Polycyclic aromatic hydrocarbons in bone homeostasis

Exposure to polycyclic aromatic hydrocarbons and bone mineral density in children and adolescents: results from the 2011-2016 National Health and Nutrition Examination Survey

Introduction

Identifying factors that hinder bone development in children and adolescents is crucial for preventing osteoporosis. Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to reduced bone mineral density (BMD), although available data, especially in children and adolescents, are limited. We examined the associations between urinary hydroxylated-PAHs (OH-PAHs) and lumbar spine BMD, pelvic BMD, and total BMD among 8-19 years participants (N = 1,332) of the 2011-2016 National Health and Nutrition Examination Survey.

Methods

Weighted linear regressions were employed to assess the associations between urinary OH-PAHs and BMD. Additionally, Bayesian kernel machine regression (BKMR) and quantile g-computation (Qgcomp) models were utilized to investigate the effect of co-exposure of PAHs on BMD.

Results

Several urinary OH-PAHs exhibited negative associations with lumbar spine BMD, pelvic BMD, and total BMD in children and adolescents. For instance, an increase of one unit in the natural log-transformed levels of urinary 1-hydroxypyrene and 2&3-Hydroxyphenanthrene was linked with a decrease of -0.014 g/cm2 (95% CI: -0.026, -0.002) and -0.018 g/cm2 (95% CI: -0.032, -0.004) in lumbar spine BMD, a decrease of -0.021 g/cm2 (95% CI: -0.039, -0.003) and -0.017 g/cm2 (95% CI: -0.033, -0.001) in pelvic BMD, and a decrease of -0.013 g/cm2 (95% CI: -0.023, -0.002) and -0.016 g/cm2 (95% CI: -0.026, -0.006) in total BMD. The body mass index modified the associations between urinary OH-PAHs and BMD, revealing negative effects on BMD primarily significant in overweight/obese individuals but not significant in underweight/normal individuals. Both the BKMR model and the Qgcomp model indicated a significant negative correlation between the overall effects of seven urinary OH-PAHs and lumbar spine BMD, pelvic BMD, and total BMD.

Conclusion

Our findings revealed that exposure to PAHs might hinder bone development in children and adolescents, potentially impacting peak bone mass-an essential factor influencing lifelong skeletal health.

Human umbilical mesenchymal stem cell-derived exosomes alleviate bone destruction and regulate bone immunity via the aryl hydrocarbon receptor to treat rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) can lead to joint deformity, loss of function, and even disability. Bone erosion is a common cause of disability in individuals with RA; bone resorption by osteoclasts (OCs) and bone immunity by regulatory T cells (Tregs) play key roles in this process. Human umbilical mesenchymal stem cells (HUMSCs) can be used to treat RA; however, the regulation of Tregs and OCs by HUMSCs and their therapeutic effects on RA have not been fully elucidated. This study aimed to reveal the effects of exosomes derived from HUMSCs carrying miRNA-150-5p on Tregs and OCs in individuals with RA and to provide innovative evidence for the ability of HUMSCs to alleviate RA.

METHODS

First, we used collagen-induced arthritis (CIA) model mice to verify the efficacy of miR-150-5pmimic-Exos and explored their effects on bone erosion in mouse joints and on Tregs in the lymph nodes. Subsequently, miR-150-5pmimic-Exos and the aryl hydrocarbon receptor (AhR) inhibitor CH223191 were used in in vitro OCs, Tregs, and OC-Treg coculture systems to determine whether miR-150-5pmimic-Exos regulate bone immune microenvironment homeostasis via AhR.

RESULTS

Treatment with miR-150-5pmimic-Exos effectively alleviated bone damage to the ankle and knee joints in CIA model mice, inhibited OC differentiation, activated the immunosuppressive function of Tregs, and regulated bone immunity by increasing the expression of AhR/CYP1A1 signalling pathway genes such as Ahr, Arnt, Ahrr, Cyp1a1/1a2 and Cyp1b1 in OCs and Tregs. By coculturing Tregs and OCs, the ability of the miR-150-5pmimic-Exos to inhibit OC differentiation was further strengthened.

