Background: Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome. Objective: To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18– 38 years living in Shanghai. Methods: Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing. Results: The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water–oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration. Conclusion: Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.

Background: Overweight and obesity have become public health problems worldwide. An increasing number of research works are focusing on skin physiology and the manifestations of obesity-associated skin diseases, but little is known about the correlations between body mass index (BMI), facial skin physiological parameters, and the facial skin microbiome in healthy women. Objective: To investigate the correlations between BMI, facial skin physiological parameters and facial bacteria and fungi in 198 women aged 18 to 35 years in Shanghai. Methods: According to the international BMI standard and Chinese reference standard, subjects were divided into three groups, “lean” B1, “normal” B2 and “overweight” B3, and the physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiota was analyzed by 16S rRNA and ITS high-throughput sequencing. Results: Compared with the skin physiological parameters of the normal group, those of the overweight group exhibited a significant increase in trans-epidermal water loss (TEWL), which indicated that the skin barrier was impaired. The skin haemoglobin content was significantly increased, and skin surface pH was significant decreased in those with a high BMI. Furthermore, α-diversity, analysed using the Shannon, Chao, Sobs, and Ace indexes, was increased in the overweight group, suggesting that the diversity and species abundance of facial bacterial and fungal microbiota were also increased. Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia, and Candida. Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida, and Cladosporium. Besides, the abundance of Malassezia was positively associated with the abundances of Staphylococcus and Corynebacterium. Conclusion: These results indicate that BMI is associated with differences in the biophysical properties and microbiome of the facial skin. A high BMI affects the integrity of skin barrier and changes the skin flora diversity and species composition.

Cordyceps cicadae (Miq.) is an edible fungus with unique and valuable medicinal properties that is commonly used in traditional Chinese medicine, but its anti-aging effects on the skin fibroblast are not well studied. The aim of the present study was to analyze the active components of aqueous C. cicadae extract (CCE), determine the effects of CCE on hyaluronan synthesis in human skin fibroblasts, and explore the underlying mechanisms. The results of this study indicate that CCE was rich in polysaccharides, five alditols (mainly mannitol), eight nucleosides, protein, and polyphenols, which were present at concentrations of 62.7, 110, 8.26, 35.7, and 3.8 mg/g, respectively. The concentration of extract required to inhibit 50% of 2,2-azino-bis (3-ethylbenzothiazo-line-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging capacities were 0.36 ± 0.03 and 4.54 ± 0.10 mg/mL, respectively, indicating that CCE exhibits excellent antioxidant activities. CCE showed no cytotoxicity to skin fibroblasts at concentrations ≤ 100 μg/mL, and promoted HA synthesis in fibroblasts. Treatment of fibroblast cells with 100 μg/mL CCE enhances the HA content to 1293 ± 142 ng/mL, which is significantly more than that in the non-treatment (NT) group (p = 0.0067). Further, RNA sequencing detected 1,192 differentially expressed genes (DEGs) in CCE-treated fibroblasts, among which 417 were upregulated and 775 were downregulated. Kyoto Encyclopedia of Genes (KEGG) and Genomes pathway (GO) analysis based on RNA sequencing revealed that CCE mainly affected cytokine-cytokine receptor interaction regulated by HA synthesis-related genes. CCE upregulated HA synthase 2 (HAS2), epidermal growth factor (EGF)-related genes, heparin-binding EGF-like growth factor, C-C motif chemokine ligand 2, interleukin 1 receptor-associated kinase 2, and other genes related to fibroblast differentiation and proliferation. CCE downregulated the gene of matrix metallopeptidase 12 (MMP12), which leads to cell matrix loss. RT-qPCR further verified CCE significantly upregulated HAS2 expression and significantly downregulated MMP12 expression, thus promoting hyaluronan synthesis. CCE shows potential as a moisturizer and anti-aging agent in functional foods and cosmetics.

