Ex Vivo Live Full-Thickness Porcine Skin Model as a Versatile In Vitro Testing Method for Skin Barrier Research.

Since the European Union (EU) announced their animal testing ban in 2013, all animal experiments related to cosmetics have been prohibited, creating a demand for alternatives to animal experiments for skin studies. Here, we investigated whether an ex vivo live porcine skin model can be employed to study the safety and skin barrier-improving effects of hydroxyacids widely used in cosmetics for keratolytic peels. Glycolic acid (1-10%), salicylic acid (0.2-2%), and lactobionic acid (1.2-12%) were used as representative substances for α-hydroxyacid (AHA), ß-hydroxyacid (BHA), and polyhydroxyacid (PHA), respectively. When hydroxyacids were applied at high concentrations on the porcine skin every other day for 6 days, tissue viability was reduced to 50-80%, suggesting that the toxicity of cosmetic ingredients can be evaluated with this model. Based on tissue viability, the treatment scheme was changed to a single exposure for 20 min. The protective effects of a single exposure of hydroxyacids on skin barrier function were evaluated by examining rhodamine permeability and epidermal structural components of barrier function using immunohistochemistry (IHC) and immunofluorescence (IF) staining. Lactobionic acid (PHAs) improved skin barrier function most compared to other AHAs and BHAs. Most importantly, trans-epidermal water loss (TEWL), an important functional marker of skin barrier function, could be measured with this model, which confirmed the significant skin barrier-protective effects of PHAs. Collectively, we demonstrated that the ex vivo live full-thickness porcine skin model can be an excellent alternative to animal experiments for skin studies on the safety and efficacy of cosmetic ingredients.

Skin wound healing effects of (+)-syringaresinol from ginseng berry.

Background: Ginseng has been used as a traditional medicine and functional cosmetic ingredients for many years. Recent studies have focused on the potential biological effects of the ginseng berry and its ingredients. (+)-Syringaresinol (SYR) is enriched in ginseng berry and its beneficial effects on the skin have been recently reported. However, little is known about the its effects on the wound healing process of skin. Methods: Here, we evaluated the skin wound healing effect of (+)-SYR using the human fibroblast Hs68 cell and ex vivo pig and human skin tissue model. Scratch wound test and hydrogen peroxide (HPO) induce chemical wound model were employed. Results: (+)-SYR promoted the migration and proliferation of Hs68 cells without significant cytotoxicity at the tested concentrations. Especially, in ex vivo pig and human skin tissue, HPO-induced chemical wound was recovered almost completely by (+)-SYR. In line with the finding in Hs68, the protein expression levels of TGF-ß and PCNA, a proliferation marker were increased, demonstrating the beneficial effects of (+)-SYR on skin wound repair. Conclusion: Collectively, we demonstrated that (+)-SYR from ginseng berry, can enhance the wound healing effect by accelerating cell proliferation and skin regeneration, suggesting the potential utility of (+)-SYR for skin wound repair.

Multilamellar ceramide core-structured microvehicles with substantial skin barrier function recovery.

This study introduces a multilamellar ceramide core-structured microvehicle platform for substantial skin barrier function recovery. Our approach essentially focused on fabricating bacterial cellulose nanofiber (BCNF)-enveloped ceramide-rich lipid microparticles (CerMPs) by solidifying BCNF-armored oil-in-water Pickering emulsions. The oil drops consisted of Ceramide NP (a phytosphingosine backbone N-acylated with a saturated stearic acid) and fatty alcohols (FAs) with a designated stoichiometry. The thin BCNF shell layer completely blocked the growth of ceramide molecular crystals from the CerMPs for a long time. The CerMP cores displayed a multilamellar structure wherein the interlayer distance and lateral packing could be manipulated using FAs with different alkyl chain lengths. The CerMPs remarkably lowered the trans-epidermal water loss while restoring the structural integrity of the epidermis in damaged skin. The results obtained herein highlight that the CerMP system provides a practical methodology for developing various types of skin-friendly formulations that can strengthen the skin barrier function.

Estimation of the costs of smoking-related oral disease: a representative South Korean study.

