Assessment of skin sensitization potential of zinc oxide, aluminum oxide, manganese oxide, and copper oxide nanoparticles through the local lymph node assay: 5-bromo-deoxyuridine flow cytometry method.

The advent of nanotechnology has significantly spurred the utilization of nanoparticles (NPs) across diverse sectors encompassing industry, agriculture, engineering, cosmetics, and medicine. Metallic oxides including zinc oxide (ZnO), copper oxide (CuO), manganese oxide (Mn2O3), and aluminum oxide (Al2O3), in their NP forms, have become prevalent in cosmetics and various dermal products. Despite the expanding consideration of these compounds for dermal applications, their potential for initiating skin sensitization (SS) has not been comprehensively examined. An in vivo assay, local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method (LLNA: BrdU-FCM) recognized as an alternative testing method for screening SS potential was used to address these issues. Following the OECD TG 442B guidelines, NPs suspensions smaller than 50 nm size were prepared for ZnO and Al2O3 at concentrations of 10, 25, and 50%, and Mn2O3 and CuO at concentrations of 5, 10, and 25%, and applied to the dorsum of each ear of female BALB/c mice on a daily basis for 3 consecutive days. Regarding the prediction of test substance to skin sensitizer if sensitization index (SI)≥2.7, all 4 NPs were classified as non-sensitizing. The SI values were below 2.06, 1.33, 1.42, and 0.99 for ZnO, Al2O3, Mn2O3, and CuO, respectively, at all test concentrations. Although data presented were negative with respect to adverse SS potential for these 4 NPs, further confirmatory tests addressing other key events associated with SS adverse outcome pathway need to be carried out to arrive at an acceptable conclusion on the skin safety for both cosmetic and dermal applications.

Evaluation of Artemisia dubia folium extract-mediated immune efficacy through developing a murine model for acute and chronic stages of atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a biphasic type of skin inflammation characterized by a predominance of type-2 (TH2) and type-1 (TH1) helper T cell-biased immune responses at the acute and persistent chronic phases, respectively. The present study was aimed to evaluate the efficacy of Artemisia dubia folium extract (ADFE) on AD-like skin lesions through developing a murine model for acute and chronic stages of AD. To induce acute phase AD, the dorsal skin of BALB/c mice was sensitized twice a week with 1% 2, 4-dinitrochlorobenzene (DNCB), followed by challenge (twice) in the following week with 0.2% DNCB. To induce persistent chronic AD, some mice were challenged twice a week for 4 more weeks. After the second challenge, the dorsal skin was exposed to 3% ADFE (five times per week) for 2 weeks (acute phase) or 4 weeks (persistent chronic phase). RESULTS: The paradigm of TH2 or TH1 predominance at the acute and chronic phase, respectively, was observed in this mouse model. During the acute phase, we observed an increased IL-4/IFN-γ ratio in splenic culture supernatants, an increased IgG1/IgG2a ratio in serum, and elevated serum IgE levels; however, the skew toward TH2 responses was diminished during the chronic stage. Compared with vehicle controls, ADFE reduced the IL-4/IFN-γ and IgG1/IgG2a ratios in acute AD, but both ratios increased during the chronic stage. CONCLUSIONS: Our results suggest that ADFE concomitantly suppresses the TH2 predominant response in acute AD, as well as the TH1 predominant response in chronic AD. Thus, ADFE is a candidate therapeutic for AD.

Oral subacute polypropylene microplastics administration effect on potential immunotoxicity in ICR mice.

