Skin Exposure Research Articles

Face Mask: As a Source or Protector of Human Exposure to Microplastics and Phthalate Plasticizers?

Wearing masks has become the norm during the Coronavirus disease pandemic. Masks can reportedly interface with air pollutants and release microplastics and plastic additives such as phthalates. In this study, an experimental device was set up to simulate the impact of five kinds of masks (activated-carbon, N95, surgical, cotton, and fashion masks) on the risk of humans inhaling microplastics and phthalates during wearing. The residual concentrations of seven major phthalates ranged from 296 to 72,049 ng/g (median: 1242 ng/g), with the lowest and the highest concentrations detected in surgical (median: 367 ng/g) and fashion masks (median: 37,386 ng/g), respectively. During the whole inhalation simulation process, fragmented and 20-100 μm microplastics accounted for the largest, with a rapid release during the first six hours. After one day's wearing, that of 6 h, while wearing different masks, 25-135 and 65-298 microplastics were inhaled indoors and outdoors, respectively. The total estimated daily intake of phthalates with indoor and outdoor conditions by inhalation and skin exposure ranged from 1.2 to 13 and 0.43 to 14 ng/kg bw/d, respectively. Overall, surgical masks yield a protective effect, while cotton and fashion masks increase human exposure to microplastics and phthalates both indoors and outdoors compared to no mask wearing. This study observed possible risks from common facemasks and provided suggestions to consumers for selecting suitable masks to reduce exposure risks from microplastics and phthalate acid.

Use of Computed Tomography in Evaluation and Management of Shell Fracture in a Red Eared Slider Turtle ( Trachemys scripta elegans) A Case report

Traumatic lesions of the shell are common problems in chelonians. Lesions of the shell vary in severity from a simple superficial abrasion (with a loss of the external skin layer and exposure of the bone) to complicated fractures of the carapace with exposure of internal organs of the coelom and injury of the soft tissues (Barten, 2006). In most shell or skeletal injuries in the turtle, plain radiographic data do not reveal the extent of complex fractures due to superimposed bone structures (Abou-Madi et al., 2002). In Comparison with conventional radiography, computed tomography (CT) allows better distinction of specific tissue densities and discrete changes in organ size, shape, margin, contour and position (Gaudron et al., 2001). Computed tomography is a non-invasive, cross-sectional diagnostic imaging technique that offers significant advantages for detection of pathologies in chelonians, and is ideal for diagnosing skeletal and soft tissue abnormalities (Gumpenberger and Henninger, 2001). The aim of the present work was to evaluate the three dimensional computed tomography (CT) for clinical examination of shell lesions in a red eared slider turtle.

Self-reported Side-effects of Ultraviolet-C Disinfection Devices.

The COVID-19 pandemic increased sales of portable UV-C devices as a means of inactivating the SARS-CoV-2 virus. Research suggests that excessive UV-C exposure to the eyes and skin can lead to side-effects, primarily photokeratitis and erythema, but these findings are limited to case studies. This study explores self-reported side-effects of UV-C devices by collating five waves of UK consumer survey data from April 2020-December 2021 (N=26 864). 30%-46% of owners report a side-effect after using a device claiming to emit UV-C. However, detailed analysis of Wave 4 data (N =309) highlights inconsistencies between reported and plausible side-effect(s) associated with skin or eye exposure from UV-C devices. Alternative explanations are considered, namely that the reported side-effect(s) were psychosomatic or misattributed to direct exposure of UV-C radiation. Data regarding awareness of warnings about device side-effect(s) supports the misattribution explanation. For risk assessment purposes, limited reliable information about specific irritation or injury to the eye and skin was found from self-reporting surveys. To optimize future data collection, we recommend addressing recall errors by: reducing the period under investigation, supplementing responses with empirical measures, and incentivizing respondents to provide accurate information about the make and model of the UV-C device.

