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1.
Cutaneous Photoprotection: A Review of the Current Status and Evolving Strategies.
Suozzi, K, Turban, J, Girardi, M
The Yale journal of biology and medicine. 2020;(1):55-67
Abstract
Ultraviolet radiation (UVR) exposure is well established as the major environmental risk factor for the development of melanoma, cutaneous squamous cell carcinoma (cSCC), and basal cell carcinoma (BCC). Additional risk factors including genetic mutations, other environmental agents, and immune status are important in modulating the effects of UVR. Dermatologists advocate a multi-pronged approach to minimizing UVR exposure including lifestyle modifications, UVR protective clothing, and topically applied sun-protective products, i.e. sunscreen. New Federal Drug Administration (FDA) regulations on sunscreen have brought certain long-standing ingredients in sunscreen products under scrutiny. The FDA's proposed rule for over the counter (OTC) monograph states that the inorganic sunscreens, zinc oxide and titanium dioxide, were found to be "generally recognized as safe and effective," but cite insufficient evidence to grant organic sunscreens the same designation. This proposed rule by the FDA and our increasing understanding of multifactorial mechanisms of UVR damage are an impetus for innovation and advances in sun protective technology. A complete set of strategies designed to limit the risk of UV-induced skin cell malignant transformation and tumor development must address the fuller consideration of genetic, environmental, and immune factors that cooperatively drive cutaneous carcinogenesis. Recent advances in our understanding of the biochemical processes underpinning UVR associated cutaneous cellular damage, genotoxicity, and clonal expansion provide investigators with a spectrum of opportunities for technologic innovation in the prevention of skin cancer. Strategies to improve upon current topical sunscreen formulations have strived for broader UVR spectral coverage, more favorable aesthetics, increased adherence, and minimal penetration into the living epidermis. In addition to improved sunscreens, future topical therapies may target processes within the epidermis that contribute to carcinogenesis. These include reactive species quenching, delivery of DNA repair enzymes, and targeting of cytokines essential to the proliferation of mutant keratinocytes.
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2.
Potential of Skin Microbiome, Pro- and/or Pre-Biotics to Affect Local Cutaneous Responses to UV Exposure.
Patra, V, Gallais Sérézal, I, Wolf, P
Nutrients. 2020;(6)
Abstract
The human skin hosts innumerable microorganisms and maintains homeostasis with the local immune system despite the challenges offered by environmental factors such as ultraviolet radiation (UVR). UVR causes cutaneous alterations such as acute (i.e., sunburn) and chronic inflammation, tanning, photoaging, skin cancer, and immune modulation. Phototherapy on the other hand is widely used to treat inflammatory skin diseases such as psoriasis, atopic dermatitis, polymorphic light eruption and graft-versus-host disease (GvHD), as well as neoplastic skin diseases such as cutaneous T cell lymphoma, among others. Previous work has addressed the use of pro- and pre-biotics to protect against UVR through anti-oxidative, anti-inflammatory, anti-aging, anti-carcinogenic and/or pro-and contra-melanogenic properties. Herein, we discuss and share perspectives of the potential benefits of novel treatment strategies using microbes and pro- and pre-biotics as modulators of the skin response to UVR, and how they could act both for protection against UVR-induced skin damage and as enhancers of the UVR-driven therapeutic effects on the skin.
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3.
The role of nutritional lipids and antioxidants in UV-induced skin cancer.
