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The potential role of antioxidants in mitigating skin hyperpigmentation resulting from ultraviolet and visible light-induced oxidative stress.
Nahhas, AF, Abdel-Malek, ZA, Kohli, I, Braunberger, TL, Lim, HW, Hamzavi, IH
Photodermatology, photoimmunology & photomedicine. 2019;(6):420-428
Abstract
Oxidative stress is an integral element that influences a variety of biochemical reactions throughout the body and is known to play a notable role in melanogenesis. Exogenous triggers of oxidative stress, such as ultraviolet radiation (UVR) and visible light (VL), lead to pigment formation through somewhat different pathways, but both share a common endpoint-the potential to generate cosmetically undesirable hyperpigmentation. Though organic and inorganic sunscreens are available to protect against the UVR portion of the electromagnetic spectrum, coverage is lacking to protect against the VL spectrum. In this manuscript, we review the phases of tanning, pathways of melanogenesis triggered by UVR and VL, and the associated impact of oxidative stress. We also discuss the known intrinsic mechanisms and paracrine regulation of melanocytes that influence their response to UVR. Understanding these mechanisms and their role in UVR-induced hyperpigmentation should potentially lead to identification of useful targets that can be coupled with antioxidant therapy to alleviate this effect.
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Overview on vitamin D and sunbed use.
Pierret, L, Suppa, M, Gandini, S, Del Marmol, V, Gutermuth, J
Journal of the European Academy of Dermatology and Venereology : JEADV. 2019;:28-33
Abstract
Vitamin D seems to be associated with a protective effect in a vast range of diseases, including cardiovascular, autoimmune and oncologic conditions. Since ultraviolet (UV) B light is the most important prerequisite for the cutaneous synthesis of vitamin D, sunbeds are able to increase serum vitamin D levels, although only transiently in most cases. In this scenario, the artificial tanning industry relentlessly tries to promote the use of sunbeds as a 'safe' therapeutic measure to achieve an adequate serum vitamin D status. The World Health Organization classified UV-emitting tanning devices, as well as the whole UV spectrum, as group-1 carcinogens, as they significantly increase the risk of melanoma and non-melanoma skin cancer. In case of vitamin D deficiency or insufficiency, the current risk-benefit ratio is therefore in favour of vitamin D supplementation instead of sunbed use. Artificial tanning devices should never be considered as an option to achieve an appropriate vitamin D status. Their supposedly beneficial effects, vastly publicised by the artificial tanning industry, are not worth the carcinogenic risk associated with sunbed use.
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A Review of the Evidence Supporting the Vitamin D-Cancer Prevention Hypothesis in 2017.
Grant, WB
Anticancer research. 2018;(2):1121-1136
Abstract
The vitamin D-cancer prevention hypothesis has been evaluated through several types of studies, including geographical ecological studies related to indices of solar ultraviolet-B (UVB) dose (the primary source of vitamin D for most people), observational studies related to UVB exposure or serum 25-hydroxyvitamin D [25(OH)D] concentrations, laboratory studies of mechanisms, and clinical trials. Each approach has strengths and limitations. Ecological studies indirectly measure vitamin D production and incorporate the assumption that vitamin D mediates the effect of UVB exposure. Findings from observational studies with long follow-up times are affected by changing 25(OH)D concentrations over time. Most clinical trials have been poorly designed and conducted, based largely on guidelines for pharmaceutical drugs rather than on nutrients. However, three clinical trials do support the hypothesis. In general, the totality of the evidence, as evaluated using Hill's criteria for causality in a biological system, supports the vitamin D-cancer prevention hypothesis.
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A Critical Appraisal of the Recent Reports on Sunbeds from the European Commission's Scientific Committee on Health, Environmental and Emerging Risks and from the World Health Organization.
