Photoaging: prevention and topical treatments

Distribution, Chemical Constituents and Biological Properties of Genus Malaxis

The genus Malaxis (family Orchidaceae), comprises nearly 183 species available across the globe. The plants of this genus have long been employed in traditional medical practices because of their numerous biological properties, like the treatment of infertility, hemostasis, burning sensation, bleeding diathesis, fever, diarrhea, dysentery, febrifuge, tuberculosis, etc. Various reports highlight their phytochemical composition and biological activities. However, there is a lack of systematic review on the distribution, phytochemistry, and biological properties of this genus. Hence, this study aims to conduct a thorough and critical review of Malaxis species, covering data published from 1965 to 2022 with nearly 90 articles. Also, it examines different bioactive compounds, their chemistry, and pharmacotherapeutics as well as their traditional uses. A total of 189 unique compounds, including the oil constituents were recorded from Malaxis species. The highest active ingredients were obtained from Malaxis acuminata (103) followed by Malaxis muscifera (49) and Malaxis rheedei (33). In conclusion, this review offers an overview of the current state of knowledge on Malaxis species and highlights prospects for future research projects on them. Additionally, it recommends the promotion of domestication studies for rare medicinal orchids like Malaxis and the prompt implementation of conservation measures.

Antioxidants in Photoaging: From Molecular Insights to Clinical Applications

Photoaging (PA) is considered a silent disease affecting millions of people globally and is defined as skin damage due to prolonged exposure to ultraviolet radiation (UVR) from the sun. Physiologically, the skin is in a state of renewal and synthesis of components of the extracellular matrix (ECM). However, exposure to UVR affects the production of the ECM, and the functioning and response of skin cells to UVR begins to change, thus expressing clinical and phenotypic characteristics of PA. The primary mechanisms involved in PA are direct damage to the DNA of skin cells, increases in oxidative stress, the activation of cell signaling pathways responsible for the loss of skin integrity, and cytotoxicity. The medical and scientific community has been researching new therapeutic tools that counteract PA, considering that the damage caused by UVR exceeds the antioxidant defense mechanisms of the skin. Thus, in recent years, certain nutraceuticals and phytochemicals have been found to exhibit potential antioxidant and photoprotective effects. Therefore, the main objective of this review is to elucidate the molecular bases of PA and the latest pharmaceutical industry findings on antioxidant treatment against the progression of PA.

Flavonoids Present in Propolis in the Battle against Photoaging and Psoriasis

The skin is the main external organ. It protects against different types of potentially harmful agents, such as pathogens, or physical factors, such as radiation. Skin disorders are very diverse, and some of them lack adequate and accessible treatment. The photoaging of the skin is a problem of great relevance since it is related to the development of cancer, while psoriasis is a chronic inflammatory disease that causes scaly skin lesions and deterioration of the lifestyle of people affected. These diseases affect the patient's health and quality of life, so alternatives have been sought that improve the treatment for these diseases. This review focuses on describing the properties and benefits of flavonoids from propolis against these diseases. The information collected shows that the antioxidant and anti-inflammatory properties of flavonoids play a crucial role in the control and regulation of the cellular and biochemical alterations caused by these diseases; moreover, flavones, flavonols, flavanones, flavan-3-ols, and isoflavones contained in different worldwide propolis samples are the types of flavonoids usually evaluated in both diseases. Therefore, the research carried out in the area of dermatology with bioactive compounds of different origins is of great relevance to developing preventive and therapeutic approaches.

An in vivo study to evaluate the influence of oil blotting paper on the efficacy of sunscreen

BACKGROUND

Ultraviolet radiation (UVR) is a major cause of photoaging and photocarcinogenesis. An appropriate application of sunscreen can effectively protect UV damage but cause unpleasant skin oiliness. Oil blotting paper is commonly used to reduce oiliness in some parts of the world although its influence on the efficacy of sunscreen has not been carefully investigated.

OBJECTIVE

To evaluate the efficacy of sunscreen after applying oil blotting paper.

MATERIALS AND METHODS

Measurement of oiliness and sunscreen efficacy was compared before and after the use of oil blotting paper in 11 healthy volunteers, 10 females, and 1 male. Specifically, 3 zones on each subject's back were exposed to UVR from a solar simulator, that is, 1) no sunscreen, 2) sunscreen (organic sunscreen at 2 mg/cm² SPF 30) left on for 30 minutes, and 3) sunscreen left on for 30 minutes followed by application of oil blotting paper. Skin oiliness was also compared before and after oil blotting using a sebumeter. All areas were phototested for the comparison of the minimal erythema dose (MED) and sun protection factor (SPF).