Black, HS
Frontiers in bioscience (Scholar edition). 2015;(1):30-9
Abstract
Two dietary tenets of the free radical theory of cancer require refinement. The first was dietary reduction of vulnerable free-radical targets, e.g., polyunsaturated lipids. The second was the addition of one or more antioxidants to the diet. Further, it was reported in 1939 that high levels of dietary fat exacerbated UV-carcinogenesis. Both lines of enquiry (dietary lipid and antioxidant effects on UV-carcinogenesis) were investigated. Both dietary lipids and antioxidants modified carcinogenic expression. Increasing levels of omega-6 polyunsaturated fatty acids (PUFA) exacerbated UV-carcinogenesis. However, omega-3 PUFA dramatically inhibited carcinogenic expression. It is probable that the action of omega-6 and-3 PUFA rests with differential metabolic intermediates, both tumor promoting and immune-modulating, that each PUFA generates through lipoxygenase and cyclooxygenase pathways. Antioxidant supplementation with butylated hydroxytoluene or beta-carotene demonstrated that each exerted its own specific antioxidant mechanism(s). When introduced into the complex milieu of the cell with its own intricate and complex antioxidant defense system, detrimental effects may ensue. These results point to oversimplification of these dietary suggestions to reduce cancer risk and the necessity to refine these dietary recommendations.
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4.
Photobiology, photodermatology and sunscreens: a comprehensive overview. Part 1: damage from acute and chronic solar exposure.
Calzavara-Pinton, P, Sala, R, Arisi, MC, Bussoletti, C, Celleno, L
Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia. 2013;(1):89-106
Abstract
Sun exposure of the skin triggers several inflammatory pathways via a multitude of photochemical and photobiological effects. Furthermore, local and systemic immune suppression develops. The main clinical effects of UV exposure can be classified schematically into immediate, including sunburn, tanning, vitamin D production and exacerbation of inherited and acquired photosensitive skin disorders and long-term, including solar ageing and skin cancer. The protection against solar radiation is afforded by a healthy behavior of reasonable sun avoidance and the use of topical sunscreens as well as topical and oral antioxidants. However, users of sunscreen products should be able to choose correctly the more convenient product according to their needs. In Europe, the sun protection factor (SPF) and the UVA-protection factor (UVA-PF) are labeled to indicate the degree of protection against UVB and UVA, respectively. However, dermatologists must be aware that the present knowledge of UV effects on human skin needs to be clarified and several regulatory issues of photo-protection remain to be clarified and standardized. Finally, much work is needed to improve water resistance, spreadability, transparency and homogeneity of the sunscreen agents.
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5.
Changes in photoinduced cutaneous erythema with topical application of a combination of vitamins C and E before and after UV exposure.
Aguilera, J, de Gálvez, MV, Sánchez, C, Herrera-Ceballos, E
Journal of dermatological science. 2012;(3):216-20
Abstract
BACKGROUND Ultraviolet radiation is harmful for human skin, and photodamaging pathologies such as actinic erythema, are formerly described as a consequence of UV direct effect on DNA and indirectly by local immune reactions. However, the degree of participation of oxidative stress in actinic erythema and the role of antioxidants in photoprotection are still not fully understood. OBJECTIVE To evaluate the possible palliative role of a combination of the antioxidants vitamins C and E in human cutaneous erythema when applied topically before and after UV exposure. MATERIALS AND METHODS The study included 20 volunteers of phototypes II, II-III and III with no solar exposure for two months prior to the study. The volunteers were submitted to a phototest consisting on the analysis of the minimal erythemal dose (MED) under different treatments: 1. Untreated irradiated skin; 2. Irradiated skin previously treated with vehicle; 3. Irradiated skin previously treated with a combination of vitamins (2.5% vit E-5% vit C); and 4. Skin treated with the antioxidant combination after irradiation. Cutaneous erythema was evaluated 24h after exposure and the MED was calculated for each treatment. RESULTS The application of vehicle did not significantly affect the MED compared to untreated irradiated skin. Application of the antioxidant combination, prior to irradiation, increased the MED in all phototypes compared with untreated irradiated skin with an average increase of 36.9%. Antioxidants applied after exposure promoted an average increase of the MED by 19.8%. CONCLUSIONS Combination of topical antioxidants (vitamins C and E) shows photoprotection activity against erythema, mainly owing to their high absorption properties. Moreover, their antioxidant activity could be considered as additive, and independent of their optical properties.
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6.
Molecular aspects of skin ageing.
