Validation of GPSkin Barrier® for assessing epidermal permeability barrier function and stratum corneum hydration in humans

Morphological characteristics of normal and oily skin in different phototypes

OBJECTIVE

A better understanding of the different skin types is very important as a support for the development of more specific cosmetics. In this context, the objective of this study was to evaluate the morphological characteristics of normal and oily skin in different phototypes by biophysical and skin imaging techniques.

METHODS

Seventy-seven females, aged 18-32 years, phototypes II-V, with oily or normal skin, participated in the study. Instrumental measurements in terms of skin surface sebum and hydration, transepidermal water loss, pore count, skin microrelief, and morphology characteristics of the skin were performed.

RESULTS

The phototype influenced pore count, sebaceous gland activity and skin topography, and skin oiliness showed higher sebaceous gland activity and pore count. Reflectance confocal microscopy image analysis showed deeper dermal papillae in phototype V, both in oily and normal skin, with a thinner epidermal and granulosum layer in oily skin. In addition, darker phototypes exhibited differences in furrow size and a higher prevalence of polycyclic dermal papillae.

CONCLUSION

This study highlights the importance of phototype and skin oiliness for a better understanding of skin characteristics, showing the impact of different skin phototypes on pore count, topography, and morphological characteristics of the skin. Thus, understanding how these factors influence skin can help the development of more targeted and effective cosmetics according to skin type.

Staphylococcus aureus colonizing the skin microbiota of adults with severe atopic dermatitis exhibits genomic diversity and convergence in biofilm traits

Atopic dermatitis (AD) is a chronic inflammatory skin disorder exacerbated by Staphylococcus aureus colonization. The specific factors that drive S. aureus overgrowth and persistence in AD remain poorly understood. This study analyzed skin barrier functions and microbiome diversity in lesional (LE) and non-lesional (NL) forearm sites of individuals with severe AD compared to healthy control subjects (HS). Notable differences were found in transepidermal water loss, stratum corneum hydration, and microbiome composition. Cutibacterium was more prevalent in HS, while S. aureus and S. lugdunensis were predominantly found in AD LE skin. The results highlighted that microbial balance depends on inter-species competition. Specifically, network analysis at the genus level demonstrated that overall bacterial correlations were higher in HS, indicating a more stable microbial community. Notably, network analysis at the species level revealed that S. aureus engaged in competitive interactions in NL and LE but not in HS. Whole-genome sequencing (WGS) showed considerable genetic diversity among S. aureus strains from AD. Despite this variability, the isolates exhibited convergence in key phenotypic traits such as adhesion and biofilm formation, which are crucial for microbial persistence. These common phenotypes suggest an adaptive evolution, driven by competition in the AD skin microenvironment, of S. aureus and underscoring the interplay between genetic diversity and phenotypic convergence in microbial adaptation.

Biofilm-mediated antibiotic tolerance in Staphylococcus aureus from spinal cord stimulation device-related infections

Staphylococcus aureus is a predominant cause of infections in individuals with spinal cord stimulation (SCS) devices. Biofilm formation complicates these infections, commonly requiring both surgical and antibiotic treatments. This study explored the biofilm matrix composition and antimicrobial susceptibility of planktonic and biofilm-growing S. aureus isolates from individuals with SCS-related infections. Whole-genome sequencing (WGS) examined genotypes, virulome, resistome, and the pan-genome structure. The study also analyzed biofilm matrix composition, early surface adhesion, hemolytic activity, and antibiotic-susceptibility testing. WGS revealed genetic diversity among isolates. One isolate, though oxacillin susceptible, contained the mecA gene. The median number of virulence factor genes per isolate was 58. All isolates harbored the biofilm-related icaA/D genes. When assessing phenotypic characteristics, all strains demonstrated the ability to form biofilms in vitro. The antimicrobial susceptibility profile indicated that oxacillin, rifampin, and teicoplanin showed the highest efficacy against S. aureus biofilm. Conversely, high biofilm tolerance was observed for vancomycin, trimethoprim/sulfamethoxazole, and levofloxacin. These findings suggest that S. aureus isolates are highly virulent and produce robust biofilms. In cases of suspected biofilm infections caused by S. aureus, vancomycin should not be the primary choice due to its low activity against biofilm. Instead, oxacillin, rifampin, and teicoplanin appear to be more effective options to manage SCS infections.IMPORTANCESCS devices are increasingly used to manage chronic pain, but infections associated with these devices, particularly those caused by Staphylococcus aureus, present significant clinical challenges. These infections are often complicated by biofilm formation, which protects bacteria from immune responses and antibiotic treatments, making them difficult to eradicate. Understanding the genetic diversity, virulence, and biofilm characteristics of S. aureus isolates from SCS infections is critical to improving treatment strategies. Our study highlights the need to reconsider commonly used antibiotics like vancomycin, which shows reduced activity against biofilm-growing cells. Identifying more effective alternatives, such as oxacillin, rifampin, and teicoplanin, provides valuable insight for clinicians when managing biofilm-related S. aureus infections in patients with SCS implants. This research contributes to the growing evidence that biofilm formation is crucial in treating device-related infections, emphasizing the importance of tailoring antimicrobial strategies to the biofilm phenotype.

Non-invasive assessment of skin hydration and sensation with diffuse reflectance spectroscopy

The skin is a vital organ in the human body, providing essential functions such as protection, sensation, and metabolism. Skin hydration is one of the crucial factors in maintaining normal skin function. Insufficient skin hydration can lead to dryness, shedding of the stratum corneum, a decrease in skin barrier function, and may cause skin inflammation. Therefore, maintaining or improving skin hydration is critical in promoting healthy skin. Currently, the commonly used method for measuring skin hydration is bioelectrical capacitance analysis, which is often affected by environmental humidity and can only provide limited information. To overcome these limitations, this study used diffuse reflectance spectroscopy (DRS) in the wavelength range of 400-1000 nm to quantify skin absorption and scattering modulation caused by changes in skin hydration states. The advantages of this technique include rapid measurements, non-invasiveness, a straightforward optical setup, and suitability for prolonged skin monitoring. We found that DRS-derived skin absorption coefficients had a correlation coefficient of 0.93 with the skin capacitance at various skin hydration states. In addition, our findings reveal that absorption and scattering coefficients may be useful in discerning skin hydration enhancement induced by applying soaked cotton pads or cosmeceutical facial masks, as well as evaluating skin sensation. This study verifies that the DRS method could be a convenient and effective tool for evaluating skin hydration related information.

