PHOTOPROTECTION FOR ALL: CURRENT GAPS AND OPPORTUNITIES

Beyond Traditional Sunscreens: A Review of Liposomal-Based Systems for Photoprotection

Sunscreen products are essential for shielding the skin from ultraviolet (UV) radiation, a leading cause of skin cancer. While existing products serve this purpose, there is a growing need to enhance their efficacy while minimizing potential systemic absorption of UV filters and associated toxicological risks. Liposomal-based formulations have emerged as a promising approach to address these challenges and develop advanced photoprotective products. These vesicular systems offer versatility in carrying both hydrophilic and lipophilic UV filters, enabling the creation of broad-spectrum sunscreens. Moreover, their composition based on phospholipids, resembling that of the stratum corneum, facilitates adherence to the skin's surface layers, thereby improving photoprotective efficacy. The research discussed in this review underscores the significant advantages of liposomes in photoprotection, including their ability to limit the systemic absorption of UV filters, enhance formulation stability, and augment photoprotective effects. However, despite these benefits, there remains a notable gap between the potential of liposomal systems and their utilization in sunscreen development. Consequently, this review emphasizes the importance of leveraging liposomes and related vesicular systems as innovative tools for crafting novel and more efficient photoprotective formulations.

New trends on personalized sunscreens

BACKGROUND/PURPOSE

Nowadays, there are emerging trends in customized and personalized photoprotection, focusing on the innovative approaches to enhance sun protection efficacy tailored to individual needs.

METHODS

We conducted an electronic search of the following databases: MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Skin Group Specialised Skin Register, and TESEO. Specific search terms related to personalized photoprotection and the variables of age, genetic predisposition, skin phototype, photodermatosis, and physiological conditions such as pregnancy, as well as lifestyle habits were used.

RESULTS/CONCLUSION

The article highlights the challenges and opportunities in adopting personalized photoprotection strategies, aiming to promote skin health and prevent the harmful effects of UV radiation in the era of precision medicine.

Awareness of sun exposure risks and photoprotection for preventing pigmentary disorders in Asian populations: Survey results from three Asian countries and expert panel recommendations

BACKGROUND

In this article, we review and discuss the photoprotection behavior of Asians based on the literature, along with a subanalysis of an original online survey, and make recommendations to optimize photoprotection for Asian populations to prevent photoaging and pigmentary disorders.

METHODS

An international panel of eight dermatologists from Asia (China, Korea, Japan, Singapore, Indonesia, and Vietnam) met to discuss sunscreen photoprotection for Asian patients. Additionally, a subanalysis of an online survey by 3000 respondents from three Asian countries (China, Indonesia, and Japan) investigated general public awareness and attitudes to sun exposure.

RESULTS

A pre-meeting survey of the eight experts from Asia showed key concerns of Asian patients consulting dermatologists are pigmentary disorders, especially actinic/senile lentigo, post-inflammatory hyperpigmentation, melasma, vitiligo, and Hori's nevus. The survey subanalysis of participants from China, Indonesia, and Japan with predominantly Fitzpatrick skin types (FST) II to IV revealed that they are particularly concerned about sun exposure causing photoaging and pigmentary disorders. Most of the respondents indicated they have limited knowledge on sunlight radiation and appropriate sunscreen protection factors. Only 22%, 13%, and 3% for China, Indonesia, and Japan, respectively, systematically use multiple protective measures (using sunscreen, avoiding midday sun, staying in the shade, wearing a hat, protective clothing, and sunglasses) when exposed to the sun.

CONCLUSIONS

Further education is needed for Asian populations on the importance of comprehensive daily photoprotection, including broad-spectrum sunscreen, with high UVA and visible light protection, to reduce and prevent photoaging and pigmentary disorders.

Sun exposure behaviours as a compromise to paradoxical injunctions: Insight from a worldwide survey

BACKGROUND

Behavioural interventions can improve attitudes towards sun protection but the impact remains inconsistent worldwide.

OBJECTIVE

To assess awareness of and attitudes towards the multiple facets of sun exposure and suggest ways to improve prevention from overexposure to the sun in all geographical zones and multiple skin types.