Overlapping Science in Radiation and Sulfur Mustard Exposures of Skin and Lung: Consideration of Models, Mechanisms, Organ Systems, and Medical Countermeasures: Overlapping science in radiation and sulfur mustard injuries to lung and skin.

To summarize presentations and discussions from the 2022 trans-agency workshop titled "Overlapping science in radiation and sulfur mustard (SM) exposures of skin and lung: Consideration of models, mechanisms, organ systems, and medical countermeasures." Summary on topics includes: (1) an overview of the radiation and chemical countermeasure development programs and missions; (2) regulatory and industry perspectives for drugs and devices; 3) pathophysiology of skin and lung following radiation or SM exposure; 4) mechanisms of action/targets, biomarkers of injury; and 5) animal models that simulate anticipated clinical responses. There are striking similarities between injuries caused by radiation and SM exposures. Primary outcomes from both types of exposure include acute injuries, while late complications comprise chronic inflammation, oxidative stress, and vascular dysfunction, which can culminate in fibrosis in both skin and lung organ systems. This workshop brought together academic and industrial researchers, medical practitioners, US Government program officials, and regulators to discuss lung-, and skin- specific animal models and biomarkers, novel pathways of injury and recovery, and paths to licensure for products to address radiation or SM injuries. Regular communications between the radiological and chemical injury research communities can enhance the state-of-the-science, provide a unique perspective on novel therapeutic strategies, and improve overall US Government emergency preparedness.

Where’s the Party? How Clothing and Context Influence Perceptions of Women

The sexual objectification of women is a large societal issue and is related to a host of negative mental and physical health implications for women. Past research has suggested that the objectification of women may be influenced by types of clothing worn and the context in which it is worn. However, it is difficult to discern how much objectification is modified by both clothing and contextual features simultaneously. We manipulated the type of clothing worn by models (high skin exposure or low skin exposure) and the type of context the clothing was allegedly worn for (a party or a job interview). Participants (N = 334) rated models on traits relating to objectification, professionalism, and capabilities. Analyses showed significant main effects for both context and outfit on most variables but no significant interactions. Results suggest that changing the context in which clothing is meant to be worn can significantly change a number of attributions made of the wearer by observers, specifically in terms of objectification. These findings may help build upon the ever-growing framework for understanding some potential mechanisms behind the objectification of women.

Needlestick Injuries among Nurses in Selangor Public Hospital, Malaysia

Background: Needlestick injuries (NSIs) are one of the greatest risks nurses face. NSIs are associated with an increased risk of diseases that can be transferred through skin exposure, such as Hepatitis B, Hepatitis C, and the human immunodeficiency virus. Certain factors can influence the mechanism and frequency of NSI among nurses. Objective: To determine the factors associated with the frequency and mechanisms of NSIs among nurses at a public hospital in Selangor. Methods: A cross-sectional study was conducted from April to September 2020. A total of 233 nurses were conveniently sampled from a public hospital in Selangor. A questionnaire was distributed to capture data on socio-demographic characteristics, frequency, and mechanisms of NSI. The inferential statistics were conducted using SPSS 22. Results: Of the 233 respondents, the incidence rate of NSI was 23.6%. Most cases of NSI occurred during the morning shift (12.4%), and the most common mechanism of NSIs was the action of recapping needles (6.9%). Factors associated with the NSI were gender, age, ward, and working experience. Conclusion: The prevalence of NSIs is relatively low in this study. However, nurses should still apply universal precautions to prevent NSIs. Several risk factors that influenced the NSI should be highlighted among nurses and nursing management to prevent its incidence.

