A World Health Organization (WHO) report from 2016 states that over 3 million people die annually from air pollution, which places air pollution as the world’s largest single environmental health risk factor. Particulate matter (PM) is one of the main components of air pollution, and there is increasing evidence that PM exposure exerts negative effects on the human skin. To see the impact of air pollution on skin aging, we analyzed the effect of PM exposure on human dermal fibroblasts (HDFs) with Western blot, enzyme-linked immunosorbent assay (ELISA), and gene analysis. Cultured HDFs were exposed to PM10 at a concentration of 30 µg/cm2 for 24 h, and their gene/protein expression of inflammatory cytokines, fibroblast chemical mediators, and autophagy were assessed. A total of 1977 genes were found to be differentially expressed following PM exposure. We observed a significantly increased expression of pro-inflammatory genes interleukin (IL)-1β, IL-6, IL-8 and IL-33 in dermal fibroblasts exposed to PM10. Protein expression of IL-6 and IL-8 also significantly increased, which complemented our gene analysis results. In addition, there was a significant increase in cytochrome P450 (CYP1A1, CYP1B1), matrix metalloproteinase (MMP-1, MMP-3) mRNA expression, and significant decrease in transforming growth factor (TGF)-β, collagen type I alpha chain (COL1A1, COL1A2), and elastin (ELN) mRNA expression in PM-exposed dermal fibroblasts. Protein expression of MMP-1 was significantly increased and that of TGF-β and procollagen profoundly decreased, similar to the gene analysis results. Autophagy, an integrated cellular stress response, was also increased while transmission electron microscopy (TEM) analysis provided evidence of PM internalization in the autolysosomes. Taken together, our results demonstrate that PM10 contributes to skin inflammation and skin aging via impaired collagen synthesis. Increased autophagy in our study suggests a reparative role of autophagy in HDFs stressed with PM, but its biological significance requires further research.

Systemic antibiotics are extensively used to control moderate to severe acne. Hence, it is crucial to understand their impact on the skin microbiota, which is supposedly perturbed. The purpose of this study was to compare the makeup and diversity of the skin microbiota in acne patients before and after taking oral antibiotics. A longitudinal cohort study was performed on 20 participants with moderate to severe facial acne with no recent use of oral and topical antibiotics/retinoids. Patients were prescribed oral doxycycline, 100 mg, twice daily for six weeks. Skin areas on the cheek were sampled for 16S ribosomal RNA gene sequencing at baseline, and after six weeks of doxycycline treatment. Ten males and 10 females aged 11 to 44 years with a median Investigator’s Global Assessment score of 3 (moderate) were enrolled. At baseline, Cutibacterium acnes (formerly Propionibacterium acnes) was the most dominant species followed by Staphylococcus epidermidis. Acne severity showed a positive correlation with the abundance of Cutibacterium acnes. Across all subjects, antibiotic treatment reduced clinical acne grades and was associated with a 1.96-fold reduction in the relative abundance of Cutibacterium acnes (p = 0.01, 95% CI −22% to −3%). Marked changes were also identified in other bacterial species, such as Cutibacterium granulosum (formerly Propionibacterium granulosum), which increased by 4.46-fold (p = 0.02, 95% CI 0.004% to 0.9%) in the treated samples. In general, antibiotics administration was associated with an increase in bacterial diversity (alpha diversity). Principal coordinates analysis showed mild clustering of samples by patient (analysis of similarity, R = 0.135, p = 0.04) whereas there was scant clustering with treatment (ANOSIM, R = 0.005; p = 0.29). In conclusion, we found individuals with acne to have a unique microbial signature. Acne treatment with systemic antibiotics was associated with changes in the composition and diversity of skin microbiota, especially Cutibacterium acnes, which correlates with acne severity. Our study provides insight into the skin microbiota in acne and how it is modulated by systemic antibiotics.

This study was conducted to investigate the changes in the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities of 80% methanol and water extracts from mustard leaf kimchi during different fermentation periods. The methanol extract exhibited higher TPC and TFC than the water extract. Both extracts from kimchi fermented for two months showed the highest antioxidant effects against the scavenging activities of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2,2-azino-bis diammonium salt (ABTS) radicals. Moreover, the methanol extract from kimchi fermented for two months showed the highest nitrite scavenging activity. The highest metal (Fe) chelating effect of the methanol extract and water extract was observed after three months and one month, respectively. Caffeic acid showed the highest increase with fermentation. These findings suggest that the antioxidant activities of kimchi depend on the fermentation period. Accordingly, this study provides basic data for improving the antioxidant activity of mustard leaf kimchi through the establishment of their fermentation period.

Autophagy is an intracellular stress response that is enhanced under starvation conditions, and also when the cellular components are damaged. Aging accompanies an increase in intracellular stress and has significant impact on the skin. Since dermal fibroblasts are a powerful indicator of skin aging, we compared the autophagic activity of human skin fibroblasts between the young and old. According to TEM analyses, the number of autophagosomes per 1 μm2 cytoplasmic area was similar between young and aged fibroblasts. The amount of LC3 (microtubule-associated protein 1 light chain 3)-II, a form associated with autophagic vacuolar membranes, was also similar between the groups from Western blot analysis. Although residual bodies were more common in aged dermal fibroblasts, LC3 turnover and p62 assay showed little difference in the rate of lysosomal proteolysis between the young and old. RNA-seq analysis revealed that the major autophagy-modulating genes (BECN1, MAP1LC3B, ATG5, ATG7, ULK1, PIK3C3, mTOR) were not differentially expressed with age. Our results suggest that the basal autophagic flux in aged dermal fibroblasts is largely comparable to that of young fibroblasts. However, with a higher speed and amount of waste production in aged cells, we postulate that such autophagic flux may not be sufficient in keeping the old cells “clean”, resulting in skin aging. Aging is a complex process and, as such, the relationship between autophagy and aging is not straightforward. That is to say, autophagy does not simply decline with age. Regardless of the controversies on autophagic activity with age, autophagy plays a crucial role in counteracting aging, and strategies aimed at its modulation should hold promise for the prevention of skin aging.

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