Effect of Occupational exposure to Lead on Serum Levels of Lipid Profile and Liver Enzymes: An Occupational Cohort Study

Artichoke water extract protects against Lead-induced hepatotoxicity by activating Nrf2 signaling and inhibiting NLRP3/caspase-1/GSDMD-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Lead (Pb), a predominant heavy metal in the environment, causes significant harm to mammalian organs by activating oxidative stress and inflammation. Artichoke (Cynarascolymus L.) is a conventional edible botanical remedy known for its diverse pharmacological attributes, including antioxidant and anti-inflammatory properties.

AIM

In this study, we aimed to investigate the effects of artichoke water extract (AWE) on Pb-induced liver toxicity and the potential underlying mechanisms.

MATERIALS AND METHODS

We identified and quantified the chemical compounds in AWE using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Fifty male C57BL/6J mice (8-week-old) were randomly divided into five groups with ad libitum access to a standard diet and water. Over six weeks of experiments, the control group was orally administered 100 μL/day of distilled water. The Pb group received orally a Pb solution at 25 mg/kg body weight (BW)/day. The Pb + AWE (0.8) group received a combination of Pb solution (25 mg/kg BW) and AWE (0.8 g/kg BW) daily. Next, the Pb + AWE (1.6) group received a combination of Pb solution (25 mg/kg BW) and AWE (1.6 g/kg BW) daily. The Pb + vitamin C group received a combination of Pb solution (25 mg/kg BW) and vitamin C (50 mg/kg BW) daily. We evaluated tissue Pb levels, serum biochemical indices, liver function parameters, and histopathology post-experiment. HepG2 cells were cultured to investigate AWE's role and underlying mechanism of action on Pb-induced pyroptosis.

RESULTS

Ninety-six major compounds were identified and quantified in AWE using UPLC-MS/MS. Treatment with AWE at 0.8 and 1.6 g/kg body weight (BW) significantly reduced tissue Pb accumulation, induced fecal Pb excretion, improved lipid profiles, and attenuated liver injury. In addition, AWE treatment increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity and decreased malondialdehyde (MDA), 8-OHdG production, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-1 beta expression in Pb-exposed mice and HepG2 cells. Mechanistically, the in vivo and in vitro results showed that AWE's antioxidant role was related to the activation of nuclear factor-E2-related factor 2 (Nrf2) signaling. Its anti-inflammatory effect was associated with the inhibition of Pb-induced pyroptosis by inhibiting the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3 (NLRP3)/caspase-1/gasdermin D (GSDMD) pathway.

CONCLUSION

These findings indicate that AWE protects against Pb-induced liver toxicity potentially through its chelating, antioxidant, and anti-inflammatory properties.

Assessing Chronic Heavy Metal Exposure by Analysis of Human Cataract Specimens and the Relationship to Metabolic Profiles

PURPOSE

With age, the mammalian lens forms successive layers of crystallin protein fibers which infoliate with lens growth and development. As heavy metals generally bind to tissue protein, heavy metals are posited to sequester within the lens with age. Therefore, this study aims to compare heavy metals in human crystalline lens of older adults to known physiologic blood and urine levels and assess the association between concentrations in the lens and metabolic biomarkers.

METHODS

Consecutive lens specimens obtained during cataract surgery by phacoemulsification were subjected to atomic spectrometry for heavy metal content. A one-sample t-test compared heavy metals in lens to known physiologic blood and urine concentrations. Linear regression models assessed the association between heavy metals and biomarkers of metabolic function. Linear discriminant analysis assessed the classification of gender and smoking status based on multiple and individual heavy metals.

RESULTS

All heavy metal levels were elevated in lens specimens compared to blood and urine with the exception of iron (p < 0.0001). Lens titanium and copper were positively associated with blood-urea nitrogen (Titanium: β ̂ = 1.14, p = 0.04, Copper: β ̂ = 1.12, p = 0.03. Lens copper was positively associated with creatinine (β ̂ = 1.10; p = 0.02), but negatively associated with glomerular filtration rate (β ̂ = 0.89; p = 0.02). Lens chromium and lead were positively associated with albumin (Chromium: β ̂ = 1.03, p = 0.03; Lead: β ̂ = 1.02, p = 0.04). Lens nickel was positively associated with bilirubin (β ̂ = 1.14; p = 0.03). Classification based on multiple or individual heavy metals for gender and smoking status was not statistically significant.

