Phthalate Exposure During the Prenatal and Lactational Period Increases the Susceptibility to Rheumatoid Arthritis in Mice

Relationship between mixed exposure to phenyl hydroxides, polycyclic aromatic hydrocarbons, and phthalates and the risk of arthritis

BACKGROUND

To determine the relationship between mixed exposure to three types of endocrine-disrupting chemicals (EDCs), namely phenyl hydroxides, polycyclic aromatic hydrocarbons (PAHs), and phthalates (PAEs), and risk of arthritis.

METHODS

Participants were selected from National Health and Nutrition Examination Survey (NHANES). The relationships between the urinary concentrations of phenyl hydroxides, PAHs, and PAEs and the risk of arthritis were analyzed by generalized linear regression model. The mixed exposure to these EDCs and the risk of arthritis was analyzed by weighted quantile sums (WQSs) and Bayesian kernel machine regression (BKMR) model.

RESULTS

Our analysis showed that participants with urinary benzophenone-3 and methylparaben concentrations in the highest quartile (Q4) had an increased risk of arthritis compared with those in Q1. For each one-unit increase in the natural logarithm-converted urinary concentrations of 1-hydroxynapthalene and 2-hydroxynapthalene, the risk of arthritis increased by 5% and 8%, respectively. Chemical mixing index coefficients were significantly associated with risk of arthritis in both WQS positive- and negative-constraint models. In the BKMR model, there was a significant positive correlation between mixed exposure and the risk of arthritis.

CONCLUSION

Mixed exposure to phenyl hydroxides, PAHs, and PAEs increased the risk of arthritis, with exposure to PAHs being the key factor.

Molecular mechanisms of environmental pollutant-induced cartilage damage: from developmental disorders to osteoarthritis

The objective of the present study was to review the molecular mechanisms of the adverse effects of environmental pollutants on chondrocytes and extracellular matrix (ECM). Existing data demonstrate that both heavy metals, including cadmium (Cd), lead (Pb), and arsenic (As), as well as organic pollutants, including polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCB), bisphenol A, phthalates, polycyclic aromatic hydrocarbons (PAH), pesticides, and certain other organic pollutants that target cartilage ontogeny and functioning. Overall, environmental pollutants reduce chondrocyte viability through the induction apoptosis, senescence, and inflammatory response, resulting in cell death and impaired ECM production. The effects of organic pollutants on chondrocyte development and viability were shown to be mediated by binding to the aryl hydrocarbon receptor (AhR) signaling and modulation of non-coding RNA expression. Adverse effects of pollutant exposures were observed in articular and growth plate chondrocytes. These mechanisms also damage chondrocyte precursors and subsequently hinder cartilage development. In addition, pollutant exposure was shown to impair chondrogenesis by inhibiting the expression of Sox9 and other regulators. Along with altered Runx2 signaling, these effects also contribute to impaired chondrocyte hypertrophy and chondrocyte-to-osteoblast trans-differentiation, resulting in altered endochondral ossification. Several organic pollutants including PCDD/Fs, PCBs and PAHs, were shown to induce transgenerational adverse effects on cartilage development and the resulting skeletal deformities. Despite of epidemiological evidence linking human environmental pollutant exposure to osteoarthritis or other cartilage pathologies, the data on the molecular mechanisms of adverse effects of environmental pollutant exposure on cartilage tissue were obtained from studies in laboratory rodents, fish, or cell cultures and should be carefully extrapolated to humans, although they clearly demonstrate that cartilage should be considered a putative target for environmental pollutant toxicity.

