Vitamin E ointment at high dose levels suppresses contact dermatitis in rats by stabilizing keratinocytes

Benefits of topical natural ingredients in epidermal permeability barrier

Because of the crucial role of epidermal permeability barrier in regulation of cutaneous and extracutaneous functions, great efforts have been made to identify and develop the regimens that can improve epidermal permeability barrier function. Studies have demonstrated that oral administration of natural ingredients can improve epidermal permeability barrier in various skin conditions, including inflammatory dermatoses and UV-irradiation. Moreover, topical applications of some natural ingredients can also accelerate the repair of epidermal permeability barrier after acute barrier disruption and lower transepidermal water loss in the intact skin. Natural ingredient-induced improvements in epidermal permeability barrier function can be attributable to upregulation of keratinocyte differentiation, lipid production, antioxidant, hyaluronic acid production, expression of aquaporin 3 and sodium-hydrogen exchanger 1. In this review, we summarize the benefits of topical natural ingredients in epidermal permeability barrier in normal skin with or without acute barrier disruption and the underlying mechanisms.

Modulation of allergic contact dermatitis via gut microbiota modified by diet, vitamins, probiotics, prebiotics, and antibiotics

Allergic contact dermatitis is one of the most common recorded occupational diseases. There are many different substances that the skin comes into contact with on a daily basis and that can cause ACD, e.g., preservatives, surfactants, and antimicrobial agents. The development of a mouse model of ACD has provided insight into the immune mechanisms involved. Drugs used in the treatment of skin diseases have many side effects. Therefore, alternative methods of suppressing the immune response to reduce the symptoms of skin diseases are being sought. In recent years, high hopes have been placed on dietary modulation and supplementation to affect the intestinal microbial composition and promote anti-inflammatory responses. In addition, other studies have shown the crucial role of intestinal microbiota in many immune-mediated diseases. Recognition and characterization of pro- and anti-inflammatory nutrients and supplements may be crucial to support the treatment of diseases such as atopic dermatitis, acne vulgaris, psoriasis, and allergic contact dermatitis.

Neem Oil or Almond Oil Nanoemulsions for Vitamin E Delivery: From Structural Evaluation to in vivo Assessment of Antioxidant and Anti-Inflammatory Activity

Purpose

Vitamin E (VitE) may be classified in "the first line of defense" against the formation of reactive oxygen species. Its inclusion in nanoemulsions (NEs) is a promising alternative to increase its bioavailability. The aim of this study was to compare O/W NEs including VitE based on Almond or Neem oil, showing themselves antioxidant properties. The potential synergy of the antioxidant activities of oils and vitamin E, co-formulated in NEs, was explored.

Patients and Methods

NEs have been prepared by sonication and deeply characterized evaluating size, ζ-potential, morphology (TEM and SAXS analyses), oil nanodroplet feature, and stability. Antioxidant activity has been evaluated in vitro, in non-tumorigenic HaCaT keratinocytes, and in vivo through fluorescence analysis of C. elegans transgenic strain. Moreover, on healthy human volunteers, skin tolerability and anti-inflammatory activity were evaluated by measuring the reduction of the skin erythema induced by the application of a skin chemical irritant (methyl-nicotinate).

Results

Results confirm that Vitamin E can be formulated in highly stable NEs showing good antioxidant activity on keratinocyte and on C. elegans. Interestingly, only Neem oil NEs showed some anti-inflammatory activity on healthy volunteers.

Conclusion

From the obtained results, Neem over Almond oil is a more appropriate candidate for further studies on this application.

Antibiotics-Free Compounds for Chronic Wound Healing

The rapid rise in the health burden associated with chronic wounds is of great concern to policymakers, academia, and industry. This could be attributed to the devastating implications of this condition, and specifically, chronic wounds which have been linked to invasive microbial infections affecting patients' quality of life. Unfortunately, antibiotics are not always helpful due to their poor penetration of bacterial biofilms and the emergence of antimicrobial resistance. Hence, there is an urgent need to explore antibiotics-free compounds/formulations with proven or potential antimicrobial, anti-inflammatory, antioxidant, and wound healing efficacy. The mechanism of antibiotics-free compounds is thought to include the disruption of the bacteria cell structure, preventing cell division, membrane porins, motility, and the formation of a biofilm. Furthermore, some of these compounds foster tissue regeneration by modulating growth factor expression. In this review article, the focus is placed on a number of non-antibiotic compounds possessing some of the aforementioned pharmacological and physiological activities. Specific interest is given to Aloevera, curcumin, cinnamaldehyde, polyhexanide, retinoids, ascorbate, tocochromanols, and chitosan. These compounds (when alone or in formulation with other biologically active molecules) could be a dependable alternative in the management or prevention of chronic wounds.

