OBJECTIVE: Obesity is not only a risk factor for lifestyle-related diseases but also causes skin barrier dysfunction, which leads to a reduced quality of life due to dryness, itching, and scratching, and thus requires appropriate treatment. However, there are no studies on this issue. Therefore, this study aimed to examine whether oral intake of linseed oil is effective for skin barrier function in obesity and to confirm how the effect is demonstrated.
METHODS: TSOD mice received either sterile distilled water (Control group) or linseed oil (Omega group), containing a high level of omega-3 fatty acids, including α-linolenic acid, orally for eight weeks. Mice were then irradiated with ultraviolet B (UVB) and three days later, transepidermal water loss (TEWL), which is the primary outcome of skin barrier function, was measured and gross skin appearance was observed. Hematoxylin and eosin (HE) staining and Ki-67 immunostaining were performed on skin samples. mRNA expression levels of the inflammatory markers Tnfα, Cox2, Mcp1, and Hmox1 were measured by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). We also performed fatty acid analysis of skin and erythrocytes by gas chromatography. Statistical analysis was performed using unpaired Student\'s t-test and Pearson\'s correlation analysis.
RESULTS: Compared with the Control group, the Omega group exhibited lower TEWL values and little skin erythema. Histological analysis revealed thinner epidermis and fewer Ki-67 positive cells. Additionally, in the Omega group, mRNA levels of four inflammation-related genes were lower, α-linolenic acid levels in both skin and erythrocytes were higher, and a lower n-6/n-3 ratio was observed. And α-linolenic acid levels in the skin were negatively correlated with the expression levels of inflammation-related genes.
CONCLUSIONS: Oral intake of linseed oil was found to inhibit skin barrier dysfunction in obesity. This effect was mediated by α-linolenic acid, a major component of linseed oil with anti-inflammatory properties, which was taken up by erythrocytes and supplied to the skin. Therefore, oral intake of linseed oil is expected to be a useful therapeutic method for skin barrier dysfunction in obesity.

Skin barrier function, prevent colon cancer, head and neck cancer, and decrease liver cholesterol. However, the mechanism of action has not yet been elucidated. In this study, we propose a new working hypothesis regarding the health benefits and functions of glucosylceramide: decreased fecal hardness. This hypothesis was verified using an in vitro hardness test. The hardness of feces supplemented with glucosylceramide was significantly lower than that of the control. Based on these results, a new working hypothesis of dietary glucosylceramide was conceived: glucosylceramide passes through the small intestine, interacts with intestinal bacteria, increases the tolerance of these bacteria toward secondary bile acids, and decreases the hardness of feces, and these factors synergistically result in in vivo effects. This hypothesis forms the basis for further studies on the health benefits and functions of dietary glucosylceramides.

BACKGROUND: Rosacea is a chronic inflammatory skin condition associated with erythema, inflammation and skin sensitivity.
OBJECTIVE: To assess the benefit of a dermocosmetic cream (DC cream) containing Sphingobioma xenophaga extract and soothing agent in adult females with rosacea-associated erythema and sensitive skin.
METHODS: During phase 1, DC was applied twice daily on the randomized half-face and compared to usual-skincare (USC) for 28 days. During phase 2, DC was applied on the full face twice daily for 56 days. Clinical, instrumental and skin sensitivity assessments were performed at all visits; demodex density (standardized skin surface biopsy (SSSB) method) was performed at baseline and D28, quality of life (QoL) was assessed using the stigmatization questionnaire (SQ), Rosacea Quality of Life index (ROSAQoL) and Dermatology Life Quality Index (DLQI) at baseline and D84.
RESULTS: At D28, a significant benefit of DC over USC was observed for erythema, tightness, burning and stinging (all p ≤ 0.05), erythema measured by chromameter (p < 0.01), corneometry and transepidermal water loss (p < 0.0001 and p < 0.05, respectively), skin sensitivity (p < 0.001) and significant reduction of mean demodex density (p < 0.05) on the DC side. At D84, DC significantly (all p < 0.05) improved clinical signs and symptoms on both sides of the face compared to baseline; SQ, ROSAQoL and DLQI scores improved by 40.4%, 25.0% and 55.7%, respectively compared to baseline. Tolerance was excellent.
CONCLUSIONS: DC significantly improved erythema, skin sensitivity, demodex count, QoL and feeling of stigmatization of subjects with rosacea and is very well tolerated.