Naylor, EC, Watson, RE, Sherratt, MJ
Maturitas. 2011;(3):249-56
Abstract
Ageing of human skin may result from both the passage of time (intrinsic ageing) and from cumulative exposure to external influences (extrinsic ageing) such as ultraviolet radiation (UVR) which promote wrinkle formation and loss of tissue elasticity. Whilst both ageing processes are associated with phenotypic changes in cutaneous cells, the major functional manifestations of ageing occur as a consequence of structural and compositional remodeling of normally long-lived dermal extracellular matrix proteins. This review briefly considers the effects of ageing on dermal collagens and proteoglycans before focusing on the mechanisms, functional consequences and treatment of elastic fibre remodeling in ageing skin. The early stages of photoageing are characterised by the differential degradation of elastic fibre proteins and whilst the activity of extracellular matrix proteases is increased in photoexposed skin, the substrate specificity of these enzymes is low. We have recently shown however, that isolated fibrillin microfibrils are susceptible to direct degradation by physiologically attainable doses of UV-B radiation and that elastic fibre proteins as a group are highly enriched in UV-absorbing amino acid residues. Functionally, elastic fibre remodeling events may adversely impact on: the mechanical properties of tissues, the recruitment and activation of immune cells, the expression of matrix metalloproteinases and cytokine signaling (by perturbing fibrillin microfibril sequestration of TGFβ). Finally, newly developed topical interventions appear to be capable of regenerating elements of the elastic fibre system in ageing skin, whilst systemic treatments may potentially prevent the pathological tissue remodeling events which occur in response to elastic fibre degradation.
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7.
Clinical evidence of benefits of a dietary supplement containing probiotic and carotenoids on ultraviolet-induced skin damage.
Bouilly-Gauthier, D, Jeannes, C, Maubert, Y, Duteil, L, Queille-Roussel, C, Piccardi, N, Montastier, C, Manissier, P, Piérard, G, Ortonne, JP
The British journal of dermatology. 2010;(3):536-43
Abstract
BACKGROUND Lactobacillus johnsonii (La1) has been reported to protect skin immune system homeostasis following ultraviolet (UV) exposure. OBJECTIVES To assess the effects of a dietary supplement (DS) combining La1 and nutritional doses of carotenoids on early UV-induced skin damage. METHODS Three clinical trials (CT1, CT2, CT3) were performed using different UV sources: nonextreme UV with a high UVA irradiance (UV-DL, CT1), extreme simulated solar radiation (UV-SSR, CT2) and natural sunlight (CT3). All three clinical trials were carried out in healthy women over 18 years of age with skin type II-IV. In CT1, early markers of UV-induced skin damage were assessed using histology and immunohistochemistry. In CT2, the minimal erythemal dose (MED) was determined by clinical evaluation and by chromametry. Chromametry was also used to evaluate skin colour. Dermatologists' and subjects' assessments were compiled in CT3. RESULTS A 10-week DS intake prevented the UV-DL-induced decrease in Langerhans cell density and the increase in factor XIIIa+ type I dermal dendrocytes while it reduced dermal inflammatory cells. Clinical and instrumental MED rose by 20% and 19%, respectively, and skin colour was intensified, as shown by the increase in the ΔE* parameter. The efficacy of DS was confirmed by dermatologists and subjects under real conditions of use. CONCLUSIONS Nutritional supplementation combining a specific probiotic (La1) and nutritional doses of carotenoids reduced early UV-induced skin damage caused by simulated or natural sun exposure in a large panel of subjects (n=139). This latter result might suggest that DS intake could have a beneficial influence on the long-term effects of UV exposure and more specifically on skin photoageing.
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8.
Topical riboflavin attenuates ultraviolet B- and ultraviolet A-induced immunosuppression in humans.