Bifenthrin induces changes in clinical poisoning symptoms, oxidative stress, DNA damage, histological characteristics, and transcriptome in Chinese giant salamander (Andrias davidianus) larvae

Bifenthrin (BF) is a broad-spectrum insecticide that has gained widespread use due to its high effectiveness. However, there is limited research on the potential toxic effects of bifenthrin pollution on amphibians. This study aimed to investigate the 50 % lethal concentration (LC50) and safety concentration of Chinese giant salamanders (CGS) exposed to BF (at 0, 6.25,12.5,25 and 50 μg/L BF) for 96 h. Subsequently, CGS were exposed to BF (at 0, 0.04, and 4 μg/L BF) for one week to investigate its toxic effects. Clinical poisoning symptoms, liver pathology, oxidative stress factors, DNA damage, and transcriptome differences were observed and analyzed. The results indicate that exposure to BF at 4 μg/L significantly decreased the adenosine-triphosphate (ATP), superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) contents in the brain, liver, and kidney of CGS. Additionally, the study found that the malondialdehyde (MDA), reactive oxygen species (ROS), and 8-hydroxydeoxyguanosine (8-OHdG) contents were increased. The liver tissue exhibited significant inflammatory reactions and structural malformations. RNA-seq analysis of the liver showed that BF caused abnormal antioxidant indices of CGS. This affected molecular function genes such as catalytic activity, ATP-dependent activity, metabolic processes, signaling and immune system processes, behavior, and detoxification, which were significantly upregulated, resulting in the differential genes significantly enriched in the calcium signaling pathway, PPARα signaling pathway and NF-kB signaling pathway. The results suggest that BF induces the abnormal production of free radicals, which overwhelms the body's self-defense system, leading to varying degrees of oxidative stress. This can result in oxidative damage, DNA damage, abnormal lipid metabolism, autoimmune diseases, clinical poisoning symptoms, and tissue inflammation. This work provides a theoretical basis for the rational application of bifenthrin and environmental risk assessment, as well as scientific guidance for the conservation of amphibian populations.

Worsening of imiquimod-induced psoriasiform inflammation in mice by environmental pollutant, di-(2-ethylhexyl) phthalate through dysregulation in IL-17A and Nrf2/iNOS signaling in peripheral myeloid and CD4 + T cells

Psoriasis is a devastating autoimmune illness resulting from excessive keratinocyte growth and leukocyte infiltration into the dermis/epidermis. In the pathogenesis of psoriasis, different immune cells such as myeloid cells and CD4 + T cells play a key role. Th17/Th1 immune responses and oxidant-antioxidant responses are critical in regulation of psoriatic inflammation. Di-2-ethylhexyl phthalate (DEHP) is one of the well-known plasticizers and has widespread use worldwide. DEHP exposure through ingestion may produce harmful effects on the skin through systemic inflammation and oxidative stress, which may modify psoriatic inflammation. However, the effect of oral DEHP exposure on inflammatory cytokines and Nrf2/iNOS signaling in myeloid cells and CD4 + T cells in the context of psoriatic inflammation has not been investigated earlier. Therefore, this study explored the effect of DEHP on systemic inflammation in myeloid cells (IL-6, IL-17A, IL-23), Th17 (p-STAT3, IL-17A, IL-23R, TNF-α), Th1 (IFN-γ), Treg (Foxp3, IL-10), and Nrf2/iNOS signaling in imiquimod (IMQ)-induced mouse model of psoriasis-like inflammation. Our study showed increased Th17 signaling in imiquimod model which was further aggravated by DEHP exposure. Further, Nrf2 and iNOS signaling were also elevated in IMQ model where DEHP exposure further increased iNOS expression but did not modify the Nrf2 expression. Most importantly, IL-17A levels were also elevated in myeloid cells along with IL-6 which were further elevated by DEHP exposure. Overall, this study shows that IL-17A signaling is upregulated, whereas there is deficiency of Nrf2/HO-1 signaling by DEHP exposure in mice with psoriasiform inflammation. These observations suggest that DEHP aggravates IL-17A-mediated signaling both in CD4 + T cells as well as myeloid cells which is linked to exacerbation of IMQ-induced psoriatic inflammation in mice. Strategies that counteract the effect of DEHP exposure in the context of psoriatic inflammation through downregulation of IL-17A may be fruitful.

Associations between exposure to phthalates and rheumatoid arthritis risk among adults in NHANES, 2007-2016

BACKGROUND

The etiology of rheumatoid arthritis (RA) is multifactorial, encompassing genetics and environment. Despite the widespread use of phthalates as chemical additives, their potential impact on RA has received limited investigation. This study aimed to evaluate the potential associations between exposure to phthalates and rheumatoid arthritis risk among adults.