CONCLUSIONS

Our results suggest the human crystalline lens accumulates heavy metals with age and demonstrate the correlation between abnormality of metabolic function and heavy metal deposition in older adult lens.

Mitigating lead acetate-induced histopathologic and physiologic disorders in rats receiving vitamin C and glutathione supplement

The present work examines the extreme impact of lead acetate and the preventive function of co-supplementation with vitamin C and glutathione. It hypothesizes that these supplements can alleviate the poisonous effects of lead exposure. Eighty male albino rats, weighing 100 ± 15 g, were categorized into four groups: the control group, the second group receiving daily supplements of 100 mg/kg of body weight glutathione and 1 mg/100 g of body weight vitamin C orally, the third group receiving 100 mg/kg body weight of lead acetate orally daily, and the fourth group receiving similar oral dosages of lead acetate along with glutathione and vitamin C. Lead exposure significantly decreased body weight and relative testis weight, while relative organ weights for the liver, kidney, and spleen increased significantly. Additionally, lead acetate increased plasma glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activities and plasma creatinine concentration (p < 0.05). Lead concentration rose significantly in blood, urine, liver, and kidney (p < 0.05). Examinations revealed that lead acetate exposure induced apoptotic DNA fragmentation in hepatocytes, significantly increasing caspase-3 activity (91 %) and annexin V indicators. Moreover, lead exposure induced a decrease in sperm count and motility, along with an increase in abnormal sperm morphology. However, vitamin C and glutathione supplementation significantly improved these adverse impacts, suggesting their protective function in counteracting the harmful impacts of lead acetate in different organs.

Hematological, cardiovascular and oxidative DNA damage markers associated with heavy metal exposure in electronic waste (e-waste) workers of Bangladesh

Electronic waste (e-waste) contains hazardous elements such as lead (Pb), cadmium (Cd), mercury (Hg), and other toxic elements that pose significant health risks to the population directly exposed. We recruited 199 e-waste recycling workers and 104 non-exposed workers in Bangladesh and analyzed heavy metals in blood and hair, as well as hematological and cardiovascular parameters including, blood lipids and blood pressure. We fitted quantile regression models at 0.5 quantile to evaluate the impact of blood Pb, Cd, and total hair Hg (THg) on hematological and cardiovascular parameters and the role of oxidative DNA damage (8-OHdG as a biomarker) in mediatin the relationship between exposures and outcomes. Exposed workers had elevated median blood Pb (11.89 vs. 3.63 µg/dL), moderate blood Cd (1.04 vs. 0.99 µg/L), and lower level of THg (0.38 vs. 0.57 ppm) in hair than non-exposed workers. Adjusted estimates showed that Pb was positively associated with red blood cell (RBC), eosinophil count, eosinophil percentage; and negatively associated with mean platelet volume (MPV), platelet large cell ratio (P-LCR) and platelet volume distribution width (PDW) (all p≤0.05). Cd was only associated with 0.57 units increase in red blood cell distribution width (RDW) percentage (95 % CI: 0.18, 0.95). In cardiovascular outcomes, Pb was associated with 1.42 units decrease in triglyceride, 1.58 units increase in low-density lipoprotein (LDL), 0.07 units increase in LDL/HDL and 0.49 units increase in systolic blood pressure (all p≤0.05). No associations were observed between THg and hematological or cardiovascular parameters. Urinary 8-OHdG concentrations were lower, and it did not mediate exposure-outcome relationships (all p≥0.05). Our data imply that e-waste exposure impairs hematological parameters, blood lipids, and blood pressure secondary to elevated Pb levels and poses a threat to exposed individuals. As such, continuous monitoring in longitudinal studies is warranted to assess the dose-response relationship and identify effective control measures.

Understanding Strongyloides Stercoralis infection and its relationship to chronic alcohol abuse: Understanding pathogenesis and therapeutic strategies

Globally, Strongyloides stercoralis is a prevalent nematode parasite infecting over 600 million individuals, predominantly in tropical regions. Despite its widespread occurrence, it is frequently underdiagnosed and neglected, posing significant health risks, particularly to immunocompromised individuals. This parasite's life cycle includes a concerning capability for autoinfection, potentially leading to hyperinfection syndrome with high mortality rates. Alcoholism is recognized as a major risk factor for exacerbating S. stercoralis infections due to its harmful impact on the immune system. Chronic alcohol consumption impairs adaptive immunity by reducing T-cell and B-cell function, which facilitates parasitic infections. This review examines the complex relationship between alcohol abuse and strongyloidiasis, emphasizing the molecular mechanisms involved. Diagnostic challenges and treatment options, particularly the efficacy of antiparasitic drugs like ivermectin, are also discussed. Understanding these interactions is essential for developing improved diagnostic and therapeutic strategies to combat strongyloidiasis, especially among vulnerable populations, highlighting areas for future study.

