Hyperbaric oxygen preconditioning protects skin from UV-A damage

Hyperbaric oxygen therapy (HBOT) is used for a number of applications, including the treatment of diabetic foot ulcers and CO poisoning. However, we and others have shown that HBOT can mobilize cellular antioxidant defenses, suggesting that it may also be useful under circumstances in which tissue protection from oxidative damage is desired. To test the protective properties of hyperbaric oxygen (HBO) on a tissue level, we evaluated the ability of a preconditioning treatment regimen to protect cutaneous tissue from UV-A-induced oxidative damage. Three groups of hairless SKH1-E mice were exposed to UV-A 3 days per week for 22 weeks, with two of these groups receiving an HBO pretreatment either two or four times per week. UV-A exposure increased apoptosis and proliferation of the skin tissue, indicating elevated levels of epithelial damage and repair. Pretreatment with HBO significantly reduced UV-A-induced apoptosis and proliferation. A morphometric analysis of microscopic tissue folds also showed a significant increase in skin creasing following UV-A exposure, which was prevented by HBO pretreatment. Likewise, skin elasticity was found to be greatest in the group treated with HBO four times per week. The effects of HBO were also apparent systemically as reductions in caspase-3 activity and expression were observed in the liver. Our findings support a protective function of HBO pretreatment from a direct oxidative challenge of UV-A to skin tissue. Similar protection of other tissues may likewise be achievable.

A reliable, non-invasive measurement tool for anisotropy in normal skin and scar tissue

BACKGROUND

Anisotropy of the skin varies depending on different locations and pathological conditions. Currently, no reliable non-invasive measurement tool is available for tissue anisotropy. The Reviscometer is an anisotropy measurement tool that measures the resonance running time (RRT) of a shock wave. This study was initiated to establish the reliability of the Reviscometer on normal skin and scars, and to provide basic information on tissue alignment in normal skin and scars.

METHODS

Fifty volunteers and 50 patients underwent measurements on normal skin and scars, respectively. All measurements were performed by the same two observers. Measurements on normal skin were performed on the forearm, upper arm, and abdomen.

RESULTS

The results showed that the intraclass correlation coefficient of the inter-observer reliability was > or =0.79 on normal skin and > or =0.86 on scars. In normal skin, the highest mean RRT was found on the abdomen (156.4+/-48.8), followed by the upper arm (123.2+/-33.6) and the forearm (112.5+/-24.3). A significantly lower mean RRT was found in scars (52.3+/-21.9) compared with normal skin (91.6+/-37.7).

CONCLUSION

Reviscometer measurements were reliable for normal skin and scars. In addition, clear differences between scars and normal skin but also within different locations on normal skin were identified. The Reviscometer can be considered for the evaluation of the efficacy of different treatments.

Kinetics of moisturizing and firming effects of cosmetic formulations

The assessment of cosmetic efficacy is rarely performed in studies comparing different concentrations of active compounds. The aim of the present study was to determine the skin hydrating and the skin firming dose-response effects of cosmetic formulations enriched in compounds derived from algae and fish collagen. A series of factors were studied including the type of formulation (cream or serum), the concentration in active ingredients, the effect of repetitive applications, as well as any residual effect of the formulations after stopping their applications. The serum enriched in marine compounds showed a better moisturizing effect in short term. The cream appeared more active later, particularly following repeat applications. A sustained tensor (firming) effect was observed during treatment with both the lotion and the cream. However, no remnant firming effect was perceived after stopping treatment.

Use of the Reviscometer for measuring cosmetics-induced skin surface effects

BACKGROUND/PURPOSE

The Reviscometer RVM600 that measures resonance running time (RRT) has been shown to be inversely related to the skin stiffness. However, very few publications describe the use of this instrument for testing the effect of cosmetic products.

METHODS

Slight xerotic skin condition was induced by using an alkaline soap for 1 week. Skin has then been rehydrated with a lotion or further dehydrated and dried with sodium lauryl sulfate (SLS). Skin condition at the different stages of the study was evaluated by visual assessment for dryness and redness and by non-invasive methods (Corneometer, Cutometer, Reviscometer, Evaporimeter and squamometry).