RESULTS

The averaged MED of our subjects is 4.3 standard erythema doses (SED) in the unprotected area. The averaged MED was decreased after oil blotting from 89.8 SED to 59.8 SED. The SPF was also decreased from 20.70 to 13.99.

CONCLUSIONS

Application of oil blotting paper significantly reduces the efficacy of organic sunscreen.

Tailoring of Retinyl Palmitate-Based Ethosomal Hydrogel as a Novel Nanoplatform for Acne Vulgaris Management: Fabrication, Optimization, and Clinical Evaluation Employing a Split-Face Comparative Study

AIM

Retinyl palmitate (RP), the most stable vitamin A derivative, is used to treat photoaging and other skin disorders. The need to minimize the adverse effects of topical drug administration has led to an enhanced interest in loading RP on ethosomes for topical drug delivery. The aim of the current study was to prepare and compare the performance of RP decorated ethosomal hydrogel with tretinoin cream in the treatment of acne vulgaris as an approach to improve drug efficacy and decrease its side effects.

METHODS

RP-loaded ethosomes were prepared using the injection sonication technique. A Box-Behnken design using Design Expert® software was used for the optimization of formulation variables. Particle size, zeta potential (ZP), entrapment efficiency percent (EE%), % drug release, and permeation over 24 h of different formulations were determined. The optimal formulation was incorporated into a hydrogel. Finally, the efficacy and tolerability of the optimized RP ethosomal hydrogel were clinically evaluated for acne treatment using a split-face comparative clinical study.

RESULTS

The optimized ethosomal RP showed particle size of 195.8±5.45 nm, ZP of -62.1±2.85 mV, EE% of 92.63±4.33%, drug release % of 96.63±6.81%, and drug permeation % of 85.98 ±4.79%. Both the optimized RP ethosomal hydrogel and tretinoin effectively reduced all types of acne lesions (inflammatory, non-inflammatory, and total lesions). However, RP resulted in significantly lower non-inflammatory and total acne lesion count than the marketed tretinoin formulation. Besides, RP-loaded ethosomes showed significantly improved tolerability compared to marketed tretinoin with no or minimal skin irritation symptoms.

CONCLUSION

RP ethosomal hydrogel is considerably effective in controlling acne vulgaris with excellent skin tolerability. Therefore, it represents an interesting alternative to conventional marketed tretinoin formulation for topical acne treatment.

Therapeutic effect of concentrated growth factor preparation on skin photoaging in a mouse model

OBJECTIVE

To establish a nude mouse model of photoaging and study the therapeutic effect of a concentrated growth factor preparation (CGF) on skin photoaging.

METHODS

CGF was prepared from blood from Sprague-Dawley rats. A skin photoaging nude mouse model was developed using UV irradiation combined with the photosensitizer, 8-methoxypsoralen. Mice were divided randomly into seven groups (n = 6 per group): normal control, photoaging, mock treatment, saline treatment, CGF treatment, Filoca 135HA treatment, and plasma skin regeneration system irradiation (the latter two were positive controls). Body weight and skin appearance were observed and pathological changes were determined by hematoxylin and eosin staining. Fiber elasticity was evaluated by Weigert staining. Expression levels of proliferating cell nuclear antigen (PCNA) and matrix metalloproteinase 1 (MMP1) were determined by immunohistochemistry.

RESULTS

A mouse model with typical features of photoaging skin was successfully developed. CGF significantly improved the skin appearance, wrinkle scores, pathological changes, and fiber elasticity, and increased PCNA and decreased MMP1 expression levels in photoaging mice, comparable to the two positive controls.

CONCLUSION

CGF can improve the symptoms of skin photoaging in mice, suggesting that it may have applications in the treatment of skin aging in humans.

The effectiveness and safety of Chinese herbal formulas on skin photoaging: A protocol for systematic review and meta-analysis

BACKGROUND

Skin photoaging (SP) is a complex and complicated process of skin characteristic changes caused by excessive sunlight. Wrinkles, looseness, coarseness, and increase or loss of pigment are the main clinical manifestations of the disease. The pathogenesis of SP mainly involving oxidative stress, inflammatory reaction, immune dysregulation and DNA damage, and so on. In recent years, traditional Chinese medicine, as an significant form of complementary and alternative medicine, has attracted the more and more attention within the field of health care and indicated a desirable effect on SP. Chinese herbal formula (CHF) is an essential part of traditional Chinese medicine interventions, and the number of clinical trails on SP treated by CHFs have shown a growing trend. Therefore, we developed this systematic review and meta-analysis protocol to assess the effectiveness and safety of CHFs in the therapy of SP, so as to provide reliable evidence-based evidence for clinical decision-making.

