Human sebum extract induces barrier disruption and cytokine expression in murine epidermis

Development and validation of a prospective questionnaire for assessing oily sensitive skin

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.

Oleic acid-induced interleukin-36γ: A possible link between facial skin redness and sebum

BACKGROUND

Redness of the facial skin is an important cosmetic concern. Although qualitative and quantitative modifications of sebum on the skin surface are major pathogenic factors of chronic inflammatory skin conditions, the relationship between skin redness, sebum, and mild inflammation on the cheeks of healthy subjects remains elusive.

AIMS

We aimed to explore the correlation between cheek redness and sebum and inflammatory cytokines in the stratum corneum (SC) of healthy subjects. We also examined the effects of representative sebum lipids on the gene expression of inflammatory cytokines in cultured keratinocytes.

PATIENTS/METHODS

This study included 198 healthy participants. Skin sebum was analyzed using flow injection analysis, and skin redness was assessed using a spectrophotometer. Inflammatory cytokines in tape-stripped SC were measured using enzyme-linked immunosorbent assay.

RESULTS

Cheek redness parameters positively correlated with the amount of skin sebum and the proportion of monounsaturated free fatty acids (C16:1 and C18:1) in the sebum. They also positively correlated with the interleukin (IL)-36γ/IL-37 ratio in the SC. Among the representative sebum lipids examined, oleic acid (C18:1, cis-9) dose- and time-dependently regulated the mRNA expression of IL-36γ and IL-37 in cultured keratinocytes, and this effect was attenuated by the N-methyl-D-aspartate (NMDA)-type glutamate receptor antagonist, MK801.

CONCLUSIONS

Skin surface sebum may be related to cheek redness in healthy subjects, and oleic acid-induced IL-36γ through NMDA-type glutamate receptors may be a link between them. Our study provides a possible skincare strategy for mitigating unfavorable increase in skin redness by targeting the facial skin sebum, particularly oleic acid.

Efficacy of the continuous use of a lotion with carbon dioxide on male subjects with mild acne

OBJECTIVE

Acne vulgaris is caused by dyslipidemia, dyskeratosis and/or abnormal bacterial growth. The obstruction of skin pores due to hyperkeratosis of the infundibulum contributes to the formation of comedones. Thus, normalizing keratinization of epidermal cells in skin pores might be useful to improve acne. Recently, it has been found that the transcutaneous application of carbon dioxide (CO₂ ) regulates imbalances of the desquamatory process. In this study, we evaluated the efficacy of a skin lotion containing CO₂ on mild acne.

METHODS

Twenty-four healthy Japanese males (20-29 years old) with mild acne attended this evaluation. The subjects were divided into 2 groups, one group used a skin lotion containing CO₂ and the other group used a skin lotion without CO₂ . Following facial washing, each subject topically applied the skin lotion with or without CO₂ twice a day for 4 weeks. Prior to the start of the evaluation (week 0) and following 2 and 4 weeks of treatment, acne symptoms were assessed by a dermatologist and by instrumental measurements.

RESULTS

Topical application of the skin lotion with CO₂ for 4 weeks significantly improved acne symptoms, which was recognized by the subjects. However, treatment with the skin lotion without CO₂ did not improve acne symptoms. This improvement of acne symptoms by CO₂ was not accompanied by changes in sebum levels, skin surface pH, skin capacitance, or porphyrin levels.

CONCLUSION

The transcutaneous application of a lotion with CO₂ improves acne symptoms by normalizing keratinization without affecting skin surface conditions.

Microneedle delivery of botulinum toxin type A combined with hyaluronic acid for the synergetic management of multiple sternal keloids with oily skin: A retrospective clinical investigation

BACKGROUND

For the treatment of sternal keloids, corticosteroid therapy has side effects including abnormal sebum secretion and acne. Relapse of keloids is common after corticosteroid injection in patients with oily skin. To reduce side effects and keloid recurrence, we used a combination of botulinum toxin type A (BTX-A) and hyaluronic acid (HA) as synergetic management for multiple sternal keloids in patients with oily skin.

METHODS

In total, 58 patients with multiple sternal keloids who received monthly steroid injections were retrospectively included. Thirty-two patients in the intervention group received an additional injection of BTX-A/HA on the same day as the first injection of the steroid, while the remaining 26 patients were treated as the control group. At baseline and follow-up visits, sebum production and transepidermal water loss (TEWL) were assessed as primary outcomes, and the Vancouver Scar Scale (VSS) score, keloid recurrence, visual analog scale (VAS) score, and patient satisfaction were assessed as secondary outcomes.