CONCLUSIONS

This study confirmed that miR-150-5pmimic-Exos can reduce bone destruction in mice with CIA. We first showed that miR-150-5pmimic-Exos acted on a Treg-OC coculture system to alleviate bone erosion and regulate bone immunity. This study is expected to provide new ideas for the treatment of RA.

Health Risks of Asphalt Emission: State-of-the-Art Advances and Research Gaps

Asphalt-related emissions pose significant health risks due to the release of volatile organic compounds (VOCs) that affect both workers in construction and the general public. Even at low concentrations, certain VOCs are highly toxic, with some of their metabolic byproducts, such as epoxides, known to cause DNA damage, oxidative stress, and other genetic alterations. The health implications are particularly concerning given that these emissions are persistent, and exposure can occur over prolonged periods, especially in urban areas where asphalt is prevalent. However, despite growing awareness, there remain significant gaps in our understanding of the long-term effects of chronic, low-level exposure to asphalt VOCs. Research to date has largely focused on acute exposure effects, particularly in occupational settings, leaving much unknown about the broader impact on the general public, especially vulnerable groups like children and the elderly. Moreover, the complex interactions between asphalt-derived VOCs and other environmental pollutants are not well understood, further complicating our understanding of their cumulative health impact. This paper provides a comprehensive overview of the current research landscape, starting with a discussion of the health risks associated with asphalt VOCs, supported by key findings from recent studies. It then explores the latest technological advancements in VOC detection, characterization, and monitoring, and identifies critical gaps in existing research.

Polycyclic aromatic hydrocarbons exposure associated with increased risk of psoriasis

Psoriasis is considered to be multifactorial, with both genetic and environmental factors contributing to its development. Polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment, originating from sources such as cigarette smoke, exhaust emissions, grilled foods, smoked foods and urban air. Researchs have established a link between PAHs exposure and autoimmune disorders; however, specific effects of PAHs on psoriasis remain underexplored. This study aims to evaluate the correlation between PAHs exposure and susceptibility to psoriasis. We analysed eight monohydroxy PAHs (1-Hydroxynaphthalene (1-NAP), 2-Hydroxynaphthalene (2-NAP), 3-Hydroxyfluorene (3-FLU), 2-Hydroxyfluorene (2-FLU), 1-Hydroxyphenanthrene (1-PHE), 1-Hydroxypyrene (1-PYR), 2-Hydroxyphenanthrene (2-PHE) and 3-Hydroxyphenanthrene (3-PHE)) in 5996 participants from the National Health and Nutrition Examination Survey (NHANES). We employed multivariate logistic regression, trend analysis, weighted quantile sum (WQS) regression and restricted cubic spline (RCS) analysis to investigate the relationship between PAHs exposure and psoriasis risk. Multivariate logistic regression and trend analysis revealed that monohydroxy PAHs, including 2-NAP, 3-FLU, 2-FLU and the mixture of 2-PHE and 3-PHE, are associated with an increased risk of psoriasis. Additionally, WQS regression showed a significant positive correlation between combined exposure to monohydroxy PAHs and psoriasis risk, with the mixture of 2-PHE and 3-PHE (47.3%) being the most influential factor. RCS regression further corroborated these findings. Specifically, 2-FLU can increase the expression of psoriasis-related inflammatory factors in HaCaT cells. In conclusion, PAHs exposure increases the risk of developing psoriasis. Efforts to reduce PAHs levels in the environment and minimise exposure are crucial for public health strategies aimed at preventing psoriasis.

Association between polycyclic aromatic hydrocarbons and periodontitis: Results from a large population-based study

AIM

To explore the association between polycyclic aromatic hydrocarbons (PAHs) (measured using urinary metabolites) and periodontitis using data from the National Health and Nutrition Examination Survey 2009-2014.

MATERIALS AND METHODS

Weighted binary logistic regression, Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression were used to evaluate independent and joint associations between the six urinary monohydroxylated metabolites of PAHs (OH-PAHs) and periodontitis.

RESULTS

In all, 3413 participants were included in this study. All six urinary OH-PAHs were present at higher levels in the periodontitis group compared with the non-periodontitis group (p < .001). Fully adjusted multivariable logistic regressions showed positive associations between the six urinary OH-PAHs and periodontitis (p < .05). Higher concentrations of OH-PAHs were also positively associated with attachment loss, periodontal pocket depth (PPD) and the number of tooth loss. BKMR and WQS regression yielded similar positive associations between OH-PAH mixtures and periodontitis.

