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Fatty acids are characterised by a wide variety of structures and properties. Their functions and the effects of their metabolites in and on the skin are correspondingly diverse. They range from physical protection to local hormonal effects. In addition to the biochemistry of the fatty acids in the epidermis, synergistic influences of the skin microbiome play a major role in physiologically intact skin. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Objective Methods Results Conclusion Skin is continuously exposed to environmental external and internal factors, including psychological stress (PS). PS has been reported to trigger different dermatoses such as psoriasis, atopic dermatitis, vitiligo, alopecia areata, and acne through the release of cortisol and epinephrine.To clinically explore PS‐induced measurable skin aging signs in subjects with moderate versus mild chronic PS, and to investigate the effect of chronic PS on DNA damage at cellular level.In vitro stress tests with cortisol and epinephrine, and with cortisol only on extracellular matrix (ECM) synthesis, as well as on normal human skin fibroblast and keratinocyte functioning, including skin barrier and wound healing were performed.Moderately stressed subjects in the context of the clinical study had a significantly decreased antioxidant potential and impacted skin barrier integrity, as well as significantly increased signs of microrelief alterations (skin texture and fine lines) reaching an increased severity of about 32.9%. At a cellular level, DNA integrity, ECM synthesis, wound healing, and skin barrier parameters were impacted by increased stress hormone levels.The clinical exploratory studies presented herewith, as well as the study of cell functioning under stress, have provided evidence that chronic PS significantly affects skin homeostasis and triggers skin aging. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aim Patients/Methods Results Conclusions Changes in the level or profile of ceramides are associated with decreased stratum corneum (SC) barrier function. Topical application of a pseudo‐ceramide (pCer)‐containing moisturizer can improve barrier function. Additionally, pCer that absorbs into the SC may improve ceramide profiles.We investigated the relationship between pCer absorption into the SC and SC properties and determined the efficacy of a pCer‐containing spray compared with that of a commercial spray without pCer.Patients with self‐perceived dry and sensitive skin and decreased barrier function (transepidermal water loss [TEWL] > 10 g/m2h) were randomized into two groups to topically apply a pCer‐containing spray (test group; N = 33) or commercial spray without pCer (control group; N = 19) twice daily as a single‐blind study. SC function and ceramide properties were investigated before and after 4 weeks of application.In the test group, the ceramide (NP)/(NS) ratio proportionally increased with the pCer application level after 4 weeks of pCer‐containing spray application. In the control group, there were no changes in SC function after topical application of the commercially available spray without pCer; however, the SC water content, TEWL, SC cell area, and scaling score improved in the test group. Furthermore, the changes in TEWL in the test group were significantly negatively correlated with the pCer application level.The efficacy of pCer‐containing sprays for those who have sensitive skin with impaired barrier function was demonstrated. Furthermore, the improvement in SC barrier function induced by pCer may contribute to normalizing the SC ceramide profile. [ABSTRACT FROM AUTHOR]

The current incidence of chronic kidney disease‐associated pruritus (CKD‐aP) in patients with end‐stage renal disease (ESRD) is approximately 70%, especially in those receiving dialysis, which negatively affects their work and private lives. The CKD‐aP pathogenesis remains unclear, but uremic toxin accumulation, histamine release, and opioid imbalance have been suggested to lead to CKD‐aP. Current therapeutic approaches, such as opioid receptor modulators, antihistamines, and ultraviolet B irradiation, are associated with some limitations and adverse effects. The skin barrier is the first defense in preventing external injury to the body. Patients with chronic kidney disease often experience itch due to the damaged skin barrier and reduced secretion of sweat and secretion from sebaceous glands. Surprisingly, skin barrier‐repairing agents repair the skin barrier and inhibit the release of inflammatory cytokines, maintain skin immunity, and ameliorate the micro‐inflammatory status of afferent nerve fibers. Here, we summarize the epidemiology, pathogenesis, and treatment status of CKD‐aP and explore the possibility of skin barrier repair in CKD‐aP treatment. [ABSTRACT FROM AUTHOR]

Atopic dermatitis is a common allergic skin disease characterized by eczema, dryness, and severe itching, which has a significant impact on patients' quality of life. Its pathogenesis involves immune dysregulation and impaired skin barrier function. In this study, the therapeutic potential of Ampelopsis brevipedunculata (Maxim.) Trautv for alleviating atopic dermatitis symptoms was investigated using the NC/Nga mouse model. A. brevipedunculata (Maxim.) Trautv was effective in attenuating the atopic dermatitis-like epidermal thickening and the immune cell infiltration in the skin lesions induced by the atopic dermatitis ointment. Additionally, A. brevipedunculata (Maxim.) Trautv suppressed the production of inflammatory mediators and chemokines associated with atopic dermatitis progression. In addition, A. brevipedunculata (Maxim.) Trautv exhibited restorative effects on skin barrier dysfunction by increasing the expression of key barrier proteins. Mechanistically, A. brevipedunculata (Maxim.) Trautv modulated the mitogen-activated protein kinase pathway and inhibited nuclear factor-kappa B activation. These findings highlight the potential of A. brevipedunculata (Maxim.) Trautv as a promising therapeutic agent for treating atopic dermatitis and provide insight into its mechanisms of action. [ABSTRACT FROM AUTHOR]

Background: Spironolactone (SPL) is an effective treatment for women acne, but other effects on skin biophysical properties remain to be investigated. Objective s : The aim of the current study was to explore the effects of oral SPL used to treat women acne on skin biophysical properties, including hydration, transepidermal water loss (TEWL), skin surface lipid (SSL) levels, mechanical properties, color, pH, and pore size. Materials and Methods: Twenty‐five Thai women with acne treated with oral SPL were followed for 6 months. Skin hydration, TEWL, SSL levels, mechanical properties, color, pH, and pore size of the forehead, chest, and inner arm were evaluated at baseline and 2, 4, and 6 months after treatment with oral SPL. Facial and upper back pore size were also assessed. Clinical outcomes were changes in these skin biophysical properties at each visit compared with baseline. Results: Skin hydration, TEWL, SSL levels, color, pH, and pore size remained stable throughout the study. Facial skin parameters at 6 months demonstrated the following changes: hydration levels, 7.60 (95% confidence interval [CI], −59.74 to 74.94); TEWL, −2.36 (95% CI, −5.77 to 1.06); L* value, 0.51 (95% CI, −0.70 to 1.72); individual typology angle, 1.65 (95% CI −2.27 to 5.57); pH, 0.01 (95% CI −0.43 to 0.46); pore size, −0.24 (95% CI, −1.21 to 0.73); and SSL levels, 7.60 (95% CI −59.74 to 74.94). Improvement of facial mechanical properties was observed. R0 (indicating skin tightness) and R1 (indicating elasticity) showed significant decreases (−0.076 [95% CI, −0.141 to −0.010] and −0.016 [95% CI, −0.033 to −0.001]). R3 and R4 (representing tiring effects) were also improved (−0.091 [95% CI, −0.158 to −0.025] and −0.022 [95% CI, −0.044 to −0.001]). Parameters in the truncal and inner arm areas remained stable, except for skin elasticity and tiring effects, which exhibited a similar trend of improvement as the facial area. The changes were notable as early as 4 months. Conclusion: Oral SPL used for acne did not impair the skin barrier. Moreover, the skin mechanical properties were improved at 4 to 6 months. [ABSTRACT FROM AUTHOR]

Mask-wearing behavior, common in the post-COVID-19 era, raises concerns for sensitive skin. This split-face study investigated mask-related changes in skin barrier function and microbiome composition among 30 female volunteers with sensitive skin and assessed the mitigating effects of a moisturizer containing biological lipids and probiotics. Skin physiological indicators (transepidermal water loss, erythema index, stratum corneum hydration, pH, temperature) of masked and unmasked areas were collected at baseline, after three hours of mask-wearing, post-tape stripping, and after 24 h, respectively. Microbiome samples collected from the masked areas before and after wearing a medical mask were analyzed with bioinformatics methods. Mask-wearing significantly weakened barrier function in both masked and adjacent unmasked areas, while reducing bacterial diversity. It was also associated with an increase in Cutibacterium (P = 0.110) and decreases in Streptococcus (P = 0.032) and Prevotella (P = 0.026) abundance. Moisturizer application prior to mask-wearing significantly reduced transepidermal water loss and erythema (both P < 0.001) and further improved erythema after 24 h (P = 0.048). These findings demonstrate that mask-wearing can disrupt the skin barrier and microbiome in individuals with sensitive skin and applying a moisturizer beforehand can mitigate mask-related discomforts by aiding barrier repair and reducing sensitivity. [ABSTRACT FROM AUTHOR]

