Lead exposure and its interactions with oxidative stress polymorphisms on lung function impairment: Results from a longitudinal population-based study

Sinapic acid protects against lead acetate-induced lung toxicity by reducing oxidative stress, apoptosis, inflammation, and endoplasmic reticulum stress damage

Lead acetate (PbAc) is a compound that produces toxicity in many tissues after exposure. Sinapic acid (SNP) possesses many biological and pharmacological properties. This study aimed to investigate the efficacy of SNP on the toxicity of PbAc in lung tissue. PbAc was administered orally at 30 mg/kg and SNP at 5 or 10 mg/kg for 7 days. Biochemical, genetic, and histological methods were used to investigate inflammatory, apoptotic, endoplasmic reticulum stress, and oxidative stress damage levels in lung tissue. SNP administration induced PbAc-reduced antioxidant (GSH, SOD, CAT, and GPx) and expression of HO-1 in lung tissue. It also reduced MDA, induced by PbAc, and thus alleviated oxidative stress. SNP decreased the inflammatory markers NF-κB, TNF-α and IL-1β levels induced by PbAc in lung tissue and exhibited anti-inflammatory effect. PbAc increased apoptotic Bax, Apaf-1, and Caspase-3 mRNA transcription levels and decreased anti-apoptotic Bcl-2 in lung tissues. SNP decreased apoptotic damage by reversing this situation. On the other hand, SNP regulated these markers and brought them closer to the levels of the control group. PbAc caused prolonged ER stress by increasing the levels of ATF6, PERK, IRE1α, GRP78 and this activity was stopped and tended to retreat with SNP. After evaluating all the data, While PbAc caused toxic damage in lung tissue, SNP showed a protective effect by reducing this damage.

Landscape fire smoke airway exposure impairs respiratory and cardiac function and worsens experimental asthma

BACKGROUND

Millions of people are exposed to landscape fire smoke (LFS) globally, and inhalation of LFS particulate matter (PM) is associated with poor respiratory and cardiovascular outcomes. However, how LFS affects respiratory and cardiovascular function is less well understood.

OBJECTIVE

We aimed to characterize the pathophysiologic effects of representative LFS airway exposure on respiratory and cardiac function and on asthma outcomes.

METHODS

LFS was generated using a customized combustion chamber. In 8-week-old female BALB/c mice, low (25 μg/m3, 24-hour equivalent) or moderate (100 μg/m3, 24-hour equivalent) concentrations of LFS PM (10 μm and below [PM10]) were administered daily for 3 (short-term) and 14 (long-term) days in the presence and absence of experimental asthma. Lung inflammation, gene expression, structural changes, and lung function were assessed. In 8-week-old male C57BL/6 mice, low concentrations of LFS PM10 were administered for 3 days. Cardiac function and gene expression were assessed.

RESULTS

Short- and long-term LFS PM10 airway exposure increased airway hyperresponsiveness and induced steroid insensitivity in experimental asthma, independent of significant changes in airway inflammation. Long-term LFS PM10 airway exposure also decreased gas diffusion. Short-term LFS PM10 airway exposure decreased cardiac function and expression of gene changes relating to oxidative stress and cardiovascular pathologies.

CONCLUSIONS

We characterized significant detrimental effects of physiologically relevant concentrations and durations of LFS PM10 airway exposure on lung and heart function. Our study provides a platform for assessment of mechanisms that underpin LFS PM10 airway exposure on respiratory and cardiovascular disease outcomes.

Arsenic exposure and pulmonary function decline: Potential mediating role of TRAIL in chronic obstructive pulmonary disease patients

BACKGROUND

Environmental arsenic (As) exposure is strongly related to the progression of chronic obstructive pulmonary disease (COPD). Pulmonary epithelial cells apoptosis is implicated in the pathophysiological mechanisms of COPD. However, the role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), one biomarker of apoptosis, remains unclear in As-mediated pulmonary function alternations in COPD patients.

METHODS

This study included 239 COPD patients. The serum level of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was measured by enzyme-linked immunosorbent assay (ELISA). The blood As level was determined through inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Blood As levels exhibited a negative and dose-dependent correlation with pulmonary function. Per unit elevation of blood arsenic concentrations was related to reductions of 0.339 L in FEV1, 0.311 L in FVC, 1.171% in FEV1/FVC%, and 7.999% in FEV1% in COPD subjects. Additionally, a positive dose-response correlation of blood As with serum TRAIL was found in COPD subjects. Additionally, the level of serum TRAIL was negatively linked to lung function. Elevated TRAIL significantly mediated As-induced decreases of 11.05%, 13.35%, and 31.78% in FVC, FEV1, and FEV1%, respectively among the COPD patients.

CONCLUSION

Blood As level is positively correlated with pulmonary function decline and serum TRAIL increase in individuals with COPD. Our findings suggest that elevated TRAIL levels may serve as a mediating mechanism through which As contributes to declining lung function in COPD patients.

