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The primary function of the skin is to form a mechanical, permeability, antimicrobial, and ultraviolet radiation barrier, which is essential for maintaining physiological homeostasis. Our previous studies demonstrated that cutaneous pigmentation could promote skin barrier function in addition to providing anti‐ultraviolet irradiation defense. The present study aimed to develop a new regimen that enhances skin barrier function by regulating skin pigmentation using low‐concentration imiquimod. Results showed that topical application of low‐concentration imiquimod effectively induced skin hyperpigmentation in the dorsal skin and external ear of mice without inducing inflammatory cell infiltration. An in vitro study also revealed that low‐concentration imiquimod did not induce any cytotoxic effects on melanoma cells but triggered excessive melanin synthesis. In coculture systems, low‐concentration imiquimod was noted to increase tyrosinase activity in a broader cellular context, revealing the potential role of neighboring cells in melanin production. The next‐generation sequencing result indicated that PKCη and Dnm3 might regulate melanin synthesis and release during imiquimod treatment. Overall, our study presents new insights into the regulation of melanin production by low‐concentration imiquimod, both in a mice model and cultured cells. Furthermore, our study highlights the potential benefits of imiquimod in promoting melanin synthesis without causing skin disruptions or inducing inflammation, validating its potential to serve as a method for enhancing skin barrier functions by regulating the epidermal melanization reaction. [ABSTRACT FROM AUTHOR]

Background: Melanogenesis is a complex process which is tightly regulated by several enzymes. However, abnormal melanogenesis can cause severe dermatological problems. Roots of Angelica dahurica have been used for skin care as a part of traditional Chinese medicine for many generations. However, the role of A. dahurica in melanogenesis remains unclear. Objective: Previous in vitro and in vivo studies have demonstrated that NK-1R exerts positive effects in melanogenesis via the Wnt/βcatenin signaling pathway. In this study, we investigated the effects of A. dahurica ethanol extract (ADE) on NK-1R and Wnt/β-catenin signaling, and evaluated the effect of NK-1R on melanogenesis in B16F0 cells. Results: Angelica dahurica ethanol extract efficiently downregulated Neurokinin-1 receptor and Wnt/β-catenin signaling by decreasing the expression of β-catenin, MITF, LEF-1, TYR, TRP1, and TRP2 and increasing the expression of GSK3β, which resulted from the weakened expression of the Neurokinin-1 receptor inhibitor [Sar9,Met(O2)11]-Substance P (SMSP). Furthermore, the intracellular melanin assay and cellular tyrosinase activity confirmed these findings. Conclusion: This study suggests that ADE has potential to downregulate Neurokinin-1 receptor in SMSP-induced B16F0 cells, thereby repressing the Wnt/β-catenin signaling and reduces melanin production. [ABSTRACT FROM AUTHOR]

SR‐T100 gel, containing solamargine extracted from Solanum undatum (synonym: Solanum incanum), had good therapeutic effects on actinic keratosis (AK) in human and ultraviolet B‐induced papilloma in mice. This study aimed to investigate the immunohistochemical changes in the human skin after SR‐T100 treatment. An immunohistochemical study was performed and the changes in photocarcinogenesis and photoaging markers after 16‐week SR‐T100 gel treatment were documented. SR‐T100 gel treatment for 16 weeks resulted in complete remission in nine AK lesions and partial remission in four AK lesions. SR‐T100 gel abolished the expression of mutant p53 and SOX2 and restored the expression of NOTCH1. Additionally, SR‐T100 gel improved wrinkling in human skin, while restoring the expression of lamin B1 and increasing synthesis of new elastic fibers. SR‐T100 gel had therapeutic effects on photocarcinogenesis and photoaging of photodamaged skin with AK. [ABSTRACT FROM AUTHOR]

Background: The cropping area of genetically modified (GM) crops has constantly increased since 1996. However, currently, cultivating GM crops is associated with many concerns. Transgenes are transferred to non-GM crops through pollen-mediated gene flow, which causes environmental problems such as superweeds and introgressive hybridization. Rapeseed (Brassica napus L.), which has many GM varieties, is one of the most crucial oil crops in the world. Hybridization between Brassica species occurs spontaneously. B. rapa grows in fields as a weed and is cultivated as a crop for various purposes. Both B. rapa weeds and crops participate in gene flow among rapeseed. Therefore, gene flow risk and the coexistence of these two species should be studied. Results: In this study, field experiments were conducted at two sites for 4 years to evaluate gene flow risk. In addition, zero-inflated models were used to address the problem of excess zero values and data overdispersion. The difference in the number of cross-pollination (CP) events was nonsignificant between upwind and downwind plots. The CP rate decreased as the distance increased. The average CP rates at distances of 0.35 and 12.95 m were 2.78% and 0.028%, respectively. In our results, zero-inflated negative binomial models were comprehensively superior to zero-inflated Poisson models. The models predicted isolation distances of approximately 1.36 and 0.43 m for the 0.9% and 3% threshold labeling levels, respectively. Conclusions: Cultivating GM crops is prohibited in Taiwan; however, the study results can provide a reference for the assessment of gene flow risk and the coexistence of these two species in Asian countries establishing policies for GM crops. [ABSTRACT FROM AUTHOR]

