-
1.
Size Matters! Issues and Challenges with Nanoparticulate UV Filters.
Surber, C, Plautz, J, Dähnhardt-Pfeiffer, S, Osterwalder, U
Current problems in dermatology. 2021;:203-222
Abstract
Preparations containing pigments have been used since ancient times to protect against negative effects of solar radiation. Since the 1950s, sunscreen products containing micronized TiO2 and ZnO have been marketed. These products were soon regarded as cosmetically unattrac-tive due to their property of remaining as a white paste on the skin, a result of particle sizes. In order to eliminate these unfavourable properties, particle size distribution was lowered into a range below 100 nm, a size threshold for decreasing the particle's optical property to reflect visible light. After 2000, new nanoparticulate organic filters were developed. Effects of both the inorganic and organic nanoparticulate substances - alone or in combination - with non-particulate UV filters were well documented and had shown great effectiveness. At the time, nanotechnology fuelled great hope in the progress of science and technology, including the health sector and cosmetics industry. Instead, influenced by images from the science fiction literature of self-replicating nanorobots destroying all living matter or health and environmental disasters caused by asbestos, fear of this new unknown amongst the general population has hindered acceptance and progress of nano-enabled products. Consumers have started to suspect that the particles permeate through skin, are absorbed by the blood and are distributed throughout the body, causing disease. Not least because of public pressure, cosmetics - which include sunscreen products - became the first product segment in which appropriately manufactured substances were subject to stringent rules. Despite advanced regulation and rigorous approval procedures for nanoparticulate UV filters, widespread reservations remain. Possible reasons could be a lack of knowledge of current legislation and unclear ideas about nature and behaviour of nanoparticles. Against this background, we discuss the nature and behaviour of nanoparticulate UV filters within finished products, on the skin and potentially in the skin, and the regulatory framework that ensures that nanoparticulate UV filters and the sunscreen products containing them are safe to use.
-
2.
The Preventive Value of Sun Protection.
Rönsch, H, Bauer, A
Current problems in dermatology. 2021;:316-328
Abstract
BACKGROUND With more than 200,000 new cases per year, skin tumours have been the most frequently reported cancers in Germany for years. We performed a systematic review to summarise the current evidence concerning the preventive value of regular sunscreen use. METHODS Systematic literature review of controlled and randomised controlled trials were performed in Ovid Embase and Ovid Medline on 21 January 2020. We included studies evaluating the effectiveness of sunscreens on epithelial skin cancer, actinic keratosis or photoageing, or side effects in humans. RESULTS Five eligible trials, each involving 28 to 1,621 participants from various populations, were identified. All 4 studies on actinic keratoses showed a significant beneficial effect of sunscreens. The 2 studies on squamous cell carcinoma demonstrated significant beneficial effects of sunscreens. The 2 studies on photoageing observed a significant reduction in the sunscreen groups. The 2 studies on basal cell carcinoma reported no significant results, but both studies reported some non-significant protective effects of sunscreen use. Sunscreens as well as vehicles sometimes had side effects affecting skin and eyes. Compared with controls, sunscreens had no significant side effects on vitamin D, bone mass density and mortality. CONCLUSION The evidence from published controlled and randomised controlled studies is limited. Especially for basal cell carcinoma, further high-quality studies including young populations are required to investigate possible protective effects of modern broad-spectrum sunscreens. The results of this systematic review do not change the current recommendations for UV protection. Sunscreens are recommended as a second-line measure against solar radiation whenever protective clothing and seeking shake are inadequate.
-
3.
Current Perspectives on the Role of Matrix Metalloproteinases in the Pathogenesis of Basal Cell Carcinoma.
Tampa, M, Georgescu, SR, Mitran, MI, Mitran, CI, Matei, C, Caruntu, A, Scheau, C, Nicolae, I, Matei, A, Caruntu, C, et al
Biomolecules. 2021;(6)
Abstract
Basal cell carcinoma (BCC) is the most common skin malignancy, which rarely metastasizes but has a great ability to infiltrate and invade the surrounding tissues. One of the molecular players involved in the metastatic process are matrix metalloproteinases (MMPs). MMPs are enzymes that can degrade various components of the extracellular matrix. In the skin, the expression of MMPs is increased in response to various stimuli, including ultraviolet (UV) radiation, one of the main factors involved in the development of BCC. By modulating various processes that are linked to tumor growth, such as invasion and angiogenesis, MMPs have been associated with UV-related carcinogenesis. The sources of MMPs are multiple, as they can be released by both neoplastic and tumor microenvironment cells. Inhibiting the action of MMPs could be a useful therapeutic option in BCC management. In this review that reunites the latest advances in this domain, we discuss the role of MMPs in the pathogenesis and evolution of BCC, as molecules involved in tumor aggressiveness and risk of recurrence, in order to offer a fresh and updated perspective on this field.