Insights into the mechanism of transcription factors in Pb2+-induced apoptosis

The health risks associated with exposure to heavy metals, such as Pb2+, are increasingly concerning the public. Pb2+ can cause significant harm to the human body through oxidative stress, autophagy, inflammation, and DNA damage, disrupting cellular homeostasis and ultimately leading to cell death. Among these mechanisms, apoptosis is considered crucial. It has been confirmed that transcription factors play a central role as mediators during the apoptosis process. Interestingly, these transcription factors have different effects on apoptosis depending on the concentration and duration of Pb2+ exposure. In this article, we systematically summarize the significant roles of several transcription factors in Pb2+-induced apoptosis. This information provides insights into therapeutic strategies and prognostic biomarkers for diseases related to Pb2+ exposure.

Moderate selenium alleviates the pulmonary function impairment induced by cadmium and lead in adults: A population-based study

Selenium (Se) has been reported to have an antagonistic effect on heavy metals in animals. However, there is no epidemiological study investigating whether Se could protect against the pulmonary toxicity of Cadmium (Cd) and Lead (Pb). Data was collected from the 2011-2012 National Health and Nutrition Examination Survey (NHANES) cycle. Pulmonary function was assessed by Forced Vital Capacity (FVC), Forced Expiratory Volume 1st Second (FEV1) and FEV1/FVC. Blood concentrations of Cd, Pb, and Se were measured using inductively coupled plasma mass spectrometry. Linear regression, restricted cubic splines, and quantile-based g-computation (qgcomp) were performed to evaluate the individual and joint associations of Cd and Pb with pulmonary function and whether Se modified these associations. In the adjusted multi-metal model, every 1-unit increase in Cd, FEV1, FVC, and FEV1/FVC decreased by 76.437 mL (95 % CI: -110.928 to -41.947), 42.719 mL (95 % CI: -84.553 to -0.885), and 0.012 (95 % CI: -0.016 to -0.007), respectively. Meanwhile, FEV1 decreased by 9.37 mL (95 % CI: -18.61 to -0.13) for every 1 unit increase in Pb. Furthermore, we found an inverted U-shape association between Se and lung function, and participants in the second quartile Se group had the highest increases in FEV1 and FVC compared with participants in the lowest quartile. Qgcomp model also revealed that the toxic metal mixture (Cd and Pb) exhibited a significant inverse association with FEV1 and FEV1/FVC. Furthermore, we found that the inverse association of Pb and Cd, either alone or in combination, with pulmonary function first diminished with increasing Se levels but was re-enforced when blood Se concentrations were in the highest quartile. Our results indicated that moderate Se attenuated the harmful effects of Cd and Pb on lung function.

Association between urinary concentrations of toxic metals/metalloids and oxidative stress in Brazilians living in areas affected by the Fundão dam failure

The Fundão Dam failure has been the most significant environmental disaster in Brazil. The catastrophe released large amounts of mining waste into the environment, including toxic metals/metalloids, which are recognized to induce carcinogenic effects. The urinary levels of 8-hydroxy-2'-deoxyguanosine (8OHdG), a widely accepted oxidative stress and carcinogenesis biomarker, provide a potential tool for assessing the disaster's health implications. This study investigated the association between urinary levels of some toxic metals/metalloids and 8OHdG in Brazilian individuals living in areas affected by the Fundão dam failure. Urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) were determined using inductively coupled plasma mass spectrometry, while 8OHdG was analyzed by liquid chromatography-tandem mass spectrometry. Non-parametric bootstrap regression was used to estimate the associations between the urinary levels of toxic elements and 8OHdG. The results showed that except for Hg, urinary concentrations of all metals/metalloids analyzed here exceeded the reference ranges for the Brazilian population. The regression analysis revealed that As (0.337; CI 95%: 0.203; 0.474), Cd (0.268; CI 95%: 0.036; 0.520), and Ni (0.296; CI 950.108; 0.469) were positively associated with creatinine-adjusted urinary 8OHdG levels. Associations were not found for Hg (0.0122; CI 95%: -0.155; 0.183) and Pb (0.201; CI 95%: -0.040; 0.498). The current findings suggest that high exposure to toxic metals/metalloids might increase 8OHdG levels with potential adverse health effects. This study is the first one in which the relationship between toxic metals/metalloids and oxidative stress biomarkers is investigated in populations affected by environmental disasters. Further prospective studies are necessary to monitor exposure levels and explore additional health impacts.