The epidermis of the skin and skin appendages, such as nails, hair and sebaceous glands, depend on a balance of cell proliferation and terminal differentiation in order to fulfill their functions at the interface of the body and the environment. The differentiation of epithelial cells of the skin, commonly referred to as keratinocytes, involves major remodeling processes that generate metabolically inactive cell remnants serving as building blocks of the epidermal stratum corneum, nail plates and hair shafts. Only sebaceous gland differentiation results in cell disintegration and holocrine secretion. A series of studies performed in the past decade have revealed that the lysosome-dependent intracellular degradation mechanism of autophagy is active during keratinocyte differentiation, and the blockade of autophagy significantly alters the properties of the differentiation products. Here, we present a model for the autophagy-mediated degradation of organelles and cytosolic proteins as an important contributor to cellular remodeling in keratinocyte differentiation. The roles of autophagy are discussed in comparison to alternative intracellular degradation mechanisms and in the context of programmed cell death as an integral end point of epithelial differentiation. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aims Methods Results Conclusions Rosacea is a chronic inflammatory skin disease characterized by flushing, erythema, papules, and pustules on the central face. It affects patient appearance and is noted for its chronicity, recurrence, and resistance to treatment. Effective rosacea treatment requires repairing the skin barrier, reducing inflammation, and promoting vasoconstriction.This study aims to evaluate the efficacy of topical ferulic acid in treating papulopustular rosacea and its impact on skin barrier function.Sixty patients with mild to moderate papulopustular rosacea were selected from the Department of Dermatology at the Affiliated Hospital of Shandong Second Medical University between January 2023 and December 2023. Patients were randomly assigned to either a control group or an observation group, with 30 patients in each group. The observation group applied ferulic acid solution to the affected areas, while the control group used normal saline, both twice daily for 6 weeks. Both groups also received 0.1 g doxycycline hydrochloride tablets orally once daily. Skin lesions and skin barrier function were assessed using VISIA imaging and self‐rating scales before and during treatment, and adverse reactions were recorded.After 6 weeks, both skin lesion assessments and self‐assessment scores improved significantly from baseline, with greater improvement in the observation group compared to the control group (p < 0.05). Indicators of skin barrier function and VISIA imaging results demonstrated the efficacy of ferulic acid in treating rosacea. The total effective rate was significantly higher in the observation group (80.00%) compared to the control group (63.33%) (p < 0.05). In the observation group, nine patients (30.00%) experienced a greasy sensation initially, one patient (3.33%) reported tingling and itching, and no serious adverse reactions were observed.Ferulic acid is effective as an adjuvant treatment for papulopustular rosacea, significantly improving skin lesions and repairing skin barrier function with minimal adverse reactions. [ABSTRACT FROM AUTHOR]

The epidermis, the most superficial layer of the human skin, serves a critical barrier function, protecting the body from external pathogens and allergens. Dysregulation of epidermal differentiation contributes to barrier dysfunction and has been implicated in the pathology of various dermatological diseases, including atopic dermatitis (AD). Mucopolysaccharide polysulphate (MPS) is a moisturising agent used to treat xerosis in patients with AD. However, its mechanism of action on keratinocytes, the main constituents of the epidermis, remains unclear. In this study, we investigated the effect of MPS on keratinocytes by subjecting adult human epidermal and three‐dimensional cultured keratinocytes to MPS treatment, followed by transcriptome analysis. The analysis revealed that MPS treatment enhances keratinocyte differentiation and suppresses proliferation. We focused on amphiregulin (AREG), a membrane protein that belongs to the epidermal growth factor (EGF) family and possesses a heparin‐binding domain, as a significant target among the genes altered by MPS. MPS exerted an inhibitory effect directly on AREG, rather than on EGF receptors or other members of the EGF family. Furthermore, AREG leads to a reduction in epidermal barrier function, whereas MPS contributes to barrier enhancement via AREG inhibition. Collectively, these findings suggest that MPS modulates barrier function through AREG inhibition, offering insights into potential therapeutic strategies for skin barrier restoration. [ABSTRACT FROM AUTHOR]

Psoriasis is an inflammatory skin disease associated with an impaired skin barrier. The skin barrier function is dependent on the extracellular lipid matrix which surrounds the corneocytes in the stratum corneum. Ceramides comprise essential components of this matrix. Alterations in the stratum corneum ceramide profile have been directly linked to barrier dysfunction and might be an underlying factor of the barrier impairment in psoriasis. In this study, we investigated the ceramide profile and barrier function in psoriasis. Lesional and non‐lesional skin of 26 patients and 10 healthy controls were analysed using in‐depth ceramide lipidomics by liquid chromatography‐mass spectrometry. Barrier function was assessed by measuring transepidermal water loss. Lesional skin showed a significant decrease in the abundance of total ceramides with significant alterations in the ceramide subclass composition compared to control and non‐lesional skin. Additionally, the percentage of monounsaturated ceramides was significantly increased, and the average ceramide chain length significantly decreased in lesional skin. Altogether, this resulted in a markedly different profile compared to controls for lesional skin, but not for non‐lesional skin. Importantly, the reduced barrier function in lesional psoriasis correlated to alterations in the ceramide profile, highlighting their interdependence. By assessing the parameters 2 weeks apart, we are able to highlight the reproducibility of these findings, which further affirms this connection. To conclude, we show that changes in the ceramide profile and barrier impairment are observed in, and limited to, lesional psoriatic skin. Their direct correlation provides a further mechanistic basis for the concomitantly observed impairment of barrier dysfunction. [ABSTRACT FROM AUTHOR]

Background: Patients with burn scars require effective treatments able to alleviate dry skin and persistent itching. Ion pairing has been employed in cosmetic formulations to enhance solubility in solvents and improve skin permeability. To evaluate the efficacy and safety of the cosmetic formula "RE:pair (arginine–glutamate ion pair)", we analyzed scar size, itching and pain, skin barrier function, scar scale evaluation, and satisfaction in our study participants. Methods: A total of 10 patients were recruited, and the formula was used twice a day for up to 4 weeks. Results: Itching was significantly alleviated after 4 weeks of treatment (95% CI = −0.11–1.71) compared to before application (95% CI = 2.11–4.68). Transepidermal water loss (TEWL) showed an 11% improvement after 4 weeks (95% CI = 3.43–8.83) compared to before application (95% CI = 3.93–9.88), and skin coreneum hydration (SCH) showed a significant 41% improvement after 4 weeks (95% CI = 43.01–62.38) compared to before application (95% CI = 20.94–40.65). Conclusions: Based on the confirmation that RE:pair improves skin barrier function and relieves itching, it is likely to be used as a topical treatment for burn scars pending evaluation in follow-up studies (IRB no. HG2023-016). [ABSTRACT FROM AUTHOR]

Fractional CO2 laser has a wide range of clinical applications and remarkable therapeutic effects in the field of skin laser aesthetics, and is often synergized with other treatments or assisted by drug delivery to further strengthen the therapeutic effects. However, it should not be ignored that fractional CO2 laser treatment is also accompanied by damage to the skin barrier structure and function, often manifested as erythema, edema, dry skin and post-inflammatory hyperpigmentation and other adverse reactions. Therefore, clinicians need to pay great attention to post-procedure skin barrier repair of fractional CO2 laser. For different skin problems, clinicians need to individually adjust the treatment parameters of fractional laser and combine the latest research results, such as peptides, polysaccharides, PRP and low-dose laser technology, in order to formulate a more perfect skin barrier repair program. [ABSTRACT FROM AUTHOR]

