Effects of a New Emollient-Based Treatment on Skin Microflora Balance and Barrier Function in Children with Mild Atopic Dermatitis.

BACKGROUND/OBJECTIVES: The use of emollients is widely recommended for the management of atopic dermatitis (AD), especially between flares. An imbalance of skin microflora is suspected of playing a key role in exacerbations of AD. Our aim was to evaluate the effect of a new emollient balm on clinical parameters (SCORing Atopic Dermatitis [SCORAD], xerosis, pruritus), skin barrier function (transepidermal water loss and loricrin, filaggrin, corneodesmosin, and involucrin expression], skin microflora biodiversity, and Staphylococcus aureus and Staphylococcus epidermidis balance in children with mild AD. METHODS: Fifty-four children (1-4 yrs old) were enrolled in this randomized, controlled study. Subjects applied a hygiene product and the emollient balm (emollient group, n = 28) or the hygiene product only (control group, n = 26) twice a day for 28 days. RESULTS: We found improvement in favor of the emollient group in SCORAD (p < 0.001), pruritus (p = 0.06), and xerosis (p = 0.06) after 28 days of application. Moreover, transepidermal water loss decreased in the emollient group by 34% (p = 0.06) and involucrin expression by 37% (p = 0.001) at day 28 from baseline in association with improvement in barrier function, whereas other barrier-specific proteins did not vary. S. aureus increased significantly in the control group only (6.5 times, p = 0.01), whereas S. epidermidis remained stable in both groups. The Shannon index (H' = 2.3) did not vary with treatment in either group. CONCLUSION: Twice-daily application of a new emollient balm in children with mild AD protected the skin from S. aureus proliferation and preserved microflora biodiversity.

In vivo assessment of the effect of a cream containing Avena Rhealba(®) extract and hyaluronic acid on the restoration of the skin barrier in de-epidermised skin produced with an erbium-YAG laser.

Wound healing studies require standardised methods for evaluating wounding and skin repair. Our study aimed to demonstrate the suitability of the erbium-YAG (Er-YAG) laser method to produce reliable epidermal lesions for evaluation of different skin repair creams. Skin de-epidermised by Er-YAG laser (four uniform epidermal ablations, area 8 × 8mm, in 21 healthy subjects) was treated with a product (A) containing Avena Rhealba(®) extract and hyaluronic acid and assessed for epidermal regeneration and barrier restoration. This treatment was compared to two reference products (B) and (C) and an untreated control. Over 22 days of treatment, double-blind measurements of wound characteristics were made for instrumental (wound surface area, barrier restoration, 3D skin topography) and clinical evaluation (lesion quality and tolerance). Tested product (A) resulted in a shorter time (9 days) and faster rate of wound closure than product C (12 days) and the untreated zone (16 days). Results for products (A) and (B) were similar. Clinical evaluation of lesion quality showed the same trends as the wound area/closure parameter. Barrier recovery assessments revealed that all three products showed a similar rate of decreasing Transepidermal Water Loss (TEWL), which was significantly faster than the rate for the control. In conclusion, the laser-induced epidermal wound model provided standardised lesions, enabling discrimination between different topical skin repair products.

Association between collagen production and mechanical stretching in dermal extracellular matrix: in vivo effect of cross-linked hyaluronic acid filler. A randomised, placebo-controlled study.

