Part 2. Comparison of emergency washing solutions in 70% hydrofluoric acid-burned human skin in an established ex vivo explants model

Background: Hydrofluoric acid (HF) is a small and partially dissociated acid (pKa 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H+) and the toxicity of the fluoride ion (F-). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination

Skin surface nanoscale topography by light interferometry

International audienceThe skin is the first thing one perceives of a person. Unconsciously, its color, its radiance and its complexion give us a first impression of a person. This is why cosmetic care and makeup products are of great importance.But how to evaluate their activity?Many methods of in vivo measurements exist to evaluate its color or shine, but the evaluation of a product activity on skin surface is much more complicated.. The relief of the skin and even more its microrelief, are largely responsible for its optical properties and therefore the image it refers.Many products have a filling or a tensor effect, modifying the depth and width of the microfolds that compose the microrelief. It is consequently necessary to measure and characterize the skin surface before and after the application of a cosmetic product with great precision.More precise than 3D scanners, or the fringe projections in vivo, light interferometry allows making a topographical survey of the skin surface with an accuracy of a few tens of nanometers.The topography by light interferometry is developed by the Polytec company whose experience in measuring equipment is no longer to be proved.This technology used in particular in the control of mechanical parts of aeronautics, offers a lateral resolution of approximately 10 μm and a vertical resolution of less than 20 nm.Depending on the light interference reflected from the surface of the skin, this technology is sensitive to vibrations which avoids its in vivo use.To benefit from this technology usually reserved for the world of precision micromechanics, we have developed a support to put under tension a human living skin explant and to maintain it in survival ex vivo.This support specially designed and printed in 3D allows stretching the skin on a reservoir of culture medium while respecting a tension similar to the in vivo conditions.The tension of the skin was measured and verified by cutometry. This measurement can also be performed during the study which can last up to 10 days.The skin thus stretched can be topographed and treated by different products. So it will be very simple to measure the roughness of the surface of the skin, the depth of its folds or their width.We applied on the surface of the skin three products, two with smoothing and filling activity. We showed a decrease in the average depth of the cutaneous microfolds as well as a decrease of the roughness of the skin.If an immediate effect can be observed in a few minutes, the ex vivo character of this model also allows evaluating a biological activity which reinforces in depth this surface-visible effect.This new and original approach, coupling light interferometry technology and human living skin explant, offers all the precision and finesse necessary for an immediate evaluation of the activity of a product on skin surface proprieties and to investigate in parallel the cutaneous-linked biological effects

The missing bridge between ex vivo and in vivo models: the Perfex vivo system

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Immediate effects of cosmetic products on skin surface highlighted by nanoscale topography on ex vivo human skin

International audienc

Protective Potential of a Botanical-Based Supplement Ingredient against the Impact of Environmental Pollution on Cutaneous and Cardiopulmonary Systems: Preclinical Study

Air pollution is a growing threat to human health. Airborne pollution effects on respiratory, cardiovascular and skin health are well-established. The main mechanisms of air-pollution-induced health effects involve oxidative stress and inflammation. The present study evaluates the potential of a polyphenol-enriched food supplement ingredient comprising Lippia citriodora, Olea europaea, Rosmarinus officinalis, and Sophora japonica extracts in mitigating the adverse effects of environmental pollution on skin and cardiopulmonary systems. Both in vitro and ex vivo studies were used to assess the blend’s effects against pollution-induced damage. In these studies, the botanical blend was found to reduce lipid peroxidation, inflammation (by reducing IL-1α), and metabolic alterations (by regulating MT-1H, AhR, and Nrf2 expression) in human skin explants exposed to a mixture of pollutants. Similar results were also observed in keratinocytes exposed to urban dust. Moreover, the ingredient significantly reduced pollutant-induced ROS production in human endothelial cells and lung fibroblasts, while downregulating the expression of apoptotic genes (bcl-2 and bax) in lung fibroblasts. Additionally, the blend counteracted the effect of urban dust on the heart rate in zebrafish embryos. These results support the potential use of this supplement as an adjuvant method to reduce the impact of environmental pollution on the skin, lungs, and cardiovascular tissues

Photobiomodulation Controls Keratinocytes Inflammatory Response through Nrf2 and Reduces Langerhans Cells Activation

International audiencePhotobiomodulation (PBM) is rapidly gaining traction as a valuable tool in dermatology for treating many inflammatory skin conditions using low levels of visible light or near-infrared radiation. However, the physiological regulatory pathways responsible for the anti-inflammatory effect of PBM have not been well defined. Since previous studies showed that nuclear factor-erythroid 2 like 2 (Nrf2) is a master regulator of the skin inflammatory response, we have addressed its role in controlling inflammation by PBM. Primary human keratinocytes (KCs) stimulated with 2,4-dinitrochlorobenzene (DNCB) to mimic pro-inflammatory stress were illuminated with two wavelengths: 660 nm or 520 nm. Both lights significantly reduced the mRNA expression of the DNCB-triggered TNF-α, IL-6, and IL-8 cytokines in KCs, while they enhanced Nrf2 pathway activation. PBM-induced Nrf2 is a key regulator of the inflammatory response in KCs since its absence abolished the regulatory effect of light on cytokines production. Further investigations of the mechanisms contributing to the immunoregulatory effect of PBM in inflamed human skin explants showed that 660 nm light prevented Langerhans cells migration into the dermis, preserving their dendricity, and decreased pro-inflammatory cytokine production compared to the DNCB-treated group. This study is the first to report that the PBM-mediated anti-inflammatory response in KCs is Nrf2-dependent and further support the role of PBM in skin immunomodulation. Therefore, PBM should be considered a promising alternative or complementary therapeutic approach for treating skin-related inflammatory diseases

New evidences of the effects of urban pollution on the skin based on ex vivo physico-chemical studies

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Transcriptomal to morhological modification induced by bacteria on human skin explants

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