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease whose incidence is increasing. Skin barrier dysfunction plays an important role in this disease. It has been observed that AD patients have higher transepidermal water loss (TEWL) and lower stratum corneum hydration (SCH); however, there is little information about skin microtopography in this pathology. The objective of this study is to evaluate skin barrier dysfunction and structural changes in patients with AD. Methods: A cross-sectional study was conducted including patients with AD. Parameters of skin barrier function were measured (TEWL, temperature, erythema, pH, skin hydration, elasticity) and also other topographical parameters (scaliness, wrinkles, smoothness, surface, contrast, variance) in both healthy skin and flexural eczematous lesions. Results: A total of 32 patients with AD were included in the study. Flexural eczematous lesions had higher erythema (369.12 arbitrary unit (AU) vs. 223.89 AU, p < 0.001), higher TEWL (27.24 g/h/m2 vs. 13.51 g/h/m2, p < 0.001), lower SCH (20.3 AU vs. 31.88 AU, p < 0.001) and lower elasticity (0.56% vs. 0.65%, p = 0.05). Regarding topographic parameters, flexural eczematous lesions presented greater scaliness (5.57 SEsc vs. 0.29 SEsc, p = 0.02), greater smoothness (316.98 SEsm vs. 220.95 SEsm p < 0.001), more wrinkles (73.33 SEw vs. 62.15 SEw p = 0.03), greater surface area (836.14% vs. 696.31%. p < 0.001), greater contrast (2.02 AU vs. 1.31 AU p = 0.01), greater variance (6.22 AU vs. 4.96 AU p < 0.001) and a lower number of cells (105.5 vs. 132.5 p < 0.001) compared to unaffected healthy skin, reflecting a decrease in skin quality in AD patients. Conclusions: Both skin barrier function and skin topography are damaged in patients with AD, with differences between healthy skin and flexural eczema. [ABSTRACT FROM AUTHOR]

Objective: To investigate the efficacy and safety of a repairing mask as an adjunctive treatment for skin barrier maintenance of mild to moderate rosacea. Methods: Patients with rosacea were recruited in this dual center randomized controlled trial from November 2019 to December 2021. A total of 64 patients were included and randomized into two groups at a ratio of 3:1 into a mask group (n = 47) and a control group (n = 17). Patients in the mask group received treatment with Dr. Yu Centella asiatica repairing facial mask three times weekly for a duration of 6 weeks. All participants were instructed to continue their regimen of 50 mg oral minocycline twice daily and to apply Dr. Yu Intensive Hydrating Soft Cream twice daily. The primary endpoint of this study was the Investigator Global Assessment (IGA) score. Results: A total of 54 patients completed this trial, with 41 in the mask group and 13 in the control group. After using this facial mask for 3 and 6 weeks, the IGA, facial skin dryness, facial flushing, and severity of skin lesion in the mask group showed significantly improvement (p < 0.05). Moreover, the change in the delta degree of skin flushing was significantly higher than that in the control group (p = 0.037). Throughout the study, no adverse events were reported in either group of participants. Conclusion: The Dr. Yu Centella asiatica repairing facial mask, as an adjunctive treatment of rosacea, appears to effectively repair and protect the skin barrier, alleviate cutaneous symptoms of rosacea, and is both efficacious and safe for patient use. [ABSTRACT FROM AUTHOR]

Surfactin is a natural surfactant almost exclusively produced by Bacillus species with excellent physical‐chemical, and biological properties. Among innovative applications, surfactin has been recently used as an ingredient in formulations. The antibacterial and anti‐acne activities, as well as the anti‐wrinkle, moisturizing, and cleansing features, are some of the reasons this lipopeptide is used in cosmetics. Considering the importance of biosurfactants in the world economy and sustainability, their potential properties for cosmetic and dermatological products, and the importance of patents for technological advancement in a circular bioeconomy system, the present study aims to review all patents involving surfactin as an ingredient in cosmetic formulas. This review was conducted through Espacenet, wherein patents containing the terms "cosmetic" and "surfactin" in their titles, abstracts, or claims were examined. Those patents that detailed a specific surfactin dosage within their formulations were selected for analysis. All patents, irrespective of their publication date, from October 1989 to December 2022, were considered. Additionally, a comprehensive search was performed in the MEDLINE and EMBASE databases, spanning from their inception until the year 2023. This complementary search aimed to enrich the understanding derived from patents, with a specific emphasis on surfactin, encompassing its associated advantages, efficacy, mechanisms of action on the skin, as well as aspects related to sustainability and its merits in cosmetic formulations. From the 105 patents analysed, 75% belong to Japan (54), China (14), and Korea (9). Most of them were submitted by Asian companies such as Showa Denko (15), Kaneka (11) and Kao Corporation (5). The formulations described are mainly emulsions, skincare, cleansing, and haircare, and the surfactin dose does not exceed 5%. Surfactin appears in different types of formulas worldwide and has a high tendency to be used. Surfactin and other biosurfactants are a promising alternative to chemical ingredients in cosmetic formulations, guaranteeing skin health benefits and minimizing the impact on the environment. [ABSTRACT FROM AUTHOR]

Objective: The structure of elastic fibres changes with ageing. Elastin microfibril interface–located protein 1 (EMILIN‐1) is known to contribute to structural changes in elastic fibres. EMILIN‐1 is one of the components of elastic fibres and also colocalizes with oxytalan fibres near the epidermis. Therefore, EMILIN‐1 may be affected by epidermal–dermal interactions. The purpose of this study is to identify the key factors involved in epidermal–dermal interactions during the structural degeneration of elastic fibres. Methods: Keratinocytes and fibroblasts were co‐cultured, and changes in elastic fibre‐related proteins were evaluated. Additionally, cytokine arrays were used to identify the factors involved in epidermal–dermal interactions. Results: EMILIN‐1 expression in fibroblasts was increased in the presence of keratinocytes, and its expression decreased when keratinocytes were stressed. Amphiregulin (AREG) and interleukin‐1α (IL‐1α) were identified as the keratinocyte‐derived cytokines that influence the production of EMILIN‐1, which is secreted by the fibroblasts. EMILIN‐1 expression was promoted by AREG and decreased by IL‐1α via an increase in cathepsin K (a catabolic enzyme). AREG and IL‐1α were associated with changes in EMILIN‐1 levels in fibroblasts. Conclusion: The findings suggest that the suppression of IL‐1α expression and promotion of AREG expression in the epidermis could be a new approach that prevents the wrinkles and sagging caused by the structural changes in elastic fibres. [ABSTRACT FROM AUTHOR]

Background: Skin type has a strong influence on how sensitive skin develops, with oily skin accounting for a larger proportion of sensitive skin. However, there has not been a scientifically sound questionnaire for determining oily sensitive (OS)‐type skin in prior studies. Objectives: In order to identify OS‐type skin in the general population, we therefore intend to create an OS‐type skin evaluation questionnaire, develop various thresholds through data analysis and classify skin based on two dimensions of sensitivity and oiliness. Methods: A questionnaire with questions regarding subjects' basic information, skin oiliness and skin sensitivity was given to each individual who participated in the study (n = 1297). To define the thresholds for OS‐type skin, receiver‐operating characteristic (ROC) curves were generated. The results of the lactic acid stinging test (LAST) and noninvasive instrument information obtained were compared with the thresholds mentioned above to verify the effectiveness of this tool. Results: According to the ROC curves, questionnaire cut‐off values of 11.5, 20.5 and 29.5 can be used to detect mildly, moderately and severely sensitive skin, respectively. In addition, the questionnaire cut‐off values of 22.5 and 31.5 can be used to detect moderately and severely oily skin, respectively. According to our study, the four sensitive‐skin groups' LAST scores differed significantly from one another, while the skin sebum levels differed significantly between the three oily groups. Additionally, the EI and LAST scores were significantly correlated with skin sensitivity levels, whereas sebum, moisture and EI were positively correlated with skin oiliness levels. Conclusions: We developed an OS‐type skin evaluation questionnaire that has been tested and shown scientifically to be a promising method for evaluating OS‐type skin and to completely examine the traits of sensitive and oily skin. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion Environmental factors are important in the generation or aggravation of sensitive skin syndrome (SSS). Creams can be useful for patients with SSS, particularly when triggering factors cannot be avoided. Several clinical studies have investigated the safety and efficacy of specific creams in patients with SSS, but the majority were assessed with a single type of triggering factor and were non‐comparative. Therefore, this study's aim was to investigate, the benefit of a specific dermo‐cosmetic product in response to physical and chemical factors in subjects with SSS.Three clinical studies were performed on subjects presenting SSS. The physical impact was assessed in a stripping test, and in a randomized intra‐individual study with a newly developed heat–cold stress model. To assess chemical factors, a capsaicin test on the nasolabial fold was performed.The product significantly reduced the increase in skin microcirculation caused by stripping after 30 min versus. The untreated condition (45.8% vs. 62.0%; p < 0.01). Immediately and at D28, the product induced a significant increase in skin hydration even after a heat–cold stress, while the overall score of unpleasant symptoms significantly decreased compared with the control (8.1 vs. 10.7 and 3.7 vs. 8.0, respectively; p < 0.01). Regarding chemical factors, a significant difference in the sensation intensity (p < 0.001) was observed after capsaicin stress, also in terms of the sensation duration due to the product application versus the control (192 s vs. 403 s; p < 0.001).These studies show that topical application of a dermo‐cosmetic product can prevent unpleasant symptoms and improve the skin state in SSS exposed to physical and chemical triggering factors. [ABSTRACT FROM AUTHOR]