Pigmentation evolved in ancestral humans to protect against toxic, ultraviolet B irradiation, but the question remains: "what is being protected?" Because humans with dark pigmentation display a suite of superior epidermal functions in comparison with their more lightly pigmented counterparts, we hypothesized and provided evidence that dark pigmentation evolved in Africa to support cutaneous function. Because our prior clinical studies also showed that a restoration of a competent barrier dampens cutaneous inflammation, we hypothesized that resistance to inflammation could have provided pigmented hominins with yet another, important evolutionary benefit. We addressed this issue here in two closely related strains of hairless mice, endowed with either moderate (Skh2/J) or absent (Skh1) pigmentation. In these models, we showed that (a) pigmented mice display a markedly reduced propensity to develop inflammation after challenges with either a topical irritant or allergen in comparison with their nonpigmented counterparts; (b) visible and histologic evidence of inflammation was paralleled by reduced levels of pro‐inflammatory cytokines (i.e., IL‐1α and INFα); (c) because depigmentation of Skh2/J mouse skin enhanced both visible inflammation and pro‐inflammatory cytokine levels after comparable pro‐inflammatory challenges, the reduced propensity to develop inflammation was directly linked to the presence of pigmentation; and (d) furthermore, in accordance with our prior work showing that pigment production endows benefits by reducing the surface pH of skin, acidification of albino (Skh1) mouse skin also protected against inflammation, and equalized cytokine levels to those found in pigmented skin. In summary, pigmentation yields a reduced propensity to develop inflammation, consistent with our hypothesis that dark pigmentation evolved in ancestral humans to provide a suite of barrier‐linked benefits that now include resistance to inflammation. [ABSTRACT FROM AUTHOR]

Plant oils have been utilized for a variety of purposes throughout history, with their integration into foods, cosmetics, and pharmaceutical products. They are now being increasingly recognized for their effects on both skin diseases and the restoration of cutaneous homeostasis. This article briefly reviews the available data on biological influences of topical skin applications of some plant oils (olive oil, olive pomace oil, sunflower seed oil, coconut oil, safflower seed oil, argan oil, soybean oil, peanut oil, sesame oil, avocado oil, borage oil, jojoba oil, oat oil, pomegranate seed oil, almond oil, bitter apricot oil, rose hip oil, German chamomile oil, and shea butter). Thus, it focuses on the therapeutic benefits of these plant oils according to their anti-inflammatory and antioxidant effects on the skin, promotion of wound healing and repair of skin barrier. [ABSTRACT FROM AUTHOR]

Background: Though vitiligo is a common depigmentary disorder, it still represents a substantial therapeutic challenge. Therapeutic options are limited in part due to its uncertain etiology. Objective: Because recent studies suggest that histamine stimulates melanogenesis in vitro, we determined here whether topical histamine stimulates repigmentation in patients with stable, nonsegmental vitiligo. Methods: A total of 23 otherwise normal volunteers with vitiligo, including 14 males and 9 females aged 6-59 years (mean age 29.2 ± 2.8), were enrolled in this study. 1% histamine in distilled water was applied to the lesions twice daily for 5 weeks, while comparable lesions, treated with distilled water alone, served as the controls. The melanin index was measured on the uninvolved and lesional skin sites before and after 5 weeks of treatments using the melanin/erythema probe connected to a Courage-Khazaka MPA5 (Cologne, Germany). Changes in epidermal permeability barrier were also assessed at the same time point. To determine whether histamine-induced repigmentation is receptor-dependent, both ears of C57BL/6J mice were treated topically with 5% cimetidine, a histamine type 2 receptor (H2r) antagonist, twice daily for 10 days. One hour after each cimetidine application, the right ear was treated topically with 10% histamine, while vehicle alone was applied to the left ear. Changes in melanin index were measured 24 h after the last application of histamine and vehicle as described in the human study. Results: In patients with vitiligo treated with vehicle alone for 5 weeks, the melanin index remained unchanged, while topical histamine treatment increased the melanin index by 38% (p < 0.001 vs. both vehicle and pretreatment), which was paralleled by a >60% reduction in lesion surface area. Moreover, topical histamine accelerated permeability barrier recovery. No adverse events were observed following histamine applications. In mice, topical histamine significantly increased the melanin index, while topical co-applications of the H2r antagonist (cimetidine) prevented the expected histamine-induced increase in melanin index. Conclusions: These studies indicate that topical histamine or an H2r agonist could be useful for treating nonsegmental vitiligo, but further clinical studies in large populations will be required to validate the efficacy and safety of this approach. [ABSTRACT FROM AUTHOR]

The beneficial effects of certain herbal medicines on cutaneous function have been appreciated for centuries. Among these agents, chrysanthemum extract, apigenin, has been used for skin care, particularly in China, for millennia. However, the underlying mechanisms by which apigenin benefits the skin are not known. In this study, we first determined whether topical apigenin positively influences permeability barrier homoeostasis, and then the basis thereof. Hairless mice were treated topically with either 0.1% apigenin or vehicle alone twice daily for 9 days. At the end of the treatments, permeability barrier function was assessed with either an electrolytic water analyzer or a Tewameter. Our results show that topical apigenin significantly enhanced permeability barrier homoeostasis after tape stripping, although basal permeability barrier function remained unchanged. Improved barrier function correlated with enhanced filaggrin expression and lamellar body production, which was paralleled by elevated m RNA levels for the epidermal ABCA12. The m RNA levels for key lipid synthetic enzymes also were upregulated by apigenin. Finally, both cathelicidin-related peptide and mouse beta-defensin 3 immunostaining were increased by apigenin. We conclude that topical apigenin improves epidermal permeability barrier function by stimulating epidermal differentiation, lipid synthesis and secretion, as well as cutaneous antimicrobial peptide production. Apigenin could be useful for the prevention and treatment of skin disorders characterized by permeability barrier dysfunction, associated with reduced filaggrin levels and impaired antimicrobial defenses, such as atopic dermatitis. [ABSTRACT FROM AUTHOR]