METHODS

Online survey was conducted from 28 September to 18 October 2021. Study population was selected from the Ipsos online Panel (3,540,000 panellists), aged ≥18 years, from 17 countries around the five continents. Demographics, sun-exposure habits and practices, understanding of risks and information on phototypes were documented and analysed using descriptive statistics.

RESULTS

Eighty-eight per cent of participants knew that sunlight can cause skin health problems (90% phototypes I-II, 82% phototypes V-VI, >90% in American and European countries, 72% in Asia and 85% in Africa). Eighty-five per cent used some form of protection against sunlight, predominantly: Seeking shade (77%), avoiding the midday sun (66%), facial application of sunscreen (60%) and wearing protective clothing (44%). The perception of sunlight itself is positive ('it gives energy' for 82%; 'tanned skin looks attractive' for 72%), although less in Asian countries and among individuals with dark skin phototypes. Eighty-three per cent reported having experienced sunburn, mainly in Australia, Canada, USA, Germany, France and Russia, and among individuals with dark skin phototypes. Only 12% systematically/often used all types of protection during exposure to the sun and 23% believed it is safe to go out in the sun with no protection when their skin is already tanned. From 13% (skin phototype I) to 26% (phototype VI) reported not using any form of protection against the sun. Knowledge and habits were significantly superior among people who are accustomed to seeing a dermatologist for a complete skin exam.

CONCLUSIONS

Dermatologists could play a crucial role in relaying novel prevention messages, more finely tailored to specific risks, populations and areas of the world.

Photoaging's portrait: The road map towards its photoprotection

OBJECTIVE

To summarize key research published by the author's group, dealing with skin photoaging and its photoprotection.

MATERIALS AND METHODS

Two methodologies (standard photographs and selfies imaging) resulting from referential skin ageing atlases were applied on 2487 subjects of different ancestries, ages and gender. These aimed at first to best assess and grade the variable severities of some facial signs (texture/wrinkles, pigmentary spots, sagging and vascular disorders) that occur progressively during the photoaging process. Second, such methodologies were used to record the benefits brought by a photoprotective regimen (671 women and men).

RESULTS

In all studied ancestries, each facial sign show an increase severity along decades, at its own pace, some showing a linear like progression, whereas some plateau at early ages. These changes differed according to skin innate colour (phototype) and with individual behaviours vis-à-vis sun exposures, more so among European women than North-East Asian women. An effect of gender (less severe alterations) was observed on Chinese men, as compared to Chinese women. Pigmentary disorders were found hallmarks of photo-aged North-East Asian women. Globally, photoaging impact the apparent age of the different subjects. The counteracting effects of strong topical Photoprotective regimens were evidenced along a 6-month seasonality in Chinese and French women or 1-year period in Brazilian women with phototypes II to VI. Photoprotection led to a more even skin complexion among Indian subjects with pigment irregularities.

CONCLUSION

Two factors clearly hamper a better assessment of the efficiency of photoprotection of the sun-induced cutaneous ageing: short durations (months) of the studies with regard to the global fate of photoaging by decades and the number of studied subjects, limited to hundreds for practical reasons. The methodology based on the automatic analysis of facial signs through selfies images could theoretically bypass both factors, allowing thousands of subjects to be studied along years.

TiO2-embedded mesoporous silica with lower porosity is beneficial to adsorb the pollutants and retard UV filter absorption: A possible application for outdoor skin protection