METHODS

Participants ≥20 years were analyzed from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. Multivariable logistic regression was used to examine the association between exposure to phthalates and RA in two models. Additionally, subgroup analyses stratified by gender and age were also performed. The nonlinear relationship between RA and phthalates was characterized by smooth curve fittings and generalized additive models.

RESULTS

Ultimately, 9322 participants (RA: 601, without RA: 8632) were analyzed. The prevalence of RA increased with higher quantiles of MECPP (Q4, OR: 1.43, 95% CI: 1.07-1.91), MBP (Q2, OR: 1.30, 95% CI: 1.01-1.67), MEHHP (Q3, OR: 1.39, 95% CI: 1.07-1.81; Q4, OR: 1.35, 95% CI: 1.02-1.87) and MEOP (Q2, OR:1.35, 95% CI: 1.03-1.76) compared to the lowest quartile. A nonlinear relationship positive association was also observed between MECPP (P for non-linearity = 0.0074)) and MEHHP (P for non-linearity = 0.0046)) levels and RA. Subgroup analysis showed the association between phthalate levels and RA was mainly present in males or participants aged more than 60 years.

CONCLUSIONS

Our results demonstrated that exposure to phthalates is associated with an increased prevalence of RA among adults. Notably, such associations appear to be more pronounced in males and older people.

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Associations between urinary phthalate metabolite concentrations and rheumatoid arthritis in the U.S. adult population

Phthalates are ubiquitous environmental contaminants. Nevertheless, limited data is available about the impacts of phthalates on rheumatoid arthritis (RA). The purpose of this study was to use National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2018 to assess the individual and combined effects of exposure to phthalate mixtures on RA in adults. A total of 8240 participants with complete data participated in the study, of whom 645 had RA. The levels of ten phthalate metabolites were detected in urine samples. In the single-pollutant models, independent associations were identified between urinary mono-(carboxyoctyl) phthalate (MCOP), mono-(3-carboxylpropyl) phthalate (MCPP), mono-isobutyl phthalate (MiBP) and mono-benzyl phthalate (MBzP) with the incidence of RA. The results of multi-pollutant models, including weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR) approaches consistently revealed that co-exposure to phthalates was positively associated with RA incidence. Such association was more pronounced in adults over 60 years of age, where MCOP was identified as the dominant positive driver. Overall, our findings add novel evidence that co-exposures to phthalates might be positively associated with RA incidence. Given the limitations of the NHANES study, well-designed longitudinal studies are required to verify or disprove these results.

MiR-326 regulates cell proliferation and apoptosis in fibroblast-like synoviocytes in rheumatoid arthritis

The dysregulation of microRNAs plays a critical role in the development of rheumatoid arthritis (RA). This study aims to explore the functional significance of miR-326 in RA. The RT-qPCR results showed that miR-326 was downregulated in synovial tissues of RA patients and RA fibroblast-like synoviocytes (RA-FLS). We found that miR-326 could target and reduce the expression of inhibitor of DNA binding 1 (Id1). MTT assay and flow cytometry were conducted to explore the biological function of miR-326. Our data revealed that the upregulation of miR-326 suppressed cell proliferation and induced apoptosis in RA-FLS. In collagen-induced arthritis mice, intraarticular injection of lentivirus carrying miR-326 overexpression vectors could reduce the arthritis score and attenuate synovial inflammation and cartilage destruction. We also found that long non-coding RNA-Ewing sarcoma-associated transcript 1 (lncRNA-EWSAT1) was significantly increased in RA synovial tissues and RA-FLS. The RNA immunoprecipitation and RNA pull-down assay indicated that lncRNA-EWSAT1 directly bound and negatively regulated the expression of miR-326. Knockdown of lncRNA-EWSAT1 could upregulate miR-326 expression and attenuate its proliferation inhibition and apoptosis induction effect in RA-FLS.  In conclusion, the lncRNA-EWSAT1/miR-326 axis might provide a novel therapeutic target in the treatment of RA.