METHODS

A overall literature retrieval will be carried out in 9 electronic journal database. We will include randomized controlled trials (RCTs) on CHFs alone or combined with routine western medicine measures in the treatment of SP. The outcomes we focused on are consists of symptom score (skin relaxation, telangiectasia, pore coarseness, pigmentation, etc), total effective rate, and adverse reactions. Meta-analysis will be performed using Stata 13.0 software. Literature retrieval and screening, data extraction, risk of bias assessment of RCTs, evidence confidence rating by grading of recommendations assessment, development, and evaluation method and methodological quality assessment of systematic review by assessment of multiple systematic reviews-2 will be conducted independently by 2 reviewers, and disagreements will be resolved through discussion or judged by a third senior reviewer.

RESULTS

This systematic review and meta-analysis will pool the proof of RCTs on SP treated by CHFs alone or combined with conventional western medicine treatments. The findings of this study will be presented at relevant conferences and submitted to peer-reviewed journals for publication.

CONCLUSION

We expect that the results of this systematic review will provide comprehensive and reliable evidence for clinicians and policy makers.

REGISTRATION NUMBER

INPLASY 2020120005.

DNA repair enzymes in sunscreens and their impact on photoageing-A systematic review

BACKGROUND

DNA damage is one of the main factors responsible for photoageing and is predominantly attributed to ultraviolet irradiation (UV-R). Photoprotection by conventional sunscreens is exclusively prophylactic, and of no value, once DNA damage has occurred. As a result, the demand for DNA repair mechanisms inhibiting, reversing or delaying the pathologic events in UV-exposed skin has sparked research on anti-photoageing and strategies to improve the effect of conventional sunscreens. This review provides an overview of recent developments in DNA repair enzymes used in sunscreens and their impact on photoageing.

METHODS

A systematic review of the literature, up to March 2019, was conducted using the electronic databases, PubMed and Web of Science. Quality assessment was carried out using the Newcastle-Ottawa scale (NOS) to ensure inclusion of adequate quality studies only (NOS > 5).

RESULTS

Out of the 352 publications, 52 were considered relevant to the key question and included in the present review. Two major enzymes were found to play a major role in DNA damage repair in sunscreens: photolyase and T4 endonuclease V. These enzymes are capable of identifying and removing UV-R-induced dimeric photoproducts. Clinical studies revealed that sunscreens with liposome-encapsulated types of photolyase and/or T4 endonuclease V can enhance these repair mechanisms.

CONCLUSION

There is a lack of randomized controlled trials demonstrating the efficacy of DNA repair enzymes on photoageing, or a superiority of sunscreens with DNA repair enzymes compared to conventional sunscreens. Further studies are mandatory to further reveal pathogenic factors of photoageing and possible therapeutic strategies against it.

Emerging Strategies to Protect the Skin from Ultraviolet Rays Using Plant-Derived Materials

Sunlight contains a significant amount of ultraviolet (UV) ray, which leads to various effects on homeostasis in the body. Defense strategies to protect from UV rays have been extensively studied, as sunburn, photoaging, and photocarcinogenesis are caused by excessive UV exposure. The primary lines of defense against UV damage are melanin and trans-urocanic acid, which are distributed in the stratum corneum. UV rays that pass beyond these lines of defense can lead to oxidative damage. However, cells detect changes due to UV rays as early as possible and initiate cell signaling processes to prevent the occurrence of damage and repair the already occurred damage. Cosmetic and dermatology experts recommend using a sunscreen product to prevent UV-induced damage. A variety of strategies using antioxidants and anti-inflammatory agents have also been developed to complement the skin's defenses against UV rays. Researchers have examined the use of plant-derived materials to alleviate the occurrence of skin aging, diseases, and cancer caused by UV rays. Furthermore, studies are also underway to determine how to promote melanin production to protect from UV-induced skin damage. This review provides discussion of the damage that occurs in the skin due to UV light and describes potential defense strategies using plant-derived materials. This review aims to assist researchers in understanding the current research in this area and to potentially plan future studies.