Lead Concentrations in Tissues of Pigeons (Columba livia) in the Urban Area of Comarca Lagunera, Mexico

The Comarca Lagunera is one of Mexico's most important productive areas. Its main economic activities are livestock, agriculture, and the processing industry. A wide variety of industries emit wastes that are considered highly toxic environmental pollutants, which have strong negative impacts on public health. The objective of this work was to determine the lead concentrations present in tissues of pigeons (Columba livia) belonging to the urban area of the Comarca Lagunera, Mexico. Specimens were collected from the localities that comprise the region and the tissue extracted; the organs were dried, calcined, and diluted in an acidic HCl solution. Lead concentrations were obtained by atomic absorption spectrometry using the graphite furnace technique. The results demonstrate the presence of lead in all the tissues analyzed, with maximum concentrations of 191.14 mg/kg and minimum concentrations of 0.86 mg/kg, the area with the highest average concentration being Torreón, Coahuila (p = 0.030). The organ with the highest concentration was the bone (p = 0.000). Evidence of lead poisoning is presented in Columba livia tissues in the Comarca Lagunera, thus demonstrating the presence of this contaminant and the ability of these pigeons to function as bioindicators of environmental contamination.

Estrogen replacement therapy reverses spatial memory loss and pyramidal cell neurodegeneration in the prefrontal cortex of lead-exposed ovariectomized Wistar rats

BACKGROUND

Although menopause is a component of chronological aging, it may be induced by exposure to heavy metals like lead. Interestingly, lead exposure, just like the postmenopausal state, has been associated with spatial memory loss and neurodegeneration; however, the impact of hormone replacement therapy (HRT) on menopause and lead-induced spatial memory loss and neurodegeneration is yet to be reported.

AIM

The present study investigated the effect and associated mechanism of HRT on ovariectomized-driven menopausal state and lead exposure-induced spatial memory loss and neurodegeneration.

MATERIALS AND METHODS

Thirty adult female Wistar rats were randomized into 6 groups (n = 5 rats/group); the sham-operated vehicle-treated, ovariectomized (OVX), OVX + HRT, lead-exposed, OVX + lead, and OVX + Lead + HRT groups. Treatment was daily via gavage and lasted for 28 days.

RESULTS

Ovariectomy and lead exposure impaired spatial memory deficit evidenced by a significant reduction in novel arm entry, time spent in the novel arm, alternation, time exploring novel and familiar objects, and discrimination index. These findings were accompanied by a marked distortion in the histology of the prefrontal cortex, and a decline in serum dopamine level and pyramidal neurons. In addition, ovariectomy and lead exposure induced metabolic disruption (as depicted by a marked rise in lactate level and lactate dehydrogenase and creatinine kinase activities), oxidative stress (evidenced by a significant increase in MDA level, and decrease in GSH level, and SOD and catalase activities), inflammation (as shown by significant upregulation of myeloperoxidase activity, and TNF-α and IL-1β), and apoptosis (evidenced by a rise in caspase 3 activity) of the prefrontal cortex. The observed biochemical and histological perturbations were attenuated by HRT.

CONCLUSIONS

This study revealed that HRT attenuated ovariectomy and lead-exposure-induced spatial memory deficit and pyramidal neurodegeneration by suppressing oxidative stress, inflammation, and apoptosis of the prefrontal cortex.

Internal blood lead exposure levels in permanent residents of Jiangxi Province and its effects on routine hematological and biochemical indices

Background

Lead exposure levels are closely linked to human health and can cause damage to multiple organ systems, including the blood system and liver. However, due to insufficient evidence, the effects of lead exposure on hematological and biochemical indices have not been fully established.

Objective

This study aims to explore the blood lead levels of permanent residents in Jiangxi Province and analyze the factors affecting blood lead levels and the impact of blood lead levels on hematological and biochemical indices.