-
4.
UV and Reactive Oxygen Species Activate Human Papillomaviruses Causing Skin Cancers.
Godar, DE
Current problems in dermatology. 2021;:339-353
Abstract
Cutaneous malignant melanoma (CMM) and nonmelanoma skin cancers (NMSC), squamous cell and basal cell carcinomas, have been increasing at exponential rates for as long as the International Agency for Research on Cancer (IARC) have been collecting data starting from 1955 in some northern European countries and 1960 in most other European countries. Different strains of the human papilloma virus (HPV) have been found in CMM and NMSC biopsies and implicated in the carcinogenic process as a "hit-and-run" mechanism and can spread at exponential rates, especially since the 1960s' sexual revolution. This chapter covers only IARC data for CMM in the European countries from 1960 to 2018, plotted by regions (northern, middle, and southern latitudes and eastern versus western longitudes), countries latitudes, and each country over time, which shows that about half have linear and the other half have exponential increases in CMM. From this analyzed data and published data in the literature, the major risk factors of CMM appear to be light hair color, especially red and white hair (reactive oxygen species and UVA; 320-400 nm), low cutaneous vitamin D3 levels, and HPV after 1960, while there was no apparent risk from exposure to UVB (290-320 nm) or sunburns.
-
5.
Adverse Reactions to Sunscreens.
Ludriksone, L, Elsner, P
Current problems in dermatology. 2021;:223-235
Abstract
Adverse reactions to sunscreens are uncommon in relation to their widespread use [Loden et al. Br J Dermatol. 2011;165(2):255-62; Jansen et al. J Am Acad Dermatol. 2013;69(6):867 e861-814; quiz 881-862] and can be related to both active and inactive ingredients in sunscreen products [DiNardo et al. J Cosmet Dermatol. 2018;17(1):15-19; Barrientos et al. Contact Dermatitis. 2019;81(2):151-52]. Pathogenetically, the main cutaneous adverse reaction patterns to sunscreens can be divided into allergic and irritant contact dermatitis, phototoxic and photoallergic contact dermatitis, contact urticaria, and, in solitary cases, anaphylactic reactions [Lautenschlager et al. Lancet. 2007;370(9586):528-37]. A summary is provided in Table 1. Nearly all adverse effects due to active sunscreen ingredients reported to date are related to the organic UV filters, which are sometimes also referred to as "chemical UV filters." This imbalance is attributable to the lipophilic character and small molecular size of the organic UV filters that allow skin penetration, which is the basic requirement to initiate the sensitization [Stiefel et al. Int J Cosmet Sci. 2015;37(1):2-30]. In contrast, cutaneous adverse reactions to inorganic UV filters, initially termed "physical UV filters" owing to their firstly known "physical" mechanism of action through reflection and scattering [Stiefel et al. Int J Cosmet Sci. 2015;37(1):2-30], are only reported by case reports. Neither zinc oxide nor titanium dioxide possesses relevant skin-irritating properties or sensitization potential [Lau-tenschlager et al. Lancet. 2007;370(9586):528-37]. Adverse reactions to UV filters currently approved in the European Union as listed in the Annex VI (updated November 7, 2019) are summarized in Table 2.
-
6.
The Formula for Best Sunscreen Performance: Beer-Lambert's Law Under the Microscope.
Herzog, B, Sohn, M
Current problems in dermatology. 2021;:133-143
Abstract
Sunscreens used for the protection of human skin work by attenuating the potentially harmful solar UV radiation. In recent years, the quantitative understanding of this attenuating effect has grown tremendously, enabling model calculations of sunscreen performance. Such calculations are based on the simulation of the UV transmission of the sunscreen film applied on human skin. However, there are 2 prerequisites assumed to hold. The first prerequisite is the applicability of the Beer-Lambert law for sunscreen films, and the second is that the thickness variation of the sunscreen film can be described with a gamma distribution of film heights. There is strong evidence from recent experimental work that both assumptions are correct. For several applications, calculations of sunscreen performance have been shown to be useful, for instance, in the design of new sunscreen formulations aiming for a certain sun protection factor or other characteristics, prediction of pre-vitamin D production in the skin in the presence of sunscreen, in vitro measurement of water resistance, and assessment of the ecotoxicological profile of a sunscreen formulation or the influence of oil polarity on UV-filter absorbance and the consequence for sunscreen performance.