Evaluation of adapted dermocosmetic regimens for perimenopausal and menopausal women using an artificial intelligence-based algorithm and quality of life questionnaires: An open observational study

BACKGROUND

The decline in estrogen levels from several years before (perimenopause) and during menopause has various negative effects, including skin specific issues, which often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life (QoL). The objective of this study was to evaluate the effectiveness of anti-aging dermocosmetic products designed for women during the perimenopause and menopause.

MATERIALS AND METHODS

An open study of 101 perimenopausal women (no menstruation for 4-12 months or irregular menstruation for <5 years) and 101 menopausal women (no menstruation for >12 months), not taking hormone replacement therapy, was conducted. Adapted dermocosmetic regimens, specific to each group (day cream, night cream and serum), were applied for 56 days. Assessments included automatic artificial intelligence diagnostics of eight clinical facial signs, hydration and transepidermal water loss (TEWL), and a menopause skin QoL questionnaire.

RESULTS

Mean age was 50 ± 3.9 years (range 41-57) and 59 ± 3.8 years (range 50-66) for the perimenopause and menopause groups, respectively. Significant improvements in wrinkles and vascular signs, increases in hydration, decreases in TEWL, and a positive impact on QoL were observed after 56 days of application of the respective dermocosmetic regimens for both the perimenopause and menopause groups.

CONCLUSION

The anti-aging skin care products designed specifically for perimenopausal and menopausal women increased skin hydration and improved wrinkles with a positive impact on QoL.

Development of multifunctional sunscreens: Evaluation of physico-mechanical and film-forming properties

The exposome consists of several factors such as solar radiation and pollution, which can provoke skin damage and lead to premature skin aging. Thus, the use of multifunctional sunscreens is critical in order to prevent this damage. In addition, film formation is very important to reach the expected SPF. Within this context, the objective of the present study was to develop and evaluate the in vivo SPF, sensory, physico-mechanical, and film-forming properties of sunscreens containing a biopolymer from Tara and red algae. A clinical study of the film-forming effect and of skin hydration was performed by instrumental measurements and by biophysical and skin imaging techniques. The SPF of both formulations, with or without the biopolymer, was 45.6. This result was 10.09% higher than expected. higher than expected. However, the sunscreen added to the biopolymer showed better sensory and texture properties, significantly increased skin hydration and reduced transepidermal water loss. The film-forming property was observed by the analysis of Reflectance Confocal Microscopy images 2, 4, and 6 h after formulation application, and this result was more pronounced for the sunscreen added to the biopolymer. Thus, the film-forming property of the biopolymer was important for prolonging the skin barrier function due to film formation and to obtain more effective and multifunctional sunscreens that provide longer protection.

Trend of changes in epidermal biophysical properties in the Chinese aged 1 month to 17-year old

BACKGROUND

Although it is known that epidermal biophysical properties vary with age and gender, the changes in epidermal biophysical properties over the time from baby to adolescence have not been elucidated yet. In the present study, we assessed the trend of changes in transepidermal water loss rates (TEWL), stratum corneum hydration, and skin surface pH in Chinese children.

PARTICIPANTS AND METHODS

A total of 780 boys and 610 girls, aged 1 month to 17-year old, were enrolled in this study. TEWL and stratum corneum hydration on the forearm and the shin were measured with GPSkin Barrier, whereas skin surface pH was measured with portable skin pH meter.

RESULTS

Overall, TEWL and stratum corneum hydration levels decreased, whereas skin surface pH increased in children from 1-month old to 17-year old. Significant decline in TEWL was observed on both the forearm and the shin of girls, and the shin of boys aged 13-17-year old. Similarly, marked decline in stratum corneum hydration levels started at ages of 6-12-year old. In contrast, decline in skin surface pH was observed in both girls and boys aged one to 12-month old except on the forearm of boys. Afterward, skin surface pH remained either stable or slight increase except on the shin of boys aged >12 months to 3-year old.

CONCLUSIONS

These results demonstrate that both TEWL and stratum corneum hydration levels decrease, whereas skin surface pH increases in children aged 1 month to 17-year old. The changes in these biophysical properties vary with age, gender, and body site.

Skin irritation in children undergoing orthodontic facemask therapy

Orthodontic facemasks are extraoral orthodontic appliances that influence maxillary and mandibular development in children with skeletal Class III malocclusion. While a facemask is most effective in patients before the growth spurt, skin irritation is common during the treatment. Therefore, this retrospective study aimed to investigate the prevalence and pattern of such skin changes and identify their possible associated risk factors. We included 177 patients with skeletal Class III malocclusion who underwent facemask therapy. Patient age and sex, orthodontic parameters expressing the severity of malocclusion, the presence of complaints in the temporomandibular joint (TMJ) areas, and the level of patient cooperation were evaluated. Additionally, the severity and onset time of skin reactions were further analyzed. The results indicated that 43.5% of patients developed skin changes typical of irritant contact dermatitis. Skin irritation was significantly associated with the presence of TMJ complaints and female sex. Furthermore, skin irritation was more common in younger patients. Clinicians should pay special attention to the skin areas that come into contact with the appliance during each follow-up visit to detect potential problems. Moreover, patients and their parents should be given adequate information about the possibility, prevention, and management of skin problems during facemask therapy.

Induction of autophagy improves skin and hair conditions in dogs with underlying diseases

Background

Autophagy was reported to play a crucial role in maintaining general and skin health.

Methods

The study used a synthesized autophagy inducer (AI) (Aquatide™ cospharm Inc.; Daejeon, Korea), for evaluating the effects of autophagy on skin and hair in dogs. Twenty-two dogs with poor skin and hair which were diagnosed with canine atopic dermatitis (CAD) or pituitary-dependent hyperadrenocorticism (PDH) were included. Clinical scores using Canine Atopic Dermatitis Extent and Severity Index-04 (CADESI-04), Pruritus Visual Analog Scale (PVAS) and skin barrier function using measurement of transepidermal water loss (TEWL) were evaluated and canine keratinocytes were also used in vitro investigation of pro-inflammatory cytokines after AI treatment.

Results

In the AI group, clinical scores and skin barrier function were improved at week 8 significantly compared to in the other groups. In particular, the AI significantly improved the hair surface damage at 8 weeks compared to the baseline. In vitro, the AI reduced pro-inflammatory cytokines by activating the 78-kDa glucose-regulated protein (GRP78).

Conclusion

AI improve skin barrier function and hair damage and reduce pro-inflammatory cytokines by inhibiting reactive oxygen species (ROS) production in dogs.

Compromised skin barrier induced by prolonged face mask usage during the COVID-19 pandemic and its remedy with proper moisturization

BACKGROUND

Prolonged face mask usage, a daily practice for the public due to the COVID-19 pandemic, creates high levels of humidity underneath the mask, which may cause unexpected skin concerns.