Associations between environmental heavy metals exposure and preserved ratio impaired spirometry in the U.S. adults

We examined 9556 individuals aged 18 to 79 years who had information on spirometry testing and heavy metals and used multivariable logistic or linear regression to evaluate associations between serum levels of cadmium, lead, and mercury and PRISm and lung function in U.S. adults, which were conducted first in all participants, and then separately in never/former smokers and current smokers. The overall prevalence of PRISm was 7.02%. High levels of serum cadmium were significantly associated with PRISm in all individuals, no matter in never/former smokers (quartile 4 vs 1, the OR = 2.517, 95% CI = 1.376-4.604, p-trend = 0.0077) and current smokers (quartile 4 vs 1, the OR = 2.201, 95% CI = 1.265-3.830, p-trend = 0.0020). Serum lead and mercury were not significantly correlated with PRISm, regardless of smoking status. Serum cadmium was strongly correlated with lower FEV1/FVC, regardless of smoking status. Besides, serum cadmium was also significantly related to lower FVC % predicted in never/former smokers and lower FEV1% predicted in current smokers. Serum lead was strongly correlated with lower FVC % predicted and FEV1/FVC in all individuals and never/former smokers. And serum mercury was significantly associated with decrements in FVC % predicted in all individuals and current smokers. These findings demonstrate that serum cadmium is associated with a higher risk of PRISm and lower lung function, with the most significant effect on FEV1/FVC in particular. Our results also indicate that exposure to lead and mercury negatively affects lung function in never/former smokers and current smokers, respectively.

Association of low-level lead exposure with all-cause and cardiovascular disease mortality in US adults with hypertension: evidence from the National Health and Nutrition Examination Survey 2003-2010

BACKGROUND

To explore the association of low-level lead exposure with all-cause mortality and cardiovascular disease (CVD) mortality among hypertensive patients.

METHODS

This cohort study enrolled 6453 adults with hypertension from the National Health and Nutrition Examination Survey 2003-2010 and followed mortality information through December 31, 2019. The baseline population were divided into four groups based on quartiles of blood lead levels (Q1: < 1.2 μg/dL, Q2: 1.2-1.6 μg/dL, Q3: 1.7-2.4 μg/dL, Q4: 2.5-4.9 μg/dL). The correlation of blood lead levels to mortality was investigated by Kaplan-Meier survival curves, restricted cubic spline (RCS), proportional hazard regression model, and subgroup analysis.

RESULTS

During a median follow-up period of 136 (interquartile range 113, 164) months, a total of 1943 (30.1%) deaths were documented, among which 553 (28.5%) were due to CVD. Blood lead showed a linear dose-response relationship with all-cause and CVD mortality. After adequate adjusting for confounders, the risk of all-cause death rose by 23% for each unit increase in continuous variable blood lead (hazard ratio (HR): 1.23; 95% confidence interval (CI):1.16-1.30). When blood lead was a quartile group variable, participants in the Q 4 group had a 73% higher risk of death than those in the Q 1 group (HR:1.73; 95% CI: 1.43-2.10; P for trend < 0.001). The association for CVD mortality was analogous. The concordant results were achieved in the subgroup analysis.

CONCLUSION

Elevated blood lead levels were strongly associated with an increased all-cause and CVD mortality in adults with hypertension, even at the reference range of blood lead.

Blood lead (Pb) is associated with lung fibrotic changes in non-smokers living in the vicinity of petrochemical complex: a population-based study

Lead (Pb) is a toxic metal that has been extensively used in various industrial processes, and it persists in the environment, posing a continuous risk of exposure to humans. This study investigated blood lead levels in participants aged 20 years and older, who resided in Dalinpu for more than two years between 2016 to 2018, at Kaohsiung Municipal Siaogang Hospital. Graphite furnace atomic absorption spectrometry was used to analyze the blood samples for lead levels, and the LDCT (Low-Dose computed tomography) scans were interpreted by experienced radiologists. The blood lead levels were divided into quartiles, with Q1 representing levels of ≤1.10 μg/dL, Q2 representing levels of >1.11 and ≤1.60 μg/dL, Q3 representing levels of >1.61 and ≤2.30 μg/dL, and Q4 representing levels of >2.31 μg/dL. Individuals with lung fibrotic changes had significantly higher (mean ± SD) blood lead levels (1.88±1.27vs. 1.72±1.53 μg/dl, p< 0.001) than those with non-lung fibrotic changes. In multivariate analysis, we found that the highest quartile (Q4: >2.31 μg/dL) lead levels (OR: 1.36, 95% CI: 1.01-1.82; p= 0.043) and the higher quartile (Q3: >1.61 and ≤2.30 μg/dL) (OR: 1.33, 95% CI: 1.01-1.75; p= 0.041) was significantly associated with lung fibrotic changes compared with the lowest quartile (Q1: ≤1.10 μg/dL) (Cox and Snell R², 6.1 %; Nagelkerke R², 8.5 %). The dose-response trend was significant (P_trend= 0.030). Blood lead exposure was significantly associated lung fibrotic change. To prevent lung toxicity, it is recommended to maintain blood lead levels lower than the current reference value.