Patch Testing With Tocopherol and Tocopherol Acetate: The North American Contact Dermatitis Group Experience, 2001 to 2016

BACKGROUND

Vitamin E (tocopherol) a naturally occurring mixture of antioxidants commonly used in topical skin care products, may cause allergic contact dermatitis.

OBJECTIVE

The aim of this study was to characterize positive patch test reactions to tocopherol and tocopherol acetate.

METHODS

This is a retrospective analysis of North American Contact Dermatitis Group patch test data to tocopherols (DL-α-tocopherol 100% and/or DL-α-tocopherol acetate 100%) from 2001 to 2016.

RESULTS

Of the 38,699 patients patch tested to tocopherol and/or tocopherol acetate, 349 (0.9%) had positive reactions; of these, 87.6% were currently relevant. Most (51.4%) were weak (+) and/or not related to occupation (99.1%). Compared with tocopherol-negative patients, tocopherol-positive individuals were more likely to be female (72.5% vs 67.2%, P = 0.0355), have a final primary diagnosis of allergic contact dermatitis (74.2% vs 52.6%, P < 0.0001), and have dermatitis in a scattered generalized distribution (23.8% vs 18.2%, P = 0.0072); they were also less likely to have hand involvement (16.6% vs 22.3%, P = 0.0064). The most common source of tocopherol was personal care products, especially moisturizers.

CONCLUSIONS

Positive patch test reactions to tocopherols were relatively rare given their widespread use. When positive, current clinical relevance was high. Tocopherol-positive patients were more likely to be female and presented with dermatitis on the face or in a scattered generalized pattern.

Protective Effects of Unsaponifiable Matter from Perilla Seed Meal on UVB-induced Damages and the Underlying Mechanisms in Human Skin Fibroblasts

Unsaponifiable matter (USM) from perilla seed meal contains numerous phytochemicals, including tocopherols, phytosterols, squalene, and policosanols, that exhibit antioxidant and health-promoting properties. In this study, the protective effects of USM on UVB-induced skin aging were investigated in Hs68 cells. UVB irradiation decreased cell viability by 26% compared to the control. However, USM blocked UVB-induced cytotoxicity. Moreover, USM treatment significantly decreased the UVB-induced production of reactive oxygen species and attenuated the UVB-induced production and mRNA expression of matrix metalloproteinases (MMPs) by inhibiting the phosphorylation of mitogen-activated protein kinases and activator protein 1 (AP-1). Furthermore, UVB exposure led to a 49.4% reduction in collagen synthesis. However, USM treatment restored collagen synthesis through upregulation of the transforming growth factor beta (TGF-β)/Smad2/3 pathways. These data indicate that USM regulates the production of MMPs and collagen by modulation of the TGF-β/Smad pathway and AP-1 activity, suggesting that USM may be a useful anti-photoaging ingredient.

Vitamin E preconditioning alleviates in vitro thermal stress in cultured human epidermal keratinocytes

AIMS

Thermal burns are the most common type of skin injuries. Clinically, the deteriorating thermal wounds have been successfully treated with skin cell sheets, suspensions or bioengineered skin substitutes. After thermal injury, oxidative microenvironment prevalent in the burnt tissue due to imbalance between production of free radicals and antioxidants defense aiding to destruction of cellular or tissue components. However, depleted antioxidant content particularly vitamin E after heat injury challenges efficient regenerative and healing capacity of transplanted cells. Thus, aim of current study was to pretreat human epidermal keratinocytes with vitamin E in order to enhance their survival rate and therapeutic ability under oxidative microenvironment induced by in vitro heat stress.

MAIN METHODS

Keratinocytes were treated with 100 μM vitamin E at 37 °C for 24 h followed by thermal stress at 51 °C for 10 min. Cell viability and cytotoxicity assays, gene expression analysis and paracrine release analysis were performed.

KEY FINDINGS

Vitamin E preconditioning resulted in significantly improved cell morphology, enhanced viability and reduced lactate dehydrogenase release. Furthermore, Vitamin E preconditioned cells exposed to thermal stress showed significant down-regulated expression of BAX and up-regulated expression of PCNA, BCL-XL, vascular endothelial growth factor (VEGF), involucrin, transglutaminase 1 (TGM1) and filaggrin (FLG) escorted by increased paracrine release of VEGF, basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF).