OBJECTIVE

To investigate the impact of repeated mask usage on the face by comparing skin properties inside and outside of the mask-covered areas.

METHODS

A double-blinded, randomized, split-face clinical study was conducted with 21 healthy female participants who wore face masks at least 6 h every day for 1 week, with one side of their face treated with a moisturizer three times daily. On day 8, after 5 h of wearing the mask, skin properties (sebum, hydration, and trans-epidermal water loss [TEWL]) were evaluated at 15, 60, and 120 min post-mask removal, followed by barrier disruption and recovery assessment.

RESULTS

Mask usage weakened stratum corneum (SC) on facial skin compared to uncovered areas, including reduced SC hydration (p < 0.02 at 15 min) and increased TEWL in response to tape stripping challenge (p < 0.03 after stripping). In addition, sebum production also increased after mask removal (p < 0.01 at 15 min). Notably, a daily moisturizer mitigated these effects by increasing SC hydration (p < 0.001) and improving SC resilience against barrier disruption.

CONCLUSION

Daily prolonged usage of a facial mask, essential due to the COVID-19 situation, generated a high-humidity microenvironment and led to compromised SC, which was revealed by a barrier challenge technique. Moreover, proper facial moisturization may help to maintain skin homeostasis and prevent the barrier impairment caused by repeated mask usage.

The Effect of Sunscreens on the Skin Barrier

Transepidermal water-loss (TEWL), stratum-corneum hydration (SCH), erythema, elasticity, pH and melanin, are parameters of the epidermal barrier function and skin homeostasis that objectively indicate the integrity of the skin barrier. Sunscreens are necessary to protect people from skin cancer, but could modify the skin barrier function. Nevertheless, there are not many studies on their impact on skin homeostasis. The aim of this study is to evaluate the impact of sunscreens on the epidermal-barrier function and skin homeostasis of healthy individuals. A prospective observational study was designed. TEWL, SCH, erythema, elasticity, pH and melanin were measured on the cheek and volar region of the forearm, using non-invasive methods before and after applying sunscreen. Four different sunscreens were tested, one full-body sunscreen and three facial sunscreens. The study included 51 healthy volunteers, 72.5% (37/51) women, with a mean age of 41.63 years. After full-body sunscreen application, temperature increased by 0.68 °C (p < 0.001), pH by 0.16 units (p < 0.001), and elasticity by 0.22% (p = 0.039), while melanin decreased by 10.95 AU (p < 0.001), erythema by 28.79 AU (p < 0.001) and TEWL by 0.66 g·m−2·h−1 (p = 0.019). On the cheek, facial sunscreen 1 increased temperature by 0.51 °C, TEWL 0.7 g·m−2·h−1 (p < 0.05), pH by 0.12 units (p < 0.001) and elasticity by 0.059% (p < 0.001), but decreased erythema by 19.87 AU (p < 0.05) and SCH by 5.63 AU (p < 0.001). Facial sunscreen 2 increased temperature by 0.67 °C, TEWL by 1.93 g·m−2·h−1 (p < 0.001), pH by 0.42 units (p < 0.001) and elasticity by 0.12% (p < 0.01), but decreased melanin by 15.2 AU (p = 0.000), erythema by 38.61 AU (p < 0.05) and SCH by 10.80 AU (p < 0.01). Facial sunscreen 3 increased temperature by 1.15 °C, TEWL by 2.29 g·m−2·h−1 (p < 0.001), pH by 0.46 units (p < 0.001) and elasticity by 0.15% (p < 0.01), but decreased erythema by 35.7 (p < 0.05) and SCH by 10.80 AU (p < 0.01). In conclusion, sunscreen could slightly modify the skin-barrier function. All of them decreased erythema, likely in relation to anti-inflammatory power.

Advanced thermal sensing techniques for characterizing the physical properties of skin

Measurements of the thermal properties of the skin can serve as the basis for a noninvasive, quantitative characterization of dermatological health and physiological status. Applications range from the detection of subtle spatiotemporal changes in skin temperature associated with thermoregulatory processes, to the evaluation of depth-dependent compositional properties and hydration levels, to the assessment of various features of microvascular/macrovascular blood flow. Examples of recent advances for performing such measurements include thin, skin-interfaced systems that enable continuous, real-time monitoring of the intrinsic thermal properties of the skin beyond its superficial layers, with a path to reliable, inexpensive instruments that offer potential for widespread use as diagnostic tools in clinical settings or in the home. This paper reviews the foundational aspects of the latest thermal sensing techniques with applicability to the skin, summarizes the various devices that exploit these concepts, and provides an overview of specific areas of application in the context of skin health. A concluding section presents an outlook on the challenges and prospects for research in this field.

The Impact of Kefir on Epidermal Water Homeostasis in Healthy Human Skin

Kefir, a symbiotic consortium of diverse bacteria and yeasts, is one of the most popular probiotic foods on the market. Its consumption has been referred to as beneficial in human skin health, namely in the reinforcement of skin's barrier function. This benefit likely results from the productive activity of lactic acid bacteria during kefir fermentation. Lactic acid is naturally present in the skin, and actively contributes to epidermal water dynamics and "barrier." Few studies have been conducted regarding the impact of probiotic consumption in human epidermal water homeostasis. Therefore, this study was designed to explore the impact of the regular consumption of kefir on the skin water dynamics in a group of participants with healthy skin. Participants (n = 27) were healthy female volunteers from whom twelve consumed 100 mL of kefir every day for eight weeks as part of their diet. The remaining (untreated) participants served as the control group. Epidermal water balance was assessed by measuring transepidermal water loss (TEWL) and stratum corneum (SC) hydration on three different occasions-at baseline (T0), after four weeks (T4) and after eight weeks (T8) of interventive kefir consumption. Our study revealed a significant reduction in TEWL (p = 0.043) in the kefir group after eight weeks of regular consumption. In the same period, no differences were found for TEWL in the control group (p = 0.997). Regarding hydration, skin dryness was progressive in the control group, with a significant reduction in SC hydration (p = 0.002) at T8 in comparison to T0. In the kefir group, SC hydration was preserved between T0 and T8 (p = 0.997), which we believe to be related to epidermal "barrier" reinforcement. Our study seems to confirm that the regular consumption of kefir does improve cutaneous water balance even in healthy skin.

Devices measuring transepidermal water loss: A systematic review of measurement properties

OBJECTIVE

The objective of this review is to examine the reliability and measurement error of devices that measure transepidermal water loss (TEWL).

