The direct cellular target of topically applied pimecrolimus may not be infiltrating lymphocytes

The Keratinocyte as a Crucial Cell in the Predisposition, Onset, Progression, Therapy and Study of the Atopic Dermatitis

The keratinocyte (KC) is the main functional and structural component of the epidermis, the most external layer of the skin that is highly specialized in defense against external agents, prevention of leakage of body fluids and retention of internal water within the cells. Altered epidermal barrier and aberrant KC differentiation are involved in the pathophysiology of several skin diseases, such as atopic dermatitis (AD). AD is a chronic inflammatory disease characterized by cutaneous and systemic immune dysregulation and skin microbiota dysbiosis. Nevertheless, the pathological mechanisms of this complex disease remain largely unknown. In this review, we summarize current knowledge about the participation of the KC in different aspects of the AD. We provide an overview of the genetic predisposing and environmental factors, inflammatory molecules and signaling pathways of the KC that participate in the physiopathology of the AD. We also analyze the link among the KC, the microbiota and the inflammatory response underlying acute and chronic skin AD lesions.

Pimecrolimus increases the melanogenesis and migration of melanocytes in vitro

Vitiligo is an intriguing depigmentary disorder and is notoriously difficult to be treated. The ultimate goal of vitiligo treatment is to replenish the lost melanocytes by immigration from hair follicle and to restore the normal function of melanogenesis by residual melanocytes. There are two types of topical calcineurin inhibitors called tacrolimus and pimecrolimus, and are recommended as the first-line treatments in vitiligo. Although pimecrolimus is efficacious for the repigmentation of vitiligo, its intrinsic mechanisms have never been investigated in vitro. This research aimed to study the ability of pimecrolimus on stimulating melanogenesis, melanocyte migration and MITF (microphthalmia associated transcription factor) protein expression. Results showed that pimecrolimus at the dosages of 1, 10, 10² nM were neither mitogenic nor cytotoxic to melanocytes. The addition of pimecrolimus at 10, 10² and 10³ nM significantly increased intracellular tyrosinase activity, which was consistent with the elevated content of melanin content at the same concentrations. The peak effect was seen at 72 h in response to 10² nM pimecrolimus. Results of the wound scratch assay and Transwell assays indicate that pimecrolimus is effective in facilitating melanocyte migration on a collagen IV-coated surface. In addition, MITF protein yield reached the highest by pimecrolimus at 10² nM. In brief, pimecrolimus enhances melanin synthesis as well as promotes migration of melanocytes directly, possibly via their effects on MITF protein expression.

Current application of phytocompound-based nanocosmeceuticals for beauty and skin therapy

Phytocompounds have been used in cosmeceuticals for decades and have shown potential for beauty applications, including sunscreen, moisturizing and antiaging, and skin-based therapy. The major concerns in the usage of phyto-based cosmeceuticals are lower penetration and high compound instability of various cosmetic products for sustained and enhanced compound delivery to the beauty-based skin therapy. To overcome these disadvantages, nanosized delivery technologies are currently in use for sustained and enhanced delivery of phyto-derived bioactive compounds in cosmeceutical sectors and products. Nanosizing of phytocompounds enhances the aseptic feel in various cosmeceutical products with sustained delivery and enhanced skin protecting activities. Solid lipid nanoparticles, transfersomes, ethosomes, nanostructured lipid carriers, fullerenes, and carbon nanotubes are some of the emerging nanotechnologies currently in use for their enhanced delivery of phytocompounds in skin care. Aloe vera, curcumin, resveratrol, quercetin, vitamins C and E, genistein, and green tea catechins were successfully nanosized using various delivery technologies and incorporated in various gels, lotions, and creams for skin, lip, and hair care for their sustained effects. However, certain delivery agents such as carbon nanotubes need to be studied for their roles in toxicity. This review broadly focuses on the usage of phytocompounds in various cosmeceutical products, nanodelivery technologies used in the delivery of phytocompounds to various cosmeceuticals, and various nanosized phytocompounds used in the development of novel nanocosmeceuticals to enhance skin-based therapy.

Atopic dermatitis: from new pathogenic insights toward a barrier-restoring and anti-inflammatory therapy

PURPOSE OF REVIEW

Recent published work on atopic dermatitis focusing on the pathogenesis and epidemiology, which have a direct effect on treatment, is presented.

RECENT FINDINGS

Worldwide, the incidence of atopic dermatitis is still increasing, although a plateau seems to be reached in certain industrialized countries. In addition to the filaggrin missense mutations, other mechanisms responsible for impaired skin-barrier function have been identified. These findings have a direct impact on therapy as well as behavior strategies. The barrier defect and the resulting inflammation in the skin, in particular interleukin (IL)-17-mediated responses, play an important role in promoting allergic airway responses and food allergy.

SUMMARY

These recent findings on epithelial barrier defects, as well as cells and cytokines important for atopic dermatitis development, provide new insights into its pathogenesis, help to characterize patient subgroups, and identify new therapeutic strategies.