Impact of DNA repair polymorphisms on DNA instability biomarkers induced by lead (Pb) in workers exposed to the metal

Although the mechanisms of Pb-induced genotoxicity are well established, a wide individual's variation response is seen in biomarkers related to Pb toxicity, despite similar levels of metal exposure. This may be related to intrinsic variations, such as genetic polymorphisms; moreover, very little is known about the impact of genetic variations related to DNA repair system on DNA instability induced by Pb. In this context, the present study aimed to assess the impact of SNPs in enzymes related to DNA repair system on biomarkers related to acute toxicity and DNA damage induced by Pb exposure, in individuals occupationally exposed to the metal. A cross-sectional study was run with 154 adults (males, >18 years) from an automotive batteries' factory, in Brazil. Blood lead levels (BLL) were determined by ICP-MS; biomarkers related to acute toxicity and DNA instability were monitored by the buccal micronucleus cytome (BMNCyt) assay and genotyping of polymorphisms of MLH1 (rs1799977), OGG1 (rs1052133), PARP1 (rs1136410), XPA (rs1800975), XPC (rs2228000) and XRCC1 (rs25487) were performed by TaqMan assays. BLL ranged from 2.0 to 51 μg dL^-1 (mean 20 ± 12 μg dL^-1) and significant associations between BLL and BMNCyt biomarkers related to cellular proliferation and cytokinetic, cell death and DNA damage were observed. Furthermore, SNPs from the OGG1, XPA and XPC genes were able to modulate interactions in nuclear bud formation (NBUDs) and micronucleus (MNi) events. Taken together, our data provide further evidence that polymorphisms related to DNA repair pathways may modulate Pb-induced DNA damage; studies that investigate the association between injuries to genetic material and susceptibilities in the workplace can provide additional information on the etiology of diseases and the determination of environmentally responsive genes.

The effects of metals and mixture exposure on lung function and the potential mediating effects of oxidative stress

Exposure to metals is associated with lung function decline. However, limited data are available about effects of co-exposure of metals on lung function. Additionally, the mechanism of the association between metals and lung function remains unclear. We conducted a longitudinal panel study in 2017-2018 among 45 healthy college students. Urinary 15 metals, lung function, biomarkers of oxidative stress and inflammation of participants were measured. Linear mixed effect (LME) and Bayesian kernel machine regression (BKMR) models were applied to explore the associations of urinary metals and mixture with lung function. Furthermore, we analyzed the mediating effect of biomarkers in the association between urinary metals and lung function. LME models showed the negative associations of aluminum (Al), vanadium (V), manganese (Mn), cobalt (Co), nickel (Ni), cadmium (Cd) or antimony (Sb) with Forced vital capacity (FVC), and V, Co, Ni, and Sb with Forced expiratory volume in one second (FEV1). BKMR models indicated the overall effect of metals mixture was negatively associated with FEV1 and FVC; urinary Sb was identified as the major contributor to decreased FVC and FEV1. Urinary 8-hydroxydeoxyguanosine mediated the association of Al, Mn, or Sb with FVC and the relationship of V with FEV1. The results revealed the longitudinal dose-response relationships of urinary metals with pulmonary function among healthy adults. Oxidative stress may be the underlying mechanisms of metals exposure associated with decreased lung function. Due to the small sample size, the interpretation of the results of this study should be cautious, and more studies are needed to verify the findings of this study.

The association between multi-heavy metals exposure and lung function in a typical rural population of Northwest China

BACKGROUND

Heavy metal exposure is acknowledged to be associated with decrease of lung function, but the relationship between metals co-exposure and lung function in rural areas of Northwest China remains unclear, particularly in an area famous for heavy metal pollution and solid fuel use. Therefore, the purpose of this study is to explore the effects of heavy metal exposure on lung function and the potential impacts of living habit in a rural cohort of Northwest China.

METHODS

The study area included five villages of two regions in Northwestern China-Gansu province. All participants were recruited from the Dongdagou-Xinglong (DDG-XL) rural cohort in the study area. Urine levels of 10 common and representative heavy metals were detected by ICP-MS, including Cobalt (Co), Nickel (Ni), Molybdenum (Mo), Cadmium (Cd), Stibium (Sb), Copper (Cu), Zinc (Zn), Mercury (Hg), Lead (Pb), and Manganese (Mn). The lung function was detected by measuring percentages of predicted forced vital capacity (FVC%) and predicted forced expiratory volume in one second (FEV1%) as well as the ratio of FEV1/FVC. We also analyzed the association between heavy metals and pulmonary ventilation dysfunction (PVD). Restricted cubic spline, logistic regression, linear regression, and bayesian kernel machine regression (BKMR) model were used to analyze the relationship between heavy metal exposure and lung function.

RESULTS

Finally, a total of 382 participants were included in this study with an average age of 56.69 ± 7.32 years, and 82.46% of them used solid fuels for heating and cooking. Single metal exposure analysis showed that the higher concentration of Hg, Mn, Sb, and lower Mo may be risk factors for PVD. We also found that FEV1% and FVC% were negatively correlated with Sb, Hg, and Mn, but positively correlated with Mo. The effect of mixed heavy metals exposure could be observed through BKMR model, through which we found the lung function decreased with the increase of heavy metal concentration. Furthermore, the males, BMI ≥ 24 kg/m2 and who used solid fuels showed a higher risk of PVD when exposed to Co, Zn, and Hg.

CONCLUSIONS

Our results suggested that heavy metal exposure was associated with decrease of lung function regardless of single exposure or mixed exposure, particularly for Sb, Hg, Mn and those who use solid fuels.