Methods

We conducted a cross-sectional study including questionnaires, health examinations, and blood sample examinations on 720 randomly selected permanent residents (3-79 years) in Jiangxi Province in 2018. The blood lead levels were measured using inductively coupled plasma mass spectrometry. Routine hematological and biochemical tests were determined by qualified medical institutions using automated hematology analyzers and biochemistry analyzers.

Results

The geometric mean of blood lead concentration in permanent residents of Jiangxi Province was 20.45 μg/L. Gender, age, annual household income, smoking, and hypertension were the influencing factors for blood lead levels. For each 1 μg/L increase in blood lead, the risks of elevated red blood cell count (from low to high), platelet volume distribution width, alkaline phosphatase (from low to high), and cholesterol increased by 2.4, 1.6, 3.6, and 2.3%, respectively, whereas the risks of elevation of direct bilirubin and total bilirubin both decreased by 1.7%.

Conclusion

The blood lead level in permanent residents of Jiangxi Province is higher than the national average. Higher blood lead levels were found in men than in women; blood lead levels were positively correlated with age but negatively correlated with annual household income; smoking and hypertension are risk factors for elevated blood lead; and blood lead levels affect routine hematological and biochemical markers such as red blood cell count, platelet volume distribution width, direct bilirubin, total bilirubin, alkaline phosphatase, and cholesterol.

The biotoxic effects of heavy metals exposure in miners and non-miners

Since little is known about the comparison of the biotoxic effects of heavy metals exposure on biochemical and hematological parameters in miners and non-miners, the current study aimed to compare the effects of arsenic (As), lead (Pb), and copper (Cu) in both groups. Demographic information and blood samples were collected from all participants and measures of As, Pb and Cu were obtained using Atomic Absorption Spectrophotometry. As and Pb mean concentrations in miners and Cu concentration were greater in non-miners. Miners also showed significantly higher level of RBC, HBG and HCT. In the adjusted model, cholesterol showed a positively association with Pb and Cu levels. Triglycerides, GGT, ALP, WBC and PLT positively and HDL-cholesterol negatively were associated with Cu. Creatinine was negatively associated with group variable. In conclusion, miners' high blood heavy metals concentrations can impact biochemical and hematological indices. These observations make monitoring of heavy metals necessary in miners.

Relationship of individual and mixed urinary metals exposure with liver function in the China National Human Biomonitoring (CNHBM) of Zhejiang Province

BACKGROUND

Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual urinary metals on specific parameters of liver function in the general population. Therefore, this study aimed to investigate their associations.

METHODS

This study involved 807 general population from the China National Human Biomonitoring of Zhejiang Province 2017-2018. Concentrations of urinary metals, including Chromium (Cr), Cobalt (Co), Nickle (Ni), Arsenic (As), Selenium (Se), Molybdenum (Mo), Cadmium (Cd), Thallium (Tl) and Lead (Pb) were measured. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein (TP), albumin (ALB), direct bilirubin (DBIL), total bilirubin (TBIL) as liver function biomarkers. Multivariable linear regression and weighted quantile sum (WQS) regression were employed to explore the associations of urinary metals with liver function biomarkers. Subgroup analysis stratified by gender and age, excluding smokers and drinkers for sensitivity analysis.

RESULTS

Both statistical models indicated that urinary metals were positively associated with ALT and AST, while negatively with TP, ALB, DBIL and TBIL. In the WQS analysis, each quartile increase in the ln-transformed levels of metal mixtures was associated with 4.11 IU/L (95% CI: 1.07, 7.15) higher ALT and 3.00 IU/L (95% CI: 1.75, 4.25) higher AST, as well as, with 0.67 g/L (95% CI: 1.24, -0.11) lower TP, 0.74 g/L (95% CI: 1.09, -0.39) lower ALB, 0.38 μmol/L (95% CI: 0.67, -0.09) lower DBIL, and 1.56 μmol/L (95% CI: 2.22, -0.90) lower TBIL. The association between urinary metals and ALT was primarily driven by Cd (55.8%), Cr contributed the most to the association with AST (20.2%) and TBIL (45.2%), while the association with TP was primarily driven by Ni (38.2%), the association with ALB was primarily driven by As (32.8%), and the association with DBIL was primarily driven by Pb (30.9%). The associations between urinary metals and liver function might differ by sex and age.