RESULTS

In the control group, average sebum production and TEWL were increased to 132% and 104% of baseline, respectively, at the 24-week follow-up. In the intervention group, average sebum production and TEWL reached nadir at the 8-week follow-up and then increased to 96% and 91% of baseline, respectively, at the 24-week follow-up. Sternal keloid relapse was observed in 88.5% of the patients in the control group and none of the patients in the intervention group. The total VSS score at 24 weeks was 11.04 ± 0.14 and 8.93 ± 0.26 (p < 0.001) in the control group and intervention group, respectively, and the VAS score was 75 ± 5.10 and 19.14 ± 3.80 (p < 0.001) in the control group and intervention group, respectively. Higher patient satisfaction was reported in the intervention group.

CONCLUSIONS

Microneedle delivery of BTX-A/HA decreases sebum production while improving skin barrier function. Thus, this combined therapy can relieve the side effects of corticosteroid therapy and reduce keloid recurrence.

Microbiota-Independent Spontaneous Dermatitis Associated With Increased Sebaceous Lipid Production in Tmem79-Deficient Mice

TMEM79 is a predisposing gene for atopic dermatitis (AD). Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The 1^st-phase dermatitis is unique, as it occurs independent of microbiota status, whereas the 2^nd-phase dermatitis is microbiota-dependent. In this study, we sought to identify key factors mediating the development of 1^st-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from 1^st-phase dermatitis. Longitudinal RNA-sequencing analysis revealed significant activation of fatty acid lipid-metabolism pathways in 1^st-phase dermatitis, whereas Th17-based immune response genes were highly expressed in 2^nd-phase dermatitis. Quantitative reverse transcription-polymerase chain reaction analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in 1^st-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 mono-unsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.

Questionnaire and Lactic Acid Sting Test Play Different Role on the Assessment of Sensitive Skin: A Cross-sectional Study

BACKGROUND

Questionnaires and lactic acid sting test (LAST) are two widely used methods to identify sensitive skin. However, the self-perceived sensitive skin by questionnaires was not consistent with the determination of LAST.

OBJECTIVE

The aim of the study was to measure the biophysical properties noninvasively of sensitive skin evaluated by questionnaire and LAST and to investigate their correlations with the scores of questionnaire and LAST.

METHODS

A total of 209 healthy Chinese females completed the study. Self-assessment questionnaire and LAST were both performed to identify sensitive skin. Epidermal biophysical properties, including skin hydration, transepidermal water loss (TEWL), sebum content, erythema index (EI), a* value, L* value, skin elasticity, and skin pH, were measured with noninvasive instruments.

RESULTS

The frequency of sensitive skin was 50.2% and 66.0% by questionnaire and LAST, respectively. Subjects with self-assessed sensitive skin had a slightly higher LAST positive rate. Skin hydration, sebum content, a* and EI values were significantly higher in the self-assessed sensitive skin group, while TEWL, a* and EI values increased but L* value decreased with significance in the LAST positive group. The LAST stingers among sensitive skin subjects had higher EI but not in the healthy skin subjects. In addition, questionnaire scores positively correlated with skin hydration, sebum content, a* and EI values, while a positive relationship of LAST scores with TEWL, a* and EI values was observed. The scores of questionnaire and LAST both negatively related to L* value.

CONCLUSION

Self-assessed questionnaire is associated with sensitive skin featured by oily and red face without impaired barrier function, whereas LAST is suitable to identify fragile skin barrier and enhanced blood flow on the face. Combination of both methods to diagnose sensitive skin might be more reliable.

Molecular perspective of efficiency and safety problems of chemical enhancers: bottlenecks and recent advances

Chemical penetration enhancer (CPE) is a preferred approach to improve drug permeability through the skin, due to its unique advantages of simple use and high compatibility. However, CPEs efficiency and safety problems frequently arise, which greatly restrains the further application in transdermal drug delivery systems (TDDS). To get access to the root of problems, the efficiency and safety of CPEs are reviewed especially from molecular perspectives, which include (1) the possible factors of CPEs low efficiency; (2) the possible contribution of CPEs in the evolution of safety problems such as skin irritation and allergic reaction; (3) the interactive relationship between CPEs efficiency and safety, as well as the bottlenecks of achieving their balance. More importantly, based on these, recent advances are summarized in improving efficiency or safety of CPEs, which offers a guidance of rationally selecting CPEs in future research.

