Changes of the human skin microbiota upon chronic exposure to polycyclic aromatic hydrocarbon pollutants

Skin, our first interface to the external environment, is subjected to oxidative stress caused by a variety of factors such as solar ultraviolet, infrared and visible light, environmental pollution, including ozone and particulate matters, and psychological stress. Excessive reactive species, including reactive oxygen species and reactive nitrogen species, exacerbate skin pigmentation and aging, which further lead to skin tone unevenness, pigmentary disorder, skin roughness and wrinkles. Besides these, skin microbiota are also a very important factor ensuring the proper functions of skin. While environmental factors such as UV and pollutants impact skin microbiota compositions, skin dysbiosis results in various skin conditions. In this review, we summarize the generation of oxidative stress from exogenous and endogenous sources. We further introduce current knowledge on the possible roles of oxidative stress in skin pigmentation and aging, specifically with emphasis on oxidative stress and skin pigmentation. Meanwhile, we summarize the science and rationale of using three well-known antioxidants, namely vitamin C, resveratrol and ferulic acid, in the treatment of hyperpigmentation. Finally, we discuss the strategy for preventing oxidative stress-induced skin pigmentation and aging.

Late cornified envelope proteins are predominantly expressed in the skin and other cornified epithelia. On the basis of sequence similarity, this 18-member homologous gene family has been subdivided into six groups. The LCE3 proteins have been the focus of dermatological research because the combined deletion of LCE3B and LCE3C genes (LCE3B/C-del) is a risk factor for psoriasis. We previously reported that LCE3B/C-del increases the expression of the LCE3A gene and that LCE3 proteins exert antibacterial activity. In this study, we analyzed the antimicrobial properties of other family members and the role of LCE3B/C-del in the modulation of microbiota composition of the skin and oral cavity. Differences in killing efficiency and specificity between the late cornified envelope proteins and their target microbes were found, and the amino acid content rather than the order of the well-conserved central domain of the LCE3A protein was found responsible for its antibacterial activity. Invivo, LCE3B/C-del correlated with a higher beta-diversity in the skin and oral microbiota. From these results, we conclude that all late cornified envelope proteins possess antimicrobial activity. Tissue-specific and genotype-dependent antimicrobial protein profiles impact skin and oral microbiota composition, which could direct toward LCE3B/C-del‒associated dysbiosis and a possible role for microbiota in the pathophysiology of psoriasis.

Skin ulcers and microbiota in Rana dybowskii: Uncovering the role of the gut-skin axis in amphibian health

Influence of wildfire ash concentration on development, survival, and skin and gut microbiota of Rana dybowskii

Impact of antibiotic therapy on cutaneous and gut microbiota in Rana dybowskii amphibians: Insights and implications

Vultures (Accipitriformes), as obligate scavengers, are regularly exposed to a diverse array of pathogens present in decomposing carcasses. Nevertheless, they exhibit a remarkable ability to resist infections, suggesting a crucial role of skin microbiota in host defense. The microbial communities residing on necrophagic birds' skin create a protective barrier through competitive interactions, antimicrobial compound production, and immunity priming. Additionally, vultures contribute to ecosystem balance by reducing the spread of infectious agents. However, they may also serve as vectors for antimicrobial resistance (AMR) due to their exposure to contaminated food sources. Understanding the dynamics of their microbiota can provide valuable insights into host-microbe interactions, wildlife conservation, and public health. This review examines the composition and functional significance of vulture cutaneous microbiota. Specifically, it explores the role of necrophagic birds' skin microbiota in pathogen exclusion, immune system modulation, and environmental adaptation, with the aim of suggesting further research routes, besides clarifying the ecological implications of such birds.

Longitudinal Evaluation of the Skin Microbiome and Association with Microenvironment and Treatment in Canine Atopic Dermatitis

Rice straw ash and amphibian health: A deep dive into microbiota changes and potential ecological consequences