CONCLUSION

Urinary metals were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.

Exploring the association of metal mixture in blood to the kidney function and tumor necrosis factor alpha using machine learning methods

This research aimed to approach relationships between metal mixture in blood and kidney function, tumor necrosis factor alpha (TNF-α) by machine learning. Metals levels were measured by Inductively Couple Plasma Mass Spectrometry in blood from 421 participants. We applied K Nearest Neighbor (KNN), Naive Bayes classifier (NB), Support Vector Machines (SVM), random forest (RF), Gradient Boosting Decision Tree (GBDT), Categorical boosting (CatBoost), eXtreme Gradient Boosting (XGBoost), Whale Optimization-based XGBoost (WXGBoost) to identify the effect of plasma metals, TNF-α, and estimated glomerular filtration rate (eGFR by CKD-EPI equation). We conducted not only toxic metals, lead (Pb), arsenic (As), cadmium (Cd) but also included trace essential metals, selenium (Se), copper (Cu), zinc (Zn), cobalt (Co), to predict the interaction of TNF-α, TNF-α/white blood count, and eGFR. The high average TNF-α level group was observed among subjects with higher Pb, As, Cd, Cu, and Zn levels in blood. No associations were shown between the low and high TNF-α level group in blood Se and Co levels. Those with lower eGFR group had high Pb, As, Cd, Co, Cu, and Zn levels. The crucial predictor of TNF-α level in metals was blood Pb, and then Cd, As, Cu, Se, Zn and Co. The machine learning revealed that As was the major role among predictors of eGFR after feature selection. The levels of kidney function and TNF-α were modified by co-exposure metals. We were able to acquire highest accuracy of over 85% in the multi-metals exposure model. The higher Pb and Zn levels had strongest interaction with declined eGFR. In addition, As and Cd had synergistic with prediction model of TNF-α. We explored the potential of machine learning approaches for predicting health outcomes with multi-metal exposure. XGBoost model added SHAP could give an explicit explanation of individualized and precision risk prediction and insight of the interaction of key features in the multi-metal exposure.

A Comprehensive Evaluation of Occupational Epidemiology in Western Iran: A Cohort Study in Ravansar Noncommunicable Diseases

OBJECTIVE

The present study aims to evaluate the prevalence of noncommunicable diseases (NCDs), biochemical and anthropometric indicators, and lifestyle among 10 occupational groups.

METHOD

The sample included 4818 men aged 35 to 65 years. The occupational group is based on the International Standard Classification of Occupations.

RESULT

The highest prevalence of cardiovascular diseases and type 2 diabetes mellitus was observed in managerial occupational groups (18.62%) and technicians and associate professionals ( 14 %), respectively. Musculoskeletal disorders were more in skilled agricultural, forestry, and fishery workers, as well as craft-related trades workers, and elementary occupations. The highest body mass index was related to the managers.

CONCLUSIONS

Noncommunicable diseases were higher in managers, while musculoskeletal disorders belonged to farmers and workers. Finally, lifestyle modification can help reduce NCDs and improve biochemical markers by increasing physical activity.

The association between blood heavy metals level and sex hormones among postmenopausal women in the US

Introduction

Environmental pollutants could be implicated in female endocrine setting Q6 beyond traditional factors. Until now, few study has focused on the association of environmental exposure to heavy metals with sex hormones in postmenopausal women. This study intended to investigate whether serum levels of heavy metals(i.e., Cd, Pb, Hg, Mn, Se) would influence sex hormones in postmenopausal women.

Methods and results

A cross-sectional study was performed on 614 nationally representative participants from 2013-2016 National Health and Nutrition Examination Survey (NHANES) in the US. Multivariate linear regression models and restricted cubic spline plots revealed cadmium(Cd) had linear positive association with TT(β=3.25, 95%CI= 1.12, 5.38), bioavailable TT(β=1.78, 95%CI=0.36,3.21) and TT/E2(β=0.76, 95%CI=0.28,1.24), which was more apparent in natural menopausal and obese women. Lead(Pb) had linear positive association with SHBG(β=12.84, 95%CI= 6.77,18.91), which was apparent in nearly all subgroups except in normal BMI group, and TT/E2 (β=0.69, 95%CI 0.134,1.25), which was apparent in natural menopausal and normal BMI women. Manganese(Mn) had non-linear association with SHBG, which was more apparent in natural menopausal and obese women, and TT/E2, which was more apparent in natural menopausal and normal BMI women. Selenium(Se) had U shaped non-linear association with TT, which was more apparent in hysterectomy, overweight and obese women, and SHBG, which was apparent in nearly all subgroups except in normal BMI group.