Exposure to microplastics may be associated with damage of immune system. Polypropylene microplastics (PP-MPs) with a wide range of beneficial applications have not been extensively studied with respect to the immune system. The aim of this investigation is to examine the influence of two different sizes of PP-MPs (5.2 and 23.9 µm diameter) on immune system components in ICR mice. PP-MPs were administered orally to female and male mice at 0 (corn oil vehicle), 500, 1000, or 2000 mg/kg/d for single and daily for 4-week repeated toxicity test, respectively. No significant differences were observed in number of thymic CD4+, CD8+, CD4+CD8+ T lymphocytes, splenic helper T cells, cytotoxic T cells, and B cells. The ratio of interferon-γ to interleukin-4 in culture supernatants from activated splenocytes ex vivo (48 hr) was lower in females which were repeatedly administered with PP-MPs compared to vehicle irrespective of PP-MPs size and dose. In contrast, the opposite trend was observed in males. Production of tumor necrosis factor-α was upregulated in females that were repeatedly exposed to PP-MPs. The serum IgG2a/IgG1 ratio was lowered in female receiving large-size PP-MPs. Data suggest that immune disturbances resulting in predominant type-2 helper T cell reactivity may occur in mice, especially in females, when repeatedly exposed to PP-MPs. Further investigations with longer exposure periods are necessary to determine the immunotoxicities attributed to PP-MPs.

Association of immunotoxicological indices with lung cancer biomarkers in poultry, grape, and rose farming workers.

Exposure to occupational hazards like dust, pesticides, diesel emission particles, or physical hazards in the agricultural sector is known to cause adverse health effects on farm workers. Our study aimed at addressing the association of immunomodulatory status with plasma levels of lung cancer biomarkers in farming population, attempting to recognition of vulnerable farming group. Blood samples from apparently healthy 51 chicken husbandry, 19 grape orchard, and 21 rose greenhouse workers were subjected to evaluate plasma levels of two representative lung cancer biomarkers, pro-gastrin releasing peptide (Pro-GRP) and cytokeratin fragment 19 (CYFRA 21-1). Peripheral blood mononuclear cells obtained from farmers were used for natural killer (NK) cell phenotyping and cytokines (interferon-gamma, IFN-γ and interleukin-13, IL-13) profiling in the culture supernatant. Compared to the rose greenhouse farmers, the grape orchard and chicken husbandry workers revealed a significantly upregulated plasma Pro-GRP and CYFRA 21-1 level. A low proportion of NK cells was observed among the female grape orchard workers and a lowered IFN- γ:IL-13 ratio was seen in the grape and chicken husbandry workers than the rose workers. Our findings imply that grape orchard and chicken husbandry workers have more disturbed immune homeostasis implicated with augmentation in the levels of lung cancer biomarkers than the rose greenhouse workers.

Immunodysregulatory potentials of polyethylene or polytetrafluorethylene microplastics to mice subacutely exposed via intragastric intubation.

Microplastics (MPs) have been recently recognized as posing a risk to human health. The adverse health effects of MP exposure have been recently reported, especially via the oral exposure route. The present study investigated whether subacute (4 week) exposure to polyethylene (PE) or polytetrafluorethylene (PTFE) MPs via gastric intubation caused immunotoxicity. Two different sizes of PE MPs (6.2 or 27.2 µm) and PTFE MPs (6.0 or 30.5 µm) were administered to 6-week-old mice of both sexes at 0 (corn oil vehicle control), 500, 1000, or 2000 mg/kg/day (n = 4/group). No significant differences were observed between groups in the major thymic or splenic immune cell populations, including thymic CD4+, CD8+, CD4+/CD8+ T lymphocytes, and splenic helper T cells, cytotoxic T cells, and B cells. The ratio of interferon-gamma (IFNγ) to interleukin-4 (IL-4) in culture supernatants from polyclonally activated splenic mononuclear cells ex vivo (48 h) was dose-dependently decreased in female mice that received small- and large-size PTFE MPs. The IFNγ/IL-4 ratio was also decreased in the female mice dosed with large-size PE MPs. The serum IgG2a/IgG1 ratio was dose-dependently increased in male and female animals dosed with small-size PE MPs, in female animals dosed with large-size PTFE MPs, and in male animals dosed with small-size PTFE MPs. The present study implies that immune functions could be affected in animals exposed to MPs via gastric intubation. These effects are dependent on MP size, MP dose, MP polymer type, and mouse sex. Further investigations with longer exposure periods could be necessary to more clearly define the immunotoxic effects of MPs. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-023-00172-6.