Strategies to Develop a Suitable Formulation for Inflammatory Skin Disease Treatment

Skin barrier functions, environmental insults, and genetic backgrounds are intricately linked and form the basis of common inflammatory skin disorders, such as atopic dermatitis, psoriasis, and seborrheic dermatitis, which may seriously affect one’s quality of life. Topical therapy is usually the first line of management. It is believed that successful topical treatment requires pharmaceutical formulation from a sufficient dosage to exert therapeutic effects by penetrating the stratum corneum and then diffusing to the target area. However, many factors can affect this process including the physicochemical properties of the active compound, the composition of the formulation base, and the limitations and conditions of the skin barrier, especially in inflammatory skin. This article briefly reviews the available data on these issues and provides opinions on strategies to develop a suitable formulation for inflammatory skin disease treatment.

Effect of Lactic Fermentation Products on Human Epidermal Cell Differentiation, Ceramide Content, and Amino Acid Production

INTRODUCTION

Lactic fermentation products (LFPs) are thought to affect "good" bacteria in the gut. We previously reported that oral administration of LFPs has beneficial therapeutic effects in a mouse model of atopic dermatitis. However, it is unclear how LFPs affect human epidermal cell differentiation, ceramide (Cer), and amino acid production.

OBJECTIVE

The aim of this study was to determine the effects of LFPs on epidermal cell differentiation, by assessing amino acid and Cer production.

METHODS

A 3-dimensional cultured human epidermis model and normal human epidermal keratinocytes were used. Cytotoxicity tests were performed using alamar Blue. Transepidermal water loss (TEWL) was used as an index to assess barrier function. Keratin 1 (K1), keratin 5 (K5), keratin 10 (K10), involucrin (INV), calpain 1, and transglutaminase (TGase) (markers of differentiation) and profilaggrin (proFLG) and bleomycin hydrolase (amino acid synthesis-related genes) expression levels were quantified by RT-PCR. In addition, TGase protein levels were measured by Western blotting. The intercellular lipid content of the stratum corneum was measured by high-performance thin-layer chromatography. Amino acids were quantified using an amino acid analyzer. Finally, bound water content in the stratum corneum was measured by differential scanning calorimetry.

RESULTS

Cell viability did not change, but TEWL was significantly decreased in the cells treated with LFPs compared with the control cells. Treatment with LFPs significantly increased expression of the late-differentiation markers INV and TGase at the RNA level. Furthermore, TGase protein expression was significantly increased by treatment with LFPs. Treating a 3-dimensional cultured epidermis model with LFPs significantly increased the intercellular lipid content of the stratum corneum and production of the amino acid arginine (Arg). The amount of bound water in the stratum corneum was increased significantly in the LFP application group.

CONCLUSION

Treatment with LFPs promotes human epidermal cell differentiation and increases the intercellular content of the free fatty acid, Chol, Cer [NS], Cer [AS], and Cer [AP]. This may result in improved skin barrier function. The increased amount of Arg observed in keratinocytes may help improve water retention.

Serum Levels of 25-Hydroxyvitamin D in Patients with Seborrheic Dermatitis: A Case-Control Study

Several autoimmune papulosquamous skin conditions such as psoriasis, systemic lupus erythematous, and lichen planus have been associated with vitamin D deficiency or correlated with serum vitamin D level. This study was aimed at comparing the 25-hydroxyvitamin D (25(OH)D) status in patients with facial or scalp seborrheic dermatitis with healthy subjects. This case-control study included 289 patients (118 with psoriasis and 171 sex- and age-matched control subjects) from the outpatient clinic of two hospital dermatology departments in the west of Mazandaran province, Iran. All patients and control subjects were studied during one season to avoid seasonal variations in vitamin D levels. Serum mean ± standard deviation of 25(OH)D levels were significantly lower in seborrheic dermatitis patients than in control subjects (20.71 ± 8.16 vs. 23.91 ± 7.78, P = 0.007). Serum 25(OH)D levels were negatively associated with the risk of developing seborrheic dermatitis (odds ratio (OR): 0.898, 95% confidence interval (Cl): 0.840-0.960, P = 0.002). Also, vitamin D under 30 ng/ml was associated with OR: 4.22 (95% Cl: 1.077-16.534, P = 0.039) for seborrheic dermatitis. The severity of scalp disease was significantly associated with serum 25(OH)D level (P = 0.003). Cases with severe scalp scores had significantly lower serum 25(OH)D level compared to moderate OR score (P = 0.036). A similar trend was not seen in the facial disease. The 25(OH)D values are significantly lower in seborrheic dermatitis patients than in healthy subjects. Furthermore, the scalp disease severity was associated with lower serum 25(OH)D level. Our results may suggest that vitamin D may play a role in the pathogenesis of seborrheic dermatitis.