CONCLUSIONS

PAHs and their mixture are positively associated with periodontitis, which may provide novel insights into periodontitis prevention from an environmental exposure perspective.

Role of active and environmental tobacco smoke on susceptibility to osteoporosis in women undergoing dual-X-ray absorptiometry

PURPOSE

Current smoking is a risk factor for osteoporosis (Op), but few data are available regarding the passive smoke impact on Op susceptibility. This cross-sectional study aimed to evaluate the association between the smoking habits and Op in community-dwelling women undergoing dual-energy X-ray absorptiometry (DXA).

METHODS

On 01/06/2018, general practitioners from "COMEGEN" Medical Cooperative, Naples, Italy, selected the medical records from the last 10 years of women who had a measurement of bone mineral density performed and simultaneously completed a questionnaire about their smoking behaviour and their cohabiters'. The binary logistic regression analysis was used to estimate the role of passive smoke on the risk of Op, adjusting for age and body mass index (BMI).

RESULTS

Among 10,616 subjects, 3942 were currently smokers [CS; mean age 69.4 ± 10.4 years; BMI 27.0 ± 4.9 kg/m2], 873 were passive smokers (PS; mean age 67.8 ± 11.6 years; BMI 27.0 ± 4.9 kg/m2) and 5781 were never smokers (NS; mean age 67.8 ± 11.6 years; body mass index (BMI) 27.0 ± 4.9 kg/m2). Of all, 8562 women (mean age 70.3 ± 10.2 yrs; BMI 27.0 ± 4.9 kg/m2) received the Op diagnosis. PS showed an increased Op risk compared to NS [odds ratio (OR) 1.38 (1.14-1.67)] and comparable to CS [OR 1.02 (0.84-1.24)].

CONCLUSION

The study results demonstrate an association between passive smoke and Op in community-dwelling women already presenting with susceptibility to Op according to Italian essential assistance levels, suggesting that passive and active smoke are equivalent Op risk factors in women.

Environmental pollutants and phosphoinositide signaling in autoimmunity

Environmental pollution stands as one of the most critical challenges affecting human health, with an estimated mortality rate linked to pollution-induced non-communicable diseases projected to range from 20% to 25%. These pollutants not only disrupt immune responses but can also trigger immunotoxicity. Phosphoinositide signaling, a pivotal regulator of immune responses, plays a central role in the development of autoimmune diseases and exhibits high sensitivity to environmental stressors. Among these stressors, environmental pollutants have become increasingly prevalent in our society, contributing to the initiation and exacerbation of autoimmune conditions. In this review, we summarize the intricate interplay between phosphoinositide signaling and autoimmune diseases within the context of environmental pollutants and contaminants. We provide an up-to-date overview of stress-induced phosphoinositide signaling, discuss 14 selected examples categorized into three groups of environmental pollutants and their connections to immune diseases, and shed light on the associated phosphoinositide signaling pathways. Through these discussions, this review advances our understanding of how phosphoinositide signaling influences the coordinated immune response to environmental stressors at a biological level. Furthermore, it offers valuable insights into potential research directions and therapeutic targets aimed at mitigating the impact of environmental pollutants on the pathogenesis of autoimmune diseases. SYNOPSIS: Phosphoinositide signaling at the intersection of environmental pollutants and autoimmunity provides novel insights for managing autoimmune diseases aggravated by pollutants.

Prenatal exposure to crude oil vapor reduces differentiation potential of rat fetal mesenchymal stem cells by regulating ERK1/2 and PI3K signaling pathways: Protective effect of quercetin