MAB3-PD-12 Introduction: Epidemiologic studies have presented strong evidence that workers with long-term exposure to coke-oven emissions have a high incidence of cancer. Urinary 1-hydroxypyrene (1-OHP) has been used as a reliable biomarker of total environmental PAH exposure. The association between PAH exposure and the temporal change of urinary 1-OHP remains unclear. Methods: Between October, 2003 and March, 2004, 52 coke-oven workers were recruited from a large steel company in southern Taiwan. Participants provided personal air samples for PAH exposure, urine samples for 1-OHP, and interview questionnaires for demographic data and potential confounding variables. Two work-period air samples and a total of 8 spot urine samples (3 pre-shift, 3 post-shift, and 2 morning samples on days off) were analyzed using gas chromatography, mass spectrometry, and high-performance liquid chromatography with fluorescence detection. Results: Topside-oven workers had significantly higher levels of PAH exposure and 1-OHP (251.3 ± 25.9 vs. 62.4 ± 18.1 mg/g creatinine, P < 0.0001) than side-oven workers did. Urinary 1-OHP levels were significantly and positively correlated with different PAH species exposure (r = 0.29–0.55). Urinary 1-OHP increased with the number of working days. After 2 days off, urinary 1-OHP levels dramatically decreased and approached the pre-shift levels of the first working day. On days off, side-oven workers who smoked showed a slight increase in urinary 1-OHP levels. Discussion and Conclusions: We suggest that the temporal change of urinary 1-OHP levels is different between top-side and oven-side workers. Smoking can partially explain the difference in urinary 1-OHP of days off in oven-side workers. Coke-oven workers are exposed to high levels of PAHs. The working cycle requires further investigation to reduce exposure to PAHs and create a more healthful environment for coke-oven workers.

Aquatic organisms are increasingly exposed to lowering of environmental pH due to anthropogenic pressure (e.g. acid rain, acid mine drainages). Such acute variations trigger imbalance of fish-associated microbiota, which in turn favour opportunistic diseases. We used the tambaqui (Colossoma macropomum), an Amazonian fish tolerant to significant pH variation in its natural environment, to assess the response of fish endogenous microbiota to acute short-term acid stress. We exposed 36 specimens of tambaquis to acidic water (pH 4.0) over 2 consecutive weeks and sampled cutaneous mucus, feces and water at 0, 7 & 14 days. The 16S RNA hypervariable region V4 was sequenced on Illumina MiSeq. After two weeks of acidic exposure, fecal and skin microbiota taxonomic structures exhibited different patterns: skin microbiota was still exhibiting a significantly disturbed composition whereas fecal microbiota recovered a similar composition to control group, thus suggesting a stronger resilience capacity of the intestinal microbiota than cutaneous microbiota.

BackgroundNumerous studies have thus far characterized the temporal dynamics of the skin microbiota of healthy individuals. However, there is no information regarding the dynamics of different microbial association network properties. Also, there is little understanding of how living conditions, specifically cohabitation and household occupancy, may be associated with the nature and extent (or degree) of cutaneous microbiota change within individuals over time. In this study, the dynamics of the skin microbiota, and its association networks, on the skin of urban residents over four seasons were characterized.ResultsSimilar to western cohorts, the individuals of this cohort show different extents of variations in relative abundance of common skin colonizers, concomitant with individual- and household-associated changes in differential abundances of bacterial taxa. Interestingly, the individualized nature of the skin microbiota extends to various aspects of microbial association networks, including co-occurring and excluding taxa, as well as overall network structural properties. Household occupancy is correlated with the extent of variations in relative abundance of Propionibacterium, Acinetobacter, and Bacillus over multiple skin sites. In addition, household occupancy is also associated with the extent of temporal changes in microbial diversity and composition within a resident’s skin.ConclusionsThis is the first study investigating the potential roles household occupancy has on the extent of change in one’s cutaneous microbiota and its association network structures. In particular, we show that relationships between the skin microbiota of a resident, his/her cohabitants, and those of non-cohabitants over time are highly personal and are possibly governed by living conditions and nature of interactions between cohabitants within households over 1 year. This study calls for increased awareness to personal and lifestyle factors that may govern relationships between the skin microbiota of one individual and those of cohabitants, and changes in the microbial association network structures within a person over time. The current study will act as a baseline for future assessments in comparing against temporal dynamics of microbiota from individuals with different skin conditions and for identifying residential factors that are beneficial in promoting the dynamics of the skin microbiota associated with health.