INTRODUCTION

TEWL is a physiological property of skin which increases when the epidermis is damaged. It is, therefore, a commonly utilised measure of skin barrier integrity. Devices measuring TEWL are available as open, semi-open or closed chamber. Studies of reliability examine the consistency of measurement, and/or responsiveness whereas measurement error scores in absolute terms the amount of error due to sources of variation.

INCLUSION CRITERIA

Studies examining the reliability and/or measurement error of TEWL measurement devices were included. Studies that only report on measurement of TEWL outcomes without examination of reliability and/or measurement error were excluded.

METHODS

The search strategy aimed to locate published and unpublished studies. Databases searched included PubMed, Embase, CINAHL and Web of Science, utilising identified keywords and limited to studies in English. Grey literature sources were searched to identify any unpublished documents. Study selection using the inclusion criteria was then assessed by two reviewers for methodological quality utilising the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) risk of bias tool to assess the reliability and measurement error of outcome measurement instruments.

RESULTS

A total of 22 devices were examined in the 38 included studies. The quality of study design was on average rated as 'Adequate' however reliability and measurement error statistical methods were on average rated as 'Doubtful'.

DISCUSSION AND CONCLUSION

TEWL measurement devices were found to demonstrate good reliability and frequently correlated with other devices. However, measurement error was highly variable but improves under in vitro conditions. Future research should consider risk of bias factors when designing studies.

Anti-inflammatory effects of Eclipta prostrata Linné on house dust mite-induced atopic dermatitis in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Atopic dermatitis (AD) is a kind of inflammation on the skin following with swollen, itchy, dryness and cracked skin. Though the exact cause of AD is unknown, there are evidence that people with AD have a compromised skin barrier along with inflammation. Eclipta prostrata Linné is a traditional herbal medicinal plant, has been used for the diabetes, obesity, jaundice, and inflammation. We supposed E. prostrata L. has an anti-inflammatory effect on the skin.

AIM OF THE STUDY

We aimed to assess the effect of E. prostrata L. EtOH extract (EP) and elucidate the associated molecular mechanisms.

MATERIALS AND METHODS

The effect of EP and the molecular mechanisms were eluciated in house dust mite (HDM)-induced AD mice model and TNF-α/IFN-γ-stimulated HaCaT keratinocytes by histological analysis, enzyme-linked immunosorbent assay, quantitative real time polymerase chain reaction, and Western blot.

RESULTS

The results revealed that EP improved the progression of AD symptoms, decreasing epidermis/dermis thickness, infiltrated immune cells, and restored the skin barrier dysfunction and imbalanced immune response. EP suppressed the expressions of T helper (Th)1, Th2, Th17 cytokines, phosphorylation of extracellular signal-regulated kinase/signal transducer and activator of transcription 1 in skin of HDM-induced AD mice as well as inhibition the translocation of nuclear factor-κB in HaCaT keratinocytes.

CONCLUSIONS

Collectively, EP improved the allergic inflammation of the skin through recovery the skin barrier, and regulation the immune balance. These results suggest EP may have therapeutic potential as an anti-atopic agent.

A Topical Emollient Mitigates the Progression of Cognitive Impairment in the Elderly: A Randomized, Open-Label Pilot Trial

BACKGROUND

Cognitive impairment is common in the elderly. Prior studies suggest a link between chronic inflammation and cognitive dysfunction, while aging-associated epidermal dysfunction has been connected to elevations in circulating cytokines.

OBJECTIVE

We assessed here whether improvements in epidermal function can mitigate the progression of cognitive impairment.

METHODS

This randomized, open-label pilot trial was carried out in two cities in northern China. A total of 200 participants aged ≥65 years were randomly assigned to the emollient-treated and untreated groups at 1:1 ratio. Participants in the treated group were treated topically with Atopalm cream® twice-daily from November to the following May each year for three consecutive years, while the untreated subjects served as controls. The Global Deterioration Scale (GDS) was used to assess the severity of cognitive impairment, while epidermal biophysical properties were measured on the forearms and the shins in parallel.

RESULTS

Over the three-year trial, GDS significantly increased from baseline (p<0.0001) in the controls, while in the treated group, GDS stabilized. While stratum corneum hydration on the forearms did not change significantly in the controls, transepidermal water loss rates (TEWL), significantly increased by the end of the trial compared to baselines in the controls (p<0.0001). On the forearms of the treated group, stratum corneum hydration increased (p<0.0001) while skin surface pH decreased from baseline (p<0.0001).

CONCLUSIONS

These results suggest that improvements in epidermal function with topical emollient can mitigate the progression of cognitive impairment. However, the sample size was relatively small, and trials in a larger cohort are needed to validate the present results.

Correlation of Body Mass Index with Epidermal Biophysical Properties Varies with Gender in Chinese

BACKGROUND

Epidermal function is associated with diabetes and renal disease. Whether obesity can reflect the changes in epidermal function is not clear yet.

OBJECTIVE

We assessed here the correlation of epidermal functions with body mass index (BMI) in a large Chinese cohort.

METHODS AND SUBJECTS

A total of 1,405 Chinese aged 21-98 years old were enrolled in this study. Epidermal functions, including transepidermal water loss (TEWL), stratum corneum hydration, and skin surface pH, were measured on the flexor forearm and the shin. Subjects' height and body weight were also measured.

RESULTS

Age positively correlated with both TEWL and skin surface pH, while it negatively correlated with stratum corneum hydration on both the forearm and the shin of females. Similarly, age positively correlated with skin surface pH, while negatively correlating with stratum corneum hydration on both the forearm and the shin of males. In females, BMI positively correlated with skin surface pH, while it negatively correlated with stratum corneum hydration on both the forearm and the shin. However, BMI correlated neither with skin surface pH on both the forearm and the shin nor with stratum corneum hydration on the shin of males.

CONCLUSION

These results demonstrate that correlations of BMI with age and epidermal functions vary with gender.