Occurrence of DDT in foodstuffs and skin wipes from a rural area, South China: insight into human exposure pathway

Dichlorodiphenyltrichloroethanes (DDTs) are ubiquitous in dust and air, which may be responsible for human dermal exposure to DDT. However, existing DDT exposure studies mainly concentrate on dietary exposure, and studies on skin exposure pathway are lacking. To gain further insight into the human exposure pathway of DDT, skin wipe and food samples were collected in a rural area in southern China, where new input of DDTs was found in both indoor and outdoor environments. The total DDT concentrations in skin wipes and foodstuffs varied from < method quantification limit (MQL) to 1470 ng/m2 and from < MQL to 12.8 ng/g wet weight, respectively. In foodstuffs, egg showed the highest DDT concentration, while forehead showed the highest DDT concentration in the four skin locations. p,p’-DDT was predominant in the hand and forearm wipes, while p,p’-DDE was dominant in the forehead, upper arm, and food samples. The total DDT daily absorption median levels via dermal contact, hand-mouth contact, and food consumption were 0.187, 0.0237, and 0.994 ng/kg/d, respectively. Organic eggs and wild fish contaminated by DDTs released locally are the main sources of human dietary exposure to DDTs, and reducing the intake of contaminated fish and eggs would help to significantly reduce human DDT absorption; in this case, the contribution of dermal exposure cannot be not negligible.

Protective Effects of Curcumin on Increased Tumor Necrosis Factor-a Level and Apoptosis in Rat Skin Exposed to Ultraviolet Light from Compact Fluorescent Lamps

ABSTRACT Background: Compact fluorescent lamps (CFLs) are a potential ultraviolet (UV) radiation source. Skin exposure to UV radiation induces inflammation and DNA damage. In this study, we aimed to evaluate the disorders caused by light from CFLs and potential protective impacts of curcumin on rat skin. Methods: We divided 24 male rats into three groups of 8: control group (I), without curcumin and CFLs exposure; fluorescent group (II), treated with 12 h exposure to CFLs for 15 days; and fluorescent with curcumin group (III), treated with 12 h CFLs exposure in addition to injection of curcumin 20 mg/kg, IP, daily for 15 days (group III). Their tumor necrosis factor-ɑ (TNF-?) levels were measured. Finally, the skins underwent H?and?E and TUNEL staining. ɑ) levels were measured. Finally, the skins underwent H and E and TUNEL staining. Results: Levels of TNF-ɑ in groups I, II, and III were 13.7 ± 0.46 ng/ml, 16.3 ± 0.48 ng/ml, and 14.1 ± 0.76 ng/ml, respectively. The difference between the groups I and II and also the groups II and III was meaningful (P < 0.0001). Apoptotic cells and epidermal hyperplasia were observed in group II. Administration of curcumin decreased inflammatory infiltrations and apoptotic cells in group III. Conclusions: Due to its anti-inflammatory effects, curcumin has protective impact on inflammatory complications of exposure to UV radiation.

Multispectroscopic, virtual and in vivo insights into the photoaging defense mediated by the natural food colorant bixin.

An upsurge in early onset of photoaging due to repeated skin exposure to environmental stressors such as UV radiation is a challenge for pharmaceutical and cosmeceutical divisions. Current reports indicate severe side effects because of chemical or synthetic inhibitors of matrix metalloproteases (MMPs) in anti-skin aging cosmeceuticals. We evaluated the adequacy of bixin, a well-known FDA certified food additive, as a scavenger of free radicals and its inhibitory mechanism of action on MMP1, collagenase, elastase, and hyaluronidase. The anti-skin aging potential of bixin was evaluated by several biotechnological tools in silico, in vitro and in vivo. Molecular docking and simulation dynamics studies gave a virtual insight into the robust binding interaction between bixin and skin aging-related enzymes. Absorbance and fluorescence studies, enzyme inhibition assays, enzyme kinetics and in vitro bioassays of human dermal fibroblast (HDF) cells highlighted bixin's role as a potent antioxidant and inhibitor of skin aging-related enzymes. Furthermore, in vivo protocols were carried out to study the impact of bixin administration on UVA induced photoaging in C57BL/6 mice skin. Here, we uncover the UVA shielding effect of bixin and its efficacy as a novel anti-photoaging agent. Furthermore, the findings of this study provide a strong foundation to explore the pharmaceutical applications of bixin in several other biochemical pathways linked to MMP1, collagenase, elastase, and hyaluronidase.