Independent and combined associations of multiple-heavy-metal exposure with lung function: a population-based study in US children

Previous research has found relationships between some single metals and lung function parameters. However, the role of simultaneous multi-metal exposure is poorly understood. The crucial period throughout childhood, when people are most susceptible to environmental dangers, has also been largely ignored. The study aimed to evaluate the joint and individual associations of 12 selected urinary metals with pediatric lung function measures using multi-pollutant approaches. A total of 1227 children aged 6-17 years from the National Health and Nutrition Examination Survey database of the 2007-2012 cycles were used. The metal exposure indicators were 12 urine metals adjusted for urine creatinine, including arsenic (As), barium (Ba), cadmium (Cd), cesium (Cs), cobalt (Co), mercury (Hg), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (Tl), tungsten (Tu), and uranium (Ur). The outcomes of interest were lung function indices, including the 1st second of a forceful exhalation (FEV₁), forced vital capacity (FVC), forced expiratory flow between 25 and 7% of vital capacity (FEF_25-75%), and peak expiratory flow (PEF). Multivariate linear regression, quantile g-computation (QG-C), and Bayesian kernel machine regression models (BKMR) were adopted. A significantly negative overall effect of metal mixtures on FEV₁ (β = - 161.70, 95% CI - 218.12, - 105.27; p < 0.001), FVC (β = - 182.69, 95% CI - 246.33, - 119.06; p < 0.001), FEF_25-75% (β = - 178.86 (95% CI - 274.47, - 83.26; p < 0.001), and PEF (β = - 424.17, 95% CI - 556.55, - 291.80; p < 0.001) was observed. Pb had the largest negative contribution to the negative associations, with posterior inclusion probabilities (PIPs) of 1 for FEV₁, FVC, and FEF_25-75%, and 0.9966 for PEF. And Pb's relationship with lung function metrics showed to be nonlinear, with an approximate "L" shape. Potential interactions between Pb and Cd in lung function decline were observed. Ba was positively associated with lung function metrics. Metal mixtures were negatively associated with pediatric lung function. Pb might be a crucial element. Our findings highlight the need for prioritizing children's environmental health to protect them from later respiratory disorders and to guide future research into the toxic mechanisms of metal-mediated lung function injury in the pediatric population.

Association between cadmium exposure and pulmonary function reduction: Potential mediating role of telomere attrition in chronic obstructive pulmonary disease patients

BACKGROUND

Environmental cadmium (Cd) exposure is linked to pulmonary function injury in the general population. But, the association between blood Cd concentration and pulmonary function has not been investigated thoroughly in chronic obstructive pulmonary disease (COPD) patients, and the potential mechanisms are unclear.

METHODS

All eligible 789 COPD patients were enrolled from Anhui COPD cohort. Blood specimens and clinical information were collected. Pulmonary function test was conducted. The subunit of telomerase, telomerase reverse transcriptase (TERT), was determined through enzyme linked immunosorbent assay (ELISA). Blood Cd was measured via inductively coupled-mass spectrometer (ICP-MS).

RESULTS

Blood Cd was negatively and dose-dependently associated with pulmonary function. Each 1-unit increase of blood Cd was associated with 0.861 L decline in FVC, 0.648 L decline in FEV1, 5.938 % decline in FEV1/FVC %, and 22.098 % decline in FEV1 % among COPD patients, respectively. Age, current-smoking, self-cooking and higher smoking amount aggravated Cd-evoked pulmonary function decrease. Additionally, there was an inversely dose-response association between Cd concentration and TERT in COPD patients. Elevated TERT obviously mediated 29.53 %, 37.50 % and 19.48 % of Cd-evoked FVC, FEV1, and FEV1 % declines in COPD patients, respectively.

CONCLUSION

Blood Cd concentration is strongly associated with the decline of pulmonary function and telomerase activity among COPD patients. Telomere attrition partially mediates Cd-induced pulmonary function decline, suggesting an underlying mechanistic role of telomere attrition in pulmonary function decline from Cd exposure in COPD patients.

Assessment of Lead (Pb) Toxicity in Juvenile Nile Tilapia, Oreochromis niloticus-Growth, Behaviour, Erythrocytes Abnormalities, and Histological Alterations in Vital Organs

Lead (Pb) is one of the toxins responsible for the deterioration of ecological health in aquatic environments. The present study investigated the effects of Pb(NO₃)₂ toxicity on growth, blood cell morphology, and the histopathology of gills, liver, and intestine of juvenile Nile tilapia, Oreochromis niloticus. A 30-day long aquarium trial was conducted by assigning three treatment groups T₁ 5.20 mg L^-1, T₂ 10.40 mg L^-1, and T₃ 20.80 mg L^-1, and a control 0 mg L^-1 following the 96 h LC₅₀ of 51.96 mg L^-1 from acute toxicity test. Overall growth performance significantly declined in all the Pb(NO₃)₂ treated groups and the highest mortality was recorded in T₃. Behavioural abnormalities were intense in all the treatment groups compared to the control. Hepatosomatic index (HSI) values were reported as higher in treatment groups. Reduced nucleus diameter and nuclei size in erythrocytes were reported for T₂ and T₃ groups. Dose-dependent histological alterations were visible in the gills, liver, and intestine of all the Pb(NO₃)₂ treated groups. The width of the intestinal villi was highly extended in T₃ showing signs of severe histological alterations. In conclusion, Pb toxicity causes a negative effect on growth performance, erythrocyte morphology, and affected the vital organs histomorphology of juvenile O. niloticus.