In situ antioxidant activity of a dermo-cosmetic product: A randomized controlled clinical study

Ultraviolet light enhances the generation of reactive oxygen species that are responsible for skin photoageing. The aim of this randomized, vehicle- and active-controlled double-blind, intra-individual monocentric study was to evaluate in situ the antioxidant activity of a dermo-cosmetic product in photoaged skin. Twenty healthy volunteers had defined skin areas randomized to receive a topical product containing 3 antioxidants (pre-tocopheryl® , retinaldehyde and glycylglycine ole-amide), its vehicle and a positive antioxidant control cream. The products were applied daily for 30-day period. The skin areas were exposed to a controlled dose of UVA rays, and the skin oxidative status was evaluated 4 and 24 hours post-UVA exposure at D0 (basal value) and after 15 and 30 days of product application. Skin layers were collected by stripping, and antioxidant capacity was measured using the ferric reducing ability of a plasma assay. Lipid peroxidation (LPO) was assessed using the malonyldialdehyde test. The tested product significantly improved the skin antioxidant capacity after 15 and 30 days and significantly decreased the basal level of the skin LPO. The skin LPO level significantly decreased 4 and 24 hours after UVA exposure at 15 and 30 days. These findings were comparable to positive control treated sites and were significantly different from the vehicle and untreated sites. This minimally invasive methodology enabled a quantitative evaluation of potent antioxidant activity in situ in the stratum corneum reflecting real-life skin conditions and confirming the benefits of the topical application of a product containing 3 antioxidants in the prevention of UVA-induced oxidative damage.

Silica-based nanosystems for therapeutic applications in the skin

Aging, exposure to oxidants, infectious pathogens, inflammogens, ultraviolet radiation and other environmental and genetic factors can result in the development of various skin disorders. Despite immense progress being made in dermatological treatments, many skin-associated problems still remain difficult to treat and various therapies have limitations. Progress in silica-based nanomaterials research provides an opportunity to overcome these drawbacks and improve therapies and is a promising tool for inclusion in clinical practice to treat skin diseases. This review focuses on the use of various types of silica nanoparticles with therapeutic applications in various skin disorders. These nanosystems improve treatment efficacy by maintaining or enhancing the effect of several drugs and are useful tools for nanomedicine, pharmaceutical sciences and future clinical applications.

Anti-photoaging effect of skin cream manufactured with ziyuglycoside I isolated from Sanguisorba officinalis on ultraviolet B-induced hairless mice

In this study, skin cream containing ziyuglycoside I isolated from Sanguisorba officinalis was manufactured and examined the protective effects of the skin cream against UVB-induced hairless mice. UVB-induced hairless mice were topically treated with the skin cream once a day for 5 weeks. Application of the skin cream did not exhibit side effect on body growth showing normal body weight and food efficiency in the mice. The skin cream treatment also was inhibited mRNA expression of interleukin (IL)-1β, matrix metalloproteinase (MMP)-2, MMP-9, and MMP-2 protein expression in the mice. Furthermore, the skin cream treatment inhibits epidermal wrinkle formation, wrinkle depth, wrinkle thickness, and collagen degradation in UVB-induced hairless mice. Therefore, the skin cream was able to play a role in the attenuation of photoaging caused by UVB irradiation via downregulation of mRNA expression of inflammatory cytokine IL-1β, MMP-2, MMP-9, and suppression of MMP-2 proteins expression.

Functional recovery in photo-damaged human dermal fibroblasts by human adipose-derived stem cell extracellular vesicles

Ultraviolet-B (UVB) irradiation causes imbalance between dermal matrix synthesis and degradation through aberrant upregulation of matrix metalloproteinases (MMPs), which leads to overall skin photoaging. We investigated the effects of extracellular vesicles (EVs) derived from human adipose-derived stem cells (HASCs) on photo-damaged human dermal fibroblasts (HDFs). EVs were isolated from conditioned media of HASCs with tangential flow filtration and characterized using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), western blotting, micro RNA (miRNA) arrays, cytokine arrays and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The effects of EVs on the UVB-irradiated HDFs were evaluated using scratch assay, ELISA and real-time PCR. Microarrays exhibited that EVs are rich in various miRNAs and proteins, and that these EV contents are linked to a broad range of biological functions, including fibroblast proliferation, UV protection, collagen biosynthesis, DNA repair and cell ageing. A scratch assay showed that HASC-EVs enhanced the migration ability of UVB-irradiated HDFs. Real-time RT-PCR and ELISA analyses revealed that the HASC-derived EVs significantly suppressed the overexpression of MMP-1, -2, -3 and -9 induced by UVB irradiation and enhanced the expression of collagen types I, II, III and V and elastin. In particular, tissue inhibitor of metalloproteinase (TIMP)-1 and transforming growth factor (TGF)-β1, which are important factors involved in MMP suppression and ECM synthesis, were upregulated in EV-treated HDFs after UVB irradiation. Overall results suggest that diverse components that are enriched in HASC-derived EVs could act as a biochemical cue for recovery from skin photoaging.