Polytetrafluorethylene microplastic particles mediated oxidative stress, inflammation, and intracellular signaling pathway alteration in human derived cell lines.

Microplastics (MPs) are now widely distributed across the aerial, terrestrial, and aquatic environments. Thus, exposure to MPs via the oral, inhalation, or dermal routes is inevitable. Polytetrafluoroethylene (PTFE)-MPs is mainly used for manufacturing nonstick cookware, semiconductors, and medical devices; however, their toxicity has been rarely studied. In the present study, six different human cell lines, which are representative of tissues and cells that directly or indirectly come into contact with MPs, were exposed to two different sizes of irregular shape PTFE-MPs (with an average diameter of 6.0 or 31.7 µm). PTFE-MPs-mediated cytotoxicity, oxidative stress, and changes in proinflammatory cytokine production were then evaluated. We found that the PTFE-MPs did not induce cytotoxicity under any of the experimental conditions. However, PTFE-MPs (especially average diameter of 6.0 µm) induced nitric oxide and reactive oxygen species production in all the cell lines tested. Moreover, both sizes of PTFE-MPs increased the secretion of tumor necrosis factor alpha and interleukin-6 from the U937 macrophage cell line and the A549 lung epithelial cell line, respectively. In addition, PTFE-MPs activated the MAPK signaling pathways, especially the ERK pathway, in A549 and U937 cells, and in the THP-1 dendritic cell line. We also found that the expression of the NLRP3 inflammasome was reduced in the U937 and THP-1 cell lines following treatment with the PTFE-MPs sized 31.7 µm average diameter. Furthermore, expression of the apoptosis regulator, BCL2, was markedly increased in the A549 and U937 cell lines. Thus, although PTFE-MPs exert different effects on different cell types, our findings suggest that PTFE-MPs-associated toxicity may be specifically linked to the activation of the ERK pathway, which ultimately induces oxidative stress and inflammation.

Comparison of Overall Immunity Levels among Workers at Grape Orchard, Rose Greenhouse, and Open-Field Onion Farm.

Background: Occupational hazards in crop farms vary diversely based on different field operations as soil management, harvesting processes, pesticide, or fertilizer application. We aimed at evaluating the immunological status of crop farmers, as limited systematic investigations on immune alteration involved with crop farming have been reported yet. Methods: Immunological parameters including plasma immunoglobulin level, major peripheral immune cells distribution, and level of cytokine production from activated T cell were conducted. Nineteen grape orchard, 48 onion open-field, and 21 rose greenhouse farmers were participated. Results: Significantly low proportion of natural killer (NK) cell, a core cell for innate immunity, was revealed in the grape farmers (19.8 ± 3.3%) in comparison to the onion farmers (26.4 ± 3.1%) and the rose farmers (26.9 ± 2.5%), whereas cytotoxic T lymphocyte proportion was lower in the grape and the onion farmers than the rose farmers. The proportion of NKT cell, an immune cell implicated with allergic response, was significantly higher in the grape (2.3 ± 0.3%) and the onion (1.6 ± 0.8%) farmers compared with the rose farmers (1.0 ± 0.4%). A significantly decreased interferon-gamma:interleukin-13 ratio was observed from ex vivo stimulated peripheral blood mononuclear cells of grape farmers compared with the other two groups. The grape farmers revealed the lowest levels of plasma IgG1 and IgG4, and their plasma IgE level was not significantly different from that of the onion or the rose farmers. Conclusion: Our finding suggests the high vulnerability of workplace-mediated allergic immunity in grape orchard farmers followed by open-field onion farmers and then the rose greenhouse farmers.

Evaluation of potential toxicity of polyethylene microplastics on human derived cell lines.