OBJECTIVES: The objectives of this study were to estimate the socioeconomic and psychological costs associated with smoking-related oral disease (SROD) with the aim of generating objective data that could be used in smoking cessation counselling by dental care providers and could also serve as data with which to set standards and criteria for use in dental health insurance. METHODS: Patients were sourced from the 11 dental hospitals associated with dental schools in South Korea. A total of 1,288 of 10,080 patients with SROD were selected to participate in the study for a period of 2 years from January 2009 to March 2011. Data collected were analysed using spss Version 17.0. RESULTS: Among the SRODs, the most common was periodontal disease (40.7%). Periodontal disease accounted for the highest social and economic costs. Mouth cancer accounted for the highest psychological cost. CONCLUSIONS: In order to reduce associated socioeconomic and psychological costs, dental care providers and government should provide more proactive and more efficient smoking cessation programmes.

Impact of In-Home Repair Services on Physical and Mental Harm among Essential Workers: The Mediating Effect of Fear and Moderating Effect of Types of Employment.

This study attempted to establish a hypothetical model describing the severity of physical and mental harm among essential workers during the COVID-19 pandemic. To this end, the mediating effect of fear on the relationship between in-home services and the severity of physical and mental harm was analyzed. Moreover, this study utilized multigroup path analysis to examine differences according to the type of employment. Thus, data from all 502 participants were included in the final analysis. The study found that in-home service did not have a direct effect on fear in the path model for the permanent employment group, but did have a direct effect on fear in the path model for the non-permanent employment group. The implications for the field are that the following is required: an anti-infection system should be incorporated at workplaces; employment stability should be provided for essential workers; providing systematic support, such as professional counseling to alleviate negative emotional responses, should be considered.

Evaluation of Skin Irritation of Acids Commonly Used in Cleaners in 3D-Reconstructed Human Epidermis Model, KeraSkinTM.

Cleaners such as dishwashing liquids contain various chemicals that cause skin damage. Alkaline agents used in cleaners alter the lipid composition of the skin and damage the skin barrier. However, little is known about the effects of acids used in cleaners on the skin. Here, we investigated the effects of acidic pH on the skin and evaluated the skin irritation of acids commonly used in cleaners with a 3D-reconstructed human epidermis model, KeraSkinTM, according to OECD TG439. First, to examine the effects of acidic pH, we evaluated the skin irritation of citrate buffers (0.1 M, McIlvaine buffer) prepared in a wide pH range (pH 1.5-6.0). Surprisingly, cell viability was not significantly affected even at pH 1.5, reflecting that the acidity alone may not be sufficient to induce skin irritation. Even after longer exposure (180 min), the cell viability was not reduced below 50%, a cutoff to determine an irritant. To examine the effect of the anionic part, several organic acids used in cleaners (citric acid, glycolic acid, lactic acid, malic acid, and succinic acid) were examined. These organic acids also failed to reduce viability at 0.1 M. However, at 1 M, most of the acids tested, except lactic acid, were determined to be skin irritants. Histology further supported the skin irritancy of acids at 1 M. Similarly, inorganic acids (hydrogen bromide, hydrogen chloride, nitric acid, and sulfuric acid) were determined to be irritants only at 1 M. In the case of alkaline agents, pH and concentrations were also important factors to determine the skin irritancy, although the epidermal structure and lipids were more damaged than acids. Collectively, we demonstrated that both the pH and concentration are important factors for the skin irritancy of acids, shedding an important insight into the mechanism of skin irritation.

Mediating Effects of Psychological States on Work Performance of Visiting Nurses According to COVID-19 Workplace Quarantine Measures: A Multi-Group Path Analysis Study.