Inhalation Bioaccessibility and Risk Assessment of Metals in PM2.5 Based on a Multiple-Path Particle Dosimetry Model in the Smelting District of Northeast China

PM2.5 can deposit and partially dissolve in the pulmonary region. In order to be consistent with the reality of the pulmonary region and avoid overestimating the inhalation human health risk, the bioaccessibility of PM2.5 heavy metals and the deposition fraction (DF) urgently needs to be considered. This paper simulates the bioaccessibility of PM2.5 heavy metals in acidic intracellular and neutral extracellular deposition environments by simulating lung fluid. The multipath particle dosimetry model was used to simulate DF of PM2.5. According to the exposure assessment method of the U.S. Environmental Protection Agency, the inhalation exposure dose threshold was calculated, and the human health risk with different inhalation exposure doses was compared. The bioaccessibility of heavy metals is 12.1−36.2%. The total DF of PM2.5 in adults was higher than that in children, and children were higher than adults in the pulmonary region, and gradually decreased with age. The inhalation exposure dose threshold is 0.04−14.2 mg·kg−1·day−1 for the non-carcinogenic exposure dose and 0.007−0.043 mg·kg−1·day−1 for the carcinogenic exposure dose. Cd and Pb in PM2.5 in the study area have a non-carcinogenic risk to human health (hazard index < 1), and Cd has no or a potential carcinogenic risk to human health. A revised inhalation health risk assessment may avoid overestimation.

Associations of multiple metals with lung function in welders by four statistical models

BACKGROUND

Exposure to heavy metals has been related to decreased lung function in workers. However, due to limitations in statistical methods for mixtures, previous studies mainly focused on single or several toxic metals, with few studies involving metal exposome and lung function.

OBJECTIVES

The study aimed to evaluate the effects of co-exposure to the metal mixtures on multiple parameters of pulmonary function tests and to identify the elements that play an essential role in elastic-net regression (ENET), multivariate linear regression, bayesian kernel machine regression (BKMR), and quantile g-computation (QG-C) models.

METHODS

We have recruited 186 welders from Anhui (China) in 2019. And their end-of-shift urine and lung function measure data were collected with informed consent. The urinary concentrations of 23 metals were measured by inductively coupled urinary mass spectrometry. The lung function measures including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and peak expiratory flow (PEF) were also detected as outcome indicators. Four statistical methods, ENET, multivariate linear regression, BKMR, and QG-C models were used to evaluate the associations of element mixtures on lung function comprehensively.

RESULTS

Lead and cadmium were negatively associated with FVC and FEV1, nickel and chromium were inversely associated with PEF, and strontium showed significant positive effects in linear regression models, which were consistent with the results in BKMR and QG-C models. Both BKMR and QG-C models showed a significantly negative overall effect of metal mixtures on lung function parameters (FVC, FEV1, and PEF). Meanwhile, BKMR showed the non-linear relationships of cadmium with FVC.

CONCLUSION

Multi-pollutant mixtures of metals were negatively associated with lung function. Lead, cadmium, nickel, and strontium might be crucial elements. Our findings highlight a need to prioritize workers' environmental health, and guide future research into the toxic mechanisms of metal-mediated lung function injury.

Prenatal lead exposure and childhood lung function: Influence of maternal cortisol and child sex

INTRODUCTION

Maternal hypothalamic-pituitary-adrenal (HPA) axis disruption in pregnancy may contribute to the programming of childhood respiratory disease and may modify the effect of chemical toxins, like lead (Pb), on lung development. Child sex may further modify these effects. We sought to prospectively examine associations between maternal HPA axis disruption, prenatal Pb and childhood lung function and explore potential effect modification by maternal cortisol and child sex on the association between prenatal Pb and lung function outcomes.

MATERIALS AND METHODS

Analyses included 222 mothers and children enrolled in a longitudinal birth cohort study in Mexico City. Maternal diurnal salivary cortisol was assessed in pregnancy; cortisol awakening response (CAR) and diurnal slope were calculated. Blood Pb was measured during the second trimester of pregnancy. Post-bronchodilator lung function was tested at ages 8-11 years. Associations were modeled using generalized linear models with interaction terms, adjusting for covariates.

RESULTS

A higher (flatter) diurnal slope was associated with lower FEV₁/FVC ratio (β: 0.433, 95%CI [-0.766, -0.101]). We did not find any main effect associations between prenatal Pb and lung function outcomes. We report an interaction between Pb and cortisol in relation to FEV₁/FVC and FEF_25-75% (p_interaction<0.05 for all). Higher prenatal Pb was associated with reduced FEV₁/FVC only in children whose mothers had a high CAR. Higher prenatal Pb was also associated with reduced FEV₁/FVC and FEF_25-75% in mothers with a flatter diurnal slope. A 3-way interaction between prenatal Pb, CAR and sex on FEV₁/FVC, indicated that boys born to women with high CAR and higher prenatal Pb levels had lower FEV₁/FVC ratios (p_interaction = 0.067).