Reichrath, J, Lindqvist, PG, DE Gruijl, FR, Pilz, S, Kimball, SM, Grant, WB, Holick, MF
Anticancer research. 2018;(2):1111-1120
Abstract
The European Commission's Scientific Committee on Health, Environmental and Emerging Risks and the World Health Organization recently published reports which concluded that a large proportion of melanoma and non-melanoma skin cancer is attributable to sunbed use, and that there is no need to use sunbeds as there are no health benefits and they are not needed to achieve an optimal vitamin D level. The overall conclusion from both bodies was that there is no safe limit for UV irradiance from sunbeds. We are, however, deeply concerned that these assessments appear to be based on an incomplete, unbalanced and non-critical evaluation of the literature. Therefore, we rebut these conclusions by addressing the incomplete analysis of the adverse health effects of UV and sunbed exposure (what is 'safe'?) and the censored representation of beneficial effects, not only but especially from vitamin D production. The stance taken by both agencies is not sufficiently supported by the data and in particular, current scientific knowledge does not support the conclusion sunbed use increases melanoma risk.
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5.
Mechanisms and prevention of UV-induced melanoma.
Sample, A, He, YY
Photodermatology, photoimmunology & photomedicine. 2018;(1):13-24
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Abstract
Melanoma is the deadliest form of skin cancer and its incidence is rising, creating a costly and significant clinical problem. Exposure to ultraviolet (UV) radiation, namely UVA (315-400 nm) and UVB (280-315 nm), is a major risk factor for melanoma development. Cumulative UV radiation exposure from sunlight or tanning beds contributes to UV-induced DNA damage, oxidative stress, and inflammation in the skin. A number of factors, including hair color, skin type, genetic background, location, and history of tanning, determine the skin's response to UV radiation. In melanocytes, dysregulation of this UV radiation response can lead to melanoma. Given the complex origins of melanoma, it is difficult to develop curative therapies and universally effective preventative strategies. Here, we describe and discuss the mechanisms of UV-induced skin damage responsible for inducing melanomagenesis, and explore options for therapeutic and preventative interventions.
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The Winding Path Towards an Inverse Relationship Between Sun Exposure and All-cause Mortality.
Lindqvist, PG
Anticancer research. 2018;(2):1173-1178
Abstract
For a long time, skin cancer has been known to be related to extensive UV exposure. New emerging data have, however, shown low UV exposure/low vitamin D levels to be related to increased mortality rate due to skin cancer. In addition, low sun exposure habits in regions of low solar intensity have been shown to be a major risk factor for all-cause mortality in the same range as that for smoking. This is mainly due to lower all-cause mortality due to cardiovascular disease (CVD) and non-CVD/non-cancer disease among women with active sun exposure. Women with active sun exposure habits were estimated to have a 1- to 2-year longer life-expectancy during the Melanoma in Southern Sweden study interval. These findings are in line with those to be expected from an evolutionary perspective and research findings, but in opposition to present guidelines and recommendations.
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The Impact of UV-dose, Body Surface Area Exposed and Other Factors on Cutaneous Vitamin D Synthesis Measured as Serum 25(OH)D Concentration: Systematic Review and Meta-analysis.