Release of PAH from Secondary Products Made from End-of-Life Tire Recyclates into 20% Aqueous Ethanol as Assessment of Human Dermal Absorption

Compliance with the legal limits set at the European level for the content of polycyclic aromatic hydrocarbons (PAH), which are harmful to human health and the environment, is of central importance for the recycling of rubber, particularly end-of-life tires (ELT), into secondary products, e.g., elastic fall protection mats or anti-slip mats for the transport sector. However, different regulations associated with different analytical methods apply to newly produced tires on the one hand and secondary products made from ELT on the other. Given these discrepancies, ELT can potentially contain levels of PAH, which can be problematic when reused in consumer products. The total PAH content, however, is not without doubt a reliable risk indicator, which should ultimately be based primarily on the transfer of the substances from the product into the skin of human beings or their release into the environment. Accordingly, additional studies are required to determine the extent to which migration-based measurements are more suitable for risk assessment and how the PAH content correlates with migration. Complementing the recently published results of PAH content in different types of ELT, this study investigates the release of PAH for a range of typical secondary materials composed entirely or partly of ELT. In the present study, migration tests with 20% aqueous ethanol were applied, a methodology that has been shown in previous investigations by others to reflect human skin exposure well, and the resulting migration rates of PAH are determined.

Exposures to Polycyclic Aromatic Hydrocarbons and Their Mitigation in Wildland Firefighters in Two Canadian Provinces.

We aimed to characterize polycyclic aromatic hydrocarbons (PAHs) in the breathing zone and on the skin of wildland firefighters and to assess their contribution to urinary 1-hydroxypyrene (1-HP) over repeated firefighting rotations. We asked if improved skin hygiene or discretionary use of an N95 mask would reduce absorption. In collaboration with wildfire services of two Canadian provinces, Alberta and British Columbia (BC), we recruited wildland firefighters from crews willing to be followed up over successive rotations and to be randomly assigned to normal practice, enhanced skin hygiene (ESH), or ESH plus discretionary use of an N95 mask. We collected spot urine samples at the beginning and end of up to four rotations/firefighter. On designated fire days, as close as possible to the end of rotation, we collected skin wipes from the hands, throat, and chest at the beginning and end of the fire day and, in BC, start of fire-day urine samples. Volunteers carried air monitoring pumps. Participants completed questionnaires at the beginning and end of rotations. Exposure since the start of the fire season was estimated from fire service records. Urinary 1-HP was analyzed by LC-MS-MS. Analysis of 21 PAHs on skin wipes and 27 PAHs from air sampling was done by GC-MS-MS. Statistical analysis used a linear mixed effects model. Firefighters in Alberta were recruited from five helitack crews and two unit crews, and in BC from two unit crews with 80 firefighters providing data overall. The fire season in BC was very active with five monitored fire days. In Alberta, with more crews, there were only seven fire days. Overall, log 1-HP/creatinine (ng/g) increased significantly from the start (N = 145) to end of rotation (N = 136). Only three PAHs (naphthalene, phenanthrene, and pyrene) were found on >20% of skin wipes. PAHs from 40 air monitoring pumps included 10 PAHs detected on cassette filters (particles) and 5 on sorbent tubes (vapor phase). A principal component extracted from air monitoring data represented respiratory exposure and total PAH from skin wipes summarized skin exposure. Both routes contributed to the end of rotation urinary 1-HP. The ESH intervention was not demonstrated to effect absorption. Allocation of an N95 mask was associated with lower 1-HP when modeling respiratory exposure (β = -0.62, 95% CI -1.15 to -0.10: P = 0.021). End of rotation 1-HP was related to 1-HP at the start of the next rotation (β = 0.25, 95% CI 0.12 to 0.39: P < 0.001). Exposures to PAHs during firefighting were significant, with samples exceeding the American Conference of Governmental Industrial Hygienists Biological Exposure Index for 1-HP suggesting a need for control of exposure. PAH exposure accumulated during the rotation and was not fully eliminated during the break between rotations. Both respiratory and skin exposures contributed to 1-HP. While improved skin hygiene may potentially reduce dermal absorption, that was not demonstrated here. In contrast, those allocated to discretionary use of an N95 mask had reduced 1-HP excretion. Wildland firefighters in North America do not use respiratory protection, but the results of this study support more effective interventions to reduce respiratory exposure.