Damian, DL, Matthews, YJ, Halliday, GM
Photodermatology, photoimmunology & photomedicine. 2010;(2):66-9
Abstract
BACKGROUND Riboflavin (vitamin B(2)) plays a key role in cellular energy metabolism. We have observed previously that nicotinamide (vitamin B(3)), which is also centrally involved in cellular energy restoration after UV irradiation, is highly immune protective in humans. We thus hypothesized that riboflavin might also confer immune protection. METHODS We irradiated healthy, nickel-allergic volunteers with narrowband UVA (385 nm) and UVB (300 nm) at separate sites on the lower back. These areas were treated with riboflavin solution or vehicle at 24 h and again at 30 min before UV exposure. Forty-eight hours after irradiation, volunteers were patch tested with nickel-containing Finn chambers, at both irradiated and nonirradiated sites, with and without prior riboflavin treatment. The resulting contact hypersensitivity reactions at each site were then measured 72 h later with a reflectance erythema meter in order to determine and compare the immune suppressive effects of each intervention. RESULTS We observed that low doses of both UVB and longwave UVA1 were immune suppressive in humans. Topical riboflavin conferred immune protection against both wavebands. CONCLUSIONS Riboflavin is immune protective in humans, and this may reflect the role of the B group vitamins in cellular energy restoration after UV exposure.
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9.
Topical application of green and white tea extracts provides protection from solar-simulated ultraviolet light in human skin.
Camouse, MM, Domingo, DS, Swain, FR, Conrad, EP, Matsui, MS, Maes, D, Declercq, L, Cooper, KD, Stevens, SR, Baron, ED
Experimental dermatology. 2009;(6):522-6
Abstract
BACKGROUND Tea polyphenols have been found to exert beneficial effects on the skin via their antioxidant properties. AIMS We sought to determine whether topical application of green tea or white tea extracts would prevent simulated solar radiation-induced oxidative damages to DNA and Langerhans cells that may lead to immune suppression and carcinogenesis. METHODS Skin samples were analysed from volunteers or skin explants treated with white tea or green tea after UV irradiation. In another group of patients, the in vivo immune protective effects of green and white tea were evaluated using contact hypersensitivity to dinitrochlorobenzene. RESULTS Topical application of green and white tea offered protection against detrimental effects of UV on cutaneous immunity. Such protection is not because of direct UV absorption or sunscreen effects as both products showed a sun protection factor of 1. There was no significant difference in the levels of protection afforded by the two agents. Hence, both green tea and white tea are potential photoprotective agents that may be used in conjunction with established methods of sun protection.
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10.
UV radiation-induced immunosuppression is greater in men and prevented by topical nicotinamide.
Damian, DL, Patterson, CR, Stapelberg, M, Park, J, Barnetson, RS, Halliday, GM
The Journal of investigative dermatology. 2008;(2):447-54
Abstract
UV radiation-induced immunosuppression augments cutaneous carcinogenesis. The incidence of skin cancer continues to increase despite increased use of sunscreens, which are less effective at preventing immunosuppression than sunburn. Using the Mantoux reaction as a model of skin immunity, we investigated the effects of solar-simulated (ss) UV and its component UVA and UVB wavebands and tested the ability of topical nicotinamide to protect from UV-induced immunosuppression. Healthy, Mantoux-positive volunteers were UV-irradiated on their backs, with 5% nicotinamide or vehicle applied to different sites in a randomized, double-blinded manner. Subsequent Mantoux testing at irradiated and adjacent unirradiated sites enabled measurement of UV-induced immunosuppression with and without nicotinamide. Suberythemal ssUV caused significant immunosuppression, although component UVB and UVA doses delivered independently did not. Men were immunosuppressed by ssUV doses three times lower than those required to immunosuppress women. This may be an important cause of the higher skin cancer incidence and mortality observed in men. Topical nicotinamide prevented immunosuppression, with gene chip microarrays suggesting that the mechanisms of protection may include alterations in complement, energy metabolism and apoptosis pathways. Nicotinamide is a safe and inexpensive compound that could be added to sunscreens or after-sun lotions to improve protection from immunosuppression. immunosuppression.JID JOURNAL CLUB ARTICLE For questions, answers, and open discussion about this article, please go to http://network.nature.com/group/jidclub