Conclusion

In summary, this cross-sectional study indicates a possible role that various degree of environmental exposure to heavy metals plays in the disruption of sex Q5 hormone levels in postmenopausal women. Further experiments are needed to elucidate the underlying mechanisms.

Lead toxicity and potential therapeutic effect of plant-derived polyphenols

BACKGROUND

Due to its unique physical and chemical properties, lead is still used worldwide in several applications, especially in industry. Both environmental and industrial lead exposures remain a public health problem in many developing and rapidly industrializing countries. Plant polyphenols are pleiotropic in their function and have historically made a major contribution to pharmacotherapy.

PURPOSE

To summarize available pre-clinical and limited clinical evidence on plant polyphenols as potential antidotes against lead poisoning and discuss toxic mechanisms of lead.

METHOD

A comprehensive search of peer-reviewed publications was performed from core collections of electronic databases such as PubMed, Web of Science, Google Scholar, and Science Direct. Articles written in English-language from inception until December 2022 were selected.

RESULTS

In this review, we review key toxic mechanisms of lead and its pathological effects on the neurological, reproductive, renal, cardiovascular, hematological, and hepatic systems. We focus on plant polyphenols against lead toxicity and involved mechanisms. Finally, we address scientific gaps and challenges associated with translating these promising preclinical discoveries into effective clinical therapies.

CONCLUSION

While preclinical evidence suggests that plant polyphenols exhibit bioprotective effects against lead toxicity, scant and equivocal clinical data highlight a need for clinical trials with those polyphenols.

The relationship between co-exposure to multiple heavy metals and liver damage

BACKGROUND

The impact of heavy metal exposure on human health has attracted widespread attention of researchers, and the impact of heavy metal exposure on liver function has also been confirmed, however, more attention is paid to the impact of single or two heavy metal exposures, and most epidemiological studies focus on heavy metal pollution areas. In this study, rural residents in non-heavy metal-contaminated areas in Northwest China were selected as the research objects to explore the comprehensive effects of co-exposure to multiple heavy metals on the liver, which can provide certain reference and support for related research.

OBJECTIVES

This study used a Bayesian nuclear machine model (BKMR) to evaluate the relationship between exposure to heavy metal mixtures and indicators of liver function in a population in rural Northwest China.

RESULTS

Exposure to higher concentrations of metal mixtures was positively correlated with total bilirubin, direct bilirubin, and aspartate aminotransferase, and negatively correlated with alanine aminotransferase, with Pb contributing the most to indicators of liver function. We also observed a possible interaction of Cd with other heavy metals in the effect of heavy metal mixtures on DB levels.

CONCLUSIONS

Concurrent exposure to higher concentrations of heavy metal mixtures (Cr, Co, Cd, and Pb) in rural China was associated with indicators representing poor liver function, of which the effect of lead on liver function should be focused. More prospective epidemiological studies and animal experiments need to be carried out to determine this relationship and possible mechanism.

Quercetin as a Dietary Supplementary Flavonoid Alleviates the Oxidative Stress Induced by Lead Toxicity in Male Wistar Rats

Quercetin is a naturally existing plant pigment belonging to the flavonoid group; it is contained in a wide range of vegetables and fruits. The accumulated evidence points to the potential uses of quercetin in protection of some disease conditions. Lead is one of the highly toxicant heavy metals that are widely spread in the environment and implicated in a wide spectrum of industries. No previous study has been reported to evaluate the effect of quercetin on lead toxicity. Therefore, the present study was conducted to elucidate some aspects of quercetin bioactivities in regard to its ability to combat the oxidative stress induced by lead toxicity. For this purpose, a total of sixty male Wistar rats were randomly and equally divided into three groups of 20 animals each; untreated control animals (group 1), lead-exposed animals (group 2; exposed to lead daily by oral gavage at the dose of 80 mg/Kg b.w.), and group 3 of animals, which were exposed to lead and daily received quercetin (10 h gap time between lead exposure and the receiving of quercetin) by oral gavage at the dose of 350 mg/Kg b.w. The experiment period was 8 weeks. All the assayed hematological and biochemical parameters of animals exposed to lead were significantly altered compared with the untreated control levels. Animals exposed to lead (group 2) exhibited significant decrements of the erythrocytic and total leucocytic counts, hemoglobin concentration, packed cell volume percent, total proteins, albumin and globulin. These animals also disclosed significantly decreased levels of antioxidant markers including total thiols, catalase and glutathione. On the other hand, these animals demonstrated significant increments in the levels of bilirubin, urea, creatinine, BUN, serum enzymes, H₂O₂ and MDA. Animals exposed to lead and given quercetin (group 3) exhibited improvement of these parameters, which were brought back at varying degrees toward the untreated control levels. Basing on the improvements of the assayed hematological and biochemical parameters, it was concluded that quercetin as a dietary supplement can act efficiently as an antioxidant to counteract the oxidative stress induced by lead toxicity and to maintain the oxidant antioxidant balance.