This multi-group path analysis study investigated the effects of verbal abuse (suspicion of infection and disrespect) on difficulties in work performance according to the workplace quarantine measures of visiting nurses during the COVID-19 pandemic. A total of 262 visiting nurses in Korea completed the online questionnaire between 10 October and 30 November 2020, and their data were included in the final analysis. The study found that experiences of verbal abuse mediated fear and anxiety to affect difficulties in work performance. In the path model of the group with a high level of workplace quarantine measures, experiences of verbal abuse (suspicion of infection and disrespect) did not directly affect fear. The opposite was true for the group with low levels of workplace quarantine measures. The implications for the field are that the following is required: heightened awareness of verbal abuse; workplace quarantine policies; and mental health management systems and intervention programs to detect the early fear and anxiety of visiting nurses.

The Effects of Work Characteristics Related to Work-Life Imbalance on Presenteeism among Female Workers in the Health and Social Work Sectors: Mediation Analysis of Psychological and Physical Health Problems.

This study is a multigroup path analysis aiming to create a theoretical model of presenteeism among female workers in the health and social work sectors, assess the mediating effects of mental health problems (sleeping trouble and psychological wellbeing), and physical health problems (fatigue and muscle aches) on the relationship between work characteristics (demands at work and social community at work) and presenteeism, and identify the differences between the effects of variables on those who reported low work-life imbalance and high work-life imbalance. Raw data from the fifth Korean Working Conditions Survey (KWCS) were analyzed. From the total sample of 50,205 people, 2209 women in health and social work were included in the study sample. The results were as follows: the demands at work had a significant and positive indirect effect on presenteeism (B = 0.0023, p < 0.001), mediated by trouble sleeping, fatigue, and muscle aches, in that order. Demands at work were also found to have a significant and negative indirect effect on presenteeism (B = -0.0017, p < 0.001), mediated by psychological wellbeing, fatigue, and muscle aches, in descending order. Social community at work had a significant and negative indirect effect on presenteeism (B = -0.0022, p < 0.001), mediated by trouble sleeping, fatigue, and muscle aches, in that order. Social community at work also had a significant and negative effect on presenteeism, mediated by psychological wellbeing, fatigue, and muscle aches, in descending order (B = -0.0097, p < 0.001). Demands at work did not have a significant effect on psychological wellbeing in the low work-life imbalance group, whereas its effect was significant and positive (ß = 0.198, p < 0.001) in the high work-life imbalance group. In conclusion, in the path model of the low work-life imbalance group, demands at work did not influence psychological wellbeing. Therefore, strategies to ameliorate work-life imbalance may be helpful components of interventions to reduce presenteeism.

Skin irritation and inhalation toxicity of biocides evaluated with reconstructed human epidermis and airway models.

Biocides are widely used in household products. Humans are exposed to biocides through dermal, inhalational, and oral routes. However, information on the dermal and inhalational toxicity of biocides is limited. We evaluated the effects of biocides on the skin and airways using the reconstructed human epidermis model KeraSkin™ and the airway model SoluAirway™. We determined the irritancy of 11 commonly used biocides (1,2-benzisothiazol-3(2H)-one [BIT], 2-phenoxyethanol [PE], zinc pyrithione, 2-bromo-2-nitropropane-1,3-diol, 3-iodoprop-2-ynyl N-butylcarbamate [IPBC], 2-octyl-1,2-thiazol-3-one, 2,2-dibromo-2-cyanoacetamide, 4-chloro-3-methylphenol [CC], 2-phenylphenol, deltamethrin, and 4,5-dichloro-2-octyl-1,2-thiazol-3-one) in the KeraSkin™ and SoluAirway™ by viability and histological examinations. BIT and CC were found to cause skin irritation at the approved concentrations or at the concentration close to approved limit while the others were non-irritants within the approved concentration. These results were confirmed via histology, wherein skin irritants induced erosion, vacuolation, and necrosis of the tissue. In the SoluAirway™, most of the biocides decreased cell viability even within the approved limits, except for PE, IPBC, and deltamethrin, suggesting that the airway may be more vulnerable to biocides than the skin. Taken together, our result indicates that some biocides can induce toxicity in skin and airway. Further studies on the dermal and inhalational toxicity of biocides are warranted.

Employment of cytology for in vitro skin irritation test using a reconstructed human epidermis model, Keraskin™.