Epidermal Barrier Function and Skin Homeostasis in Atopic Dermatitis: The Impact of Age

Skin is damaged in atopic dermatitis (AD) patients. Age is also believed to have a negative effect on epidermal barrier function. The aim of this study was to investigate skin barrier function changes with age in AD patients. A cross-sectional study was conducted including 162 participants, 81 AD patients and 81 healthy volunteers. Skin barrier function parameters, such as transepidermal water loss (TEWL), erythema, temperature, stratum corneum hydration (SCH), pH, and elasticity, were evaluated. Healthy volunteers were evaluated on the volar forearm. AD patients were measured on two regions: on an eczematous lesion on the volar forearm and on a non-involved area 5 cm from the affected area. TEWL was lower on healthy skin than uninvolved AD skin (9.98 vs. 25.51 g·m⁻²·h⁻¹, p < 0.001) and AD eczematous lesions (9.98 vs. 28.38 g·m⁻²·h⁻¹, p < 0.001). SCH was lower on AD eczematous lesions than uninvolved AD skin (24.23 vs. 39.36 AU, p < 0.001) and healthy skin (24.23 vs. 44.36 AU, p < 0.001). Elasticity was lower on AD eczematous lesions than uninvolved AD skin (0.69 vs. 0.74, p = 0.038) and healthy skin (0.69 vs. 0.77, p = 0.014). A negative correlation was found between age and elasticity in all the population (r = −0.383, p < 0.001). This correlation was stronger in AD patients (r = −0.494, p < 0.001) than in controls (r = −0.266, p = 0.092). After conducting a linear regression model in AD patients adjusted by age, sex, and SCORing Atopic Dermatitis (SCORAD), it was found that elasticity was impaired by an increasing age (β = −0.004, p < 0.001) and a higher SCORAD (β = −0.003, p < 0.001). The skin barrier function is impaired by age and AD, reflected mainly in poor elasticity values in older AD patients.

Pilot Study on the Forehead Skin Microbiome and Short Chain Fatty Acids Depending on the SC Functional Index in Korean Cohorts

Dry skin is one of the indicators of a compromised skin barrier. An intact skin barrier is not only important to reserve the hydration within the epidermal tissue but also to protect our skin from environmental stressors and inhibit pathogen invasion; damage to the skin barrier may lead to inflammatory skin diseases. Some microbial metabolites such as short chain fatty acids may inhibit or destroy harmful bacteria and regulate the host immune system. The impact of the skin microbiome and short chain fatty acids on skin barrier function was studied in two groups of 75 participants each. The cohort was equally divided in dry and moist skin types, based on stratum corneum (SC) functionality index (SCFI), reflecting the ratio of transepidermal water loss (TEWL). A dry group represents a low SCFI and a moist group a high SCFI. Compared with the dry skin group, propionate and Cutibacterium levels (previously known as Propionibacterium acnes) were significantly higher (p < 0.001) in the moist group. Levels of Cutibacterium were negatively correlated with those of Staphylococcus (p < 0.0001) in both dry and moist groups. The moist group also had a significantly higher propionate concentration (p < 0.001). This study showed that the microbial community and short chain fatty acid concentration may be considered as significant determinants of the SCFI of the skin.

Skin moisture assessment using Hydration Sensor Patches coupled with smartphones via Near Field Communication (NFC). A pilot study with the first generation of patches that allow self-recordings of skin hydration

OBJECTIVES

To evaluate the potency of a new skin hydration sensor patch in the fast self-recording of skin hydration.

MATERIAL AND METHODS

The Skin Hydration Sensor Patch (SHSP) turns the user's smartphone into a wireless skin moisture measuring device. The SHSP combines a capacitive measurement unit and Near Field Communication technology (NFC) for transmitting data and energy. The probe is fixed onto the back of the smartphone and pressed to the skin for a few seconds where the application immediately calculates the capacitance value. Once recorded, the probe is then immediately taken off from the skin. In a first study, this system was compared to the Corneometer^® technique, in vivo, on various skin sites of 23 healthy French women. In a second study, 20 women with moderate dry skin on face and forearm self-recorded, through the SHSP the changes in skin hydration induced by a Xanthan gel containing 3% (w/w) of Glycerol, along 24 hours. A questionnaire based on 5 types of questions was established to be filled by subjects about their perception of the use of this new system.

RESULTS

In the first study, the values recorded by the SHSP were found highly correlated with those provided by the Corneometer^® . The second study allowed to observe significant differences in skin hydration of both sites at all times, as compared to values obtained before the application of the gel. Differences between both sites were observed, the face being less hydrated than forearm. From a practical aspect, the self-recordings on the face show a higher variability (approx. 10% than those of the forearm). The questionnaire led to positive answers on almost all points.

CONCLUSION

This SHSP appears as a promising approach in the field of connected skin-related devices. As such, it opens or enlarges a new paradigm in the relationships between a consumer and a cosmetic product.

Impact of Gloves and Mask Use on Epidermal Barrier Function in Health Care Workers

BACKGROUND

Coronavirus disease 2019 has rapidly spread all over the world. Personal protective equipment (PPE) including masks and gloves is needed to avoid transmission. Adverse skin reactions associated with PPE have been described, but there is no information regarding objective measures to assess skin impairment related to PPE.

OBJECTIVE

The aim of the study was to evaluate the impact of using facial mask and nitrile gloves on epidermal barrier function and skin homeostasis.

METHODS

A cross-sectional study was designed. Thirty-four health care workers wearing nitrile gloves and a mask for 2 hours were included. Transepidermal water loss, stratum corneum hydration, erythema, and temperature were measured.

RESULTS

Transepidermal water loss (31.11 vs 14.24 g·m-2·h-1), temperature (33.29°C vs 32.57°C), and erythema were significantly greater at the area covered by gloves compared with the noncovered area. Transepidermal water loss (22.82 vs 13.69 g·m-2·h-1), temperature, and erythema (411.43 vs 335.52 arbitrary units) were significantly increased at the area covered by mask, whereas stratum corneum hydration was lower. Transepidermal water loss was greater at the area covered by a surgical mask than at a filtering respirator mask coded filtering facepiece 2 (27.09 vs 18.02 g·m-2·h-1, P = 0.034).

CONCLUSIONS

Skin homeostasis and epidermal barrier function may be impaired by gloves and mask use. High-quality PPE should be provided, and adequate skin prevention measures should be implemented to reduce epidermal barrier damage.

Skin Barrier Function in Psoriasis and Atopic Dermatitis: Transepidermal Water Loss and Temperature as Useful Tools to Assess Disease Severity

Multiple diagnostic tools are used to evaluate psoriasis and atopic dermatitis (AD) severity, but most of them are based on subjective components. Transepidermal water loss (TEWL) and temperature are skin barrier function parameters that can be objectively measured and could help clinicians to evaluate disease severity accurately. Thus, the aims of this study are: (1) to compare skin barrier function between healthy skin, psoriatic skin and AD skin; and (2) to assess if skin barrier function parameters could predict disease severity. A cross-sectional study was designed, and epidermal barrier function parameters were measured. The study included 314 participants: 157 healthy individuals, 92 psoriatic patients, and 65 atopic dermatitis patients. TEWL was significantly higher, while stratum corneum hydration (SCH) (8.71 vs. 38.43 vs. 44.39 Arbitrary Units (AU)) was lower at psoriatic plaques than at uninvolved psoriatic skin and healthy controls. Patients with both TEWL > 13.85 g·m⁻²h⁻¹ and temperature > 30.85 °C presented a moderate/severe psoriasis (psoriasis area severity index (PASI) ≥ 7), with a specificity of 76.3%. TEWL (28.68 vs. 13.15 vs. 11.60 g·m⁻² h⁻¹) and temperature were significantly higher, while SCH (25.20 vs. 40.95 vs. 50.73 AU) was lower at AD eczematous lesions than uninvolved AD skin and healthy controls. Patients with a temperature > 31.75 °C presented a moderate/severe AD (SCORing Atopic Dermatitis (SCORAD) ≥ 37) with a sensitivity of 81.8%. In conclusion, temperature and TEWL values may help clinicians to determine disease severity and select patients who need intensive treatment.