Protease-activated receptor-2 (PAR2) is a class-A G protein-coupled receptor (GPCR) activated by serine proteases and is expressed by multiple tissues, including the skin. PAR2 is involved in the skin inflammatory response, promoting Th2 inflammation, delaying skin barrier repair, and affecting the differentiation of keratinocytes. It also participates in the transmission of itch and pain sensations in the skin. Increasing evidence indicates that PAR2 plays an important role in the pathogenesis of inflammatory skin diseases such as acne vulgaris, rosacea, psoriasis, and atopic dermatitis. Additional focus will be placed on potential targeted therapies based on PAR2. The Goal of this review is to outline the emerging effects of PAR2 activation in inflammatory skin disease and highlight the promise of PAR2 modulators. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion Basic therapy is an integral part of the treatment of chronic skin diseases. However, the formulation of skin products should be analysed with respect to the physical stability and tolerance by the patients before applying them to diseased skin. In particular, the suitability of the formulation for use on damaged skin should be taken into consideration so that no exacerbation of the condition is caused.The following approach investigated two formulations with the emulsifier sorbitan monostearate and one with the addition of polyethylene glycol 100 stearyl ether. The characterization included rheology, macroscopic and microscopic cream analysis compared to marketed products for basic therapy. Pyranine staining of stratum corneum (SC) and trans‐epidermal water loss (TEWL) measurements were performed with ex vivo porcine SC to asses skin barrier function.The rheological characterization showed a gel‐like, viscoelastic behaviour of the formulations and a viscosity in the same order of magnitude as the marketed products. Staining with pyranine revealed that skin damage caused by sodium lauryl sulfate was compensated by treatment with the developed formulations. Following the same trend, TEWL results clearly showed decreasing values, which evidence improved skin barrier function.In conclusion, the developed sorbitan monostearate formulations can potentially improve deficient skin barrier function as a part of basic therapy of skin diseases and act as a superior alternative to market products comprising a minimum of well‐chosen ingredients. [ABSTRACT FROM AUTHOR]

Reconstructed epidermal equivalents (REEs) consist of two distinct cell layers – the stratum corneum (SC) and the keratinocyte layer (KL). The interplay of these layers is particularly crucial in pruritic inflammatory disorders, like psoriasis, where a defective SC barrier is associated with immune dysregulation. However, independent evaluation of the skin barrier function of the SC and KL in REEs is highly challenging because of the lack of quantitative methodologies that do not disrupt the counter layer. Here, a non‐invasive impedance spectroscopy technique is introduced for dissecting the distinct contributions of the SC and KL to overall skin barrier function without disrupting the structure. These findings, inferred from the impedance spectra, highlight the individual barrier resistances and maturation levels of each layer. Using an equivalent circuit model, a correlation between impedance parameters and specific skin layers, offering insights beyond traditional impedance methods that address full‐thickness skin only is established. This approach successfully detects subtle changes, such as increased paracellular permeability due to mild irritants and the characterization of an immature SC in psoriatic models. This research has significant implications, paving the way for detailed mechanistic investigations and fostering the development of therapies for skin irritation and inflammatory disorders. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion Skin elasticity, which is vital for a youthful appearance, depends on the elastic fibres in the dermis. However, these fibres deteriorate with ageing, resulting in wrinkles and sagging. Changes that occur in the elastic fibres in living human skin and the relationship between elastic fibres and the state of the skin surface remain unclear. Therefore, it is necessary to verify the relationship between elastic fibres and skin elasticity. In this study, we investigated the association of the elastic fibre structure with skin elasticity and stratum corneum protein content in living human skin.Thirty‐five female volunteers aged 25–66 years were included in this study. Elastic fibres were observed using a multiphoton scanning laser biomicroscope. Skin elasticity was measured using a Cutometer, and stratum corneum proteins (Heat‐shock protein 27 [HSP27] and galectin‐7 [Gal‐7]) in tape‐stripped samples were analysed using an enzyme‐linked immunosorbent assay.Elastic fibres exhibited increased curvature and thickness with increased age, with fragmentation observed in women aged >60 years. Elastin scores, which reflect thinness and curvature, were negatively correlated with age, whereas they were positively correlated with R7 elasticity (recovery ability). In individuals aged 20–30 years, higher levels of inflammatory markers (HSP27 and Gal‐7) correlated with lower elastin scores; however, this trend was not observed in older participants.Elastic fibre deterioration worsened after 40 years of age, and this effect correlated with reduced skin recovery and increased wrinkles. In younger individuals, inflammatory markers affected elastic fibres. These findings can guide anti‐ageing strategies that focus on elastic fibre preservation and inflammation control. [ABSTRACT FROM AUTHOR]

The aim of this cross-sectional field study was to establish the condition of hand and forearm skin barrier among dentists and physicians and how it may be associated with personal and work-related factors. The study consisted of an occupational questionnaire, clinical examination of skin on hands, and transepidermal water loss (TEWL) and pH measurements on hands and forearms. The participants were divided in the following groups (N=37 each, N=148 in total): physicians, medical surgeons, dentists, and dental surgeons. We calculated the difference between hand and forearm TEWL and pH (ΔTEWL and ΔpH, respectively) and divided it by the forearm values (ΔTEWL% and ΔpH%, respectively). There was a clear trend of increasing median ΔTEWL%, starting from physicians with non-surgical specialisation (56 %) to medical surgeons (65 %), dentists (104 %), and dental surgeons (108 %), with the latter two groups showing particularly worrisome signs of work-related skin barrier impairment, since they had double the TEWL on hands than on forearms. Although less prominent, the same worsening trend was noted for skin pH, with dental surgeons having on average a 0.3 points higher skin pH on hands than on forearms. These findings were mainly associated with prolonged glove use and male sex. Our findings also suggest that comparing TEWL and pH between hands and forearms can better establish occupational skin barrier impairment on hands. [ABSTRACT FROM AUTHOR]

The skin barrier is essential for maintaining the body's internal homeostasis, protecting against harmful external substances, and regulating water and electrolyte balance. Traditional Chinese Medicine (TCM) offers notable advantages in restoring skin barrier function due to its diverse components, targets, and pathways. Recent studies have demonstrated that active ingredients in TCM can safely and effectively repair damaged skin barriers, reinstating their proper functions. This review article provides a comprehensive overview of the mechanisms underlying skin barrier damage and explores how the bioactive constituents of TCM contribute to skin barrier repair, thereby offering a theoretical framework to inform clinical practices. [ABSTRACT FROM AUTHOR]

Little is known about how sun exposure may affect the maternal skin barrier during pregnancy when many hormonal and physiological changes occur. In this longitudinal observational study, 50 pregnant women were recruited at 18–24 weeks' gestation, 25 in summer–autumn, and 25 in winter–spring. At three time points in pregnancy at 18–24, 28–30, and 36–38 weeks' gestation, participants completed a validated sun exposure questionnaire and had skin permeability and surface pH measured on the volar forearm. We identified an association between increased sun exposure and increased skin permeability at 18–24 weeks' gestation (β = 0.85, p = 0.01). Lower transepidermal water loss (decreased skin permeability), mean = 12.1 (SD = 5.1) at 28–30 weeks' gestation was observed, compared to mean = 12.6 (SD = 4.0) at 18–24 weeks' and mean = 13.7 (SD = 8.5) at 36–38 weeks' gestation (n = 27, β = −1.83, p = 0.007). Higher skin pH readings, mean = 5.80 (SD = 0.58) were found at 28–30 weeks' gestation, compared to mean = 5.25 (SD = 0.62) at 18–24 weeks' and mean = 5.47 (SD = 0.57) at 36–38 weeks' gestation (n = 27, β = 0.40, p = 0.004). These gestational fluctuations remained after adjusting for Fitzpatrick skin type, season, and sun exposure. We observed gestational fluctuations in both skin permeability and skin pH, with 28–30 weeks' gestation being a significant point of difference compared to mid‐ and late‐pregnancy periods. [ABSTRACT FROM AUTHOR]