Potential diagnostic biomarkers for lead-induced hepatotoxicity and the role of synthetic chelators and bioactive compounds

Lead (Pb2+) poisoning is a public health concern of global dimensions. Although several public health guidelines and workplace safety policies are existing and enforced, lead toxicity cases are drastically increasing. Lead exposure leads to numerous harmful consequences and causes adverse effects on different body organs and systems, mainly via the generation of reactive oxygen species, leading to augmented oxidative stress, competing with metal ions, and binding with the sulfhydryl groups. In several instances, lead poisoning cases remain undiagnosed and untreated or receive only symptomatic treatment. Estimation of blood lead levels reflects only a recent exposure, however, which does not reveal the total body burden. This review summarizes the effects of lead with special reference to hepatotoxicity and some of the potential diagnostic biomarkers. Furthermore, it also focuses on synthetic chelators used in the treatment of lead poisoning and the advantage of using bioactive compounds with an emphasis on the ameliorative effect of garlic.

Associations of blood metals with liver function: Analysis of NHANES from 2011 to 2018

BACKGROUND

Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual blood metals on specific parameters of liver function in the general population. Hence, this study aimed to elucidate their associations.

METHODS

Data from National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in this cross-sectional study. Multivariate linear, and a quantile-based g-computation (qgcomp) were applied to explore the associations between blood metals [mercury (Hg), manganese (Mn), lead (Pb), cadmium (Cd), selenium (Se)], alone and in combination, and liver function parameters [alanine transaminase (ALT), aspartate transaminase (AST), ALT/AST, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and serum total bilirubin (TBIL)].

RESULTS

A total of 15,328 were included. Multivariate linear models indicated that liver function was significantly associated with blood heavy metals. The most significant relationship was found between Se and AST (β 5.09, 95%CI (3.28,6.91), p＜0.001), Mn and ALT (β 1.24, 95%CI (0.57, 1.91), p＜0.001). Furthermore, the qgcomp analysis showed that the combination of five blood metals was positively associated with AST, ALT, GGT, TBIL and HSI. Cd contributed the most to the correlation of AST (weight = 0.447), Se contributed the most to the association of ALT (weight = 0.438) and HSI (weight = 0.570), Pb contributed the most to the association of GGT (weight = 0.421) and Hg contributed the most to the correlation of TBIL (weight = 0.331).

CONCLUSIONS

Blood heavy metal levels were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.

Epidemiological characteristics of occupational chemical poisonings in Zhejiang, China from 2006 to 2020: A descriptive analysis

Objective

As the second most common occupational disease in China, occupational poisoning is one of the major public health problems that seriously affect workers' health. This study aimed to investigate the epidemiological and occupational characteristics of acute and chronic occupational poisoning cases in Zhejiang Province, so as to provide a scientific basis for proposing intervention measures and preventive strategies of occupational poisoning.

Methods

The data on occupational poisoning cases in Zhejiang Province from 2006 to 2020 was derived from the National Occupational Disease Network Direct Report System. A descriptive statistical analysis was employed on this data utilizing R software.