Microplastics bare of major concern for environmental conservation and animal welfare in recent years as its use has increased tremendously. Polyethylene microplastics (PE-MPs) are the most common microplastics and could get exposed to humans via different routes with oral>inhalation>dermal. Internalization of MPs through epithelial tissue could expose MPs to various cells such as dendritic cells, macrophages/monocytes, and/or T cells. In this study, we aimed at identifying the effects of two different sized (30.5 ± 10.5 and 6.2 ± 2.0 µm) PE-MPs on different human cell lines representing different tissues or cells that get exposed to MPs directly or indirectly. Six cell lines were cultured with different concentrations of PE-MPs and cell viability, intracellular reactive oxygen species (ROS), nitric oxide (NO), and cytokines were measured. PE-MPs did not substantially lower the cell viability of cells however highest concentration (1000 µg/mL) of both sized MPs slightly reduced cell viability in intestinal epithelial Caco-2 and lung epithelial A549 cells. Both sized PE-MPs induced higher NO in all the cell lines and upregulation of ROS generation was demonstrated at THP-1, Jurkat, and U937 immune cell lines. A pro-inflammatory cytokine response was seen in HaCaT keratinocyte cells when cultured with PE-MPs whereas the opposite effect was observed in THP-1 and U937 cells except with THP-1 cells cultured with larger-sized MPs. We found that the PE-MPs do not have the same effects on all kinds of cells and tissues exposed and the immune modulation is not necessarily inflammatory. Thus, this study gives insight into why more detailed studies focused on exposure routes and organ-specific effects of different MPs need to be carried out.

Exposure to lead on expression levels of brain immunoglobulins, inflammatory cytokines, and brain-derived neurotropic factor in fetal and postnatal mice with autism-like characteristics.

Autism spectrum disorders (ASD) are neurodevelopmental disorders, and their incidence is increasing worldwide. Increased exposure to environmental metal lead (Pb) has been proposed as a risk factor associated with ASD. In the present study, BTBR T+ tf/J (BTBR) mice with ASD-like behavioral characteristics and control FVB mice were exposed gestationally and/or neonatally to Pb, and compared with highly social FVB mice to investigate neuroimmunological abnormalities. IgG1 and IgG2a levels in fetal brains from BTBR dams exposed to Pb (BTBR-Pb) were significantly higher than those of BTBR-controls (BTBR-C). However, this change did not occur in FVB mice exposed to Pb. The IgG1:IgG2a ratio was higher in both fetal and postnatal brains of BTBR mice compared to FVB animals regardless of Pb exposure. The IL-4:IFN-γ ratio was elevated in BTBR-Pb relative to BTBR-C mice, but this ratio was not markedly affected following Pb exposure in FVB animals. These findings suggest the potential for a Pb-driven predominant TH2-like reactivity profile in brain microenvironment present in BTBR mice. Brain-derived neurotrophic factor was decreased in fetal and postnatal BTBR-Pb brains relative to BTBR-C brains but not in FVB-Pb relative to FVB-C mice. Taken together, data demonstrate that Pb exposure might contribute to developmental brain abnormalities associated with ASD, particularly in individuals with genetic susceptibility to ASD.

Dysregulation of murine immune functions on inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole, or propionic acid.

Animal husbandry workers are exposed to various malodorous compounds in the workplace. Although these compounds cause severe nuisance, no systemic investigation of their effects on the immune system has been conducted. To address this issue, we evaluated the effects of inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole (3-MI), and propionic acid (PA), representing four major groups of malodorous compounds, on humoral and cellular immunity in mice. Mice were exposed to the substances (low dose: 10 µL and high dose: 200 µL) for 10 min/day for 4 weeks in a modified standard mouse cage. Neutrophil% and splenic cytotoxic T cell% were significantly lower in the high-dose ammonia group than in the vehicle control. Exposure to ammonia and 3-MI increased immature thymic T lymphocyte% relative to control and concomitantly decreased both mature helper and cytotoxic T-cell populations in the thymus. In the ammonia exposure group, levels of serum immunoglobulin E and immunoglobulin A were elevated, and the IgG2a:IgG1 ratio in the serum was reduced in a dose-dependent manner. Splenic natural killer cell activity was significantly less in the PA exposure group than in the control. Overall, our findings suggest that inhalational exposure to these malodorous substances disturbs immune homeostasis in vivo.

