Exposome and Skin. Part 2. The Influential Role of the Exposome, Beyond UVR, in Actinic Keratosis, Bowen's Disease and Squamous Cell Carcinoma: A Proposal

Exploring the impact of solar radiation on skin microbiome to develop improved photoprotection strategies

The skin microbiome undergoes constant exposure to solar radiation (SR), with its effects on health well-documented. However, understanding SR's influence on host-associated skin commensals remains nascent. This review surveys existing knowledge on SR's impact on the skin microbiome and proposes innovative sun protection methods that safeguard both skin integrity and microbiome balance. A team of skin photodamage specialists conducted a comprehensive review of 122 articles sourced from PubMed and Research Gateway. Key terms included skin microbiome, photoprotection, photodamage, skin cancer, ultraviolet radiation, solar radiation, skin commensals, skin protection, and pre/probiotics. Experts offered insights into novel sun protection products designed not only to shield the skin but also to mitigate SR's effects on the skin microbiome. Existing literature on SR's influence on the skin microbiome is limited. SR exposure can alter microbiome composition, potentially leading to dysbiosis, compromised skin barrier function, and immune system activation. Current sun protection methods generally overlook microbiome considerations. Tailored sun protection products that prioritize both skin and microbiome health may offer enhanced defense against SR-induced skin conditions. By safeguarding both skin and microbiota, these specialized products could mitigate dysbiosis risks associated with SR exposure, bolstering skin defense mechanisms and reducing the likelihood of SR-mediated skin issues.

Impact of particulate-matter air pollution on 25-hydroxyvitamin D levels: a mendelian randomisation study

OBJECTIVES

In observational studies, the 25-hydroxyvitamin D (25(OH)D) level in body has been found to be closely related to particulate matter (PM) air pollution. In this study, we used the two-sample mendelian randomisation (MR) method to investigate and discuss the potential causal relationship and mode of influence.

STUDY DESIGN

MR study.

METHODS

PM data (PM10, PM2.5-10, PM2.5, PM2.5 absorbance) came from the UK Biobank database, and 25(OH)D data came from European Bioinformatics Institute (EBI) database. The analysis was conducted utilising three prominent methods (inverse-variance-weighted [IVW], MR-Egger, weighted median, weighted mode, and simple mode). The primary emphasis was placed on IVW, accompanied by heterogeneity and horizontal pleiotropy tests. Furthermore, sensitivity analysis was undertaken.

RESULTS

The MR analysis revealed a significant association between exposure to PM10 and a decrease in levels of 25(OH)D (odds ratio [OR]: 0.878, 95% confidence interval [CI]: 0.789-0.977). However, no significant relationship was observed between PM2.5 exposure and 25(OH)D (OR: 0.943, 95%CI: 0.858-1.037). Further analysis indicated that the main contributor to the decline in 25(OH)D levels is linked to PM2.5-10 exposure (OR: 0.840, 95%CI: 0.751-0.940) and PM2.5 absorbance (OR: 0.875, 95%CI: 0.824-0.929). No heterogeneity and horizontal pleiotropy existed.

CONCLUSIONS

The MR results suggest that PM (PM10, PM2.5-10 and PM2.5 absorbance) exposure lowers vitamin D (VD) levels, but PM2.5 was not found to have a significant effect on VD in humans.

Clinical and histopathological characteristics, diagnosis and treatment, and comorbidities of Bowen's disease: a retrospective study

Background

Bowen's disease (BD) is a slow-growing precancerous skin condition, often concurrent with other diseases, with a high misdiagnosis rate. Previous studies show that patients with BD in different populations have differentiated characteristics.

Materials and methods

A retrospective study was conducted in a tertiary hospital in Shenzhen, China. Data about demographic information, diagnosis and treatment, clinical and pathological characteristics, and comorbidities of 50 patients with BD were collected and analyzed.

Results

Clinical data of onset age and disease course of 43 patients with BD were available, the average onset age of male and female patients are 55.1 (standard deviation (SD) = 15.29) and 58.2 (SD = 15.59) years old, respectively; the average disease course of male and female patients are 25.3 (SD = 28.63) and 33.9 (SD = 49.65) months, respectively. The onset age (p = 0.52) and disease course (p = 0.49) between male and female patients are not significantly different. Interestingly, there is a negative correlation between onset age and disease course (r = -0.245, p = 0.11). The correct rate of clinical diagnosis is relatively low (54.00%); Some patients with BD are misdiagnosed as Bowenoid papulosis (10.00%), actinic keratosis (8.00%), basal cell carcinoma (8.00%), seborrheic keratosis (6.00%), and pigmented naevus (4.00%). Trunk and limbs are the most common distribution sites of BD lesions, and 94.00% patients with BD are treated with surgical resection; 66.00% patients with BD had comorbidities, including skin diseases (48.48%), cardiovascular diseases (39.39%), gastrointestinal diseases (30.30%), respiratory diseases (27.27%), and tumors (18.18%). The most commonly observed histopathological characteristics of BD are squamous-cell hyperplasia (86.00%), disordered maturation with atypical keratinocytes (74.00%), atypical mitoses (60.00%), hyperkeratosis with hypokeratosis (48.00%), dermal inflammatory cell infiltration (36.00%), and koilocytosis (22.00%).

Conclusion

BD often occurs in middle-aged and elderly people and is easily misdiagnosed. The onset age and disease course of patients with BD are not significantly different between males and females, whereas there is a negative correlation between the onset age and disease course. BD is more likely to occur in trunk and limbs in the Chinese population, and most patients with BD are concurrent with comorbidities.

Effects of Air Pollution on Cellular Senescence and Skin Aging

The human skin is exposed daily to different environmental factors such as air pollutants and ultraviolet (UV) light. Air pollution is considered a harmful environmental risk to human skin and is known to promote aging and inflammation of this tissue, leading to the onset of skin disorders and to the appearance of wrinkles and pigmentation issues. Besides this, components of air pollution can interact synergistically with ultraviolet light and increase the impact of damage to the skin. However, little is known about the modulation of air pollution on cellular senescence in skin cells and how this can contribute to skin aging. In this review, we are summarizing the current state of knowledge about air pollution components, their involvement in the processes of cellular senescence and skin aging, as well as the current therapeutic and cosmetic interventions proposed to prevent or mitigate the effects of air pollution in the skin.