Background The aim of this study was to assess changes in skin microbiota of wrestlers during training sessions and to determine the sensitivity of hemolytic bacterial isolates to antiseptics. Methods The main skin bacterial isolates obtained from the skin of 15 wrestlers were identified by cultivation method, with the following MALDI Biotyper and 16S rRNA gene sequencing methods. The sensitivity of hemolytic isolates to antiseptics (Veltosept-2, Cutasept F, Chlorhexidine, Miramistin, and Hydrogen Peroxide) was evaluated by measuring the size of bacterial growth inhibition zone on agar plates. Results Opportunistic bacteria of the species Bacillus cereus, Staphylococcus aureus, S. epidermidis, and S. saprophyticus were the most commonly found species in skin microbiota of wrestlers before and after training sessions. Representatives of all these species mostly had a hemolytic activity. An alcohol-containing antiseptic Veltosept-2 showed the strongest inhibitory effect on the bacterial isolates of athletes' skin microbiota most frequently detected in this study. Conclusions The general increase in the bacterial colonization of wrestlers' skin, as well as the presence of hemolytic forms of opportunistic bacteria in cutaneous microbiota, indicates dysbiotic changes and a decrease in the protective features of the host organism. Veltosept-2 application can reduce the incidence of skin infections in contact sports athletes with the highest efficiency.

BackgroundPolycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that may contribute to the etiology of obesity. However, it is unclear whether PAHs from environmental sources are associated with regional body fat distribution, and whether the association varies across racial/ethnic groups who may have differential PAH exposure patterns.ObjectivesTo examine correlations between PAHs and body fat distribution, and potential racial/ethnic differences among U.S. adults.MethodsTen PAHs were measured in spot urine samples from 2691 non-smoking adults (age ≥ 20 years) in the NHANES 2001–2016. Dual-energy X-ray absorptiometry was used to measure fat mass percent (FM%). Partial Pearson correlation coefficients (r) with multivariable adjustment were used to assess PAH-FM% associations.ResultsIn the total population, 1-naphthalene, 3-fluorene, and 1-pyrene were inversely correlated with total FM% or trunk FM% (adjusted r ranged: − 0.06 to − 0.08), while 2-naphthalene, 9-fluorene, and 4-phenanthrene were positively correlated with the FM% measurements (r: 0.07–0.11). PAH levels are highest among non-Hispanic Blacks, followed by Hispanics and Whites and some of the correlations were different by these races/ethnicities. Among non-Hispanic Whites, no PAH was correlated with FM%. In contrast, 9-fluorene was positively correlated with total FM% (r = 0.20) and trunk FM% (r = 0.22) among Blacks, and 4-phenanthrene was positively correlated with total FM% (r = 0.23) and trunk FM% (r = 0.24) among Hispanics (P-interaction: 0.010–0.025).DiscussionIn this US adult population, certain PAHs are significantly associated with higher body fat contents among non-Hispanic Blacks and Hispanics but not non-Hispanic Whites, suggesting that minority groups might be particularly susceptible to PAH’s obesogenic effects or the effects of other factors that determine the PAH exposure levels. Alternatively, differences in body composition may contribute to differential PAH metabolism in minority groups. Future studies are warranted to explore the racial/ethnic disparity in PAH exposures, drivers of these exposure differences, and mechanisms through which PAHs may influence body composition by races/ethnicities.

Parasitism reduces oxidative stress of fish host experimentally exposed to PAHs

Dysbiosis of skin microbiota is associated with several inflammatory skin conditions, including atopic dermatitis, acne, and hidradenitis suppurativa. There is a surge of interest by clinicians and the lay public to explore targeted bacteriotherapy to treat these dermatologic conditions. To date, skin microbiota transplantation studies have focused on moving single, enriched strains of bacteria to target sites rather than a whole community. In this prospective pilot study, we examined the feasibility of transferring unenriched skin microbiota communities between two anatomical sites of the same host. We enrolled four healthy volunteers (median age: 28 [range: 24, 36] years; 2 [50%] female) who underwent collection and transfer of skin microbiota from the forearm to the back unidirectionally. Using culture methods and 16S rRNA V1-V3 deep sequencing, we compared baseline and mixed ("transplant") communities, at T = 0 and T = 24 hours. Our ability to detect movement from one site to the other relied on the inherent diversity of the microenvironment of the antecubital fossa relative to the less diverse back. Comparing bacterial species present in the arm and mixed ("transplant") communities that were absent from the baseline back, we saw evidence of transfer of a partial DNA signature; our methods limit conclusions regarding the viability of transferred organisms. We conclude that unenriched transfer of whole cutaneous microbiota is challenging, but our simple technique, intended to move viable skin organisms from one site to another, is worthy of further investigation.