Anti-Photoaging Effects of Low Molecular-Weight Fucoidan on Ultraviolet B-Irradiated Mice

Ultraviolet (UV) B exposure induces DNA damage and production of reactive oxygen species (ROS), which causes skin photoaging through signaling pathways of inflammation and modulation of extracellular matrix remodeling proteins, collagens, and matrix metalloproteinase (MMP). As low molecular-weight fucoidan (LMF) has potential antioxidant and anti-inflammatory properties, we examined the protective effects of LMF against UVB-induced photoaging. A UVB-irradiated mouse model was topically treated with myricetin or LMF at 2.0, 1.0 and 0.2 mg/cm² (LMF2.0, LMF1.0 and LMF0.2, respectively) once a day for 15 weeks. Wrinkle formation, inflammation, oxidative stress, MMP expression, and apoptosis in the treated regions were compared with those in a distilled water-treated photoaging model (UVB control). LMF treatments, particularly LMF2.0 and LMF1.0, significantly inhibited the wrinkle formation, skin edema, and neutrophil recruitment into the photo-damaged lesions, compared with those in the UVB control. While LMF decreased interleukin (IL)-1β release, it increased IL-10. The LMF treatment inhibited the oxidative stresses (malondialdehyde and superoxide anion) and enhanced endogenous antioxidants (glutathione). Additionally, LMF reduced the mRNA expression of MMP-1, 9, and 13. The histopathological analyses revealed the anti-photoaging effects of LMF exerted via its antioxidant, anti-apoptotic, and MMP-9-inhibiting effects. These suggest that LMF can be used as a skin-protective remedy for photoaging.

Dual Effects of Alpha-Hydroxy Acids on the Skin

AHAs are organic acids with one hydroxyl group attached to the alpha position of the acid. AHAs including glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid are often used extensively in cosmetic formulations. AHAs have been used as superficial peeling agents as well as to ameliorate the appearance of keratoses and acne in dermatology. However, caution should be exercised in relation to certain adverse reactions among patients using products with AHAs, including swelling, burning, and pruritus. Whether AHAs enhance or decrease photo damage of the skin remains unclear, compelling us to ask the question, is AHA a friend or a foe of the skin? The aim of this manuscript is to review the various biological effects and mechanisms of AHAs on human keratinocytes and in an animal model. We conclude that whether AHA is a friend or foe of human skin depends on its concentration. These mechanisms of AHAs are currently well understood, aiding the development of novel approaches for the prevention of UV-induced skin damage.

Studies on secondary metabolite profiling, anti-inflammatory potential, in vitro photoprotective and skin-aging related enzyme inhibitory activities of Malaxis acuminata, a threatened orchid of nutraceutical importance

Malaxis acuminata D. Don., a small, terrestrial orchid, is endemic to tropical Himalayas at an altitude of 1200-2000m asl. The dried pseudobulbs are important ingredients of century old ayurvedic drug 'Ashtavarga' and a polyherbal immune-booster nutraceutical 'Chyavanprash', known to restore vigour, vitality and youthfulness. Considering tremendous medicinal importance of this threatened orchid species, a detailed study was undertaken for the first time to address its antioxidant potential, secondary metabolite contents and biological activities against skin-aging related enzymes (anti-collagenase, anti-elastase, anti-tyrosinase and xanthine oxidase) and anti-inflammatory activity (5-lipoxygenase and hyaluronidase) in different plant parts of wild and in vitro-derived plants of M. acuminata. Methanolic leaf and stem extracts were further evaluated for in vitro photoprotective activity against UV-B and UV-A radiations. Furthermore, secondary metabolite profiling of various plant parts was carried out by Gas Chromatography Mass Spectrometry (GC-MS). A significantly higher antioxidant potential (DPPH, metal chelating and ABTS^•+) with a comparative higher yield of secondary metabolites was observed in in vitro-derived plantlets as compared to the wild plants. Among various solvent systems used, methanolic leaf and stem extracts showed promising inhibitory activity against major skin aging-related enzymes and anti-inflammatory potential. Methanolic leaf and stem extracts of both wild and in vitro-derived plants showed promising photoprotective activity against UV-B and UV-A radiations in vitro with comparatively higher sun protection factor (SPF). Furthermore, GC-MS analysis of methanolic extracts of leaves and stems of wild as well as in vitro-derived plantlets revealed presence of many bioactive metabolites such as, dietary fatty acids, α-hydroxy acids, phenolic acids, sterols, amino acids, sugars and glycosides which substantially explain the use of M. acuminata as one of the potential rejuvenator and anti-aging ingredient in many Ayurvedic formulations.