Background: Microencapsulation of hydroxypinacolone retinoate (HPR) can improve its application in cosmetics. Objective: To investigate the safety and efficacy of Spherulites Paeony Superior Retinol, a HPR microcapsule containing 5%–10% peony seed oil, 0.01%–1% epigallocatechin gallatyl glucoside (ECGG), and 0.1%–1% HPR. Methods: The safety of Spherulites Paenoy Superior Retinol was evaluated with zebrafish embryo self‐rotation irritation test and developmental toxicity test. SymRenew™ HPR was used as a reference. The skin care efficacies of Spherulites Paenoy Superior Retinol were evaluated using zebrafish embryos covering antioxidation, anti‐inflammation, blood circulation, whitening, wound healing, skin barrier protection, Type I collagen, elastin, and 5α‐reductase genes expression activities. Results: The irritation test revealed that 250 μg/mL Spherulites Paenoy Superior Retinol did not, while 20 μg/mL SymRenew™ HPR significantly (p < 0.05) increased zebrafish embryo self‐rotation frequency. The developmental toxicity test found the teratogenicity index (half lethal concentration/half toxicity concentration) of Spherulites Paenoy Superior Retinol and SymRenew™ HPR were 1.9 and 3.1, respectively. The efficacy analysis results showed that 5 μg/mL Spherulites Paenoy Superior Retinol significantly (p < 0.05) exerted 7.1% anti‐ROS, 20% anti‐inflammation, 14% enhanced blood circulation, 10% suppressed melanin synthesis, 9% enhanced tail fin regeneration, 72% elicited skin barrier protection activity, enhanced the expression of Type I collagen genes col1a1, col1a2, and col1a2 by 34%, 51%, and 42%, respectively, and elastin gene elna by 46%, and suppressed the expression of 5α‐reductase genes srd5a1, srd5a2a, and srd5a2b by 52%, 15%, and 30%, respectively. Conclusion: This study demonstrated that Spherulites Paenoy Superior Retinol is a safe cosmetic ingredient with multi‐skin care efficacies. [ABSTRACT FROM AUTHOR]

The primary function of the skin is to form a mechanical, permeability, antimicrobial, and ultraviolet radiation barrier, which is essential for maintaining physiological homeostasis. Our previous studies demonstrated that cutaneous pigmentation could promote skin barrier function in addition to providing anti‐ultraviolet irradiation defense. The present study aimed to develop a new regimen that enhances skin barrier function by regulating skin pigmentation using low‐concentration imiquimod. Results showed that topical application of low‐concentration imiquimod effectively induced skin hyperpigmentation in the dorsal skin and external ear of mice without inducing inflammatory cell infiltration. An in vitro study also revealed that low‐concentration imiquimod did not induce any cytotoxic effects on melanoma cells but triggered excessive melanin synthesis. In coculture systems, low‐concentration imiquimod was noted to increase tyrosinase activity in a broader cellular context, revealing the potential role of neighboring cells in melanin production. The next‐generation sequencing result indicated that PKCη and Dnm3 might regulate melanin synthesis and release during imiquimod treatment. Overall, our study presents new insights into the regulation of melanin production by low‐concentration imiquimod, both in a mice model and cultured cells. Furthermore, our study highlights the potential benefits of imiquimod in promoting melanin synthesis without causing skin disruptions or inducing inflammation, validating its potential to serve as a method for enhancing skin barrier functions by regulating the epidermal melanization reaction. [ABSTRACT FROM AUTHOR]

As a natural macromolecular protein extracted from silk, silk fibroin (SF) has been widely used as biological material in recent years due to its antioxidant and photodamage reduction effects. To study the protective effect of silk fibroin against skin photodamage, the immortalized human keratinocyte line (HaCaT) was used as a model for study of UVB injury. Intracellular reactive oxygen species (ROS) and the levels of calcium ions (Ca2+) were measured by ELISA and fluorescence microscopy. The expression of transient receptor potential cation channel subfamily V member 1 (TRPV1) and the expression of Claudin-1 were detected by immunofluorescence assay. In addition, western blotting was used to analyze the expression of tight junction proteins occludin and Claudin-1. The results showed that 120 mJ/cm2 of UVB stimulation significantly reduced cell viability, while the presence of 100 μg/mL silk fibroin significantly increased cell viability. UVB stimulation could increase the level of intracellular ROS, activate TRPV1 channels, and induce the increase of intracellular Ca2+ level. Meanwhile, the levels of inflammatory cytokines interleukin- 1α (IL-1α) (P<0.01) and S100A8 (P<0.05) were also significantly increased, which caused inflammation. However, the effect of UVB on HaCaT cells with the addition of silk fibroin was significantly decreased (P<0.05). In conclusion, UVB could disrupt the structural integrity of barrier proteins, resulting in the decreased expression of the barrier proteins Claudin-1 and occludin. The addition of silk fibroin could reduce such effect and protect the tightly connected structure. Therefore, silk fibroin might have great potential to protect skin from UV-induced inflammation, barrier damage and oxidative stress damage. [ABSTRACT FROM AUTHOR]

Background: Intense pulsed light (IPL) has been widely used to improve cutaneous photoaging in recent years. Several studies began to explore the changes of skin barrier function after treatment, but the changes of skin surface lipids (SSL), especially specific lipid content and types are still unclear. Methods: A total of 25 female volunteers were included in our study, and each of them received three full-face treatments with one month apart. Before the first treatment and 1 month after the last treatment, we collected clinical photos and skin stratum corneum samples from individuals. A 5-level scale was used to evaluate the efficacy of IPL treatment, liquid chromatography-mass spectrometry (LC-MS), and Orthogonal Partial Least Squares Discrimination Analysis (OPLS-DA) were used to analyze the changes of SSL. Results: Two patients got no improvement after treatment, 6 patients had poor improvement and mild improvement was achieved in 9 patients, 5 and 3 patients reported moderate and significant improvement. The overall "effective" rate was 68 % and the "significant effective" rate was 32 %. The results showed 18 lipid subclasses and 487 lipid molecules were identified. The change of total lipid volume was not statistically significant (P = 0.088>0.05), but lipid subclass analysis showed the amount of Triglyceride (TG), Phosphatidic Acid (PA), Phosphatidylglycerol (PG) and Lysophosphatidylglycerol (LPG) were significantly increased (P < 0.05). There were 55 kinds of lipid molecules with significant difference after treatment (P < 0.05), and 51 of them belong to TG. The analysis of chain saturation of TG showed that the quantity of TG with 0, 1 and 2 unsaturated bonds increased significantly (P < 0.05). Conclusions: IPL treatment does not have a significant effect on the overall amount of lipids while the amount of TG, PA, PG, LPG were significantly increased. These lipid changes may potentially improve the skin barrier function, but more high-quality and comprehensive studies are still needed. Bullet Point: Lipidomics analysis based on LC-MS; Changes of skin surface lipid after IPL treatment; the relationships between skin surface lipid and skin barrier functions. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. [ABSTRACT FROM AUTHOR]

Abstract Mask-wearing behavior, common in the post-COVID-19 era, raises concerns for sensitive skin. This split-face study investigated mask-related changes in skin barrier function and microbiome composition among 30 female volunteers with sensitive skin and assessed the mitigating effects of a moisturizer containing biological lipids and probiotics. Skin physiological indicators (transepidermal water loss, erythema index, stratum corneum hydration, pH, temperature) of masked and unmasked areas were collected at baseline, after three hours of mask-wearing, post-tape stripping, and after 24 h, respectively. Microbiome samples collected from the masked areas before and after wearing a medical mask were analyzed with bioinformatics methods. Mask-wearing significantly weakened barrier function in both masked and adjacent unmasked areas, while reducing bacterial diversity. It was also associated with an increase in Cutibacterium (P = 0.110) and decreases in Streptococcus (P = 0.032) and Prevotella (P = 0.026) abundance. Moisturizer application prior to mask-wearing significantly reduced transepidermal water loss and erythema (both P