The impact of particulate matter (PM2.5) on skin barrier revealed by transcriptome analysis: Focusing on cholesterol metabolism

Accumulating evidence suggests that particulate matter (PM2.5), as a major air pollutant, imposes a certain degree of destruction and toxicity to the skin. It particularly impairs the structure and function of the epidermis. To study the impact of PM2.5 on the skin, transcriptome analysis was performed on PM2.5-exposed human primary keratinocytes. Functional annotation analysis demonstrates that PM2.5 significantly up-regulates cholesterol-metabolism-related genes. Via lipid extraction from PM2.5 treated three-dimensional epidermis tissue model (3D-ETM) and subsequent characterization via mass spectrometry, it was confirmed that PM2.5 significantly increases epidermal cholesterol levels in vitro. Conversely, the amount of squalene in 3D-ETM was significantly reduced by PM2.5. Interestingly, neither cholesterol nor squalene showed significant fluctuations in the green tea extract (GTE) treated epidermis tissue model under PM2.5 exposure. This study shows that PM2.5 may cause barrier disorders by increasing cholesterol synthesis, leading to transient accumulation of epidermal cholesterol and decrease of squalene. It was suggested that cholesterol and squalene, which are the key substances affecting skin barrier function, can be used as new biomarkers of skin damage induced by PM2.5. Moreover, it was demonstrated that GTE can reduce damage caused by PM2.5 exposure by not only anti-inflammatory and antioxidant mechanisms, but also by off-setting the disturbance to epidermal lipid homeostasis. This study demonstrates the strong potential of GTE as an active ingredient to be utilized in cosmetic products to effectively reduce the damage PM2.5 induces in skin.

Impact of Acacia bark extract tablets on the skin of healthy humans: a randomized, double-blind, placebo-controlled study

This study investigated the effects of proanthocyanidins derived from Acacia (Acacia mearnsii) bark extract in healthy Japanese adult subjects experiencing uncomfortable skin symptoms. All subjects were randomly allocated into two groups (n = 33 each) using a computerized random-number generator. The subjects received either Acacia bark extract tablets or placebo for 8 weeks. Evaluations included water content in the stratum corneum, transepidermal water loss (TEWL), Skindex-16, dermatology life quality index (DLQI), visual analog scale for desire to scratch, and blood tests. At 4 weeks, the symptom/feeling score of DLQI, subjective symptoms related to uncomfortable skin, and the desire to scratch were significantly reduced in the intervention group than in the placebo group. At 8 weeks, the intervention group exhibited significantly lower TEWL on facial skin than that in the placebo group. In conclusion, the intake of Acacia bark extract tablets reduced TEWL and improved dry and uncomfortable skin.

Mechanisms of lipid extraction from skin lipid bilayers by sebum triglycerides

Microsecond computations identify the pathways leading to the extraction of skin lipids by sebum triglycerides and the associated energetic costs.

Niacinamide and 12-hydroxystearic acid prevented benzo(a)pyrene and squalene peroxides induced hyperpigmentation in skin equivalent

Skin surface is constantly exposed to environmental and secreted stressors such as UV, air pollution and peroxidized sebum. The current study aims to use reconstructed human skin equivalents to demonstrate topical stressor-induced hyperpigmentation and evaluate bioactives' potential protective effect. Given that polycyclic aromatic hydrocarbons are representative airborne particle-bound organic compounds with known relevance to pigmentation pathways, benzo(a)pyrene was selected as surrogate environmental toxin. On the other hand, squalene monohydroperoxides are well-characterized sebum peroxidation product under UV and pollutant exposure, thus are used as another representative skin stressor. With 3-day continuous exposure, 30 pmol/cm² of benzo(a)pyrene and 3.4 nmol/cm² of squalene monohydroperoxides induced significant viability loss, inflammatory response, and approximately 10 shades of pigmentation increase in pigmented living skin equivalents. At the same time, pretreatment and co-treatment with 12-hydroxystearic acid (12-HSA, 20 μmol/L) or niacinamide (5 mmol/L) ameliorated such stressor-induced consequences. Niacinamide was particularly effective against benzo(a)pyrene damage, probably as a substrate for important NAD+ dependent detoxification pathways, while 12-HSA was potent against squalene monohydroperoxides through barrier enhancing, anti-inflammatory, and anti-oxidative mechanisms. In summary, topical stressor-induced hyperpigmentation was achieved in vitro, with known bioactives showing protective benefits.