Registered human trials addressing environmental and occupational toxicant exposures: Scoping review of immunological markers and protective strategies

Exposure to pollution is a worldwide societal challenge participating in the etiology and progression of different diseases. However, the scarce information hinders our understanding of the actual level of human exposure and its specific effects. Inadequate and excessive immune responses underlie diverse chronic diseases. Yet, it is unclear which and how toxicant exposures affect the immune system functions. There is a multiplicity of immunological outcomes and biomarkers being studied in human trials related to exposure to different toxicants but still without clear evidence of their value as biomarkers of exposure or effect. The main aim of this study was to collect scientific evidence and identify relevant immunological biomarkers used at the clinical level for toxicant exposures. We used the platform clinical trials.gov as a database tool. First, we performed a search combining research items related to toxicants and immunological parameters. The resulting117 clinical trials were examined for immune-related outcomes and specific biomarkers evaluated in subjects exposed to occupational and environmental toxicants. After categorization, relevant immunological outcomes and biomarkers were identified related to systemic and airway inflammation, modulation of immune cells, allergy and autoimmunity. In general, the immune markers related to inflammation are more frequently investigated for exposure to pollutants, namely IL-6, C-reactive protein (CRP) and nitric oxide (NO). Nevertheless, the data also indicated that prospective biomarkers of effect are gaining ground and a guiding representation of the established and novel biomarkers is suggested for upcoming trials. Finally, potential protective strategies to mitigate the adverse effects of specific toxicants are underlined for future studies.

High-Temperature Soup Foods in Plastic Packaging Are Associated with Phthalate Body Burden and Expression of Inflammatory mRNAs: A Dietary Intervention Study

Plastic packaging material is widely used to package high-temperature soup food in China, but this combination might lead to increased exposure to phthalates. The health effects and potential biological mechanisms have not been well studied. This study aimed to examine urinary phthalate metabolites and the expression of inflammatory cytokines in the blood before, during, and after a "plastic-packaged high-temperature soup food" dietary intervention in healthy adults. The results showed that compared with those in the preintervention period, urinary creatinine-adjusted levels of monomethyl phthalate (MMP), mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MIBP), and total phthalate metabolites in the intervention period were significantly higher, with increases of 71.6, 41.8, 38.8, and 29.8% for MMP, MBP, MIBP, and the total phthalate metabolites, respectively. After intervention, the mean levels of IL-1β, IL-4, and TNF-α mRNA increased by 19.0, 21.5, and 25.0%, respectively, while IL-6 and IFN-γ mRNA decreased by 24.2 and 32.9%, respectively, when compared with the preintervention period. We also observed that several phthalates were associated with the mRNA or protein expression of IL-8, TNF-α, and IL-10. Therefore, consumption of plastic-packaged high-temperature soup food was linked to increased phthalate exposure and might result in significant changes in mRNA expression of several inflammatory cytokines.

Endocrine Disorders in Autoimmune Rheumatological Diseases: A Focus on Thyroid Autoimmune Diseases and on the Effects of Chronic Glucocorticoid Treatment

Autoimmune rheumatological diseases’ incidence and prevalence have risen over the last decades and they are becoming increasingly important worldwide. Thyroid autoimmune diseases share with them an imbalance in the immune system that lead to a pro-inflammatory environment. Usually this is the result of a multi-factorial process. In fact, it includes not only a possible genetic predisposition, but also environmental causes like microbiota dysbiosis, diet rich in processed foods, exposure to toxicants and infections. However, many aspects are currently under study. This paper aims to examine the factors that participate in the developing of rheumatological and thyroid autoimmune diseases. Moreover, as glucocorticoids still represent a leading treatment for systemic autoimmune rheumatological diseases, our secondary aim is to summarize the main effects of glucocorticoids treatment focusing on iatrogenic Cushing’s syndrome and glucocorticoids’ withdrawal syndrome.