SIGNIFICANCE

Results of the current study suggest that clinical transplantation of vitamin E preconditioned keratinocytes alone or in combination with dermal fibroblasts in skin substitutes for the treatment of thermally injured skin.

Safety Assessment of Tocopherols and Tocotrienols as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) assessed the safety of 14 tocopherols and tocotrienols and concluded these ingredients are safe as used in cosmetics. The tocopherols are reported to function in cosmetics as antioxidants or skin-conditioning agents; in contrast, tocotrienols are not reported to function as an antioxidants in cosmetics but as a light stabilizer, oral care agent, or skin-conditioning agent. The Panel reviewed the new and existing animal and clinical data to determine the safety of these ingredients and found it appropriate to extrapolate the existing information to conclude on the safety of all the tocopherols and tocotrienols.

Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils

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.

Formulations of hydrogels and lipogels with vitamin E

Vitamin E, a topically administered antioxidant, reduces erythema, photoaging, photocarcinogenesis, edema, and skin hypersensitivity associated with exposure to ultraviolet B (UVB) radiation. Virgin olive oil, which also has antioxidant properties, reduces the number of, and delays the onset of skin cancer induced by UVB radiation when used after sunbathing. Topical use after sunbathing of formulations that contain virgin olive oil and vitamin E may therefore reduce the number and delay the onset of UVB-related skin cancer in humans. We designed formulations of gels with olive oil (lipogels) and hydrogels containing 2% tocopherol. The formulations were optimized on the basis of rheological, organoleptic, biopharmaceutical, and cosmetic criteria. Different formulae for hydrogels with vitamin E were ideal for application after exposure to solar radiation because of their good organoleptic properties. Vitamin E lipogels are of potential use in cosmetics such as locally acting anti-aging treatments because of the antioxidant effects of vitamin E.

Topical application of silymarin reduces chemical-induced irritant contact dermatitis in BALB/c mice

Irritant contact dermatitis (ICD) is a non-allergic local inflammatory reaction of a skin and one of the most frequent occupational health problems. Silymarin has been clinically used in Europe for a long time to treat liver diseases and also known to have anti-cancer and anti-inflammatory activities. In the present study, we report that topical application of silymarin reduces chemical-induced ICD. Topical application of 2,4-dinitrochlorobenzene (DNCB) induced an ear swelling in BALB/c mice and silymarin suppressed DNCB-induced increase in ear thickness. Prophylactic and therapeutic application of silymarin showed similar effect on DNCB-induced increase in ear thickness and skin water content. In addition, phobor ester- or croton oil-induced increase in ear thickness was also inhibited by silymarin treatment. Silymarin also blocked neutrophil accumulation into the ear induced by these irritants. Further study demonstrated that DNCB-induced tumor necrosis factor-alpha (TNF-alpha) expression in mouse ear was suppressed by silymarin. DNCB-induced expression of KC, one of the main attractors of neutrophil in mice, and adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and E-selectin in mouse ear were also inhibited by silymarin. Moreover, TNF-alpha-induced expression of cytokines, such as TNF-alpha and IL-1beta, and a chemokine, IL-8, were suppressed by silymarin treatment in human keratinocyte cell line, HaCaT. Silymarin also blocked TNF-alpha- and DNCB-induced NF-kappaB activation in HaCaT. Collectively, these results demonstrate that topically applied silymarin inhibits chemical-induced ICD in mice and this might be mediated, at least in part, by blocking NF-kappaB activation and consequently inhibiting the expression of cytokines and adhesion molecules.

Vitamin E in human skin: organ-specific physiology and considerations for its use in dermatology

Vitamin E has been used for more than 50 years in experimental and clinical dermatology. While a large number of case reports were published in this time, there is still a lack of controlled clinical studies providing a rationale for well defined dosages and clinical indications. In contrast, advances in basic research on the physiology, mechanism of action, penetration, bioconversion and photoprotection of vitamin E in human skin has led to the development of numerous new formulations for use in cosmetics and skin care products. This article reviews basic mechanisms and possible cosmetic as well as clinical implications of the recent advances in cutaneous vitamin E research. Experimental evidence suggests that topical and oral vitamin E has antitumorigenic, photoprotective, and skin barrier stabilizing properties. While the current use of vitamin E is largely limited to cosmetics, controlled clinical studies for indications such as atopic dermatitis or preventions of photocarcinogenesis are needed to evaluate the clinical benefit of vitamin E.