Epidermal barrier changes in patients with psoriasis: The role of phototherapy

BACKGROUND

Some skin diseases may modify epidermal barrier function. Psoriasis is a chronic multi-systemic inflammatory disease that affects the epidermal barrier. Phototherapy is an option for treating psoriasis, but little is known about how epidermal barrier function is modified by phototherapy in psoriatic patients.

OBJECTIVES

(a) To compare skin homeostasis between involved and uninvolved skin in psoriatic patients with healthy controls (b) To evaluate changes in the epidermal barrier function in psoriatic patients treated with phototherapy.

METHODS

Sixty patients with plaque-type psoriasis and sixty gender and age-matched healthy controls were enrolled. Temperature, transepidermal water loss (TEWL), stratum corneum hydration (SCH), pH, elasticity, erythema and melanin index were measured using non-invasive tools in the healthy control and involved and uninvolved psoriatic skin before and after phototherapy.

RESULTS

Healthy controls had lower TEWL and erythema index and higher SCH than psoriatic patients, both at uninvolved psoriatic skin and psoriasis plaques. TEWL was higher at psoriasis plaques than at uninvolved skin (19.20 vs 11.57 g/h/m² ; P < .001). Following phototherapy, a decreasing trend was observed for TEWL, of 1.03 (SD 0.75) and 0.97 (SD 0.81) g/h/m² for uninvolved and involved skin respectively. SCH was significantly lower at psoriatic plaques than at uninvolved skin (7.32 vs 36.62Arbitrary Units [AU]; P < .001). SCH increased by 1.15AU (SD 0.26) on psoriatic plaques after the phototherapy session (P < .001).

CONCLUSION

Psoriatic plaques showed epidermal barrier dysfunction compared to uninvolved skin and healthy controls. Phototherapy may improve epidermal barrier function in psoriatic patients. SCH increased after a phototherapy session on the psoriatic plaques.

Reliable, low-cost, fully integrated hydration sensors for monitoring and diagnosis of inflammatory skin diseases in any environment

Present-day dermatological diagnostic tools are expensive, time-consuming, require substantial operational expertise, and typically probe only the superficial layers of skin (~15 μm). We introduce a soft, battery-free, noninvasive, reusable skin hydration sensor (SHS) adherable to most of the body surface. The platform measures volumetric water content (up to ~1 mm in depth) and wirelessly transmits data to any near-field communication-compatible smartphone. The SHS is readily manufacturable, comprises unique powering and encapsulation strategies, and achieves high measurement precision (±5% volumetric water content) and resolution (±0.015°C skin surface temperature). Validation on n = 16 healthy/normal human participants reveals an average skin water content of ~63% across multiple body locations. Pilot studies on patients with atopic dermatitis (AD), psoriasis, urticaria, xerosis cutis, and rosacea highlight the diagnostic capability of the SHS (P _AD = 0.0034) and its ability to study impact of topical treatments on skin diseases.

Changes in facial signs due to age and their respective weights on the perception of age and skin plumpness among differently aged Korean women

OBJECTIVE

To determine the respective weights of certain facial signs on the assessment of perceived age and plumpness on Korean women of different ages.

MATERIAL AND METHODS

Photographs were taken of the faces of 112 Korean women of different ages (18-80 years) under standardized conditions. These photographs allowed to focus and define 19 facial signs, which were then graded by 15 experts and dermatologists, using standardized scales provided by a reference Skin Aging Atlas. The facial signs were dispatched into 5 clusters, namely Wrinkles/Texture, Ptosis/Sagging, Pigmentation disorders, Vascular disorders, and Cheek skin pores. A naïve panel, composed of 92 Korean women, of similar age range were asked, when viewing full-face photographs, to: (a) attribute on a 0-10 scale their perception of the skin plumpness (ie supple/hydrated/nourished) and (b) estimate the age of the subject.

RESULTS

With the exception of Vascular disorders, the severity of all 4 clusters increased with age, although at different rates. The Wrinkles/Texture or Ptosis/Sagging showed a rather regular progression. Although perceived ages and real ages were found highly correlated, half of the subjects were judged older by 2-12 years. The facial signs/clusters were significantly correlated with perceived age, with the exceptions of vascular disorders, size of pigmentary spots and cheek skin pores. The weights in perceived ages of Wrinkles/Texture and Ptosis/Sagging represent 37% each and Pigmentation disorders at 26%. Skin plumpness was logically found significantly anti-correlated with perceived age. If, surprisingly, Vascular disorders were found not impacting the plumpness aspect, Cheek skin pores presented a clear influence.

CONCLUSION

Within facial clinical clusters, Wrinkles/Texture, Ptosis/Sagging, and Pigmentation disorders are major factors in the assessment of perceived age in Korean women. The perception of a decreased skin plumpness is significantly associated with increased perceived age.

A Split-Face Study Assessing the Clinical Benefit, Tolerability and Subject Satisfaction of a Dermocosmetic in Subjects with Rosacea Associated with Erythema and Sensitive Skin

Objective

This study assessed the efficacy and tolerability of M89 in patients with rosacea associated with erythema and sensitive skin.

Methods

Intra-individual study in a split-face design comparing after 30 days M89 twice daily and usual skin care in 20 adult subjects with rosacea and sensitive skin. M89 contains 89% Vichy volcanic mineralizing water (VVMW) and 0.4% hyaluronic acid. It is hypoallergenic and contains no perfume and this convenes in rosacea. Contained minerals reinforce the natural defences of the skin in restoring the natural skin barrier, stimulating antioxidant activity and reducing inflammation, commonly observed in subjects with rosacea. Clinical evaluations included assessment of erythema, desquamation, papules and pustules, skin tightness, dryness, burning sensation, itching, stinging and stinging test as well as local tolerability. Instrumental evaluations included skin hydration and TEWL. Subject satisfaction was assessed at Days 15 and 30. Demodex density was assessed at Day 30.