A Scoping Review on the Effects of Carotenoids and Flavonoids on Skin Damage Due to Ultraviolet Radiation.

Skin exposure to ultraviolet (UV) rays in the sun causes premature ageing and may predispose to skin cancers. UV radiation generates excessive free radical species, resulting in oxidative stress, which is responsible for cellular and DNA damage. There is growing evidence that phytonutrients such as flavonoids and carotenoids may impede oxidative stress and prevent photodamage. We conducted a systematic review of the literature to explore the effects of certain phytonutrients in preventing skin photodamage. We searched the electronic Medline (Ovid) and Pubmed databases for relevant studies published between 2002 and 2022. The main inclusion criteria were articles written in English, and studies reporting the effects of phytonutrient-containing plants of interest on the skin or skin cells exposed to UV radiation. We focused on tea, blueberries, lemon, carrot, tomato, and grapes, which are rich in flavonoids and/or carotenoids. Out of 434 articles retrieved, 40 were identified as potentially relevant. Based on our inclusion criteria, nine articles were included in the review. The review comprises three combined in vitro and animal studies, four human studies, one in vitro research, and one mixed in vitro and human study. All the studies reported positive effects of flavonoids and carotenoid-containing plant extract on UV-induced skin damage. This evidence-based review highlights the potential use of flavonoids and carotenoids found in plants in preventing the deleterious effects of UV radiation on the skin. These compounds may have a role in clinical and aesthetic applications for the prevention and treatment of sunburn and photoaging, and may potentially be used against UV-related skin cancers.

Aetiology of occupational hand eczema in hairdressers: Tackling the complexity of exposure combinations to identify patterns associated with increased risk of hand eczema.

Hairdressers are exposed to wet work and manifold allergens at work, rendering exposure complex and the aetiology of occupational hand eczema (OHE) often multifactorial in this occupational group. To identify exposure patterns associated with increased risk of hand eczema in hairdressers. All hairdressers graduating from 2004 to 2007 and 2015 to 2018 received a questionnaire in 2009 and 2020, respectively. Current exposures (with or without regular glove use) and OHE were self-reported, and their association examined. Patterns of exposure were identified by latent class analysis (LCA). A total response of 39.9% (668/1675) was obtained. Six exposure profiles (#1-6) were identified by LCA across 11 tasks performed with or without gloves as well as deep conditioning, that is, 23 task items. Compared to profile #1 with the lowest OHE risk (reference) an increased risk of current OHE were seen in profile #4 [adjusted odds ratio [aOR] 6.5, 95% confidence interval [CI] 1.5-44.8 and #6 (aOR 39.4, 95%CI 6.1-362.8)] in logistic regression analysis. Profile #1 and #6 had performed the same tasks, but in profile #6 regular glove use was performed in 9.1% (1/ 11) of tasks compared to 72.7% (8/11) of tasks in profile #1 (p= 0.002). Although occupational exposures in hairdressing are complex, meaningful patterns associated with a wide range of OHE risk can be identified by LCA. The increase of OHE risk seems predominantly to be due to poor compliance with protective gloves. LCA could be applied to further fields of complex (skin) exposures.