An equilibrium of skin microbiome is crucial for maintaining skin barrier function. However, external factors such as air pollution have the potential to disrupt this equilibrium. Hence, further investigation into the influence of air pollution on the skin microbiome emerges as a critical imperative. Healthy women matched for age from two different ambient air cities in Thailand: Bangkok, characterized by highly polluted air (HPA) (n = 33), and Songkhla, characterized by less polluted air (LPA) (n = 33) were recruited. Skin barrier physiological parameters were measured on the forehead skin. Microbiome samples were collected via the scraping and swabbing technique from the forehead skin and analyzed for microbiome profiles using amplicon sequencing. We found that the abundant microbiome at the phylum level was comparable between HPA- and LPA-exposed skin. However, microbiome diversity was decreased at genus level of fungus and species level of bacteria on HPA-exposed skin. Interestingly, some relatively higher enriched microbiome correlated with skin barrier physiological parameters. Specifically, a higher enrichment of Streptococcus parasanguinis on LPA-exposed skin correlated with both lower skin pH and higher stratum corneum (SC) hydration. Conversely, a higher enrichment of Malassezia spp. and Aureobasidum spp. on HPA-exposed skin was correlated with increased transepidermal water loss and decreased SC hydration, respectively. In conclusion, air pollution potentially affects the skin microbiome by reducing its diversity, disrupting its beneficial correlations with barrier physiology, and promoting the overgrowth of pathogenic microbiome, resulting in decreased hydration and increased pH levels. These factors could ultimately lead to skin barrier dysfunction. [ABSTRACT FROM AUTHOR]

Skin barrier dysfunction and thin epidermis are hallmarks of sensitive skin and contribute to premature aging. Avenanthramides are the primary bioactive components of colloidal oatmeal, a commonly used treatment to enhance skin barrier function. This study investigated the relationship between skin barrier function and epidermal characteristics and explored the potential of dihydroavenanthramide D (dhAvD), a synthetic avenanthramide, to improve the skin barrier. We observed a significant correlation between impaired skin barrier function and decreased epidermal thickness, suggesting that a weakened barrier contributes to increased sensitivity. Our in vitro results in HaCaT cells demonstrated that dhAvD enhances keratinocyte proliferation, migration, and tight junction protein expression, thereby strengthening the skin barrier. To mimic skin barrier dysfunction, we treated keratinocytes and full-thickness skin equivalents with IL-4 and IL-13, cytokines that are implicated in atopic dermatitis, and confirmed the downregulation of tight junction and differentiation markers. Furthermore, dhAvD treatment restored the barrier function and normalized the expression of key epidermal components, such as tight junction proteins and natural moisturizing factors, in keratinocytes treated with inflammatory cytokines. In the reconstructed human skin model, dhAvD promoted both epidermal and dermal restoration. These findings suggest that dhAvD has the potential to alleviate skin sensitivity and improve skin barrier function.

Abstract Background Atopic dermatitis (AD) is characterized by skin barrier dysfunction and immune dysregulation. Autophagy, which is important for the epidermal differentiation, is impaired in AD. The treatment with dupilumab, an interleukin (IL)‐4/IL‐13 receptor blocker, has been shown to reduce skin inflammation and restore the skin barrier. Objectives This study aimed to investigate the effect of dupilumab on the expression of key proteins involved in autophagy and lysosomal degradation. Methods We performed immunofluorescence staining and microscopic analyses of skin specimens of AD patients, taken before and under (6–10 weeks) therapy with dupilumab, to investigate the expression of autophagy‐related (ATG) 5 and ATG7 proteins, beclin‐1, microtubule‐associated protein light chain 3 (LC3B), sequestosome‐1 (p62), lysosomal proteases (cathepsins B, D and L), serine protease inhibitors (SERPINB3, SERPINB4) as well as IL‐33 and thymic stromal lymphopoietin (TSLP). Results The expression of LC3B and p62 as well as SERPINB3 and SERPINB4 was highly increased in untreated AD skin compared to non‐lesional skin and normal skin and decreased upon dupilumab therapy. In contrast, the AD‐associated increased expression of both ATG5 and ATG7 further increased under therapy. Before therapy, cathepsin D and L expression levels were significantly lower compared to normal skin, but increased following the initiation of dupilumab therapy. The increased expression of IL‐33 and TSLP in the epidermis of AD patients correlated with that of LC3B and p62. Conclusions Our study provides further evidence that autophagy is inhibited in lesional AD skin owing to lysosomal dysfunction. Upon dupilumab therapy, a restoration of dysregulated key players of autophagy is observed.

Background: Tapinarof is a nonsteroidal, topical, aryl hydrocarbon receptor agonist. Tapinarof has been shown to be efficacious and have acceptable safety profile in the treatment of atopic dermatitis (AD). Objective: We sought to evaluate the improvement effect of tapinarof on skin barrier function in patients with AD. Methods: This was an open-label, uncontrolled, single-center study. Japanese patients aged ≥20 years with AD (N = 30) were included in this study. Patients applied tapinarof cream 1% once daily to the target areas on the volar forearm for 8 weeks. The primary endpoints were changes from baseline in stratum corneum hydration (SCH) and transepidermal water loss (TEWL) at the target affected area at week 8. Results: The mean SCH value at the target affected area was 13.656 AU at baseline, 16.904 AU at week 4, and 16.423 AU at week 8. The SCH at the target affected area significantly increased from baseline to week 8, with a mean change of 2.826 AU (p = 0.0433). The mean TEWL value at the target affected area was 17.35 g/m2/hr at baseline, 10.01 g/m2/hr at week 4, and 9.52 g/m²/hr at week 8. The TEWL at the target affected area significantly decreased from baseline to week 8, with a mean change of -8.03 g/m2/hr (p < 0.0001). Clinical signs of AD at the target affected area were improved over time. No serious, severe, or treatment-related AEs were reported. Conclusion: Treatment with tapinarof led to an increase in SCH and a decrease in TEWL in patients with AD, indicating the potential improvement effect of tapinarof on skin barrier function. [ABSTRACT FROM AUTHOR]

Propolis is a natural resinous substance made by bees through mixing various plant sources. Propolis has been widely recognized as a functional food due to its diverse range of beneficial bioactivities. However, the therapeutic effects of consuming propolis against atopic dermatitis (AD) remain largely unknown. The current study aimed to investigate the potential efficacy of propolis against AD and explore the active compound as well as the direct molecular target. In HaCaT keratinocytes, propolis inhibited TNF‐α‐induced interleukin (IL)‐6 and IL‐8 secretion. It also led to a reduction in chemokines such as monocyte chemoattractant protein‐1 (MCP‐1) and macrophage‐derived chemokine (MDC), while restoring the levels of barrier proteins, filaggrin and involucrin. Propolis exhibited similar effects in AD‐like human skin, leading to the suppression of AD markers and the restoration of barrier proteins. In DNCB‐induced mice, oral administration of propolis attenuated AD symptoms, improved barrier function, and reduced scratching frequency and transepidermal water loss (TEWL). In addition, propolis reversed the mRNA levels of AD‐related markers in mouse dorsal skin. These effects were attributed to caffeic acid phenethyl ester (CAPE), the active compound identified by comparing major components of propolis. Mechanistic studies revealed that CAPE as well as propolis could directly and selectively target MKK4. Collectively, these findings demonstrate that propolis may be used as a functional food agent for the treatment of AD. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is a prevalent and chronic inflammatory skin condition characterized by a multifaceted pathophysiology that gives rise to diverse clinical manifestations. The management of AD remains challenging due to the suboptimal efficacy of existing treatment options. Nonetheless, recent progress in elucidating the underlying mechanisms of the disease has facilitated the identification of new potential therapeutic targets and promising drug candidates. In this review, we summarize the newest data, considering multiple connections between IL-22 and AD. The presence of circulating IL-22 has been found to correlate with the severity of AD and is identified as a critical factor driving the inflammatory response associated with the condition. Elevated levels of IL-22 in patients with AD are correlated with increased proliferation of keratinocytes, alterations in the skin microbiota, and impaired epidermal barrier function. Collectively, these factors contribute to the manifestation of the characteristic symptoms observed in AD. [ABSTRACT FROM AUTHOR]

