3-O-Laurylglyceryl ascorbate improves the development of sensitive skin through the reduction of oxidative stress

Management of triggering factor effects in sensitive skin syndrome with a dermo-cosmetic product

OBJECTIVE

Environmental factors are important in the generation or aggravation of sensitive skin syndrome (SSS). Creams can be useful for patients with SSS, particularly when triggering factors cannot be avoided. Several clinical studies have investigated the safety and efficacy of specific creams in patients with SSS, but the majority were assessed with a single type of triggering factor and were non-comparative. Therefore, this study's aim was to investigate, the benefit of a specific dermo-cosmetic product in response to physical and chemical factors in subjects with SSS.

METHODS

Three clinical studies were performed on subjects presenting SSS. The physical impact was assessed in a stripping test, and in a randomized intra-individual study with a newly developed heat-cold stress model. To assess chemical factors, a capsaicin test on the nasolabial fold was performed.

RESULTS

The product significantly reduced the increase in skin microcirculation caused by stripping after 30 min versus. The untreated condition (45.8% vs. 62.0%; p < 0.01). Immediately and at D28, the product induced a significant increase in skin hydration even after a heat-cold stress, while the overall score of unpleasant symptoms significantly decreased compared with the control (8.1 vs. 10.7 and 3.7 vs. 8.0, respectively; p < 0.01). Regarding chemical factors, a significant difference in the sensation intensity (p < 0.001) was observed after capsaicin stress, also in terms of the sensation duration due to the product application versus the control (192 s vs. 403 s; p < 0.001).

CONCLUSION

These studies show that topical application of a dermo-cosmetic product can prevent unpleasant symptoms and improve the skin state in SSS exposed to physical and chemical triggering factors.

Human skin responses to environmental pollutants: A review of current scientific models

Whatever the exposure route, chemical, physical and biological pollutants modify the whole organism response, leading to nerve, cardiac, respiratory, reproductive, and skin system pathologies. Skin acts as a barrier for preventing pollutant modifications. This review aims to present the available scientific models, which help investigate the impact of pollution on the skin. The research question was "Which experimental models illustrate the impact of pollution on the skin in humans?" The review covered a period of 10 years following a PECO statement on in vitro, ex vivo, in vivo and in silico models. Of 582 retrieved articles, 118 articles were eligible. In oral and inhalation routes, dermal exposure had an important impact at both local and systemic levels. Healthy skin models included primary cells, cell lines, co-cultures, reconstructed human epidermis, and skin explants. In silico models estimated skin exposure and permeability. All pollutants affected the skin by altering elasticity, thickness, the structure of epidermal barrier strength, and dermal extracellular integrity. Some specific models concerned wound healing or the skin aging process. Underlying mechanisms were an exacerbated inflammatory skin reaction with the modulation of several cytokines and oxidative stress responses, ending with apoptosis. Pathological skin models revealed the consequences of environmental pollutants on psoriasis, atopic dermatitis, and tumour development. Finally, scientific models were used for evaluating the safety and efficacy of potential skin formulations in preventing the skin aging process or skin irritation after repeated contact. The review gives an overview of scientific skin models used to assess the effects of pollutants. Chemical and physical pollutants were mainly represented while biological contaminants were little studied. In future developments, cell hypoxia and microbiota models may be considered as more representative of clinical situations. Models considering humidity and temperature variations may reflect the impact of these changes.

Anti-allergic effect of ascorbic acid derivative DDH-1 in a mouse model of atopic dermatitis

Atopic dermatitis (AD) is the most common inflammatory skin disease, which is characterized by excessive Th2 immune responses. In AD patients, the expression of the chemokines CCL17 and CCL22 is increased in skin lesions, leading to the infiltration of Th2 cells. In addition, typical pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, have also been shown to be associated with the pathogenesis of AD. Recently, DDH-1, an ascorbic acid derivative, has been synthesized and demonstrated to have a more stabilized structure and better skin penetrability. Furthermore, DDH-1 has been shown to suppress pro-inflammatory cytokine expression in vitro and in vivo. Therefore, using an AD mouse model, we evaluated the effect of DDH-1 to reduce allergic skin inflammation. We found that cutaneous administration of DDH-1 significantly reduced the expression levels of TNF-α, IL-1β, and IL-6 in the skin lesions of AD-like mice. Additionally, DDH-1 administration also significantly reduced the expression levels of CCL17 and CCL22, resulting in decreased skin infiltration of Th2 cells. Consequently, DDH-1 reduced ear and epidermal thickness, the serum IgE levels, and the number of infiltrating inflammatory cells and mast cells into the AD-like skin lesions. Combination treatment with DDH-1 and corticosteroid more efficiently improved the skin lesions compared to corticosteroid alone. Collectively, our results suggest that DDH-1 has an anti-allergic effect in an AD mouse model by reducing not only the pro-inflammatory cytokine expression but also the Th2-associated chemokine expression. Thus, DDH-1 may be beneficial for AD treatment and prevention as a monotherapy or in combination with corticosteroids.