Ceramide-Containing Adjunctive Skin Care for Skin Barrier Restoration During Acne Vulgaris Treatment.

Barrier damage caused by facial acne vulgaris can be magnified by topical medication, such as adapalene (0.3%) and benzoyl peroxide (2.5%)(A/BPO), which utilizes a retinoid to normalize follicular keratinization and BPO to decrease the C. acnes population. Disease-induced irritation combined with topical medication-induced irritation results in dryness and enhanced inflammation leading to lower compliance and increased skin healing time. Ceramide-based moisturizers have documented barrier repair benefits for eczema but have not been studied for acne. The objective of this double-blind study was to measure the impact of acne treatment on skin barrier function and tolerance when paired with a ceramide routine. Participants were prescribed an A/BPO gel once daily. The treatment group received a ceramide-containing foaming facial cleanser and facial lotion, and the control group received basic foaming face wash for twice-daily use. Participant and investigator tolerability and efficacy were evaluated by both ordinal and clinical measures. Acne lesion counts and Investigator’s Global Assessments (IGA) of acne were obtained along with transepidermal water loss (TEWL) measurements for barrier function. TEWL for the treatment group remained significantly lower than the control at all timepoints and significantly improved from baseline by week 12. The treatment group had statistically lower mean investigator scores for dryness at all timepoints. Inflammatory lesion counts were significantly lower for the treatment group. A/BPO damaged the skin barrier, demonstrated by elevated TEWL, contributing to dryness, redness, and scaling. Use of a ceramide-containing cleanser and moisturizer significantly reduced severity and incidence of dryness, erythema, and scaling while more quickly resolving barrier damage and restoring function. Draelos ZD, Baalbaki N, Colon G, et al. Ceramide-containing adjunctive skin care for skin barrier restoration during acne vulgaris treatment. J Drugs Dermatol. 2023;22(6):554-558. doi:10.36849/JDD.7142 .

Alteration to the Skin Ceramide Profile Following Broad-Spectrum UV Exposure.

The epidermal stratum corneum (SC) lipid matrix, principally consisting of an equimolar ratio of ceramides, free fatty acids, and cholesterol, plays a crucial role in maintaining proper skin barrier function. Conditions which impair barrier integrity, such as in atopic dermatitis, correlate with the alternation of key ceramide subclasses and reduced chain length of acyl moieties. However, there is limited knowledge about the impact of unprotected repeat sun exposure on the skin lipid composition, especially ceramide profiles.This study investigated the effects of ultraviolet (UV) radiation on the ceramide profile using both an ex vivo skin and a clinical model. Lipidomic analysis of UV-exposed skin showed shifts to the composition of ceramide subclasses essential in repairing and strengthening the SC barrier (including CER1[EOS], CER3[NP], and CER6[AP]) and reduced very long-chain acyl moieties. Gene expression analysis and immunohistochemical staining of key enzymes (aSMase, DES1, CerS5, CerS3) suggested that lipid alterations can be attributed to changes within the ceramide biosynthesis process. Topical application of ceramide-containing suncare products help maintain SC-essential ceramide subclasses and proper ceramide chain length, demonstrating the importance of proper photoprotection to maintain healthy skin barrier and ceramide quality during daily sun exposure. J Drugs Dermatol. 2022;21(1):77-85. doi:10.36849/JDD.6331.

ARTICLE: Alteration to the Skin Barrier Integrity Following Broad-Spectrum UV Exposure in an Ex Vivo Tissue Model.

Dynamic changes to the skin barrier’s molecular structure and ceramide profile are well-documented in skin conditions such as atopic dermatitis and psoriasis. Pathological and environmental factors have been shown to impair barrier integrity and demonstrate shifts in ceramide composition in the skin. However, the relationship between acute and prolonged sun exposure and its effects on skin barrier homeostasis is insufficiently investigated. This study aims to uncover new scientific evidence to elucidate the relationship of UV irradiation with the skin barrier using an ex vivo tissue model following simulated UVA/UVB exposure. Fresh ex vivo human skin pretreated either with or without a broad-spectrum sunscreen was exposed to either a physiological or elevated UV condition. Following eight days in culture, structural and molecular changes were evaluated. UV irradiated skin displayed epidermal cell death and altered expression of key barrier proteins. TEM analysis demonstrated disruption to adherens junctions and dissociation between tissue layers following both physiological and extensive UV exposures. An effective broad-spectrum sunscreen containing essential skin ceramides completely protected the skin from such changes. This is one of the first works demonstrating a clear correlation of altered skin barrier integrity using a physiologically relevant dose in an ex vivo tissue model. Our findings also further support the additional importance and benefits of sun protection among the consumers. J Drugs Dermatol. 20(4 Suppl):s23-28. doi:10.36849/JDD.S589D.