Jager, N, Schöpe, J, Wagenpfeil, S, Bocionek, P, Saternus, R, Vogt, T, Reichrath, J
Anticancer research. 2018;(2):1165-1171
Abstract
BACKGROUND/AIM: To optimize public health campaigns concerning UV exposure, it is important to characterize factors that influence UV-induced cutaneous vitamin D production. This systematic review and meta-analysis investigated the impact of different individual and environmental factors including exposed body surface area (BSA), UVB dose and vitamin D status, on serum 25(OH)D concentration. MATERIALS AND METHODS In accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses, and Meta-analysis of Observational studies in Epidemiology guidelines, a systematic literature search was conducted (MEDLINE; 01/1960-07/2016) investigating the impact of these factors on vitamin D status after artificial UV exposure as main outcome measure. Summary mean differences [and 95% confidence interval (CI)] were derived from random-effects meta-analysis to account for possible heterogeneity across studies. Meta-regression was conducted to account for impact of UVB dose, baseline 25(OH)D level and BSA. RESULTS We identified 15 studies, with an estimated mean 25(OH)D rise per standard erythema dose (SED) of 0.19 nmol/l (95% CI 0.11-0.26 nmol/l). Results from meta-regression suggest a significant impact of UV dose and baseline 25(OH)D concentration on serum 25(OH)D level (p<0.01). Single UVB doses between 0.75 and 3 SED resulted in the highest rise of serum 25(OH)D per dose unit. BSA exposed had a smaller, non-proportional, not significant impact. Partial BSA exposure resulted in relatively higher rise compared to whole-body exposure (e.g. exposure of face and hands caused an 8-fold higher rise of serum 25(OH)D concentration/SED/1% BSA compared to whole-body exposure). Our findings support previous reports, estimating that the half-life of serum 25(OH)D varies depending on different factors. CONCLUSION Our results indicate that partial BSA exposure (e.g. 10%) with moderate UV doses (e.g. 1 SED) is effective in generating or maintaining a healthy vitamin D status. However, due to limitations that include possible confounding factors such as skin type, which could not be considered, these findings should be interpreted with caution.
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Hormonal Regulation of the Repair of UV Photoproducts in Melanocytes by the Melanocortin Signaling Axis.
Jarrett, SG, D'Orazio, JA
Photochemistry and photobiology. 2017;(1):245-258
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Abstract
Melanoma is the deadliest form of skin cancer because of its propensity to spread beyond the primary site of disease and because it resists many forms of treatment. Incidence of melanoma has been increasing for decades. Although ultraviolet radiation (UV) has been identified as the most important environmental causative factor for melanoma development, UV-protective strategies have had limited efficacy in melanoma prevention. UV mutational burden correlates with melanoma development and tumor progression, underscoring the importance of UV in melanomagenesis. However, besides amount of UV exposure, melanocyte UV mutational load is influenced by the robustness of nucleotide excision repair, the genome maintenance pathway charged with removing UV photoproducts before they cause permanent mutations in the genome. In this review, we highlight the importance of the melanocortin hormonal signaling axis on regulating efficiency of nucleotide excision repair in melanocytes. By understanding the molecular mechanisms by which nucleotide excision repair can be increased, it may be possible to prevent many cases of melanoma by reducing UV mutational burden over time.
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Sunscreens: An Update.
Mancuso, JB, Maruthi, R, Wang, SQ, Lim, HW
American journal of clinical dermatology. 2017;(5):643-650
Abstract
Sunscreens have been widely used by the general public for their photoprotective properties, including prevention of photocarcinogenesis and photoaging and management of photodermatoses. It is important to emphasize to consumers the necessity of broad-spectrum protection, with coverage of both ultraviolet A (320-400 nm) and ultraviolet B (290-320 nm) radiation. This review discusses the benefits of sunscreen, different ultraviolet filters, sunscreen regulations and controversies, the importance of broad-spectrum protection, issues of photostability and formulation, and patient education and compliance.
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Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin.
Riahi, RR, Bush, AE, Cohen, PR
American journal of clinical dermatology. 2016;(3):265-76
Abstract
Retinoids are a group of substances comprising vitamin A and its natural and synthetic derivatives. Retinoids were first used in dermatology in 1943 by Straumfjord for acne vulgaris. Since that time, retinoids have been utilized in the management and treatment of various skin conditions, including photoaging. Photodamage of the skin occurs as a consequence of cumulative exposure to solar ultraviolet radiation (UVR) and is characterized by deep wrinkles, easy bruising, inelasticity, mottled pigmentation, roughness, and telangiectasias. The mechanism of UVR-induced photodamage is multifactorial. Retinoids have demonstrated efficacy in the treatment of photoaged skin. Indeed, understanding the pathophysiology of photoaging and the molecular mechanism of retinoids can not only provide insight into the effects retinoids can exert in treating photoaging but also provide the rationale for their use in the treatment of other dermatologic diseases.