Skin irritation tests using reconstructed human epidermis (RhE) employ viability as an endpoint, but color interference or borderline results are often problematic. We examined whether the cytology of cells from treated RhE could determine skin irritancy. Six chemicals (three irritants; DnP, 1-B, PH, three non-irritants; DP, APA, HS) were evaluated in a RhE, Keraskin™. DP, HS, and PH were clearly classified with viability, but DnP, 1-B, and APA were often falsely determined, due to borderline values falling near the cutoff, 50%. In histology, the tissues treated with DnP, 1-B, and PH showed erosion of the stratum corneum, vacuolization, and necrosis in the basal layer. DP- and HS-treated tissues showed relatively normal morphology but APA induced necrosis similar to irritants. Cytology revealed that DnP, 1-B or PH depleted cells and induced irregular and abnormal cell shapes. In contrast, relatively regular and normal shapes and clear distinction between the nucleus and cytoplasm was observed for DP, APA and HS. To further confirm it, additional 10 substances, including false positives from OECD TG 439, were tested. Overall (16 substances in total), cytology: total area predicted the skin irritancy of test chemicals with the highest accuracy (87.5%) followed by cytology: cell count (81.3%), histology (75%) and viability (68.8%), confirming the utility of cytology as an alternative endpoint in the skin irritation test using RhE.

Investigation of dermal toxicity of ionic liquids in monolayer-cultured skin cells and 3D reconstructed human skin models.

Ionic liquids have gained increasing attention in the chemical industry as potential green substitutes for traditional solvents. However, little is known about toxicity of ionic liquids on the skin, a major exposure portal to toxic substances. Here, we evaluated dermal toxicity of ionic liquids using human keratinocyte and fibroblast cell line, 3D reconstructed human epidermis, and full-thickness model to investigate underlying mechanisms. Cytotoxicity of ionic liquids was evaluated for representative anions, [TFSI], [PF6], [BF4], and [DCA], as well as for cations, [EMIM], [BMPY], [TBA] and [Zn], in human keratinocyte cell line, HaCaT, and human dermal fibroblasts. In our results, significant cytotoxicity was induced by ionic liquids with [TFSI] in both cell lines. Notably, cytotoxicity of [TFSI] containing ionic liquids was comparable to xylene, a toxic conventional organic solvent. Fluorescent and flow cytometric analysis revealed that [TFSI]-exposed cells underwent necrotic cell death. Reactive oxygen species (ROS) was increased while the amount of glutathione was decreased by [TFSI] in dose-dependent manner, which was reversed by antioxidant, N-acetylcysteine. In 3D reconstructed human epidermis and full-thickness model, a single application of [TFSI] induced toxicity although it was minimal and largely limited to epidermal layer. Collectively, these results demonstrated potential dermal toxicity of ionic liquids.

Skin irritation and sensitization potential of oxidative hair dye substances evaluated with in vitro, in chemico and in silico test methods.

Permanent oxidative hair dyes are widely used but their toxicity is not well-established. Here we aimed to evaluate the skin sensitization and irritation of nine hair dye substances (MAP, MRP-N, RS, PAOX, 2,4-DAPE, 2,6-PYR, PPD, Grey HED and PM) permitted for use in EU and Korea, using in vitro and in chemico and in silico test methods. Skin sensitization was evaluated by the KeratinoSens™ assay, Direct Peptide Reactivity Assay (DPRA) and DEREK. Six of nine dyes tested were determined as sensitizers in common. However, the decision for MAP, RS or PAOX was diverged across assays showing 2 positives and 1 negative. Skin irritation of hair dye substances was assessed with or without 6% H2O2 on a reconstructed human epidermis, Epiderm™, which demonstrated that H2O2 increased the skin irritation potential of some hair dyes. PPD and PM were determined to be irritants with H2O2. Epidermal damages by hair dye and H2O2 could be further confirmed through the histology of tissue remaining after MTT assay. Collectively, our study demonstrated that hair dyes possess potential skin sensitization and irritation issues which could be further aggravated by H2O2.

Alternatives to In Vivo Draize Rabbit Eye and Skin Irritation Tests with a Focus on 3D Reconstructed Human Cornea-Like Epithelium and Epidermis Models.

Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornea-like epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility.

Magnetic resonance imaging as a determinant for surgical release of congenital muscular torticollis: correlation with the histopathologic findings.

OBJECTIVE: (1) To present the magnetic resonance imaging (MRI) findings of congenital muscular torticollis (CMT) of subjects who underwent surgical release and subjects who showed a good prognosis with stretching exercises and (2) to correlate the MRI findings with the histopathologic findings of CMT for subjects who underwent surgical release in order to examine the hypothesis that the MRI findings of CMT can be used as a determinant to perform surgical release of CMT. METHOD: The neck MRI findings of 33 subjects who underwent surgical release for CMT were compared with those of 18 subjects who were successfully managed only with conservative management. The MRI findings were correlated with the histopathologic sections of the CMT mass. RESULTS: All 33 subjects (100%) who underwent surgical release showed one or more low signal intensities within the involved sternocleidomastoid muscle (SCM) on the T1- and T2-weighted images of neck MRI. The eighteen non-surgical candidates showed only enlargement of the SCM without low signal intensity within the SCM. The histopathologic findings showed interstitial fibrosis and/or the presence of aberrant tendon-like excessive dense connective tissue that was either well-arranged or disorganized. CONCLUSION: The histopathologic findings and MRI findings showed good correlation in terms of the amount of fibrosis and aberrant dense connective tissue within the SCM. If multiple or large low signal intensities within the SCM are noted, we think that surgical release should be considered.

Usefulness of (18)f-fluorodeoxyglucose positron emission tomography/computed tomography in management of cervical dystonia.

OBJECTIVE: To evaluate the usefulness of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in the management of cervical dystonia (CD) with botulinum toxin type A (BoNT-A) injection. METHOD: Thirty two subjects with CD were included. A BoNT-A injection was provided either by clinically targeting method (group 1) or by (18)F-FDG PET/CT-assisted, clinically targeting method (group 2). In group 2, selection of target muscles and dosage of BoNT-A were determined according to the increased (18)F-FDG uptake, in addition to physical examination and functional anatomy. The outcomes of BoNT-A injection was compared between the two groups, in terms of the number of subjects who had reinjection before and after 6 months, the number of reinjections, the interval of reinjections, the duration to the minimal Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), the number of adverse events, the reduction rate of TWSTRS at 1-3 months and 3-6 months after injection, and the probability of reinjection-free living. RESULTS: The number of subjects who had reinjection within 6 months was significantly lower in group 2 than in group 1 (10 in group 1 vs. 3 in group 2). The reduction rate of TWSTRS after 3-6 months (37.8±15.7% of group 1 vs. 63.3±28.0% of group 2) and the probability of reinjection-free living were significantly higher in group 2 than in group 1. CONCLUSION: These findings suggest that (18)F-FDG PET/CT study could be useful in management of CD in terms of the identification of dystonic muscles if there is an increase in the (18)F-FDG uptake in the cervical muscle of the images.

Comparison of clinical severity of congenital muscular torticollis based on the method of child birth.

OBJECTIVE: To compare the clinical severity of congenital muscular torticollis (CMT) based on the method of child birth. METHOD: Children diagnosed with CMT and who were < 6-years-of-age at the time of their first visit at the Center for Torticollis, Ajou Medical Center, were included in this study. The medical records were retrospectively reviewed with reference to the method of child birth and the clinical severity of CMT. The clinical severity of CMT was determined either by whether stretching exercises were needed for the children <6-month-of-age or whether surgical release was required for the children ≥6-months-of-age at the time of the first visit. RESULTS: One hundred seventy eight subjects with CMT were enrolled. There was no significant difference in the rate of surgical release according to the method of child birth. For 132 patients <6-month-of-age there was also no significant difference in the rate of stretching exercises. CONCLUSION: There was no significant difference in the clinical severity of CMT based on the method of child birth. This finding suggests that prenatal factors alone could be a cause of CMT and that the clinical severity of CMT in children delivered by Cesarean section is not different when compared with the severity of CMT in children born through vaginal delivery.