Our skin protects us from external threats including ultraviolet radiation, pathogens and chemicals, and prevents excessive trans-epidermal water loss. These varied activities are reliant on a vast array of lipids, many of which are unique to skin, and that support physical, microbiological and immunological barriers. The cutaneous physical barrier is dependent on a specific lipid matrix that surrounds terminally-differentiated keratinocytes in the stratum corneum. Sebum- and keratinocyte-derived lipids cover the skin\'s surface and support and regulate the skin microbiota. Meanwhile, lipids signal between resident and infiltrating cutaneous immune cells, driving inflammation and its resolution in response to pathogens and other threats. Lipids of particular importance include ceramides, which are crucial for stratum corneum lipid matrix formation and therefore physical barrier functionality, fatty acids, which contribute to the acidic pH of the skin surface and regulate the microbiota, as well as the stratum corneum lipid matrix, and bioactive metabolites of these fatty acids, involved in cell signalling, inflammation, and numerous other cutaneous processes. These diverse and complex lipids maintain homeostasis in healthy skin, and are implicated in many cutaneous diseases, as well as unrelated systemic conditions with skin manifestations, and processes such as ageing. Lipids also contribute to the gut-skin axis, signalling between the two barrier sites. Therefore, skin lipids provide a valuable resource for exploration of healthy cutaneous processes, local and systemic disease development and progression, and accessible biomarker discovery for systemic disease, as well as an opportunity to fully understand the relationship between the host and the skin microbiota. Investigation of skin lipids could provide diagnostic and prognostic biomarkers, and help identify new targets for interventions. Development and improvement of existing in vitro and in silico approaches to explore the cutaneous lipidome, as well as advances in skin lipidomics technologies, will facilitate ongoing progress in skin lipid research.

BACKGROUND: Spironolactone (SPL) is an effective treatment for women acne, but other effects on skin biophysical properties remain to be investigated.
OBJECTIVE: 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.
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.
CONCLUSIONS: Oral SPL used for acne did not impair the skin barrier. Moreover, the skin mechanical properties were improved at 4 to 6 months.

In the interfollicular epidermis, keratinocyte stem cells (KSC) generate a short-lived population of transit amplifying (TA) cells that undergo terminal differentiation after several cell divisions. Recently, we isolated and characterized a highly proliferative keratinocyte cell population, named \"early\" TA (ETA) cell, representing the first KSC progenitor with exclusive features. This work aims to evaluate epidermis, with a focus on KSC and ETA cells, during transition from infancy to childhood. Reconstructed human epidermis (RHE) generated from infant keratinocytes is more damaged by UV irradiation, as compared to RHE from young children. Moreover, the expression of several differentiation and barrier genes increases with age, while the expression of genes related to stemness is reduced from infancy to childhood. The proliferation rate of KSC and ETA cells is higher in cells derived from infants\' skin samples than of those derived from young children, as well as the capacity of forming colonies is more pronounced in KSC derived from infants than from young children\'s skin samples. Finally, infants-KSC show the greatest regenerative capacity in skin equivalents, while young children ETA cells express higher levels of differentiation markers, as compared to infants-ETA. KSC and ETA cells undergo substantial changes during transition from infancy to childhood. The study presents a novel insight into pediatric skin, and sheds light on the correlation between age and structural maturation of the skin.

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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.

BACKGROUND: Psychological stress alters epidermal barrier function. While intensive studies on the underlying mechanism have been performed in mice, human studies are limited. Non-invasive skin-physiology measures have not yet been directly linked to non-invasive psycho-physiological assessments.
METHODS: Standard measures of (I) transepidermal water loss prior to and after experimental barrier perturbation via tape stripping, (II) skin surface pH, (III) electrodermal activity, and (IV) heart rate function were taken over a 24 h time period. To document perceived stress, a standardized stress self-assessment questionnaire, namely the Trierer Inventar zum chronischen Stress (TICS), was utilized.
RESULTS: Twenty healthy, Caucasian (Fitzpatrick skin phototype I-II), female volunteers (21-32 years, mean age 27, SD = 3.67 years) were included in this study (random sample). Significant correlations were shown for 24 h delta transepidermal water loss changes, that is, barrier repair kinetics (sympathetic activity) and heart rate variability (parasympathetic activity). Further correlations were noted for electrodermal activity and skin surface pH. Perceived stress, as documented by the TICS questionnaire, did not correlate with psycho- and skin physiological parameters, respectively.
CONCLUSIONS: The presented approaches may provide a basis for non-invasive objective research on the correlation between psychological stressors and epidermal barrier function.

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.
CONCLUSIONS: 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.