Purpose: Everyone pursues perfect skin, but there exist significant differences between cultures, and no commonly accepted standards have been established. Therefore, our study attempted to define the “ideal skin” of oriental women and analyze the relationship between different skin physiological parameters and microbiomes. Patients and Methods: Based on our customized grading standard, the VISIA CR photos of 111 young women aged from 18 to 25 in Shanghai were collected and scored by the severity of pores, acne, spots, and wrinkles. The volunteers were then divided into “ideal skin” (W1), “normal skin” (W2), and “undesirable skin” (W3) groups. The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA and ITS high-throughput sequencing. Results: From “ideal skin” to “undesirable skin”, the skin physiological parameters, α-diversity, and composition of the facial microbiome showed noticeable regular changes. Compared with the “normal skin” (W2) and “undesirable skin” (W3), the “ideal skin” (W1) group had lower sebum content, TEWL, melanin, hemoglobin, and roughness but higher hydration content and skin pH value. Furthermore, the Shannon index of skin bacteria was significantly increased in W1 (P = 0.004), suggesting that the ideal skin had higher species diversity. From W1 to W3, the species composition was changed significantly. The abundance of Actinobacteria was increased, while Proteobacteria and Bacteroidetes were decreased. Correspondingly, the abundances of lipophilic Propionibacterium and Malassezia were increased, while the abundances of Stenotrophomonas, Pseudomonas, Ralstonia, and Streptococcus, were significantly decreased. Additionally, Spearman correlation analysis revealed strong correlations between the physiological parameters and the microbiota. Notably, the Shannon index of skin bacteria was significantly positively correlated with skin hydration (P = 0.03) but negatively correlated with the abundance of Cutibacterium (P = 0.000), hemoglobin content (P = 0.025), and sebum content (P = 0.5). Therefore, the skin hydration content and the abundance of Cutibacterium played an important role in maintaining the α-diversity and skin homeostasis. Conclusion: Ideal skin had better water-oil balance and barrier function, higher microbial diversity, and more reasonable species distribution. Therefore, daily skincare needs to control skin oil and maintain skin microecological balance to achieve ideal skin conditions for young women aged 18– 25 years old.

Objective: Oxidative stress activates the reactive oxygen species (ROS) and excessive ROS can damage skin cells, initiating oxidative stress responses that contribute to inflammation, aging, and other skin issues. As a resident skin bacterium, Cutibacterium acnes (C. acnes) plays an important role in maintaining skin homeostasis and provides antioxidant benefits. However, the metabolite components and mechanisms of C. acnes exerting antioxidant activity are not yet clear. This study aimed to analyze the potential antioxidant effects of C. acnes cell‐free supernatant and the mechanisms.Methods: The antioxidant effects were evaluated by measuring the scavenging activities of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonic acid ammonium salt) (ABTS) radicals, and hydroxyl radicals, as well as the effects on ROS levels in menadione‐induced primary human keratinocytes in vitro. Additionally, western blot analysis was performed to assess the antioxidant effects of the C. acnes CCSM0331 cell‐free supernatant (CFS).Results: C. acnes CCSM0331 was isolated from the facial skin of healthy individuals. This strain, classified as type II, is associated with healthy skin. The CFS of strain CCSM0331 contained various short‐chain fatty acids (SCFAs), glutathione peroxidase (GSH‐Px), and total superoxide dismutase(T‐SOD), exhibiting strong DPPH and ABTS radical scavenging capabilities, thus demonstrating substantial antioxidant activity. In a reactive oxygen species model induced by menadione in primary human keratinocytes, the addition of 5% of the fermentation supernatant from this strain significantly reduced ROS levels, indicating a notable ROS‐scavenging effect. Western blot analysis further confirmed that the CCSM0331 fermentation supernatant activated the expression of Nrf‐2 and HO‐1 proteins, thereby activating the Nrf‐2 oxidative stress pathway and exerting antioxidant effects.Conclusion: C. acnes CCSM0331 is a promising skin probiotic with notable antioxidant properties. The activity of this strain exhibited significant free radical scavenging activity, suggesting its potential application in the development of antiaging products. This study provides theoretical support for the screening of functional skin bacteria or skin probiotics.