CONCLUSIONS

Associations between prenatal Pb and childhood lung function were modified by disrupted maternal cortisol in pregnancy and child sex. These findings underscore the need to consider complex interactions to fully elucidate effects of prenatal Pb exposure on childhood lung function.

Flavonoid fractions of diosmin and hesperidin mitigate lead acetate-induced biochemical, oxidative stress, and histopathological alterations in Wistar rats

This study aims at investigating the protective effects of flavonoid fractions of diosmin and hesperidin in mitigating sub-chronic lead acetate-induced biochemical, oxidative stress, and histopathological alterations in adult male Wistar rats. Forty animals were randomly assigned into five groups, each consisting of eight animals. Group I animals was treated with deionised water only, group II, IV, and V were administered lead acetate 90 mg/Kg body weight (1/20th of the LD₅₀), groups III, and IV was administered Daflon (100 mg/Kg), while group V was administered Daflon (200 mg/Kg), 30 min prior treatment with lead acetate. All treatments lasted for 42 days. Blood lead levels, electrolyte parameters, zinc protoporphyrin (ZPP) levels, activities of antioxidant enzymes, and histopathology of vital organs, were evaluated following standard practice. Sub-chronic lead acetate exposure induced a decrease in levels of serum electrolytes, and activities of antioxidant enzymes, while blood lead levels, ZPP, and malondialdehyde levels were increased. Lead exposure also instigated marked variation in histopathology of vital organs. Conversely, co-treatment with graded doses of daflon improved the levels of blood lead, electrolytes, ZPP, activities of antioxidant enzymes, and histopathology of vital organs. Data obtained from the current study indicate that rats exposed to sub-chronic doses of lead acetate show increased blood lead levels, electrolyte imbalance, alongside impairment in ZPP levels, activities of antioxidant enzymes, and histopathology, while pretreatment using daflon mitigated the ensued perturbations. This, therefore, suggests that consumption of foods enriched with flavonoid fractions of diosmin and hesperidin may be beneficial for individuals inhabiting lead-polluted environments.

Trans-ethnic genome-wide association study of severe COVID-19

COVID-19 has caused numerous infections with diverse clinical symptoms. To identify human genetic variants contributing to the clinical development of COVID-19, we genotyped 1457 (598/859 with severe/mild symptoms) and sequenced 1141 (severe/mild: 474/667) patients of Chinese ancestry. We further incorporated 1401 genotyped and 948 sequenced ancestry-matched population controls, and tested genome-wide association on 1072 severe cases versus 3875 mild or population controls, followed by trans-ethnic meta-analysis with summary statistics of 3199 hospitalized cases and 897,488 population controls from the COVID-19 Host Genetics Initiative. We identified three significant signals outside the well-established 3p21.31 locus: an intronic variant in FOXP4-AS1 (rs1853837, odds ratio OR = 1.28, P = 2.51 × 10-10, allele frequencies in Chinese/European AF = 0.345/0.105), a frameshift insertion in ABO (rs8176719, OR = 1.19, P = 8.98 × 10-9, AF = 0.422/0.395) and a Chinese-specific intronic variant in MEF2B (rs74490654, OR = 8.73, P = 1.22 × 10-8, AF = 0.004/0). These findings highlight an important role of the adaptive immunity and the ABO blood-group system in protection from developing severe COVID-19.

Urinary trace elements in association with disease severity and outcome in patients with COVID-19

BACKGROUND

The dynamics of urinary trace elements in patients with COVID-19 still remains to be investigated.

METHODS

A retrospective study was performed on a cohort of 138 confirmed COVID-19 patients for their urinary levels of essential and/or toxic metals including chromium, manganese, copper, arsenic, selenium, cadmium, mercury, thallium and lead according to the different disease severity (severe or non-severe) and outcome (recovered or deceased).

RESULTS

Urinary concentrations of chromium, manganese, copper, selenium, cadmium, mercury and lead after creatinine adjustment were found to be higher in severe patients than the non-severe cases with COVID-19. And among the severe cases, these elements were also higher in the deceased group than the recovered group. When the weeks of the post-symptom onset were taken in account, the changes of these urinary elements were existed across the clinical course since the disease onset. These urinary elements were found to be mostly positively inter-correlated, and further positively correlated with other laboratory inflammatory parameters including serum cytokines (IL-1B, IL2R, IL6, IL8, IL10, TNFα), ferritin, and neutrophil count and white blood cell count. As a independently predictive factor, urinary creatinine-adjusted copper of ≥25.57 μg/g and ≥99.32 μg/g were associated with significantly increased risk of severe illness and fatal outcome in COVID-19, respectively.