RESULTS

All methods showed highly significant changes after the slight drying phase with the soap usage. They illustrated skin repair after lotion treatment and further skin impairment after SLS application. Nevertheless, the Reviscometer was able to better statistically discriminate between the treatments (water, lotion, SLS) than the Cutometer . Measurement of the RRT along the transversal axis of the forearms was the most sensitive for differentiating between normal and dry skin and between the treatments on the basis of skin mechanical properties.

CONCLUSION

The Reviscometer RVM600 is a sensitive instrument able to detect slight skin surface effect of cosmetics. Combined with published literature on the interpretation of RRT measurements on polymeric gel or in different skin conditions (elderly skin and photoaged skin), the Reviscometer looks to be a recommendable instrument to measure slight changes in SC stiffness/suppleness induced by cosmetic products.

Randomised, placebo-controlled, double-blind, split-face study on the clinical efficacy of Tricutan on skin firmness

Tricutan is a combination product of herbal extracts traditionally used for treatment of skin conditions, together with dimethylaminoethanol. The effectiveness of Tricutan in improving skin firmness and elasticity in photoaged facial skin was examined in a randomised, placebo-controlled, double-blind, split-face study in 28 women, 34-67 years old. Treatment with Tricutan and placebo was given for 4 weeks. Skin firmness and elasticity was evaluated using the speed of propagation of ultrasound shear waves in the skin as end point (Reviscometer RVM 600). The study was completed by 25 women. The Tricutan treatment resulted in a significantly reduced propagation speed indicating increased firmness. There was no immediate effect by Tricutan application on propagation speed. At self evaluation the women evaluated the treatment effect of Tricutan to be significantly better than the treatment effect of placebo. The clinical evaluation also showed Tricutan to give a significantly better treatment result than placebo. Tolerance to Tricutan was generally good. However, three women did not complete the study because of mild irritative contact dermatitis. The results show that Tricutan can increase skin firmness both objectively and subjectively. Further studies are warranted, especially to investigate if Tricutan can delay the need for surgical face-lift procedures.

Skin capacitance imaging and corneosurfametry. A comparative assessment of the impact of surfactants on stratum corneum

Silicon image sensor (SIS) technology was recently introduced as an innovative tool (SkinChip, L'Oréal) providing sensitive imaging of the skin capacitance. This method can detect discrete focal variations in skin surface hydration, and thus early discrete manifestations of skin irritation induced by surfactants. In the present in vivo study, 2 neat and diluted shampoos, and 5% and 10% sodium laurylsulfate solutions were tested on human skin. Each surfactant solution was gently rubbed on the skin using wet hair wicks mimicking the casual use of a shampoo on the scalp. Clinical and SIS evaluations were carried out. In addition, the same products were tested using the ex vivo corneosurfametry bioassay performed on human stratum corneum (SC) harvested by cyanoacrylate skin surface strippings. The colourimetric index of mildness (CIM) was measured on these samples. The product reactivity with the SC was recognized by darker skin capacitance images, and by both lowered SkinChip-generated values and lowered CIM values. The extent in changes varied according to the nature of the test products and their concentrations. The SkinChip image changes likely corresponded to the acute surfactant-induced water swelling of the corneocytes. Skin capacitance imaging and corneosurfametry allow to disclose discrete surfactant-induced alterations of corneocytes.

Silicon Image Sensor Technology for in vivo Detection of Surfactant-Induced Corneocyte Swelling and Drying

BACKGROUND

Several instrumental methods can indirectly assess some specific aspects of cutaneous irritation at the level of the stratum corneum (SC).

OBJECTIVE

There is a need for developing more sensitive approaches in this field.

METHODS

We assessed a recently introduced innovative tool (SkinChip) based on capacitive pixel-sensing technology in its potential to detect early discrete manifestations of skin irritation. The sensor generates a detailed non-optical picture corresponding to a capacitance map of the skin surface reaching 50 microm pixel resolution. Some topographical details can be easily disclosed and the SC hydration as well. Two surfactant solutions were tested on volunteers. These solutions were applied under test patches for 2 days on the volar forearms. Clinical and SkinChip assessments were performed 3 h after removing the patch.

RESULTS

The generated images allowed a precise observation of skin irritation which appeared as a two-step process. Early changes consisted of darker pixels corresponding to overhydrated swollen corneocytes at the irritated sites. Two days later, the same area appeared as white pixels, indicating the loss of corneocyte hydration.

CONCLUSION

The SkinChip device appears to be a very sensitive tool for detecting the early steps of surfactant-induced skin irritation affecting the SC.