Phosphatidylcholine liposomes as carriers to improve topical ascorbic acid treatment of skin disorders

Liposomes have been intensively investigated as carriers for different applications in dermatology and cosmetics. Ascorbic acid has potent antioxidant and anti-inflammatory properties preventing photodamage of keratinocytes; however, due to its instability and low skin penetration, an appropriate carrier is mandatory to obtain desirable efficacy. The present work investigates the ability of a specific ascorbate phosphatidylcholine (PC) liposome to overcome the barrier of the stratum corneum and deliver the active agent into the dermis to prevent photodamage. Abdominal skin from ten patients was used. Penetration of PC liposomes was tested ex vivo in whole skin, epidermis, and dermis by means of fluorescein and sodium ascorbate. Histology and Franz diffusion cells were used to monitor the percutaneous absorption. Ultraviolet (UV)-high performance liquid chromatography was used to analyze diffusion of sodium ascorbate through the different skin layers, while spectrofluorimetry and fluorescent microscopy were used for fluorescein monitoring. UVA/UVB irradiation of whole skin was applied to analyze the antioxidant capacity by Trolox assay and anti-inflammatory effects by tumor necrosis factor alpha and interleukin 1 beta enzyme-linked immunoassay. PC liposomal formulation improved skin penetration of fluorescein and ascorbate. Fluorescein PC liposomes showed better diffusion through epidermis than dermis while ascorbate liposomes showed better diffusion through the dermis than the epidermis. Ascorbate PC liposomes showed preventive antioxidant and anti-inflammatory properties on whole human skin irradiated with UVA/UVB. In summary, ascorbate PC liposomes penetrate through the epidermis and allow nonstable hydrophilic active ingredients reach epidermis and dermis preventing skin photodamage.

Using Imiquimod-Induced Psoriasis-Like Skin as a Model to Measure the Skin Penetration of Anti-Psoriatic Drugs

Objective

Psoriasis is a chronic inflammatory skin disease and topical therapy remains a key role for treatment. The aim of this study is to evaluate the influence of psoriasis-like lesions on the cutaneous permeation of anti-psoriatic drugs.

Methods

We first set up imiquimod-induced dermatitis in mice that closely resembles human psoriasis lesions. The development of the lesions is based on the IL-23/IL17A axis for phenotypical and histological characteristics. Four drugs, 5-aminolevulinic acid (ALA), tacrolimus, calcipotriol, and retinoic acid, were used to evaluate percutaneous absorption.

Results

The most hydrophilic molecule, ALA, revealed the greatest enhancement on skin absorption after imiquimod treatment. Imiquimod increased the skin deposition and flux of ALA by 5.6 to 14.4-fold, respectively, compared to normal skin. The follicular accumulation of ALA was also increased 3.8-fold. The extremely lipophilic drug retinoic acid showed a 1.7- and 3.8-fold increase in skin deposition and flux, respectively. Tacrolimus flux was enhanced from 2 to 21 μg/cm²/h by imiquimod intervention. However, imiquimod did not promote skin deposition of this macrolide. The lipophilicity, but not the molecular size, dominated drug permeation enhancement by psoriatic lesions. The in vivo percutaneous absorption of ALA and rhodamine B examined by confocal microscopy confirmed the deficient resistance of epidermal barrier for facilitating cutaneous delivery of drugs via psoriasis-like skin.

Conclusion

We established the topical delivery profiles of anti-psoriatic drugs via imiquimod-treated psoriasis-like skin.

Lipid nanoparticles for the topical delivery of retinoids and derivatives

Retinoids are lipophilic compounds that are highly used in cosmetics/therapeutics for skin disorders. Conventional formulations are limited by poor water solubility, high chemical/photochemical instability and the irritation of retinoids. Interestingly, lipid nanoparticles enable the administration of retinoids in aqueous media, providing drug stabilization and controlled release. Recently, it has been demonstrated that retinoids in solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules can decrease degradation, improve targeting and enhance efficacy for the treatment of skin disorders. This article focuses on the formulation, fabrication, characterization and in vitro/in vivo evaluation of solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules loaded with retinoids for skin administration. Furthermore, the incorporation of these lipid nanoparticles into secondary vehicles is discussed.

