Acidic Skin Care Promotes Cutaneous Microbiome Recovery And Skin Physiology in An Acute Stratum Corneum Stress Model

Background: The skin microbiome and skin physiology are important indicators of the epidermal homeostasis status. Stress models are used to reveal pathological conditions and modulating effects. The recovery phase served to investigate the cutaneous microbiome in relation to skin physiology after mild tape stripping without treatment compared to two cosmetic leave-on lotions (pH 5.5 vs. pH 9.3). Material and MethodsThe prospective, randomized, controlled study was performed in 25 healthy volunteers: The microbiome was assessed via swabs and subsequent 16S-rRNA-gene amplicon sequencing. Skin physiology was analyzed in terms of barrier function, stratum corneum hydration, surface-pH, skin color non-invasively. All parameters were assessed before and immediately after 2hrs., 2 days and 7 days after tape stripping. Lotion A (pH 5.5) and the identical lotion B (pH 9.3) were applied 2-times per day for 7 days on the volar forearm.ResultsTape stripping reduced the alpha diversity with a recovery over 7 days without treatment. Both lotions significantly accelerated the recovery of the alphadiversity already after 2 days with a slightly higher rate for lotion A (pH 5.5). After tape stripping, the relative abundance of Proteobacteria was increased, whereas Actinobacteria were reduced. Further, mean relative abundances of typical skin-associated genera were reduced after tape stripping. Taxa compositions returned to normal levels after 7 days in all treatment groups, and an accelerated normalization could be observerd with treatment by both lotions already after tow days. A significant difference in skin-pH was observed at day2 and day7 with an increased pH in lotion B treatment. Both lotions induced an increase in stratum corneum hydration. Barrier function was only changed by tape stripping. DiscussionThe study proved the suitability of an experimental stress model in the assessment of skin surface microbiome in relation to skin physiology. Stratum corneum hydration increased significantly with both lotions already at day 2. Microbiome parameters (alpha-diversity, mean relative taxa, abundance of selected genera) normalized over 2-7 days. Three potential mechanisms could be responsible for the accelerated normalization: a) optimized hydration during the recovery phase b) the composition of the lotion, c) acidic pH of the lotion.

Erythema Increase Predicts Psoriasis Improvement after Phototherapy

Psoriasis is a major global health problem. There is a need to develop techniques to help physicians select the most appropriate cost-effective therapy for each patient. The main objectives of this study are (1) to evaluate changes in epidermal barrier function and skin homeostasis after phototherapy and (2) to explore potentially predictive values in epidermal barrier function and skin homeostasis to assess clinical improvement after fifteen sessions of phototherapy. A total of 76 subjects, 38 patients with plaque-type psoriasis and 38 gender- and age-matched healthy volunteers, were included in the study. Erythema, transepidermal water loss (TEWL), temperature, stratum corneum hydration (SCH), pH, sebum, and antioxidant capacity were measured before and after the first and fifteenth phototherapy session. Erythema (401.09 vs. 291.12 vs. 284.52 AU, p < 0.001) and TEWL (18.23 vs. 11.44 vs. 11.41 g·m−2·h−1, p < 0.001) were significantly higher at psoriatic plaques than in uninvolved psoriatic skin and healthy volunteers, respectively, while SCH was lower (9.71 vs. 44.64 vs. 40.00 AU, p < 0.001). After fifteen phototherapy sessions, TEWL (–5.19 g·m−2·h−1, p = 0.016) decreased while SCH (+7.01 AU, p = 0.013) and erythema (+30.82 AU, p = 0.083) increased at psoriatic plaques. An erythema increase exceeding 53.23 AU after the first phototherapy session, with a sensitivity of 71.4% and specificity of 84.2%, indicates that a patient may improve Psoriasis Area and Severity Index (PASI) by ≥3 points after fifteen phototherapy sessions. In conclusion, phototherapy improves epidermal barrier function in psoriatic patients and the erythema increase after one phototherapy session could help doctors select psoriasis patients who are more likely to respond to phototherapy.

A comparison of the effect of indoor thermal and humidity condition on young and older adults' comfort and skin condition in winter

Dry indoor air has been identified as the main cause of dry skin in winter which greatly affects older occupants' wellbeing, but HVAC design standards are based on average adults and do not specify a humidity level that can prevent dry skin. A field study was carried out to understand the difference between the younger and older people with regards to thermal and humidity comfort and skin condition in winter. The study proves a research procedure that is friendly to and preferred by the participants to measure the effect of the indoor environment on their comfort and skin condition in a real living environment setting. The results suggest that younger and older occupants are different in thermal comfort, specifically older occupants prefer a warmer environment than younger occupants, and the neutral temperature produced by the predicted mean vote method is not warm enough for older occupants. The study also suggests stratum corneum hydration appears to be a good indicator to present the effect of indoor humidity on the occupants' skin condition, which can be used to determine the minimum humidity level to reduce the risk of suffering dry skin in winter.