Results

A significant superiority of M89 over the standard skin care was observed for erythema, skin tightness and dryness (all P≤0.05) as early as Day 15, the skin stinging test was significantly in favour of M89 (P<0.05 at Day 15 and P<0.01 at Day 30) and for skin hydration (P<0.0001) at Day 15 and 30 with no difference in mean Demodex density between M89 and usual skin care after 30 days. Tolerance was excellent and subject satisfaction very high.

Conclusion

Study results concerning M89 are encouraging for its use either alone or as an adjuvant daily skin care to topical medication in patients with persistent centrofacial erythema of rosacea with no more than 3 papules and pustules.

Can a handheld device accurately measure barrier function in ichthyoses?

BACKGROUND

Transepidermal water loss (TEWL) is a surrogate measure of skin barrier dysfunction. Historically, devices that measure TEWL are expensive, complex, and require connection to a computer and energy source. Consequently, measurement of skin's TEWL has been limited to the research setting.

OBJECTIVES

Evaluate the accuracy of the handheld device gpskin Barrier Light^® in comparison with a standardly used device, AquaFlux AF200^® , for measuring TEWL.

METHODS

Transepidermal water loss measurements by gpskin Barrier Light^® and AquaFlux AF200^® in ichthyotic and healthy skin were compared.

RESULTS

AquaFlux AF200^® TEWL readings were consistently higher than those from gpskin Barrier Light^® . In the pooled cohort, TEWL values were strongly correlated and both devices had excellent reliability. When subjects and controls were examined separately, there was moderate correlation between devices, with stronger agreement at higher TEWL values.

LIMITATIONS

Transepidermal water loss was determined at one time point. There is no formally established industry standard TEWL-assessing device.

CONCLUSION

Although gpskin Barrier Light^® and AquaFlux AF200^® devices cannot be used interchangeably, correlation in measuring TEWL was strong in patients with skin disease. This finding suggests that the low-cost, handheld device can accurately capture change in TEWL to track disease improvement.

Transdermal delivery of topical lidocaine in a mouse model is enhanced by treatment with cold atmospheric plasma

BACKGROUND

Topical anesthetics are widely used in dermatology and cosmetology to alleviate the pain from nonsurgical cosmetic procedures, while the transdermal drug delivery is limited by the skin barrier. Cold atmospheric plasma (CAP) is a potential approach used for skin pretreatment to enhance transdermal delivery of topical medications.

AIMS

To assess the efficacy of CAP as a pretreatment to improve the transdermal delivery of topical anesthetic.

METHODS

First, we conducted ex vivo permeation studies on 30 mice with a Franz cell diffusion experiment. CAP irradiations of different intensity and duration were pretreated on the epidermal layer of mice before topical lidocaine applied, with the control group received no pretreatment. The amount of drug penetrated through the skin and drug flux were determined by high-performance liquid chromatography. Then, we treated 3 living mice with CAP followed by application of methylene blue cream (MB) and used skin biopsies to measure penetration depth by microscope. Last, we measured the transepidermal water loss (TEWL) of mouse skin in vivo before and after CAP treatment to observe its effect on the skin barrier function.

RESULTS

In the permeation study, the transdermal flux of lidocaine was enhanced to 1.97 times of the control samples by CAP pretreatment. We also observed that the accumulative amount of lidocaine varied with the duration of the CAP treatment in a biphasic manner. In the MB penetration study, significant amount of MB deposition was observed under the epidermis and deeper parts of the skin after CAP pretreatment compared with the control sample. A sharp increase in TEWL value was observed directly after the CAP treatment, but 30 minutes later, it began to decrease and recovered to baseline in the next 3 hours, indicating that the skin barrier property had been changed reversibly.

CONCLUSIONS

Our studies suggested that the transdermal absorption of topical lidocaine can be efficiently and safely enhanced by pretreatment of the skin with CAP. We believe that CAP could be used as an assistance to improve analgesia in dermatology.

Value of GPSkin for the measurement of skin barrier impairment and for monitoring of rosacea treatment in daily practice

Background

Stratum corneum hydration (SCH) and transepidermal water loss (TEWL) provide useful information about skin barrier function. This study aimed to determine the value of GPSkin Pro, a new handheld device determining both SCH and TEWL, to measure skin barrier impairment and to monitor barrier function in rosacea in daily practice.

Materials and Methods

Two pilots were performed. Pilot 1: in 27 healthy participants, GPSkin SCH and TEWL were compared to Aquaflux^® and Epsilon^® values at the forearm before and after skin barrier perturbation via tapestripping. Moreover, GPSkin values were measured at both cheeks without intervention. Pilot 2: in 16 rosacea patients, GPSkin measurements were performed at the forearm, and at both cheeks before and during anti‐inflammatory treatment. They were compared to clinical symptoms and to GPSkin values from pilot 1.

Results

Pilot 1: after merging data from before and after tapestripping, a strong correlation was observed between GPSkin TEWL and Aquaflux^® (R_s = 0.9256), and GPSkin SCH and Epsilon^® (R_s = 0.8798). Pilot 2: SCH was significantly lower at the cheeks of rosacea patients compared to controls, with a normalizing trend during successful treatment. TEWL was comparable among patients and controls and did not change during treatment at all locations.

Conclusion

The GPSkin determines TEWL and SCH accurately in healthy and impaired skin barrier state and can monitor skin barrier function in rosacea during treatment. The GPSkin device is much more practical compared to previous skin barrier tools when used in clinical practice. Its further validation in other inflammatory skin diseases is recommended.

Caffeoyl-Pro-His amide relieve DNCB-Induced Atopic Dermatitis-Like phenotypes in BALB/c mice

The main factors involved in the pathogenesis of atopic dermatitis (AD) are skin barrier abnormality, allergy/immunology, and pruritus. Considering how oxidative stress influences these factors, antioxidant agents may be effective candidates in the treatment of AD. To evaluate the effect of Caffeoyl–Pro–His amide (CA-PH), an antioxidant agent, on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like phenotypes in BALB/c mice. Topical sensitization and challenge by DNCB were performed on the dorsal skin of BALB/c mice to induce AD-like cutaneous lesions, phenotypes, and immunologic response. CA-PH was applied topically for 2 weeks to assess its effects on DNCB-induced AD-like phenotypes. As a result, CA-PH relieved DNCB-induced AD-like phenotypes quantified by dermatitis severity score, scratching duration, and trans-epidermal water loss. Histopathological analysis showed that CA-PH decreased epidermal thickening, the number of mast cells, and eosinophil infiltration in dermis. Immunohistochemical staining revealed that CA-PH recovered skin barrier-related proteins: filaggrin, involucrin, and loricrin. As for the immunologic aspects, CA-PH treatment lowered mRNA or protein levels of interleukin (IL)-4, IL-6, IL-17a, IL-1b, IL-31, and IL-33 levels and thymic stromal lymphopoietin (TSLP) levels in cutaneous tissue, reducing the DNCB-induced serum IgE level elevation. In conclusion, topical CA-PH may be a therapeutic option for the treatment of AD.