The purpose of the current investigation was to develop multifunctional TiO₂-embedded mesoporous silica incorporating avobenzone to protect against environmental stress through pollutant adsorption and UVA protection. We sought to explore the effect of the mesoporous porosity on the capability of contaminant capture and the suppression of avobenzone skin penetration. The porosity of the mesoporous silica was tuned by adjusting the ratio of template triblock copolymers (Pluronic P123 and F68). The Pluronic P123:F68 ratios of 3:1, 2:2, and 1:3 produced mesoporous silica with pore volumes of 0.66 (TiO₂/SBA-L), 0.47 (TiO₂/SBA-M), and 0.25 (TiO₂/SBA-S) cm³/g, respectively. X-ray scattering and electron microscopy confirmed the SBA-15 structure of the as-prepared material had a size of 3-5 μm. The maximum adsorbability of fluoranthene and methylene blue was found to be 43% and 53% for the TiO₂/SBA-S under UVA light, respectively. The avobenzone loaded into the mesoporous silica demonstrated the synergistic effect of in vitro UVA protection, reaching an UVA/UVB absorbance ratio of near 1.5 (Boots star rating = 5). The encapsulation of avobenzone into the TiO₂/SBA-S lessened cutaneous avobenzone absorption from 0.76 to 0.50 nmol/mg, whereas no reduction was detected for the TiO₂/SBA-L. The avobenzone-loaded TiO₂/SBA-S hydrogel exhibited a greater improvement in skin barrier recovery and proinflammatory mediator mitigation compared to the SBA-S hydrogel (without TiO₂). The cytokines/chemokines in the photoaged skin were reduced by two- to three-fold after TiO₂/SBA-S treatment compared to the non-treatment control. Our data suggested that the mesoporous formulation with low porosity and a specific surface area showed effective adsorbability and UVA protection, with reduced UVA filter absorption. The versatility of the developed mesoporous system indicated a promising potential for outdoor skin protection.

Photolyase Production and Current Applications: A Review

The photolyase family consists of flavoproteins with enzyme activity able to repair ultraviolet light radiation damage by photoreactivation. DNA damage by the formation of a cyclobutane pyrimidine dimer (CPD) and a pyrimidine-pyrimidone (6-4) photoproduct can lead to multiple affections such as cellular apoptosis and mutagenesis that can evolve into skin cancer. The development of integrated applications to prevent the negative effects of prolonged sunlight exposure, usually during outdoor activities, is imperative. This study presents the functions, characteristics, and types of photolyases, their therapeutic and cosmetic applications, and additionally explores some photolyase-producing microorganisms and drug delivery systems.

Self-Emulsifying Phospholipid Preconcentrates for the Enhanced Photoprotection of Luteolin

Exposure to ultraviolet B (UVB) leads to the overproduction of reactive oxygen species (ROS), causing higher risks of skin disorders. Luteolin (Lut) is a naturally occurring antioxidant that can absorb a broad range of ultraviolet light, but its water solubility and skin permeability are limited and insufficient. The aim of the current study was to develop a Lut-loaded self-emulsifying phospholipid preconcentrate (LSEPP) for enhancing the solubility, permeability, and photoprotective activity of Lut. The designed formulations were firstly examined for their droplet size, zeta potential, dispersity, and in vitro corneum permeability after dispensing the preconcentrate to form an emulsion; the optimized formulation was further characterized for its emulsified morphology, compatibility with excipients, stability in the preconcentrate form, and photoprotective activity by the HaCaT cell model under the emulsified status. The optimized LSEPP formulation attained a smaller droplet size (140.6 ± 24.2 nm) with the addition of 1,8-cineole and increased the permeability of Lut by 7-fold. As evidenced in the cell model studies, the optimized LSEPP formulation can efficiently deliver Lut into HaCaT cells after emulsification and result in a 115% better cell viability as well as a 203% stronger ROS scavenging capability, compared with those of unformulated Lut after UVB irradiation. To sum up, we have successfully developed an LSEPP formulation, which is a safe and promising topical delivery system for enhancing the photoprotective effects of Lut.

[Sunscreens of the future: challenges and opportunities]

Sunscreens provide excellent protection against erythema and against chronic damage such as photoaging and skin cancer. Today's challenges concern safety of the products and improved methods for standardizing the evaluation of their efficacy. Other important topics are the further development of sunscreen products, as well as personalization of use. Personalized sun protection based on the phenotype, the genetic profiles and moreover the skin's microbiome - all linked to the identification of certain consumer susceptibility factors - is an exciting new area of research. In particular, the expansion with innovative topical agents such as DNA repair liposomes in improved galenic formulations with UV filters tailored to the skin phototype and new topical antioxidants could in future provide even more comprehensive sun protection. New antioxidants and other agents such as nicotinamide could increase systemic photoprevention. Sustainability will also be an important aspect to protect consumers, but also the environment (i.e. especially marine wildlife) from toxic effects of sunscreens.