Prediction of Skin Sensitization Potential of Silver and Zinc Oxide Nanoparticles Through the Human Cell Line Activation Test.

The development of nanotechnology has propagated the use of nanoparticles (NPs) in various fields including industry, agriculture, engineering, cosmetics, or medicine. The use of nanoparticles in cosmetics and dermal-based products is increasing owing to their higher surface area and unique physiochemical properties. Silver (Ag) NPs' excellent broad-spectrum antibacterial property and zinc oxide (ZnO) NPs' ability to confer better ultraviolet (UV) protection has led to their maximal use in cosmetics and dermal products. While the consideration for use of nanoparticles is increasing, concerns have been raised regarding their potential negative impacts. Although used in various dermal products, Ag and ZnO NPs' skin sensitization (SS) potential has not been well-investigated using in vitro alternative test methods. The human Cell Line Activation Test (h-CLAT) that evaluates the ability of chemicals to upregulate the expression of CD86 and CD54 in THP-1 cell line was used to assess the skin sensitizing potential of these NPs. The h-CLAT assay was conducted following OECD TG 442E. NPs inducing relative fluorescence intensity of CD86 ≥ 150% and/or CD54 ≥ 200% in at least two out of three independent runs were predicted to be positive. Thus, Ag (20, 50, and 80 nm) NPs and ZnO NPs were all predicted to be positive in terms of SS possibility using the h-CLAT prediction model. Although further confirmatory tests addressing other key events (KEs) of SS adverse outcome pathway (AOP) should be carried out, this study gave an insight into the need for cautious use of Ag and ZnO NPs based skincare or dermal products owing to their probable skin sensitizing potency.

Prediction of the skin sensitization potential of polyhexamethylene guanidine and triclosan and mixtures of these compounds with the excipient propylene glycol through the human Cell Line Activation Test.

Household products often contain an antimicrobial agent such as biocides, polyhexamethylene guanidine (PHMG), triclosan (TCS), and propylene glycol (PG) as an excipient to dissolve the active ingredients. The skin sensitization (SS) potentials of each of these substances or mixtures of PHMG or TCS with PG have not been investigated through in vitro alternative test methods. The in vitro alternative assay called human Cell Line Activation Test (h-CLAT) served to address these issues. The h-CLAT assay was conducted in accordance with OECD TG 442E. On three independent runs, all the three substances were predicted to be sensitizers according to the SS positivity with relative fluorescence intensity of CD86 ≥ 150% and/or CD54 ≥ 200% at any tested concentrations. Mixtures of PHMG or TCS with PG at ratios of 9:1, 4:1, or 1:4 weight/volume were all positive in terms of SS potential. Since humans can be occupationally or environmentally exposed to mixtures of excipients with active ingredients of biocides, the present study may give insights into further investigations of the SS potentials of various chemical mixtures.

Prediction of the skin sensitization potential of polyhexamethylene guanidine phosphate, oligo(2-(2-ethoxy)ethoxyethyl) guanidinium chloride, triclosan, and mixtures of these compounds with the excipient propylene glycol through the local lymph node assay: BrdU-FCM.

The guanidine family of antimicrobial agents, which includes polyhexamethylene guanidine phosphate (PHMG) and oligo(2-(2-ethoxy)ethoxyethyl) guanidinium chloride (PGH), and chlorophenol biocidal chemicals such as 2,4,4'-trichloro-2'-hydroxydiphenyl ether (triclosan) are used in various occupational and environmental biocidal applications. The excipient propylene glycol (PG) is used to dissolve the active ingredients. The skin sensitization (SS) potential of these substances has not been systemically investigated and is still debated. Moreover, mixtures of PHMG, PGH, or triclosan with PG have not been evaluated for SS potency. An in vivo assay known as the local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method (LLNA: BrdU-FCM) was recently adopted as an alternative testing method and was used to address these issues. Via the LLNA: BrdU-FCM, PHMG, PGH, and triclosan were predicted to be sensitizers, while PG was predicted to be a nonsensitizer. In addition, d-limonene, which is used as a flavoring in various consumer products, was also predicted to be a sensitizer, although no unanimous conclusion has been reached regarding its SS potential. Mixtures of PHMG, PGH, triclosan, or d-limonene with PG at ratios of 9:1, 4:1, and 1:4 (w/w) were all positive in terms of SS potential, indicating that the PG excipient does not influence the SS predictions of these chemicals. Since humans can be occupationally and environmentally exposed to mixtures of excipients with active ingredients, the present study may give insight into further investigations of the SS potentials of various chemical mixtures.

