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Background: With growing interest in hair health, researchers are exploring aspects beyond the surface qualities of hair, such as its porous inner structure. While previous studies have focused on the effects of treatments such as perming and hair dying on hair porosity, less emphasis has been paid to the effects of harmful environmental factors such as ultraviolet (UV) rays and particulate matter on the porous nature of hair. Aims: The aim of this study was to bridge this gap by investigating how UV rays and particulate matter affect hair porosity in different ways. Our study could help elucidate how these external factors influence hair health and shed light on previously unknown aspects of hair porosity. Methods: Hair tresses were bleached, cut into 1 cm‐long sections, and stained with methylene blue. The sections were then irradiated with UV light or exposed to particulate matter. Results: Bleached hair absorbed more methylene blue than normal hair. UV radiation‐induced hair porosity occurred at 3 h after irradiation and increased with time. Particulate matter alone did not affect the porosity of the damaged hair; however, in combination with UV irradiation, it substantially increased hair porosity. Conclusion: Environmental challenges such as a depleted ozone layer and increasing pollution may increase hair porosity, which can be prevented by maintaining healthy hair. [ABSTRACT FROM AUTHOR]

Background: Transient receptor potential vanilloid 1 (TRPV1) is associated with skin sensitivity and mainly activated by capsaicin and heat. Interestingly, troxerutin can inhibit TRPV1 activation. However, its efficacy in reducing skin sensitivity remains undetermined. Aims: We evaluated the efficacy of troxerutin in alleviating skin sensitivity using clinical tests and in vitro experiments. Methods: For the in vitro experiment, HaCaT keratinocytes were pretreated with different concentrations of troxerutin, followed by incubation with 50 μM capsaicin for 1, 24, or 48 h. The gene and protein expressions of four inflammatory cytokines involved in skin irritation were determined. Among 35 Korean women with sensitive skin recruited for the clinical trial, 13 were involved in assessing the immediate soothing effects of 0.1% and 0.0095% troxerutin following capsaicin irritation, whereas 22 participated in evaluating the preventive soothing effect of 10% and 1% troxerutin over 4 weeks against capsaicin‐ and heat‐induced irritation. We evaluated the soothing rate using skin redness, visual analog scale, and high temperature sensitive index as evaluation indices. Results: Troxerutin inhibited the mRNA and protein expressions of cytokines in capsaicin‐treated keratinocytes. In the clinical study, 0.1% and 0.0095% troxerutin promptly alleviated capsaicin‐induced skin redness, whereas 10% troxerutin notably decreased both the visual analog scale and high temperature sensitive index for capsaicin‐ and heat‐related irritation. However, 1% troxerutin was only effective in reducing the visual analog scale in response to capsaicin irritation. Conclusions: Troxerutin can inhibit TRPV1 activation in clinical and in vitro tests. [ABSTRACT FROM AUTHOR]

Background: Oxygen has several positive effects on the skin, including improving collagen synthesis and accelerating wound healing. However, only a few studies have investigated the relationship between skin oxygenation and skin aging parameters. Therefore, this study aimed to assess the correlation between skin oxygenation and skin aging parameters—elasticity, hydration, sebum, color (lightness, redness), and blood perfusion—in Korean women. Materials and Methods: We evaluated the transcutaneous partial pressure of oxygen, also known as transcutaneous oxygen tension (TcPO2), and skin aging parameters, including elasticity, hydration, sebum, color (lightness or redness), and blood perfusion, in the cheek of 34 healthy women (aged 20‐69 years) and assessed the correlation between TcPO2 and other skin aging parameters using IBM SPSS Statistics 25 software (SPSS Inc). Results: Facial TcPO2 was negatively correlated with age (P <.05). There were positive correlations between facial TcPO2 and elasticity parameters (P <.01). We noted no correlation between facial TcPO2 and skin lightness; however, skin lightness tended to slightly improve with increasing TcPO2. Skin aging parameters, including hydration, sebum, skin redness, and blood perfusion, showed no correlations with TcPO2. Conclusion: In Korean women, facial TcPO2 tends to decrease with increasing age and is positively correlated with gross, net, and biological skin elasticity. Therefore, this study demonstrated that oxygen tension of facial skin can be a major causative factor of skin aging. [ABSTRACT FROM AUTHOR]

Cutibacterium acnes , one of the most abundant skin microbes found in the sebaceous gland, is known to contribute to the development of acne vulgaris when its strains become imbalanced. The current limitations of acne treatment using antibiotics have caused an urgent need to develop a systematic strategy for selectively targeting C. acnes , which can be achieved by characterizing their cellular behaviors under various skin environments. To this end, we developed a genome-scale metabolic model (GEM) of virulent C. acnes , i CA843, based on the genome information of a relevant strain from ribotype 5 to comprehensively understand the pathogenic traits of C. acnes in the skin environment. We validated the model qualitatively by demonstrating its accuracy prediction of propionate and acetate production patterns, which were consistent with experimental observations. Additionally, we identified unique biosynthetic pathways for short-chain fatty acids in C. acnes compared to other GEMs of acne-inducing skin pathogens. By conducting constraint-based flux analysis under endogenous carbon sources in human skin, we discovered that the Wood-Werkman cycle is highly activated under acnes-associated skin condition for the regeneration of NAD, resulting in enhanced propionate production. Finally, we proposed potential anti- C. acnes targets by using the model-guided systematic framework based on gene essentiality analysis and protein sequence similarity search with abundant skin microbiome taxa., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kim, Lee, Lee, Lee, Rho, Kim, Seo, Youn, Hwang, Kang, Lee, Park and Lee.)