The Effect of a Ceramide-Containing Product on Stratum Corneum Lipid Levels in Dry Legs.

Roughly equimolar concentrations of ceramides, cholesterol, and free fatty acids arranged in lamellar sheets form the intercellular lipid barrier in the stratum corneum (SC). Intercellular lipid deficiencies, specifically ceramides, and barrier disruption are associated with many dermatologic conditions, including dry skin. This study explored the relationship between the improvement in the signs of dry skin and the amounts of ceramides in the SC by combining clinical observations with a biochemical analysis to quantify the level of SC intercellular lipids. The efficacy of a multilamellar vesicular emulsion (MVE), ceramide-containing moisturizing cream was evaluated in a randomized, investigator-blinded, split-leg study on female subjects with dry, itchy skin. The cream increased skin hydration and demonstrated an immediate and sustained reduction in the visible signs of dry skin and subject perceived sensory discomfort. Additionally, ceramide, cholesterol and free fatty acid levels in the SC significantly increased after 4 weeks of moisturizer application. Thus, the clinical effect of the ceramide-containing moisturizing cream on dry, itchy skin was accompanied by an increase in SC intercellular lipid levels. J Drugs Dermatol. 2020;19(4):372-376. doi:10.36849/JDD.2020.4796.

The influence of cellulosic coacervate composition on the flux of an entrained agent through a coacervate/sebum barrier.

Complex coacervation is the primary mechanism used in rinse-off formulations to deliver topical agents to the skin and hair; this process produces polycation-surfactant anion coacervates that entrain the agent and enhance its substantivity at these sites. This study investigates the relationship between the transport of agents released from a coacervate vehicle into artificial sebum and the coacervate's composition and properties. The flux of a model compound, kinetin, through a variety of cellulosic coacervate/sebum composite barriers prepared on cell culture inserts was determined. These values were interpreted according to a semi-empirical model based on the composition of the coacervate, polymer properties, and the material stiffness. A multivariate analysis using composition and polymer descriptors yielded a strong correlation (r2=0.72) to the experimental kinetin transport data. Variables that describe the degree of entanglement of the surfactant-linked polymer chain web (specifically, the molar ratio of anions to cations and wt% water) emerged as important predictive variables for kinetin transport. According to the developed model, compositional or ingredient manipulations that expand and untangle the web favor a more rapid release of entrained agents from the coacervate into sebum and, consequently, higher bioavailability on the skin surface.

Evaluating the Transport Kinetics of a Model Compound Released From Cellulosic Coacervate Compositions Into Artificial Sebum.

Complex coacervates of cationic polymers and anionic surfactants, which are produced spontaneously during the use of rinse-off formulations, represent an important delivery vehicle for topical agents to the skin surface and appendages. In this study, an artificial sebum-loaded cell culture insert method for determining the sebum diffusion properties of topical agents was optimized for in vitro release testing. This method was subsequently used to evaluate the transport kinetics of a model compound, kinetin, released from semi-solid coacervate formulations into sebum. Coacervate compositions were prepared with cationic-hydroxyethyl cellulose dodecyl sulfate (cat-HECDS), sodium dodecyl sulfate (NaDS), and water. Tested compositions ranged from 90 to 50 wt% water and had a cat-HECDS to NaDS wt% ratio of 2:1, 1:1, or 1:2, mimicking the in vivo hydration range and relative excess surfactant content expected from commercial rinse-off formulations. Steady-state flux of the model compound from each coacervate composition was found to vary with water content of the composition. When flux was plotted versus [(cat-HECDS:NaDS) × (1 - weight fraction water)]-1, a strong linear correlation (R2 = 0.89) emerged. The in vitro release testing method proved capable of discriminating between clinically relevant differences in transport kinetics from different coacervate formulations using a practical sample size.