Interplay Between Endocrine Disruptors and Immunity: Implications for Diseases of Autoreactive Etiology

The sex-bias of disease susceptibility has remained a puzzling aspect of several autoimmune conditions, including post-infection viral autoimmunity. In the last half of the twentieth century, the incidence rate of female-biased autoimmunity has steadily increased independent of medical advances. This has suggested a role for environmental factors, such as endocrine disrupting chemicals, which have been described to interfere with endocrine signaling. Endocrine involvement in the proper function of innate and adaptive immunity has also been defined, however, these two areas have rarely been reviewed in correlation. In addition, studies addressing the effects of endocrine disruptors have reported findings resulting from a broad range of exposure doses, schedules and models. This experimental heterogeneity adds confusion and may mislead the translation of findings to human health. Our work will normalize results across experiments and provide a necessary summary relevant to human exposure. Through a novel approach, we describe how different categories of ubiquitously used environmental endocrine disruptors interfere with immune relevant endocrine signaling and contribute to autoimmunity. We hope this review will guide identification of mechanisms and concentration-dependent EDC effects important not only for the sex-bias of autoimmunity, but also for other conditions of immune dysfunction, including post-infection autoreactivity such as may arise following severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, Herpes Simplex virus.

Environmental Factor-Mediated Transgenerational Inheritance of Igf2r Hypomethylation and Pulmonary Allergic Response via Targeting Dendritic Cells

The developmental origin of allergic diseases has been suggested, but the molecular basis remains enigmatic. Exposure to environmental factors, such as di-(2-ethylhexyl) phthalate (DEHP; a common plasticizer), is suggested to be associated with increased childhood allergic asthma, but the causal relationship and its underlying mechanism remain unknown. This study explored the transgenerational mechanism of DEHP on allergic asthma and dendritic cell (DC) homeostasis through epigenetic modification. In a murine model, ancestral exposure of C57BL/6 mice to low-dose DEHP led to trans-generational promoter hypomethylation of the insulin-like growth factor 2 receptor (Igf2r), concomitant with enhanced Igf2r expression and increased apoptosis prominently in CD8α+ DCs upon ligand stimulation, with consequent reduction in their IL-12 secretion and subsequent T cell-derived IFN-γ, thereby promoting a default Th2-associated pulmonary allergic response. Increased apoptosis was also noted in circulating IGF2Rhigh human DCs. Further, in human placenta, the methylation level at the orthologous IGF2R promoter region was shown to be inversely correlated with the level of maternal DEHP intake. These results support the importance of ancestral phthalate exposure in conferring the trans-generational risk of allergic phenotypes, featuring hypo-methylation of the IGF2R gene and dysregulated DC homeostasis.

How microplastic components influence the immune system and impact on children health: Focus on cancer

BACKGROUND

As a result of human socioeconomic activity, industrial wastes have increased distressingly. Plastic pollution is globally distributed across the world due to its properties of buoyancy and durability. A big health hazard is the sorption of toxicants to plastic while traveling through the environment. Two broad classes of plastic-related chemicals are of critical concern for human health-bisphenols and phthalates. Bisphenol A (BPA) is an endocrine-disruptor compound (EDC) with estrogenic activity. It is used in the production of materials that are used daily. The endocrine modulating activity of BPA and its effects on reproductive health has been widely studied. BPA also has effects on the immune system; however, they are poorly investigated and the available data are inconclusive. Phthalates are also EDCs used as plasticizers in a wide array of daily-use products. Since these compounds are not covalently bound to the plastic matrix, they easily leach out from it, leading to high human exposure. These compounds exert several cell effects through modulating different endocrine pathways, such as estrogen, androgen, peroxisome proliferator-activated receptor gamma, and arylhydrocarbon receptor pathways. The exposure to both classes of plastic derivatives during critical periods has detrimental effects on human health.

METHODS

In this review, we have compiled the most important of their perinatal effects on the function of the immune system and their relationship to the development of different types of cancer.

RESULTS/CONCLUSION

The administration of bisphenols and phthalates during critical stages of development affects important immune system components, and the immune function; which might be related to the development of different diseases including cancer.