The development of alternative approaches for safety and efficacy testing that avoid the use of animals is a worldwide trend, which relies on the improvement of current models and tools so that they better reproduce human biology. Human skin from elective plastic surgery is a promising experimental model to test the effects of topically applied products. As the structure of native skin is maintained, including cell population (keratinocytes, melanocytes, Langerhans cells and fibroblasts) and dermal matrix (containing collagen, elastin, glycosaminoglycans, etc.), it most closely matches the effects of substances on in vivo human skin. In this review, we present a collection of results that our group has generated over the last years, involving the use of human skin and scalp explants, demonstrating the feasibility of this model. The development of a test system with ex vivo skin explants, of standard size and thickness, and cultured at the air–liquid interface, can provide an important tool for understanding the mechanisms involved in several cutaneous disorders.
BACKGROUND
Pollution, especially cigarette smoke, is a major cause of skin damage.
OBJECTIVES
To assess the effects of the small molecule polyphenol, honokiol, on reversing cigarette smoke induced damage in vitro to relevant skin cells.
METHODS
Keratinocytes (HaCat) cultures were exposed to cigarette smoke and, after 48 hours, IL-1α and IL-8 were measured in cell supernatants. Moreover, TIMP-2 production, apoptosis rate, and senescence β-galactosidase expression were evaluated in primary human fibroblasts (HFF-1) cultures.
RESULTS
Honokiol at 10 μM reduced IL-1α production by 3.4 folds (p<0.05), and at 10 and 20 μM reduced IL-8 by 23.9% and 53.1% (p<0.001), respectively, in HaCat keratinocytes. In HFF-1, honokiol restored TIMP-2 production by 96.9% and 91.9% (p<0.001), respectively, at 10 and 20 μM, as well as reduced apoptosis by 47.1% (p<0.001) and 41.3% (p<0.01), respectively. Finally, honokiol reduced senescence associated β-galactosidase expression in HFF-1.
CONCLUSION
Honokiol protects both HFF-1 and HaCat against cigarette smoke induced inflammation, collagenolysis, apoptosis, and senescence.
Background: Melanin plays an important role in protecting the skin against the harmful effects of solar radiation, but its abnormal accumulation may become an aesthetic problem, such as melasma and age spots. Aims: The aim of this study was to evaluate the antiangiogenic and whitening effects of a depigmentation formulation (BLTX) using an in vitro model of human cell and skin culture. Methods: Human fibroblasts, keratinocytes or melanocytes were treated with BLTX and subjected to oxidative stress by UV radiation or inflammatory stress with IL-1α for quantification of melanin, tyrosinase, endothelin-1, PAR-2, VEGF and iNOS. Fragments of human skin, from elective plastic surgery, were treated with BLTX and subjected to histological evaluation with hematoxylin/eosin associated with Fontana-Masson technique for melanin view. A parametric method, the one-way analysis of variance (ANOVA) followed by the Bonferroni test, was used to compare data among all groups. Results: The results demonstrated that BLTX promotes a reduction in VEGF and iNOS protein synthesis in cultured dermal fibroblasts, indicating an antiangiogenic property. In relation to whitening effect, BLTX was able to reduce the production of melanin in both systems, melanocytes and human skin cultures. The depigmenting action was also revealed by decreasing the levels of endothelin-1, PAR-2 and activity of tyrosinase, when compared to cultures exposed to UV radiation. Conclusion: The results allow us to infer that BLTX presents an antiangiogenic effect indicating a role in the vascular component of melasma. Furthermore, the whitening property observed reinforces its use in the prevention and treatment of melasma.
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