Vitamin E: Critical Review of Its Current Use in Cosmetic and Clinical Dermatology

BACKGROUND AND OBJECTIVE

The lipophilic antioxidant vitamin E has been used for more than 50 years in clinical and experimental dermatology. However, although a large number of case reports were published, there is still a lack of controlled clinical studies providing a rationale for clinical indications and dosage. In contrast, advances in basic research on the physiology, mechanism of action, penetration, bioconversion, and photoprotection of vitamin E in human skin have led to the development of numerous new formulations for use in cosmetics and skin care products.

RESULTS

This article reviews the basic mechanisms and possible cosmetical and clinical implications of the recent advances in cutaneous vitamin E research. Experimental evidence suggests that topical and oral vitamin E has anticarcinogenic, photoprotective, and skin barrier-stabilizing properties.

CONCLUSION

Although its current use is largely limited to cosmetics, controlled clinical studies for indications such as atopic dermatitis or prevention of photocarcinogenesis are needed to evaluate the clinical benefit of vitamin E.

Cytotoxicity of trichloroethylene and perchloroethylene on normal human epidermal keratinocytes and protective role of vitamin E

Trichloroethylene (TCE) and perchloroethylene (PERC), the most common alkenyl halides, have been extensively used in industry, and can cause skin damage. To evaluate their cytotoxic potential on skin, the effects of these agents on the normal human epidermal keratinocytes (NHEK) were investigated. Their action on cell viability, membrane integrity and lipid peroxidation (LPO) was assessed by neutral red uptake (NRU) assay, lactate dehydrogenase (LDH) release test and measurement of malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity. In addition, the protective effect of antioxidatant vitamin E on the cytotoxicity was also studied. Incubation of NHEK with various concentrations (0.01-31.6 mM) of TCE or PERC caused a dose-dependent decrease in cell viability, with 80% reduction at 31.6 mM. NR50 values from the cytotoxicity assay was found to be 4.53 and 2.16 mM for TCE and PERC, respectively. A time- and concentration- dependent release of LDH were observed at 1, 2, 3, 4 h after cells were exposed to different doses of TCE or PERC. These agents also caused an increase of MDA, whilst an inhibition of SOD activity, in a concentration-dependent manner. Pre-treatment of the cells with vitamin E at 10-200 mM dose-dependently attenuated the cytotoxic effect of TCE or PERC. Pre-treatment with vitamin E also reversed subsequent TCE or PERC-induced release of LDH, elevation of lipid peroxidation and decline of anti-oxidant enzyme activities. These results suggest that TCE and PERC could induce cytotoxicity to NHEK associated with oxidative stress and antioxidatant vitamin E could effectively protect NHEK from TCE- or PERC-induced cytotoxicity, which may be associated to the superoxide scavenging effect and enhancement of anti-oxidant enzyme activities.

Topical α-Tocopherol Acetate in the Bulk Phase: Eight Years of Experience in Skin Treatment

Clinical practice in dermatology indicates that alpha-tocopherol acetate is beneficial in xerosis, hyperkeratosis, asteatotic eczema, atopic dermatitis, superficial burns, cutaneous ulcers, onychoschizia and, in general, skin diseases in which an inflammatory process is activated. The positive effect results from the combination of biological activity, the absence of adverse reactions, and the physical effect of the alpha-tocopherol acetate oil. The viscosity of this oil in bulk phase accounts for a remarkable moisturizing effect and minimization of transepidermal water loss. This effect combines well with the antioxidant capacity of alpha-tocopherol released from the ester, and the recently emerging effect on reprogramming of gene expression.

Synthesis of Pyrimidine Derivatives Possessing an Antioxidative Property and Their Inhibitory Effects on Picryl Chloride-Induced Contact Hypersensitivity Reaction

We conducted a preliminary structure-activity relationship (SAR) study of some barbituric acid and uracil derivatives against the picryl chloride-induced contact hypersensitivity reaction. The introduction of an antioxidative moiety to the side chain of the C(6)-position of uracil was effective against this model. The introduction of dimethoxyphenol (8b) or dimethylphenol (8c) instead of di-t-butylphenol (8a) as an antioxidative moiety gave diminished activities, so, the reactive oxygen would contribute to the inflammation of this model, and an antioxidative activity was required for exhibiting the inhibitory activity. The inhibitory activity was significantly affected by the substituent at the N(1)-phenyl moiety.