Prediction of the skin sensitization potential of didecyldimethylammonium chloride and 3,7-dimethyl-2,6-octadienal and mixtures of these compounds with the excipient ethylene glycol through the human Cell Line Activation Test and the Direct Peptide Reactivity Assay.

In commercial products such as household deodorants or biocides, didecyldimethylammonium chloride (DDAC) often serves as an antimicrobial agent, citral serves as a fragrance agent, and the excipient ethylene glycol (EG) is used to dissolve the active ingredients. The skin sensitization (SS) potentials of each of these substances are still being debated. Moreover, mixtures of DDAC or citral with EG have not been evaluated for SS potency. The in vitro alternative assay called human Cell Line Activation Test (h-CLAT) and Direct Peptide Reactivity Assay (DPRA) served to address these issues. On three independent runs of h-CLAT, DDAC and citral were predicted to be sensitizers while EG was predicted to be a non-sensitizer and also by the DPRA. Mixtures of DDAC or citral with EG at ratios of 7:3 and 1:4 w/v were all positive by the h-CLAT in terms of SS potential but SS potency was mitigated as the proportion of EG increased. Citral and its EG mixtures were all positive but DDAC and its EG mixtures were all negative by the DPRA, indicating that the DPRA method is not suitable for chemicals with pro-hapten characteristics. Since humans can be occupationally or environmentally exposed to mixtures of excipients with active ingredients, the present study may give insights into further investigations of the SS potentials of various chemical mixtures.

Major environmental characteristics of swine husbandry that affect exposure to dust and airborne endotoxins.

Inhalation of organic dust or endotoxin in the dust is considered a major risk factor for occupational respiratory illnesses. Eighteen environmental characteristics associated with animal husbandry were surveyed at 36 swine farms in seven provinces throughout South Korea. Association of these factors with levels of indoor inhalable or respirable dust or endotoxin in each type of dust was analyzed using backward stepwise multiple linear regression models. Mean levels of inhalable and respirable dust were 0.5 ± 0.35 and 0.13 ± 0.12 mg/m3 air, respectively, and mean endotoxin levels were 676 ± 463 and 48.4 ± 68.2 EU/m3, respectively, in each dust. Factors negatively associated with inhalable dust levels included pig age, indoor farm temperature, number of pigs in the building, hr/week of indoor farm work, and partly slatted floor. Factors positively associated with inhalable dust levels included floor cleaning by manual scraping and slurry deposit duration. Factors negatively associated with the level of endotoxin in inhalable dust included pig age, temperature, number of pigs, hr/week of indoor farm work, and partly slatted floor. Factors negatively associated with respirable dust level included area of the confinement building, whereas factors positively associated with respirable dust level included the number of pigs and stocking density. Endotoxin levels in respirable dust were negatively associated with h/week of indoor farm work and partly slatted floor. Overall, data suggest that husbandry variables may be adjusted to control dust and airborne endotoxin levels in swine farms.

Mental distress and the coping strategies of elderly Indian immigrant women.

This article explores how elderly English-speaking Indian immigrant women living in Edmonton, Alberta, Canada perceive and manage mental distress. With elders' consent, in-depth interviews were recorded, transcribed and transcripts were thematically analyzed. The findings suggest that these women believed that to lower the risk of mental distress it is critical for individuals to ;maximize control over inner self' by ;being busy.' The elder's busy behavior is framed within the Indian cultural and spiritual/faith matrix in dialogue with acculturation experiences in Canada. ;Staying busy' allows these elders to use culture as a ;moral medicine' to facilitate coping and adaptation.