CONCLUSIONS

These results suggest abnormities in urinary levels of the trace metals were tightly associated with the severe illness and fatal outcome of COVID-19.

Epidemiologic evidence linking oxidative stress and pulmonary function in healthy populations

Respiratory health in the general population declines regardless of the presence of pulmonary diseases. Oxidative stress has been implicated as one of the mechanisms involved in respiratory dysfunction. This review was to evaluate studies that relate oxidative stress factors with pulmonary function among the general population without prior respiratory illnesses. The search yielded 54 citations. Twenty-one studies qualified for incorporation in this review. Owing to the heterogeneity of the review, studies were discussed based on identified oxidative stress factors responsible for pulmonary dysfunction. Oxidative stress biomarkers, including gene polymorphisms of nuclear factor erythroid 2-related factor 2, heme oxygenase 1, glutathione S transferase, superoxide dismutase, and lipid peroxidation products were involved in lung function decline. In addition, the antioxidant status of individuals in reference to dietary antioxidant intake and exposure to environmental pollutants affected oxidative stress and pulmonary function, as indicated by forced expired volume in one second, forced vital capacity, and forced expiratory flow at 25%–75%_. This review indicated that oxidative stress is implicated in the gradual decline of lung function among the general population, and gene polymorphism along the antioxidant defense line and/or their interaction with air pollutants reduce lung function. Different polymorphic forms among individuals explain why the rate of lung function decline differs among people. Dietary antioxidants have respiratory health benefits in antioxidant gene polymorphic forms. Therefore, the genetic composition of an individual may be considered for monitoring and identifying people at risk of respiratory illnesses.

Circulating lead modifies hexavalent chromium-induced genetic damage in a chromate-exposed population: An epidemiological study

Chromium (Cr) can coexist with other heavy metals in the blood of chronically chromate-exposed individuals. However, few studies have explored the health impacts of other hazardous metals after exposure to hexavalent chromium [Cr(VI)]. This study aimed to assess the modification effects of blood lead (Pb) on the genetic damage induced by Cr(VI). During 2010-2019, 1000 blood samples were collected from 455 workers exposed to chromate and 545 workers not exposed to chromate from the same factory with similar labor intensity. The levels of Cr and Pb were measured in whole blood samples. Micronucleus frequency (MNF) and urinary 8-hydroxydeoxyguanosine (8-OHdG) were measured to reflect different types of genetic damage. Multivariate linear regression analyses were performed to evaluate the associations between hazardous metals and the modification effects of Pb on genetic damage. The geometric mean levels of Cr and Pb in the exposure group were significantly higher than those in the control group [Cr: 6.42 (6.08- 6.79) vs. 1.29 (1.22- 1.36) μg/L; Pb: 38.82 (37.22- 40.50) vs. 34.47 (33.15- 35.85) μg/L]. The geometric means of urinary 8-OHdG and MNF in exposure group were 4.00 (3.64- 4.40) μg/g and 5.40 (4.89- 5.97) ‰, respectively, significantly higher than the 3.20 (2.94- 3.48) μg/g and 4.57 (4.15- 5.03) ‰, respectively, in control group. log₂Cr was independently and positively associated with urinary 8-OHdG (β_-adjusted = 0.143, 95% CI: 0.082- 0.204) and MNF (β_-adjusted = 0.303, 95%CI: 0.020- 0.587). With the change in circulating Pb levels, the types of genetic damage induced by Cr(VI) were different. At low levels of circulating Pb (<30.80 μg/L), chromate mainly caused changes in 8-OHdG, while at high circulating Pb levels (≥44.88 μg/L), chromate induced alterations in MNF. The findings suggested that chromate exposure could cause multiple types of genetic damage, and circulating Pb might modify the association between circulating Cr and the form of genetic damage.

Toxic metal exposure as a possible risk factor for COVID-19 and other respiratory infectious diseases

Multiple medical, lifestyle, and environmental conditions, including smoking and particulate pollution, have been considered as risk factors for COronaVIrus Disease 2019 (COVID-19) susceptibility and severity. Taking into account the high level of toxic metals in both particulate matter (PM2.5) and tobacco smoke, the objective of this review is to discuss recent data on the role of heavy metal exposure in development of respiratory dysfunction, immunotoxicity, and severity of viral diseases in epidemiological and experimental studies, as to demonstrate the potential crossroads between heavy metal exposure and COVID-19 severity risk. The existing data demonstrate that As, Cd, Hg, and Pb exposure is associated with respiratory dysfunction and respiratory diseases (COPD, bronchitis). These observations corroborate laboratory findings on the role of heavy metal exposure in impaired mucociliary clearance, reduced barrier function, airway inflammation, oxidative stress, and apoptosis. The association between heavy metal exposure and severity of viral diseases, including influenza and respiratory syncytial virus has been also demonstrated. The latter may be considered a consequence of adverse effects of metal exposure on adaptive immunity. Therefore, reduction of toxic metal exposure may be considered as a potential tool for reducing susceptibility and severity of viral diseases affecting the respiratory system, including COVID-19.