Altered Epidermal Permeability Barrier Function in the Uninvolved Skin Supports a Role of Epidermal Dysfunction in the Pathogenesis of Occupational Hand Eczema

Although a compromised epidermal permeability barrier can contribute to the development of contact dermatitis, whether subjects with hand eczema display abnormalities in baseline epidermal permeability barrier function in their uninvolved skin remains unknown. The aim of the present study was to assess epidermal permeability barrier function in subjects with and without hand eczema in clothing manufacturers. Upon approval by the institutional review board, volunteers were recruited from clothing manufacturers in Guangzhou City, China. An 11-item questionnaire was used to collect general data from the volunteers. The diagnoses of self-proclaimed hand eczema were further confirmed by a dermatologist. Epidermal biophysical properties, including transepidermal water loss (TEWL) rates, stratum corneum hydration and skin surface pH were measured on the flexural surface of the left forearm in all volunteers. Epidermal biophysical properties were compared among cohorts of subjects with active hand eczema, a prior history of hand eczema and without any history of hand eczema. A total of 650 questionnaires were collected from 462 females and 188 males, with a mean age of 36.7 ± 0.46 years (range 16-69 years; 95% CI 35.8-37.59). Thirty-five subjects (5.4%) currently had hand eczema, while 28 subjects (4.3%) reported a prior history of hand eczema that was inactive currently. The prevalence of hand eczema did not differ significantly between genders. Neither a prior personal nor a family history of allergies was associated with the prevalence of hand eczema, but certain occupations and frequent contact with disinfectants were independently associated with the prevalence of hand eczema. In the overall cohort, males displayed higher TEWL rates and stratum corneum hydration levels than did females. Both skin surface pH and TEWL rates differed significantly among normal controls and subjects with active hand eczema or a prior history of hand eczema (p < 0.05). In conclusion, the uninvolved skin site of subjects with hand eczema exhibits abnormalities in epidermal perme-ability barrier, supporting a pathogenic role of epidermal dysfunction in hand eczema. Whether subjects with hand eczema in other occupations also display altered epidermal function on uninvolved skin remains to be explored.

Comparison of transepidermal water loss rates in subjects with skin patch test positive vs negative to skin care products

BACKGROUND

Adverse cutaneous reactions to skin care products (SCP) are becoming increasingly common and may be indicative of defective permeability barrier function.

AIM

To determine the differences in transepidermal water loss rates (TEWL) between skin patch positive vs negative to skin care products in normal Chinese females.

METHODS

Skin patch test reactions to nine skin care products were assessed in 65 normal Chinese females. Correlations of cutaneous reactions to a panel of nine foreign and domestic SCP with permeability barrier function and stratum corneum (SC) hydration levels were analyzed.

RESULTS

Out of 65 subjects, 24 (37%) displayed positive reactions to one or more SCP. However, the occurrence of positive reactions to patch tests did not correlate with either transepidermal water loss rates or SC hydration levels.

CONCLUSIONS

Though a substantial proportion of normal females display adverse reactions to SCP, this problem cannot be attributed to differences in the qualities of their epidermal permeability barriers, and therefore, these reactions more likely reflect the potential adverse events of the SCP themselves. However, further studies in large cohort of both males and females would be helpful to ascertain whether TEWL levels can predict cutaneous reactions to SCP.

Portable Skin Analyzers with Simultaneous Measurements of Transepidermal Water Loss, Skin Conductance and Skin Hardness

Simultaneous measurement of skin physiological and physical properties are important for the diagnosis of skin diseases and monitoring of human performance, since it provides more comprehensive understanding on the skin conditions. Current skin analysis devices, however, require each of probes and unique protocols for the measurement of individual skin properties, resulting in inconvenience and increase of measurement uncertainty. This paper presents a pen-type skin analyzing device capable tomeasure three key skin properties at the same time: transepidermal water loss (TEWL), skin conductance, and skin hardness. It uses a single truncated hollow cone (THC) probe integrated with a humidity sensor, paired electrodes, and a load cell for the multimodal assessment of the skin properties. The present device measured TEWL with a sensitivity of 0.0068 (%/s)/(g/m²/h) and a linearity of 99.63%, conductance with a sensitivity of 1.02 µS/µS and a linearity of 99.36%, and hardness with a sensitivity of 0.98 Shore 00/Shore 00 and a linearity of 99.85%, within the appropriate ranges for the human skin. The present pen-type device has a high potential for the skin health diagnosis as well as the human performance monitoring applications.

Hydrangea serrata (Thunb.) Ser. Extract Attenuate UVB-Induced Photoaging through MAPK/AP-1 Inactivation in Human Skin Fibroblasts and Hairless Mice

Skin photoaging is mainly caused by exposure to ultraviolet (UV) light, which increases expressions of matrix metalloproteinases (MMPs) and destroys collagen fibers, consequently inducing wrinkle formation. Nutritional factors have received scientific attention for use as agents for normal skin functions. The aim of this study was to investigate the effect of hot water extracts from the leaves of Hydrangea serrata (Thunb.) Ser. (WHS) against ultraviolet B (UVB)-induced skin photoaging and to elucidate the underlying molecular mechanisms in human foreskin fibroblasts (Hs68) and HR-1 hairless mice. WHS recovered UVB-reduced cell viability and ameliorated oxidative stress by inhibiting intracellular reactive oxygen species (ROS) generation in Hs68 cells. WHS rescued UVB-induced collagen degradation by suppressing MMP expression, and reduced the mRNA levels of inflammatory cytokines. These anti-photoaging activities of WHS were associated with inhibition of the activator protein 1 (AP-1), signal transduction and activation of transcription 1 (STAT1), and mitogen-activated protein kinase (MAPK) signaling pathways. Oral administration of WHS effectively alleviated dorsal skin from wrinkle formation, epidermal thickening, collagen degradation, and skin dehydration in HR-1 hairless mice exposed to UVB. Notably, WHS suppressed UVB activation of the AP-1 and MAPK signaling pathways in dorsal mouse skin tissues. Taken together, our data indicate that WHS prevents UVB-induced skin damage due to collagen degradation and MMP activation via inactivation of MAPK/AP-1 signaling pathway.