Comparison of skin decontamination strategies in the initial operational response following chemical exposures

In mass casualty incidents including hazardous chemical skin exposure, decontamination is the primary intervention to avoid systemic uptake of the toxic compound. The protocol needs to be both simple and efficient to enable a rapid response and avoid delay of patient management. In the present study, decontamination strategies included in the initial operational response were evaluated following human skin exposure in vitro to four different contaminants.Results demonstrated that the efficacy of selected decontamination procedures was highly dependent on the chemical contaminant used. Dry removal of the sulfur mustard simulant methyl salicylate prior to wet decontamination was found beneficial compared to wet decontamination alone. Rapidly initiated wet decontamination was more efficient compared to dry and wet removal of the industrial chemical 2-butoxyethanol and the nerve agent tabun. Following VX-exposure, all wet decontamination procedures resulted in increased agent penetration compared to the control.In conclusion, challenges in establishing simple and efficient decontamination procedures for a broad-spectrum of chemicals have been demonstrated. The impact of including a dry removal step during decontamination was evidently agent specific. Despite the variation in efficacy, immediately initiated dry removal may facilitate patient management until wet decontamination resources are available and to reduce the risk of secondary contamination.

Immunofluorescent Distribution of SIRT1, SIRT2, SIRT6 Protein in the Skin of SKH1 Mouse after Ultraviolet B Irradiation for 10 Weeks

The skin, located on the outermost part of the body, is always exposed to external stimuli such as sunlight. The exposure of skin to ultraviolet B (UVB) radiation from sunlight is known to be a major environmental factor in inducing photoaging. After exposure to UVB, an increase in reactive oxygen species can affect the expression and activity of many critical proteins depending on the duration and dose of the UVB radiation. Mammalian sirtuins (SIRTs), which are nicotinamide dinucleotide-dependent protein deacetylases, are well known for playing a role in cellular longevity. However, little is known about SIRT protein alterations in keratinocytes upon UVB irradiation according to SIRT subtypes. Therefore, in this study, the distribution of non-mitochondrial SIRT1, SIRT2, and SIRT6 proteins was investigated by immunofluorescence (IF) staining of the skin of SKH-1 mice (n=12) after UVB irradiation for 10 weeks. After UVB irradiation for 10 weeks, the IF of both SIRT1 and SIRT6 was significantly increased in the UVB-irradiated mice group (UG), but the difference in SIRT2 IF was not statistically significant between the control group (CG) and the UG. The translocation of both SIRT1 and SIRT6 IF from the nucleus to the cytoplasm of keratinocytes was observed in the upper epidermis of the UG, whereas SIRT2 IF was localized in the cytoplasm of keratinocytes in the epidermis in both the CG and the UG. The translocation of SIRT1 and SIRT6 IF from the nucleus to the cytoplasm of keratinocytes may account for the physiologically protective action of keratinocytes against UVB irradiation. However, the exact role of SIRT1 and SIRT6 translocation in keratinocytes, where SIRT1 and SIRT6 shuttle from the nucleus to the cytoplasm, is not well known. Therefore, further studies are needed to understand the molecular mechanisms of SIRT1 and SIRT6 translocation in keratinocytes upon UVB irradiation.

Improving Hospital-Acquired Pressure Injury Outcomes by Overcoming Barriers to Implementing Patient Positioning Devices.

Improving Hospital-Acquired Pressure Injury Outcomes by Overcoming Barriers to Implementing Patient Positioning Devices.

Systemic Prostacyclin Analogues for Frostbite Require Careful Monitoring.

Frostbite interventions are not well studied, but recent evidence suggests combining a prostacyclin analog with hyperbaric oxygen can be beneficial.1 We treated an otherwise healthy 24-year-old, 75-kg female who had been found unresponsive in the snow with significant skin exposure for 2 hours. She had bradycardia to the 30’s (beats per minute), an initial esophageal temperature of 24°C, and suffered significant grade 3 frostbite on her feet and toes. She received standard treatments per hospital protocol including rewarming and bilateral catheter-directed intra-arterial infusions of alteplase 0.5 mg/h and heparin 250 units/h. Both medications were stopped after 4 hours for profound thrombocytopenia (platelets 45 × 103/μL). The thrombocytopenia was associated with a 4 g/dL drop in hemoglobin, although she had no obvious bleeding. Subcutaneous heparin was continued for deep vein thrombosis prophylaxis, but no other anti-coagulant or anti-platelet agents were used during her admission. Epoprostenol, a prostacyclin analogue, was started as an IV infusion at 0.5–2 ng/kg/min for 6 hours on hospital day 2 and repeated daily for 6 days.1 Studies from Europe and Canada suggest prostacyclin analogues, classically used for treating pulmonary arterial hypertension, can reduce amputation rates in cases of severe frostbite, due to vasodilatory effects.2