It has been indicated that crude oil vapor (COV) induces tissue damage by several molecular mechanisms. Quercetin (QT) as an important component of food with antioxidant properties has a protective role against cell toxicity caused by many pollutants. However, data related to the adverse effects of crude oil vapor (COV) on stem cell fate and differentiation and the role of quercetin (QT) in protecting stem cells against the toxicity caused by these pollutants is very limited. This study aimed to explore the protective effect of QT against the adverse effects of COV on fetal mesenchymal stem cells (fMSCs) differentiation. Twenty-four pregnant Wistar rats were categorized into 4 groups including the control, COV, COV+QT, and QT. Rats were exposed to COV from gestational day (GD) 0-15 and received QT by gavage. The fMSCs were isolated from fetuses, and cell proliferation, differentiation potential, expression of osteogenesis and adipogenesis-related genes, and phosphorylation of PI3K and ERK1/2 signaling proteins were evaluated. The results showed that COV reduced the proliferation and differentiation of fMSCs through the activation of PI3K and ERK1/2 signaling pathways. Also, COV significantly decreased the expression of osteonectin, ALP, BMP-6, Runx-2, PPARγ, and CREBBP genes in differentiated cells. QT treatment increased the proliferation and differentiation of fMSCs in COV-exposed rats. In conclusion, our findings suggest that prenatal exposure to COV impaired fMSCs differentiation and QT reduced the adverse effects of COV by regulating ERK1/2 and PI3K signaling pathways.

Environmental polycyclic aromatic hydrocarbon exposure is associated with low back pain

Several studies have assessed the influence of several often-ignored environmental factors on low back pain (LBP), but the effects of environmental polycyclic aromatic hydrocarbon (PAH) exposure on LBP are unclear. During the 2001-2004 cycle of the National Health and Nutrition Examination Survey (NHANES), our study was given to a representative sample of US participants older than 20 (N = 2743). Environmental PAH exposure was calculated using urinary PAH metabolite concentrations. Weighted logistic regression was performed to assess the connection between PAH levels and LBP, with mediation analysis utilised to explore the underlying mechanism. Levels of 1-hydroxynaphthalene (1-OHNa), 2-hydroxynaphthalene (2-OHNa) and total PAHs had a statistically significant positive association with LBP. The odds ratios per 1-unit increase for log-transformed levels of urinary 1-OHNa, 2-OHNa, and total PAHs with LBP were 1.01 (95% CI 1.02-1.19), 1.19 (95% CI 1.04-1.36) and 1.16 (95% CI 1.03-1.32), respectively. The results revealed a strong dose-response association between 1-OHNa, 2-OHNa, total PAHs, and LBP risk. Subgroup analysis indicated that 2&3-OHPh may increase the risk of LBP in the lower family income subgroup. Gamma-glutamyl transaminase (GGT), known as a biomarker of oxidative stress, was strongly related to PAHs. The relationship between total PAHs and LBP was mediated in part by GGT. Our study demonstrates associations between environmental PAH exposure and LBP that need more research to determine the precise effects of various PAH compounds on LBP.

Associations of urinary polycyclic aromatic hydrocarbons with bone mineral density at specific body sites in U.S. adults, NHANES 2001-2004

OBJECTIVE

We aimed to analyze the association between certain types of urinary polycyclic aromatic hydrocarbons (PAHs) and bone mineral density (BMD) at specific sites of the body.

METHODS

A total of 2,978 eligible participants from the National Health and Nutrition Examination Survey (NHANES 2001-2004) were included in this study. Data of eight urinary PAHs and BMDs of three skeleton sites and the total body were analyzed. Univariate and multivariate linear regression analyses were performed to explore the association between urinary PAHs and BMDs. Subgroup analyses stratified by gender and body mass index (BMI) were also performed.

RESULTS

After adjustment for all confounders, elevated 3-fluorene [β=0.046; 95% confidence intervals (CI), 0.007-0.084] and 2-fluorene (β=0.054; 95%CI, 0.007-0.100) were associated with greater left arm BMD, while no statistical differences were observed in the relationship between other PAHs and BMDs (all P>0.05). Higher 3-fluorene and 2-fluorene levels were still associated with increased left arm BMD in males (P<0.05), while higher 2-phenanthrene was related to decreased left arm BMD [β=-0.062; 95%CI, -0.105-(-0.019)], right arm BMD [β=-0.059; 95%CI, -0.091-(-0.027)], and total BMD [β=-0.065; 95%CI, -0.119-(-0.012] in females. Similar results were also found in different BMI populations (all P<0.05).

CONCLUSION

Certain urinary PAHs are associated with BMDs at specific body sites. Future studies are needed to illustrate the mechanisms behind the association to establish a causal relationship and explain the variations in the associations.