BACKGROUND: The effects of hyaluronic acid (HA) injection on tissue collagen anabolism are suggested to be related to the induction of mechanical stress, causing biochemical changes in skin physiology. OBJECTIVES: To ascertain the association between dermal mechanics modulated by a hyaluronic acid-based filler effect and metabolism. METHODS: Sixty females were randomised to receive a 0.5mL injection of HA gel or isotonic sodium chloride (control) in the arm. Skin biopsies were taken at baseline and after 1, 3 and 6 months. Protein and gene expression of procollagen, matrix metalloproteinases (MMP) and MMP tissue inhibitors (TIMP1) were measured blind by ELISA and qPCR, respectively. Injected volumes were measured by high-frequency ultrasound and radiofrequency analysis. Skin layer effects of injections were analysed by finite element digital modelling. RESULTS: One month after injection, the filler induced an increase in procollagen (p=0.0016) and TIMP-1 (p=0.0485) levels and relative gene expression of procollagen III and I isoforms compared with the controls. After 3 months, procollagen levels remained greater than in the controls (p=0.0005), whereas procollagen expression and TIMP-1 and MMP content were no longer different. Forty-three percent of the injected filler volume was found at 1 month, 26% after 3 months and 20% after 6 months. LIMITATIONS: The ultrasound imaging technique limited the scope of the investigation and precluded an evaluation of the action of the filler at the hypodermic level. CONCLUSIONS: Integrating both mechanical and biological aspects, our results suggest that mechanical stress generated by cross-linked HA plays a role in dermal cell biochemical response.

Superficial wounding model for epidermal barrier repair studies: comparison of Erbium:YAG laser and the suction blister method.

BACKGROUND AND OBJECTIVES: Wound-healing studies use mainly mechanical methods for wound induction, which are laborious and difficult to standardize. Objective of this study was to evaluate the Erbium:Yttrium-Aluminium-Garnet (Er:YAG) laser method as a model of epidermis ablation on human skin in vivo and to compare the quality and healing rates of Er:YAG laser and suction blister (SB) wounds. MATERIALS AND METHODS: Er:YAG laser and SB wounds were made on the forearms of 10 healthy volunteers. Post-wounding measurements including wound surface area (WSA) from photographs, wound depth from 3D volume analysis, trans-epidermal water loss (TEWL), laser doppler blood flow (LDBF), and optical coherence tomography (OCT) imaging were made daily over 7 days. Biopsies were taken on Days 4 and 7. RESULTS: 3D analysis showed laser wounds to be shallower and more uniform in depth than SB: 54 ± 14 µm versus 140 ± 102 µm, respectively, with histology demonstrating complete epidermal removal using SB. SB wounds were more variable in size with a WSA of 0.47 ± 0.24 cm(2) compared to 1.17 ± 0.14 cm(2) for laser wounds. Healing rates were similar in both groups, as measured by TEWL, LDBF, and WSA. OCT imaging on Days 3-4 revealed new epidermis below the fibrin clot, similar to histology, and a visible stratum corneum on Day 7, but no apparent epidermal hyperplasia in contrast to histology. CONCLUSION: Compared to the SB model, Er:YAG laser achieved rapid standardized epidermal ablation, which despite morphological differences, was similar in terms of epidermal regeneration/barrier formation.

Validation of a model of itch induction for brain positron emission tomography studies using histamine iontophoresis.

Skin-brain signalling in itch reactions has been demonstrated with neuroimaging techniques showing specific brain activation. With positron emission tomography (PET), the itch model used must be adapted to technical and practical constraints. The technique of itch induction by histamine iontophoresis enables modulation of the sensation via the electrical charge applied. This itch model was validated on normal forearm skin of 56 subjects, with itch visual analogue scores peaking to approximately 1.0 cm after 3-4 min, falling to 0.2 cm at 15 min, with no influence of sex, zone, or order. Subsequently, the model was used in a PET study on 14 male volunteers, comparing histamine with physiological saline (control). The results show that the brain is able to discriminate these two conditions, with activated areas similar to those described previously, with, in addition, the anterior cingulate cortex and the insula being positively correlated with the intensity of the sensation.

Comparison of perceived itch induced by skin prick-tests with histamine and codeine.

The role of personal factors makes it difficult to correlate subjective data, such as those obtained with the use of a visual analogue scale, and objective data, such as a quantity of injected histamine. In this study, prick tests with histamine and codeine on the forearms allowed a coherent variation in itch scores to be obtained over time, with highly significant differences from controls and with a peak at 4 minutes. These tests are therefore valuable for screening anti-pruritic agents. A significant difference between initial scores and scores for new prick tests after 7 days suggest that tachyphylaxis persists.