Characterization of Permeability Barrier Dysfunction in a Murine Model of Cutaneous Field Cancerization Following Chronic UV-B Irradiation: Implications for the Pathogenesis of Skin Cancer

Chronic ultraviolet B (UV-B) irradiation is known to be one of the most important hazards acting on the skin and poses a risk of developing photoaging, skin with cutaneous field cancerization (CFC), actinic keratosis (AKs), and squamous cell carcinomas (SCCs). Most of the UV-B light is absorbed in the epidermis, affecting the outermost cell layers, the stratum corneum, and the stratum granulosum, which protects against this radiation and tries to maintain the permeability barrier. In the present work, we show an impairment in the transepidermal water loss, stratum corneum hydration, and surface pH after chronic UV-B light exposure in an immunologically intact mouse model (SKH1 aged mice) of skin with CFC. Macroscopic lesions of AKs and SCCs may develop synchronically or over time on the same cutaneous surface due to both the presence of subclinical AKs and in situ SCC, but also the accumulation of different mutations in keratinocytes. Focusing on skin with CFC, yet without the pathological criteria of AKs or SCC, the presence of p53 immunopositive patches (PIPs) within the epidermis is associated with these UV-B-induced mutations. Reactive epidermis to chronic UV-B exposure correlated with a marked hyperkeratotic hyperplasia, hypergranulosis, and induction of keratinocyte hyperproliferation, while expressing an upregulation of filaggrin, loricrin, and involucrin immunostaining. However, incidental AKs and in situ SCC might show neither hypergranulosis nor upregulation of differentiation markers in the upper epidermis. Despite the overexpression of filaggrin, loricrin, involucrin, lipid enzymes, and ATP-binding cassette subfamily A member 12 (ABCA12) after chronic UV-B irradiation, the permeability barrier, stratum corneum hydration, and surface pH were severely compromised in the skin with CFC. We interpret these results as an attempt to restore the permeability barrier homeostasis by the reactive epidermis, which fails due to ultrastructural losses in stratum corneum integrity, higher pH on skin surface, abundant mast cells in the dermis, and the common presence of incidental AKs and in situ SCC. As far as we know, this is the first time that the permeability barrier has been studied in the skin with CFC in a murine model of SCC induced after chronic UV-B irradiation at high doses. The impairment in the permeability barrier and the consequent keratinocyte hyperproliferation in the skin of CFC might play a role in the physiopathology of AKs and SCCs.

Study of Skin Barrier Function in Psoriasis: The Impact of Emollients

Psoriasis is a chronic multi-systemic inflammatory disease that affects the epidermal barrier. Emollients can be used as a coadjutant therapy for psoriasis management, but little is known about how the epidermal barrier function in psoriatic patients is modified by moisturizers. The objective of this study is to evaluate the effect of Vaseline jelly and a water-based formula on epidermal barrier function in psoriatic patients. Thirty-one patients with plaque-type psoriasis and thirty-one gender and age-matched healthy controls were enrolled in the study. Temperature, transepidermal water loss (TEWL), stratum corneum hydration (SCH), pH, elasticity and the erythema index were measured using non-invasive tools before and after applying Vaseline jelly and a water-based formula. TEWL was higher in psoriatic plaques than uninvolved psoriatic skin (13.23 vs. 8.54 g·m−2·h−1; p < 0.001). SCH was lower in psoriatic plaques than uninvolved psoriatic skin and healthy skin (13.44 vs. 30.55 vs. 30.90 arbitrary units (AU), p < 0.001). In psoriatic plaques, TEWL decreased by 5.59 g·m−2·h−1 (p = 0.001) after applying Vaseline Jelly, while it increased by 3.60 g·m−2·h−1 (p = 0.006) after applying the water-based formula. SCH increased by 9.44 AU after applying the water-based formula (p = 0.003). The use of emollients may improve epidermal barrier function in psoriatic patients. TEWL is decreased by using Vaseline, and SCH is increased by using the water-based formula.