Skin aging modulates percutaneous drug absorption: the impact of ultraviolet irradiation and ovariectomy

Ultraviolet (UV) exposure and menopause are known as the inducers of damage to the skin structure. The combination of these two factors accelerates the skin aging process. In this study, we aimed to evaluate the influence of UV and ovariectomy (OVX) on the permeation of drugs through the skin. The role of tight junctions (TJs) and adherens junctions (AJs) in the cutaneous absorption of extremely lipophilic permeants and macromolecules was explored. The OVX nude mouse underwent bilateral ovary removal. Both UVA and UVB were employed to irradiate the skin. The physiological and biochemical changes of the skin structure were examined with focus on transepidermal water loss (TEWL), skin color, immunohistochemistry, and mRNA levels of proteins. UVB and OVX increased TEWL, resulting in stratum corneum (SC) integrity disruption and dehydration. A hyperproliferative epidermis was produced by UVB. UVA caused a pale skin color tone due to keratinocyte apoptosis in the epidermis. E-cadherin and β-catenin showed a significant loss by both UVA and UVB. OVX downregulated the expression of filaggrin and involucrin. A further reduction was observed when UV and OVX were combined. The in vitro cutaneous absorption demonstrated that UV increased the skin permeation of tretinoin by about twofold. However, skin accumulation and flux of estradiol were not modified by photoaging. OVX basically revealed a negligible effect on altering the permeation of small permeants. OVX increased tretinoin uptake by the appendages from 1.36 to 3.52 μg/cm(2). A synergistic effect on tretinoin follicular uptake enhancement was observed for combined UV and OVX. However, the intervention of OVX to photoaged skin resulted in less macromolecule (dextran, molecular weight = 4 kDa) accumulation in the skin reservoir because of retarded partitioning into dry skin. The in vivo percutaneous absorption of lipophilic dye examined by confocal microscopy had indicated that the SC was still important to controlling topical delivery, although the role of epidermal junctions could not be simply ignored.

Gardenia jasminoides Extract Attenuates the UVB-Induced Expressions of Cytokines in Keratinocytes and Indirectly Inhibits Matrix Metalloproteinase-1 Expression in Human Dermal Fibroblasts

Ultraviolet radiation (UV) is a major cause of photoaging, which also involves inflammatory cytokines and matrix metalloproteinases (MMP). The present study was undertaken to examine the UVB-protecting effects of yellow-colored plant extracts in cell-based assays. HaCaT keratinocytes were exposed to UVB in the absence or presence of plant extracts, and resulting changes in cell viability and inflammatory cytokine expression were measured. Of the plant extracts tested, Gardenia jasminoides extract showed the lowest cytotoxicity and dose-dependently enhanced the viabilities of UVB-exposed cells. Gardenia jasminoides extract also attenuated the mRNA expressions of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in HaCaT cells stimulated by UVB. Conditioned medium from UVB-exposed HaCaT cells was observed to stimulate MMP-1 protein expression in human dermal fibroblasts, and this effect was much smaller for the conditioned medium of HaCaT cells exposed to UVB in the presence of Gardenia jasminoides extract. Gardenia jasminoides extract also exhibited antioxidative and antiapoptotic effects in HaCaT cells exposed to UVB. These results indicated that UVB-induced injury and inflammatory responses of skin cells can be attenuated by yellow-colored plant extracts, such as Gardenia jasminoides extract.

The impact of intradermal injections of modified hyaluronic acid on the morphological skin condition in female patients with involutional changes

Goal. To provide a clinical assessment of the efficacy and tolerance of hyaluronic acid (HA) drugs modified with vitamin С and amino acids in patients with involutional skin changes. Methods. As many as 90 female patients underwent a course of treatment for age-related skin changes including three procedures of intradermal injections of modified HA. The skin condition was assessed prior to and after the treatment by using non-invasive methods (corneometry, pH-metry, sebometry, elastometry, visio-scanning, ultrasonic derma-scanning and confocal laser scanning microscopy). Results. The authors demonstrated good tolerance of modified HA and skin condition improvement (better elasticity, moisture level, improvement of the skin structure and microrelief, reduction in the intensity of expression and static wrinkles, restoration of color uniformity and elimination of xerosis manifestations). Conclusion. The study results are sufficient to recommend modified HA drugs for correcting involutional skin changes.

