Conclusion: These findings demonstrate that FFA‐containing formulations can repair damaged ex vivo skin and point to a repair mechanism in which topically applied palmitic and stearic acids, (which boost lipid levels and elongation) can increase the production and transport of lipids into a repaired SC and thus rebuild an effective skin barrier. [ABSTRACT FROM AUTHOR]