The inevitable attrition of skin due to ultraviolet radiation, termed photoaging, can be partially restored by treatment with retinoid compounds. Photoaged skin in lightly pigmented individuals, clinically presents with the appearance of wrinkles, increased laxity, and hyper‐ and hypopigmentation. Underlying these visible signs of ageing are histological features such as epidermal thinning, dermal–epidermal junction flattening, solar elastosis and loss of the dermal fibrillin microfibrillar network, fibrillar collagen and glycosaminoglycans. Retinoid compounds are comprised of three main generations with the first generation (all‐trans retinoic acid, retinol, retinaldehyde and retinyl esters) primarily used for the clinical and cosmetic treatment of photoaging, with varying degrees of efficacy, tolerance and stability. All‐trans retinoic acid is considered the ‘gold standard’ for skin rejuvenation; however, it is a prescription‐only product largely confined to clinical use. Therefore, retinoid derivatives are readily incorporated into cosmeceutical formulations. The literature reported in this review suggests that retinol, retinyl esters and retinaldehyde that are used in many cosmeceutical products, are efficacious, safe and well‐tolerated. Once in the skin, retinoids utilize a complex signalling pathway that promotes remodelling of photoaged epidermis and dermis and leads to the improvement of the cutaneous signs of photoaging. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To investigate the repairing and anti‐wrinkle efficacy of the facial cream enriched with C‐xyloside, aiming at comprehensively evaluating its skin anti‐ aging effect and clarify its potential mechanism of action.The repairing efficacy was studied on 3D epidermis skin model and the antiaging efficacy was studied on ex‐vivo human skin. Two clinical studies were conducted with Chinese females. In the first study, 49 subjects aged between 30 and 50 with wrinkle concerns were recruited and instructed to apply the investigational cream containing C‐xyloside for 8 weeks. Wrinkles attributes were assessed by dermatologist. Instrumental measurements on skin hydration, trans‐epidermal water loss (TEWL), and skin elasticity were also conducted. In the second study, 30 subjects aged between 25 and 60 with self‐declared sensitive skin and facial redness were recruited and instructed to apply the cream for 4 weeks. Biomarker analysis of the stratum corneum was conducted through facial tape strips.The cream improved the histomorphology of the 3D epidermis skin model after SLS stimulation, and significantly increase the expression of LOR and FLG. On human skin, the cream improved the histopathology induced by UV, and significantly increased the protein content of COL I and COL III, collagen density and the number of Ki‐67 positive cell of skin compared with model group (n = 3, p < 0.01). The results from the first clinical study demonstrate a significant increased the skin hydration and elasticity by 21.90%, 13.08% (R2) and 12.30% (R5), respectively (n = 49, p < 0.05), and the TEWL values decreased by 33.94% (n = 49, p < 0.05), after 8 weeks application of the cream. In addition, the scores for nasolabial folds, glabellar wrinkle, underneath eye wrinkles, crow's feet wrinkle and forehead wrinkle in the volunteers exhibited a significant reduction of 34.02%, 43.34%, 50.03%, 33.64% and 55.81% respectively (n = 49, p < 0.05). The (rCE)/(fCE) ratio of volunteers based on tape stripping significant increased after using the sample cream (n = 30, p < 0.05).The cream containing C‐xyloside showed improvement of skin wrinkles and enhancement of skin barrier function. These efficacies may be attributed to the fact that the sample cream can increase the expression of skin barrier related proteins LOR and FLG, promote the maturation of cornified envelope, enhance collagen I and III protein expression and stimulate skin cell proliferation, to provide sufficient evidence supporting its antiaging efficacy of skin. [ABSTRACT FROM AUTHOR]

Introduction: The integrity of the stratum corneum (SC) is crucial for the skin's barrier function, protecting against environmental stressors and minimizing transepidermal water loss. Advances in skincare formulations have introduced multilamellar systems designed to emulate the SC's lipid composition and organization. This study hypothesizes that the application of a multilamellar cream will significantly impact the SC's lipid content and lamellar structure, thereby enhancing the epidermal barrier. Methods: A saturated phosphatidylcholine‐based multilamellar cream was applied to a cohort of adult subjects with very dry skin. Electron microscopy was utilized to analyse the micro‐morphology of the cream and its integration into the lipid‐depleted SC. Lipid analysis was conducted to quantify changes in the intercellular lipid matrix. Results: Transmission‐electron microscopy (TEM) imaging demonstrated that the multilamellar cream possesses a structured arrangement comparable to the natural SC architecture. Short‐term application revealed a time‐dependent restoration of lipid bilayers, while a 14‐day regimen showed a marked increase in lipid lamellae density and length within the SC. Lipid analysis indicated a significant increase in total lipid content, with notable enhancements in ceramide and free fatty acid levels, without altering cholesterol levels. Lipid ratio analysis further confirmed the rebalancing of the SC's lipid composition. Discussion: The multilamellar cream selectively increased specific lipids critical for barrier function, suggesting an action mechanism that aligns with the skin's natural regulatory processes. This selective augmentation indicates the potential of the formulation to not only restore but also enhance the epidermal barrier, with the maintenance of physiological lipid ratios suggesting compatibility with intrinsic repair mechanisms. Conclusion: The study confirms that a multilamellar cream can significantly improve the SC's lipid composition and structural integrity, indicating enhanced barrier function. They are pivotal for skincare professionals, dermatologists, and product developers, enriching the understanding of multilamellar creams' benefits and applications in improving epidermal barrier function. [ABSTRACT FROM AUTHOR]

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]

The stratum corneum (SC), the outermost epidermal layer, plays a pivotal role in skin barrier function. This review delves into the intricate process of protein degradation within the stratum corneum, elucidating the roles of specific enzymes, regulatory mechanisms and the consequent impact on various skin conditions. Protein degradation is a finely tuned process, orchestrated by a suite of proteolytic enzymes like kallikreins. These enzymes are responsible for the breakdown of corneodesmosomes and the orderly desquamation of corneocytes, a process essential for skin homeostasis. Another critical enzymatic process is the breakdown of proteins like filaggrin and the generation of amino acids and their derivatives, required in the physiological water‐handling properties of the SC. Regulation of these proteolytic activities is complex, involving a balance between endogenous inhibitors and other factors like pH, hydration and environmental stressors. Dysregulation of protease activity is linked to a spectrum of skin conditions, ranging from xerosis to inflammatory diseases like atopic dermatitis and psoriasis. Aberrant protein degradation can lead to compromised skin barrier function, increased tissue water loss and heightened susceptibility to infections and allergens. Understanding the factors affecting protein degradation can inform the development of targeted skincare products. Advances in biochemistry and dermatology have paved the way for the search for active ingredients designed to modulate protease activity. Such innovations may offer promising therapeutic avenues for enhancing skin barrier function and treating skin disorders. This review underscores the significance of enzymatic protein degradation in the SC and its regulatory mechanisms. It provides insights into the pathophysiology of skin diseases and outlines the potential for novel skincare interventions. By bridging the gap between fundamental research and practical applications, this article aims to inspire further investigation for better understanding of skin physiology and innovation in the realm of skincare product development. [ABSTRACT FROM AUTHOR]

Ceramides are a family of lipids constituted by a sphingoid base and a fatty acid. In the skin, they are mainly present in the stratum corneum where, with cholesterol and free fatty acids, they constitute the inter‐corneocyte lipids. With the other lipid groups, they play a key role in the formation of dense lamellar structures between adjacent corneocytes, collectively ensuring the vital efficient barrier to water evaporation and protection from foreign agents´ penetration. Changes in ceramide level and relative composition, with potential impairment of lipid arrangement, have been evidenced in different skin conditions and skin diseases. Therefore, use of suitably formulated ceramides has been proposed for topical treatment to help re‐structure damaged lipid arrangement and repair impaired skin barrier function. Nonetheless, the formulation of ceramides in products necessitates specific processes such as heating to high temperature before their introduction in the final formula. In this review on the structure, the role and the potential of ceramides for skincare, we point out the necessity of rigorous process when formulating ceramides into the final product. We demonstrate the counterproductive effects of undissolved ceramides on skin barrier repair capacity of the formulas, when assessed in different in vitro models of disrupted skin barrier. [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]