Photodamage: treatments and topicals for facial skin

This article provides an overview of current therapies for photodamaged facial skin and their efficacy, with particular focus on studies that use the objective, quantitative evaluation methods discussed in the previous article. The role of topically applied agents including prescription drugs and cosmetics is discussed. From this information, a schema for the relative effectiveness of therapeutic modalities in reducing perceived age is presented. This information assists the facial plastic surgeon in evaluating patient expectations and selecting the most effective program.

Effect of Artocarpus communis Extract on UVB Irradiation-Induced Oxidative Stress and Inflammation in Hairless Mice

Administration of antioxidants and anti-inflammatory agents is an effective strategy for preventing ultraviolet (UV) irradiation-induced skin damage. Artocarpus communis possesses several pharmacological activities, such as antioxidant, anticancer and anti-inflammation. However, the photoprotective activity of methanol extract of A. communis heartwood (ACM) in ultraviolet irradiation-induced skin damage has not yet been investigated. The present study was performed using ultraviolet absorption, histopathological observation, antioxidant and anti-inflammation assays to elucidate the mechanism of the photoprotective activity of ACM. Our results indicated that ACM displayed a UVA and UVB absorption effect and then effectively decreased scaly skin, epidermis thickness and sunburn cells during ultraviolet irradiation in hairless mice. ACM not only decreased ultraviolet irradiation-mediated oxidative stress, including lowering the overproduction of reactive oxygen species and lipid peroxidation (p < 0.05), but also reduced the levels of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin 1β. Additionally, ACM can decrease the synthesis of cytosolic phospholipase A2, cyclooxygenase, inducible nitric oxide synthase and vascular cell adhesion molecular-1 via inhibiting TNF-α-independent pathways (p < 0.05) in UVB-mediated inflammation and formation of sunburn cells. Consequently, we concluded that ACM extract has a photoprotective effect against UVB-induced oxidative stress and inflammation due to its sunscreen property, and its topical formulations may be developed as therapeutic and/or cosmetic products in further studies.

Study on the roles of β-catenin in hydrogen peroxide-induced senescence in human skin fibroblasts

Oxidative stress is one of the most important causes of the cellular senescence process. Previous studies showed that β-catenin can regulate FoxO3a and this association was enhanced in cells exposed to oxidative stress. It has also been reported that β-catenin can regulate some senescence-related proteins. We propose that β-catenin may play a crucial role in senescence of normal human primary skin fibroblasts (NHSFs). Here, we explored the roles and mechanisms of β-catenin on H(2)O(2)-induced senescence in NHSFs. β-catenin expression was decreased in NHSFs after H(2)O(2) treatment. Overexpression of β-catenin in NHSFs led to a marked delay of many senescent phenotypes induced by H(2)O(2). Furthermore, overexpression of β-catenin in NHSFs can antagonise the alteration of reactive oxygen species accumulation and some senescence-related proteins expression induced by H(2)O(2) treatment. Our data demonstrated that β-catenin can protect NHSFs from H(2)O(2)-induced premature senescence by alleviating oxidative stress and regulating some senescence-related molecules.

Main approaches for delivering antioxidant vitamins through the skin to prevent skin ageing

INTRODUCTION

One of the major contributions to skin photoageing and diseases is oxidative stress, caused by UV radiation inducing reactive oxygen and nitrogen species. Successful prophylaxis and therapy would necessitate control of the oxidant/antioxidant balance at the affected site, which can be achieved through the external supply of endogenous antioxidants.

AREAS COVERED

This review discusses possible strategies for dermal delivery of the antioxidant vitamins E and C, as oral supplementation has proved insufficient. These antioxidants have low skin bioavailability, owing to their poor solubility, inefficient skin permeability, or instability during storage. These drawbacks can be overcome by various approaches, such as chemical modification of the vitamins and the use of new colloidal drug delivery systems. New knowledge is included about the importance of: enhancing the endogenous skin antioxidant defense through external supply; the balance between various skin antioxidants; factors that can improve the skin bioavailability of antioxidants; and new delivery systems, such as microemulsions, used to deliver vitamins C and E into the skin simultaneously.

EXPERT OPINION

A promising strategy for enhancing skin protection from oxidative stress is to support the endogenous antioxidant system, with antioxidants containing products that are normally present in the skin.