Insights into the Dermal Absorption, Deposition, and Elimination of Poly- and Perfluoroalkyl Substances in Rats: The Importance of Skin Exposure.

Humans are frequently exposed to poly- and perfluoroalkyl substances (PFASs) via direct skin contact with personal care and consumer products containing them. Here, we used a rat model to estimate the dermal penetration efficiency of 15 representative PFASs. After 144 h post-dosing, 4.1-18.0 and 5.3-15.1% of the applied PFASs in the low (L) and high (H) groups, respectively, were absorbed into the rats. PFAS absorption and permeation were parabolically associated with the perfluorinated carbon chain length (CF), peaking for perfluoroheptanoic acid (PFHpA). The lipid-rich stratum corneum of the skin barrier substantially suppressed the penetration of less hydrophobic short-chain PFASs, whereas the water-rich viable epidermis and dermis served as obstacles to hydrophobic long-chain PFAS permeation. However, the renal clearance (CLrenal) of the target PFAS decreased with increasing CF, suggesting that urinary excretion is crucial to eliminate less hydrophobic short-chain PFASs. Notably, the peak times of PFASs in the systemic circulation of rats (8-72 h) were remarkably longer than those after oral administration (1-24 h). These results suggest that dermal penetration can be long-lasting and contribute considerably to the body burden of PFASs, especially for those with moderate hydrophobicity due to their favorable skin permeation and unfavorable urinary excretion.

205 Topical application of Bisphenol A leads to atopic dermatitis-like features

In the past decades, the incidence of atopic dermatits (AD) has been increasing in adult population, raising the question of potential environmental triggers. We hypothesized that pollution might be a contributing factor. Bisphenol A (BPA) is an endocrine disruptor with unkown pathophysiological consequences of its repeated skin exposure. We aimed to decipher the effects of topical application of BPA onto human epidermal equivalents (HEEs) generated with keratinocytes isolated from healthy skin biopsies.

Post-Translational Modifications Evoked by Reactive Carbonyl Species in Ultraviolet-A-Exposed Skin: Implication in Fibroblast Senescence and Skin Photoaging.

Photoaging is an accelerated form of aging resulting from skin exposure to ultraviolet (UV) radiation. UV-A radiation deeply penetrates the dermis and triggers the generation of reactive oxygen species (ROS) which promotes damage to DNA, lipids and proteins. Lipid peroxidation results from the oxidative attack of polyunsaturated fatty acids which generate a huge amount of lipid peroxidation products, among them reactive carbonyl species (RCS) such as α, β-unsaturated hydroxyalkenals (e.g., 4-hydroxynonenal), acrolein or malondialdehyde. These highly reactive agents form adducts on free NH2 groups and thiol residues on amino acids in proteins and can also modify DNA and phospholipids. The accumulation of RCS-adducts leads to carbonyl stress characterized by progressive cellular and tissular dysfunction, inflammation and toxicity. RCS-adducts are formed in the dermis of skin exposed to UV-A radiation. Several RCS targets have been identified in the dermis, such as collagen and elastin in the extracellular matrix, whose modification could contribute to actinic elastosis lesions. RCS-adducts may play a role in fibroblast senescence via the modification of histones, and the sirtuin SIRT1, leading to an accumulation of acetylated proteins. The cytoskeleton protein vimentin is modified by RCS, which could impair fibroblast motility. A better identification of protein modification and carbonyl stress in the dermis may help to develop new treatment approaches for preventing photoaging.