Introduction: Complexities of robotic distal gastrectomy (RDG) give reason to assess physician's surgical skill. Varying levels in surgical skill affect patient outcomes. We aim to investigate how a novel artificial intelligence (AI) model can be used to evaluate surgical skill in RDG by recognizing surgical instruments. Methods: Fifty‐five consecutive robotic surgical videos of RDG for gastric cancer were analyzed. We used Deeplab, a multi‐stage temporal convolutional network, and it trained on 1234 manually annotated images. The model was then tested on 149 annotated images for accuracy. Deep learning metrics such as Intersection over Union (IoU) and accuracy were assessed, and the comparison between experienced and non‐experienced surgeons based on usage of instruments during infrapyloric lymph node dissection was performed. Results: We annotated 540 Cadiere forceps, 898 fenestrated bipolars, 359 suction tubes, 307 Maryland bipolars, 688 harmonic scalpels, 400 staplers, and 59 large clips. The average IoU and accuracy were 0.82 ± 0.12% and 87.2 ± 11.9% respectively. Moreover, the percentage of each instrument's usage to overall infrapyloric lymphadenectomy duration predicted by AI were compared. The use of stapler and large clip were significantly shorter in the experienced group compared to the non‐experienced group. Conclusions: This study is the first to report that surgical skill can be successfully and accurately determined by an AI model for RDG. Our AI gives us a way to recognize and automatically generate instance segmentation of the surgical instruments present in this procedure. Use of this technology allows unbiased, more accessible RDG surgical skill. [ABSTRACT FROM AUTHOR]

Introduction: Stratum corneum (SC) is essential for skin barrier function, mitigating water loss and shielding against potentially harmful substances and allergens. The SC's lipid matrix, arranged in a lamellar structure, is integral to its protective role. Our study explores the restoration effects of a multilamellar cream with an acidic pH compared to a basic placebo cream on skin physiology and its interaction with the skin microbiome after stress induction via tape stripping (TS). Materials and Methods: In this double‐blind study, 14 healthy participants aged 21–58 years were assessed pre‐ and post‐tape stripping, followed by a 14 days application of a multilamellar test cream and a placebo cream with evaluations on days 7, 14 and 17 for sustained effects. Skin physiology was analysed in terms of epidermal barrier function, SC hydration and surface pH. The microbiome was analysed by 16S rRNA amplicon sequencing the 16S rRNA gene using Illumina MiSeq, with subsequent species identification. Results: Our study showed significant improvements in skin barrier repair and SC hydration with verum, particularly after 14 days of application, while both creams initially enhanced stratum corneum hydration. No significant changes in surface‐pH were detected. The skin microbiome analysis revealed that TS slightly decreased alpha diversity, a trend that verum significantly reversed, enhancing diversity beyond baseline levels after 14 days. Overall, while both creams contributed to a broader microbial phyla diversity over time, no significant changes in the abundance of specific genera or species were noted between treatments. Discussion and Conclusion: Our study delineates the efficacy of a pH‐optimized multilamellar cream in enhancing epidermal barrier recovery and SC hydration post‐sequential TS, in contrast to an unstructured basic placebo. Verum cream significantly improved skin barrier function and SC hydration at day 14, with sustained effects evident beyond the treatment period. Furthermore, the multilamellar formulation facilitated the restitution of cutaneous microbiome diversity, a key indicator of healthy skin ecology, underscoring the symbiotic relationship between barrier integrity and microbial composition. These findings underscore the importance of multilamellar emollient structures in dermatological therapeutics, with potential implications for the design of advanced skincare interventions that holistically support cutaneous resilience and homeostasis. [ABSTRACT FROM AUTHOR]

Anthony V. Rawlings has had 30+ years of experience in the general area of skin science. He has many scientific publications, and his work has been highly cited. He has made major contributions to our understanding of skin physiology, including xerosis and hydration, barrier function, desquamation, the corneocyte envelope, physical chemistry of stratum corneum lipids, photodamage and ethnic variation. He has held management positions with several companies in the US and UK, established AVR Consulting in 2002 and maintained a long‐standing relationship with colleagues at University College London. His time as the Editor in Chief of the International Journal of Cosmetic Science was pivotal in the development of the journal. He worked hard and succeeded in getting the IJCS included in the PubMed database. [ABSTRACT FROM AUTHOR]

Glucocorticoids are often used and highly effective anti-inflammatory medications, but prolonged topical application may alter the epidermis' normal structure and function, potentially resulting in a number of adverse effects. Topical glucocorticoid-induced skin inflammation is a dangerous condition that develops after topical glucocorticoid use. The patients become dependent on the medication and, even after the medication is stopped, the dermatitis symptoms recur, severely impairing their quality of life. Thus, the need to aggressively confront Topical glucocorticoid-induced skin inflammation is critical. Prior research has demonstrated that topical administration of licorice's flavonoid component liquiritin stimulates epidermal proliferation, which in turn enhances the creation of collagen and the healing of wounds. Therefore, the purpose of this work was to determine if topical use of liquiritin carbomer gel can treat glucocorticoid-induced changes in mice skin epidermal function, and the mechanisms involved. The findings demonstrated that, in the mice model of topical glucocorticoid-induced skin inflammation, liquiritin carbomer gel aided in the restoration of skin barrier function. These outcomes may have been caused by enhanced expression of the proteins Aquaporin 3, Keratin 10, and Claudin-1, as well as the restoration of epidermal hyaluronan content. In the meantime, liquiritin carbomer gel dramatically decreased the expression of TNF-α, IL-1β, IL-6, IFN-γ, and IgE in mice, according to ELISA tests. Furthermore, topical treatment of liquiritin carbomer gel boosted the expression of superoxide dismutase, catalase, and decreased malondialdehyde expression, potentially counteracting the detrimental effects of glucocorticoids on the epidermis. In summary, these findings imply that topical liquiritin carbomer gel can treat glucocorticoid-induced skin damage through various mechanisms of action. [ABSTRACT FROM AUTHOR]

Ceramides are essential lipids for skin barrier function, and various classes and species exist in the human stratum corneum (SC). To date, the relationship between skin conditions and ceramide composition in healthy individuals has remained largely unclear. In the present study, we measured six skin condition parameters (capacitance, transepidermal water loss, scaliness, roughness, multilayer exfoliation, and corneocyte cell size) for the SC of the cheeks and upper arms of 26 healthy individuals and performed correlation analyses with their SC ceramide profiles, which we measured via liquid chromatography–tandem mass spectrometry. In the cheeks, high levels and/or ratios of two free ceramide classes containing an extra hydroxyl group in the long-chain moiety and a protein-bound ceramide class containing 6-hydroxysphingosine correlated with healthy skin conditions. In contrast, the ratios of two other free ceramide classes, both containing sphingosine, and a protein-bound ceramide class containing 4,14-sphingadiene correlated with unhealthy skin conditions, as did shortening of the carbon chain of the fatty acid portion of two ceramide classes containing non-hydroxy fatty acids. Thus, our findings help to elucidate the relationship between skin conditions and ceramide composition. [ABSTRACT FROM AUTHOR]

Background: Exposure to environmental stressors like particulate matter (PM) and ultraviolet radiation (UV) induces cutaneous oxidative stress and inflammation and leads to skin barrier dysfunction and premature aging. Metals like iron or copper are abundant in PM and are known to contribute to reactive oxygen species (ROS) production. Aims: Although it has been suggested that topical antioxidants may be able to help in preventing and/or reducing outdoor skin damage, limited clinical evidence under real‐life exposure conditions have been reported. The aim of the present study was to evaluate the ability of a topical serum containing 15% ascorbic acid, 0.5% ferulic acid, and 1% tocopherol (CF Mix) to prevent oxinflammatory skin damage and premature aging induced by PM + UV in a human clinical trial. Methods: A 4‐day single‐blinded, clinical study was conducted on the back of 15 females (18–40 years old). During the 4 consecutive days, the back test zones were treated daily with or without the CF Mix, followed by with/without 2 h of PM and 5 min of UV daily exposure. Results: Application of the CF Mix prevented PM + UV‐induced skin barrier perturbation (Involucrin and Loricrin), lipid peroxidation (4HNE), inflammatory markers (COX2, NLRP1, and AhR), and MMP9 activation. In addition, CF Mix was able to prevent Type I Collagen loss. Conclusion: This is the first human study confirming multipollutant cutaneous damage and suggesting the utility of a daily antioxidant topical application to prevent pollution induced skin damage. [ABSTRACT FROM AUTHOR]