-
7.
What Are the Options Beyond SPF 50+? A View on Consumer Behavior and the Sensory Features of Sunscreens.
Vollhardt, J, Marchini, M
Current problems in dermatology. 2021;:112-123
Abstract
Skin cancer rates have been on the rise for decades and are still growing in spite of the availability of high-performance sunscreens that provide sufficient protection against the damaging effect of UV radiation everywhere on this globe. This paper investigates behaviors and attitudes to sunscreen use that may cause an increased UV exposure risk, for example, not using sunscreen at all. Alongside educational reasons, there is a link to some aspects of applying sunscreens that seem to be disliked universally. Therefore, the sensory features of 73 globally sourced commercial sunscreens were measured using quantitative descriptive sensory analysis. This revealed the ranges of sensory intensity currently available, which were then compared with what consumers really want, and showed that only a few sunscreens currently fulfill the needs of people in the most abundant consumer group - "dry touch seekers." All this contributes to insufficient or no use at all of sunscreens during sun exposure, which could result in significant UV dosages that turn out to be relevant for skin cancer development. A more integral approach to improving sunscreen formulas, along with more targeted communication to connect more effectively with consumers who currently show those avoidance behaviors, is needed.
-
8.
Spectral Homeostasis - The Fundamental Requirement for an Ideal Sunscreen.
Dudley, DK, Laughlin, SA, Osterwalder, U
Current problems in dermatology. 2021;:72-92
Abstract
Sunscreen application to UV-exposed skin is promoted to prevent skin cancer and sun damage, within a comprehensive photoprotection strategy that also includes sun avoidance and wearing UV protective clothing. The benefits of sunscreen are verified in preventing sunburn but appear to be largely presumptive in skin cancer prevention. Contemporary science establishes UVA as a primary driver of melanoma and photoaging. Consequentially, the traditional UVB-skewed protection of sunscreens provides an intellectual and logical explanation for rising skin cancer rates and, in particular, their failure to protect against melanoma. Better protection could be achieved with more balanced UVB/UVA sunscreens, toward spectral homeostasis protection. Greater balanced protection has another advantage of attenuating fewer UVB rays, which aid synthesis of vitamin D and nitric oxide. Percutaneous absorption of Soluble Organic UV Filters leads to systemic exposure, which becomes the relevant safety consideration. It is minimized by selecting Insoluble UV Filters with low absorption potential from a molecular weight above 500 Da. The filters must also be very hydrophilic, very lipophilic, or consist of particles. The risk-benefit ratio is a medical imperative, more so for cosmetics or sunscreens, since in principle there should be no risk from their use. The production of ideal sunscreens that mimic the effective, balanced UVB/UVA attenuation of textiles and shade is now possible, while maintaining an acceptable therapeutic margin of safety in humans and a favorable ecologic profile. Sunscreens with a favorable risk-benefit ratio and good esthetic properties or other consumer-friendly attributes will improve compliance and may achieve substantial clinical benefits.
-
9.
Daily Lifestyle and Cutaneous Malignancies.
Sawada, Y, Nakamura, M
International journal of molecular sciences. 2021;(10)
Abstract
Daily lifestyle is a fundamental part of human life and its influence accumulates daily in the human body. We observe that a good daily lifestyle has a beneficial impact on our health; however, the actual effects of individual daily lifestyle factors on human skin diseases, especially skin cancers, have not been summarized. In this review, we focused on the influence of daily lifestyle on the development of skin cancer and described the detailed molecular mechanisms of the development or regulation of cutaneous malignancies. Several daily lifestyle factors, such as circadian rhythm disruption, smoking, alcohol, fatty acids, dietary fiber, obesity, and ultraviolet light, are known to be associated with the risk of cutaneous malignancies, malignant melanoma, squamous cell carcinoma, basal cell carcinoma, and Merkel cell carcinoma. Although the influence of some daily lifestyles on the risk of skin cancers is controversial, this review provides us a better understanding of the relationship between daily lifestyle factors and skin cancers.
-
10.
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.