Role of Centella asiatica and ceramide in skin barrier improvement: a double blind clinical trial of Indonesian batik workers

Objectives Batik dyes contain irritant chemicals that increase the risk of skin barrier disruption. This study aims to determine the effect of Centella asiatica and ceramide in transepidermal water loss (TEWL), hydration of the stratum corneum and skin acidity (pH). Methods This was a double blind clinical trial of 30 Indonesian batik workers who suffered from skin dryness, but had no clinical manifestation of contact dermatitis. Subjects were given cream containing C. asiatica or ceramide that formulated and randomly labeled by manufacturer (PT Paragon Technology and Innovation). Both subjects and researchers were blinded to the type of the cream. Cream was applied to the hands and arms twice a day. Biological function of the skin (TEWL, stratum corneum hydration level, and skin acidity) was examined by Cutometer dual MP-580. Baseline was recorded in the first examination, followed by second and third examinations at two and four weeks after treatment. Results After four weeks treatment, there were significant improvement of C. asiatica application in evaluation of corneometer palmar (p=0.007; CI 95%), corneometer dorsum (p=0.001; CI 95%), and skin acidity dorsum (p=0.017; CI 95%). Ceramide application also gave significant improvement of corneometer palmar (0.038; CI 95%), skin acidity palmar (p=0.001; CI 95%), TEWL dorsum (p=0.023; CI 95%), corneometer dorsum (p=0.002; CI 95%) and skin acidity dorsum (p=0.011; CI 95%). There were no significant differences of C. asiatica effectiveness compared to ceramide in skin barrier improvement. Conclusions C. asiatica and ceramide can improve skin barrier hydration in order to prevent the risk of contact dermatitis in batik workers.

Modeling Stratum Corneum Swelling for the Optimization of Electrode-Based Skin Hydration Sensors

We present a novel computational model of the human skin designed to investigate dielectric spectroscopy electrodes for stratum corneum hydration monitoring. The multilayer skin model allows for the swelling of the stratum corneum, as well as the variations of the dielectric properties under several hydration levels. According to the results, the stratum corneum thickness variations should not be neglected. For high hydration levels, swelling reduces the skin capacitance in comparison to a fixed stratum corneum thickness model. In addition, different fringing-field electrodes are evaluated in terms of sensitivity to the stratum corneum hydration level. As expected, both conductance and capacitance types of electrodes are influenced by the electrode geometry and dimension. However, the sensitivity of the conductance electrodes is more affected by dimension changes than the capacitance electrode leading to potential design optimization.

Beneficial effects of oral supplementation with ferulic acid, a plant phenolic compound, on the human skin barrier in healthy men

Ferulic acid (FA) is a phytochemical compound with various physiologic functions. To clarify the effect of FA intake on skin barrier function (SBF), we conducted a placebo-controlled double-blind pilot trial. Sixteen healthy subjects were divided into 2 groups (n = 8) and ingested capsules containing either FA (200 mg) or placebo daily for 2 weeks. Two measures of SBF, transepidermal water loss and stratum corneum hydration, were assessed before and 2 weeks after the start of the study. Autonomic nervous activity, which is suggested to be related to SBF, was also measured. Compared with the values obtained before the start of the study, FA intake significantly reduced transepidermal water loss (from 6.1 ± 1.1 to 4.8 ± 1.0 g/m2/h, p = 0.005) and increased stratum corneum hydration (from 30.1 ± 7.6 to 32.3 ± 8.1 a.u., p = 0.027) after 2 weeks. In addition, the amount change in sympathetic nervous activity was significantly reduced after ingesting the FA capsules compared with the placebo capsules (−0.7 ± 1.6 vs. 1.1 ± 1.4, p = 0.035). These findings suggest that FA supplementation decreases sympathetic nervous activity and strengthens SBF in healthy men.

Topical Applications of a Novel Emollient Inhibit Inflammation in Murine Models of Acute Contact Dermatitis

The benefits of emollients for eczematous dermatitis and psoriasis have been thought to be due to the improvements in epidermal function, including epidermal permeability barrier, stratum corneum hydration, and stratum corneum pH. We determined here whether emollient can direct inhibit cutaneous inflammation. Ear inflammation was induced by topical application of either 12-O-tetradecanoylphorbol-13-acetate (TPA) or 1-fluoro-2,4-dinitrofluorobenzene (DNFB). Either 1% hydrocortisone cream or the novel emollient was applied to the right ear of the mice 45 min and 2 hours after TPA or DNFB application. The untreated left ear served as untreated controls. Both ear weight and ear thickness were measured 24 hours after TPA and DNFB application. Topical applications of either hydrocortisone cream or emollient significantly decreased both ear thickness and ear weight in comparison to untreated controls. In DNFB model, hydrocortisone significantly lowered expression levels of mRNA for IL-1α, IL-1β, and TNFα, while the emollient markedly decreased expression levels of IL-1α and TNFα mRNA. In TPA model, both hydrocortisone and emollient significantly decreased expression levels of IL-1α, IL-1β, IL-6, and TNFα mRNA. In parallel, inflammatory infiltration was also reduced by topical applications of either hydrocortisone or emollient. These results demonstrate that this novel emollient can directly inhibit cutaneous inflammation in murine models of both acute irritant contact dermatitis and acute allergic contact dermatitis. However, whether this emollient could also alleviate eczematous dermatitis in humans remains to be explored.