High Staphylococcus epidermidis Colonization and Impaired Permeability Barrier in Facial Seborrheic Dermatitis

BACKGROUND

Seborrheic dermatitis (SD) is a common inflammatory skin condition. The etiology is unclear, although overgrowth of Malassezia on the skin has been suggested to cause SD. This study investigated whether colonization with Staphylococcus plays a role in facial SD, which was not well addressed previously.

METHODS

The study was conducted from September 1, 2011 to February 20, 2012 in the First Hospital of China Medical University. In the first phase, the study evaluated the level of transepidermal water loss (TEWL) and the number of colony-forming units (CFU) of Staphylococcus in defined skin areas of SD patients who were human immunodeficiency virus (HIV) seropositive (HIV [+] SD [+] group, n = 13), classical SD (HIV [-] SD [+] group, n = 24) patients, HIV seropositive-non-SD (HIV [+] SD [-] group, n = 16) patients, and healthy volunteers (HIV [-] SD [-] group, n = 16). In the second phase, we enrolled another cohort of HIV (-) SD (+) patients who applied topical fusidic acid (n = 15), tacrolimus (n = 16), or moisturizer (n = 12). Changes in the Seborrheic Dermatitis Area Severity Index (SDASI), TEWL, and Staphylococcus density were evaluated 2 weeks later. Comparisons of each index were performed using analysis of variance (ANOVA) and least significant difference method.

RESULTS

The level of TEWL was greater through lesional sites in the HIV (+) SD (+) group than that in HIV (+) SD (-) and HIV (-) SD (-) groups (95% confidence interval [CI]: 18.873-47.071, P < 0.001 and 95% CI: 28.755-55.936, P < 0.001, respectively). The number of CFU of Staphylococcus was greater in the HIV (+) SD (+) group than that in HIV (+) SD (-) and HIV (-) SD (-) groups (95% CI: 37.487-142.744, P = 0.001 and 95% CI: 54.936-156.400, P < 0.001, respectively). TEWL was significantly more improved in patients treated with tacrolimus and fusidic acid than that in those treated with moisturizers (95% CI: 7.560-38.987, P = 0.004 and 95% CI: 4.659-37.619, P = 0.011, respectively). Topical tacrolimus and fusidic acid were significantly associated with decreased SDASI as compared with moisturizer (95% CI: 0.03-0.432, P = 0.025 and 95% CI: 0.033-0.44, P = 0.024, respectively).

CONCLUSIONS

High colonization with Staphylococcus epidermidis, along with impaired skin permeability barrier function, contributes to the occurrence of SD.

Development of stratum corneum chymotrypsin-like protease activity and natural moisturizing factors from birth to 4 weeks of age compared with adults

BACKGROUND

From birth, the functional properties of the neonatal epidermal barrier mature whereby the stratum corneum (SC) hydrates and the skin surface acidifies. The identification of a thinner infant SC compared with adults suggests underdeveloped mechanisms underlying differentiation and desquamation.

OBJECTIVES

To assess the functional properties of the neonatal SC from birth, in conjunction with the quantification of superficial chymotrypsin-like protease activity [kallikrein-7 (KLK-7)] and filaggrin-derived natural moisturizing factors (NMF).

METHODS

A total of 115 neonates recruited to the Oil in Baby SkincaRE (OBSeRvE) randomized controlled trial underwent a full evaluation of the SC at birth (< 72 h old) and at 4 weeks of age (n = 39, no oil control group) using minimally invasive instrumentation and methodology. A cohort of 20 unrelated adults was recruited for comparison.

RESULTS

At birth NMF levels correlated with SC hydration (r = 0·50) and skin-surface pH (r = -0·54). From birth to 4 weeks, transepidermal water loss (TEWL), superficial KLK-7 activity and filaggrin-derived NMF significantly elevated. Impaired epidermal barrier function at birth (> 75th percentile TEWL) was accompanied by significantly elevated chymotrypsin-like protease activity and reduced levels of NMF.

CONCLUSIONS

The biophysical, biological and functional properties of the developing neonatal SC are transitional from birth to 4 weeks of age and differ significantly from adults. The presence of impaired barrier function with elevated protease activity and reduced NMF at birth suggests why certain infants are predisposed to epidermal barrier breakdown and the development of atopic dermatitis.