An ex vivo skin model to probe modulation of local cutaneous arachidonic acid inflammation pathway

Secretome of human umbilical cord mesenchymal stem cell maintains skin homeostasis by regulating multiple skin physiological function

Skin is the largest organ in the body and the first defense to resist various diseases and external stimuli that easily cause infection and inflammation. Aseptic inflammation, barrier damage, and foreign aid pressure induce the destruction and damage to the skin microenvironment. Subsequently, it destroys the skin's physiological function, leading to the maintenance and circulation of steady-state imbalance and aggravating the process of skin disorders. Our study evaluated the therapeutic potential of the secretome of human umbilical cord mesenchymal stem cells (UC-CM) for dermatological diseases in adult human skin cells, ex vivo skin tissue, and a 3D skin model. Our data suggested several advantages of UC-CM due to (1) their low cytotoxicity and sensitization properties; (2) their anti-inflammatory capacity for treating inflammatory chronic cutaneous diseases; (3) their enhanced capacity of the skin barrier for treating abnormal barrier metabolism; and (4) their positive impact on restoring skin homeostasis due to effective regulation ability of skin physiological function including cell apoptosis, detoxification, and anti-aging. We thus envisage that the possibility of harnessing the therapeutic potential of UC-CM might benefit patients suffering from inflammatory skin disorders such as atopic dermatitis, acne, and psoriasis.

Common cosmetic compounds can reduce air pollution-induced oxidative stress and pro-inflammatory response in the skin

Introduction: Constantly increasing air pollution (AP) poses a concern negatively affecting our health including the skin. A typical manifestation of the skin damage induced by AP is its premature aging, irritation, skin barrier impairment, pigmentation disorders and development or exacerbation of various skin diseases. For these reasons, it is crucial to protect the skin from the negative effects of AP. In this study we evaluated the ability of some compounds commonly used in dermatological or cosmetic preparations with various biological activities to reduce AP-induced skin damage. Methods: We established a new experimental model using porcine skin explants exposed to cigarette smoke (CS) where we determined the level of reactive oxygen species (ROS) in the stratum corneum, skin barrier lipids peroxidation and gene expression of the pro-inflammatory cytokine IL-6 in the epidermis. We then tested several polysaccharides and their derivatives such as sodium hyaluronate (SH) of different molecular weights (MW, 1,6 MDa, 300 kDa, 15 kDa, 5 kDa), yeast glucomannan, schizophyllan and carboxymethyl β-glucan, a vitamin C derivative sodium ascorbyl phosphate, niacinamide and D-panthenol for their ability to prevent CS-induced skin damage. For the evaluation and comparison of their mechanism of action, film-forming effect was determined by TEWL and gloss measurements and the antioxidant properties were assessed by DPPH assay. Results: In the skin samples exposed to CS we observed significant negative changes such as the presence of large amount of ROS in the stratum corneum, a high level of skin barrier lipids peroxidation and upregulated IL6 gene expression. Pretreatment of the skin samples with all the tested substances significantly prevented CS-induced skin damage. The most effective was high MW SH probably due to its best film-forming effect and sodium ascorbyl phosphate with the best antioxidant properties. Conclusion: AP leads to a significant skin damage which can be effectively prevented by using some conventional cosmetic and dermatological ingredients with various mechanisms of action.

Use of Cytokine Mix-, Imiquimod-, and Serum-Induced Monoculture and Lipopolysaccharide- and Interferon Gamma-Treated Co-Culture to Establish In Vitro Psoriasis-like Inflammation Models

Psoriasis (Ps), commonly perceived as a skin and joint disorder, has a complex basis and results from disturbances in the sophisticated network between skin and the immune system. This makes it difficult to properly depict the complete pathomechanism on an in vitro scale. Deciphering the complicated or even subtle modulation of intra- and intercellular factors, assisted by the implementation of in vitro human skin models, may provide the opportunity to dissect the disease background step by step. In addition to reconstructed artificial skin substitutes, which mimic the native physiological context, in vitro models are conducive to the broad “3 Rs” philosophy (reduce, refine, and replace) and represent important tools for basic and applied skin research. To meet the need for a more comprehensive in vitro Ps model, a set of various experimental conditions was applied in this study. The selection of in vitro treatment that mimicked the Ps phenotype was illustrated by analyses of discriminating biomarker genes involved in the pathogenesis of the disease, i.e., keratinocyte differentiation markers, antimicrobial peptides, chemokines, and proliferation markers. This resulted in a reproducible protocol for the use of the primary skin keratinocyte (pKC) monoculture treated with a cytokine cocktail (5MIX, i.e., interleukin (IL) 1 alpha (IL-1α), IL-17A, IL-22, oncostatin M (OSM), and tumour necrosis factor alpha (TNF-α)) at a calcium (Ca²⁺) concentration (i.e., 2 mM) in an applied medium, which best mirrored the in vitro Ps-like inflammatory model. In addition, based on waste skin material, the method has the potential for extensive experimentation, both in detailed molecular studies and preclinical tests.

Dermal Penetration Analysis of Curcumin in an ex vivo Porcine Ear Model Using Epifluorescence Microscopy and Digital Image Processing

INTRODUCTION

Curcumin is a promising drug candidate, but its use for dermal application is limited due to its poor aqueous solubility. Thus, formulations that increase the solubility of curcumin are needed to fully exploit the therapeutic potential of curcumin. Various previous studies address this issue, but a comparison of the efficacy between these formulations remains difficult. The reason for this is a missing standard formulation as benchmark control and an easy-to-use skin penetration model that allows for a fast discrimination between different formulations.

OBJECTIVE

Thus, the aims of this study were the development of a curcumin standard formulation and a screening tool that allows for a fast discrimination between the dermal penetration efficacies of curcumin from different formulations.

METHODS

Ethanolic curcumin solutions were selected as simple and easy to produce standard formulations, and the ex vivo porcine ear model, coupled with epifluorescence microscopy and subsequent digital image analysis, was utilized to determine the dermal penetration efficacy of curcumin from the different formulations.

RESULTS

Results show that the utilized skin penetration model is a suitable and versatile tool that enables not only a fast determination of the dermal penetration efficacy of curcumin from different formulations but also a detailed and mechanistic information on the fate of chemical compounds after dermal penetration. Ethanolic solutions containing 0.25% curcumin were found to be the most suitable standard formulation.

CONCLUSIONS

Results of the study provide a new, effective screening tool for the development of dermal formulations for improved dermal delivery of curcumin.