Results

From 2006 to 2020, 1,008 occupational poisoning cases were reported in Zhejiang Province, with a downward trend since 2007. Of these cases, 81.94% were chronic poisoning and 18.06% were acute poisoning. Ningbo reported the most occupational poisoning cases among the 11 cities in Zhejiang Province, accounting for 20.34% of the total cases. Besides, the occupational poisoning cases in Wenzhou, Jiaxing, and Shaoxing also accounted for 18.15%, 18.06%, and 17.76% of the total number of cases, respectively. Occupational poisoning in male were 693 cases and in female 315 cases. Most of the occupational poisoning cases studied involved people aged between 40 and 49 years (38.19%). The length of work in chronic occupational poisoning cases was significantly higher than that of acute occupational poisoning cases (P < 0.05). Benzene and lead and its compounds (excluding tetraethyl lead) were the major toxicants causing occupational poisoning. More than 60% of occupational poisoning cases were reported in private enterprises. Meanwhile, over 90% of the cases were distributed in medium enterprises and small enterprises. The type of industry with the most occupational poisoning cases was the manufacturing industry.

Conclusion

Although the cases of occupational poisoning in Zhejiang Province have declined, more comprehensive and effective prevention and control measures are still needed. More attention ought to be paid to the management of key points according to the epidemiological and occupational characteristics of occupational poisoning cases.

Aluminum, Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Mercury, Molybdenum, Nickel, Platinum, Thallium, Titanium, Vanadium, and Zinc: Molecular Aspects in Experimental Liver Injury

Experimental liver injury with hepatocelluar necrosis and abnormal liver tests is caused by exposure to heavy metals (HMs) like aluminum, arsenic, beryllium, cadmium, chromium, cobalt, copper, iron, lead, mercury, molybdenum, nickel, platinum, thallium, titanium, vanadium, and zinc. As pollutants, HMs disturb the ecosystem, and as these substances are toxic, they may affect the health of humans and animals. HMs are not biodegradable and may be deposited preferentially in the liver. The use of animal models can help identify molecular and mechanistic steps leading to the injury. HMs commonly initiate hepatocellular overproduction of ROS (reactive oxygen species) due to oxidative stress, resulting in covalent binding of radicals to macromolecular proteins or lipids existing in membranes of subcellular organelles. Liver injury is facilitated by iron via the Fenton reaction, providing ROS, and is triggered if protective antioxidant systems are exhausted. Ferroptosis syn pyroptosis was recently introduced as mechanistic concept in explanations of nickel (Ni) liver injury. NiCl2 causes increased iron deposition in the liver, upregulation of cyclooxygenase 2 (COX-2) protein and mRNA expression levels, downregulation of glutathione eroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), nuclear receptor coactivator 4 (NCOA4) protein, and mRNA expression levels. Nickel may cause hepatic injury through mitochondrial damage and ferroptosis, defined as mechanism of iron-dependent cell death, similar to glutamate-induced excitotoxicity but likely distinct from apoptosis, necrosis, and autophagy. Under discussion were additional mechanistic concepts of hepatocellular uptake and biliary excretion of mercury in exposed animals. For instance, the organic anion transporter 3 (Oat3) and the multidrug resistance-associated protein 2 (Mrp2) were involved in the hepatic handling of mercury. Mercury treatment modified the expression of Mrp2 and Oat3 as assessed by immunoblotting, partially explaining its impaired biliary excretion. Concomitantly, a decrease in Oat3 abundance in the hepatocyte plasma membranes was observed that limits the hepatic uptake of mercury ions. Most importantly and shown for the first time in liver injury caused by HMs, titanium changed the diversity of gut microbiota and modified their metabolic functions, leading to increased generation of lipopolysaccharides (LPS). As endotoxins, LPS may trigger and perpetuate the liver injury at the level of gut-liver. In sum, mechanistic and molecular steps of experimental liver injury due to HM administration are complex, with ROS as the key promotional compound. However, additional concepts such as iron used in the Fenton reaction, ferroptosis, modification of transporter systems, and endotoxins derived from diversity of intestinal bacteria at the gut-liver level merit further consideration.

Role of Ape1 in Impaired DNA Repair Capacity in Battery Recycling Plant Workers Exposed to Lead

Exposure to lead in environmental and occupational settings continues to be a serious public health problem. At environmentally relevant doses, two mechanisms may underlie lead exposition-induced genotoxicity, disruption of the redox balance and an interference with DNA repair systems. The aim of the study was to evaluate the ability of lead exposition to induce impaired function of Ape1 and its impact on DNA repair capacity of workers chronically exposed to lead in a battery recycling plant. Our study included 53 participants, 37 lead exposed workers and 16 non-lead exposed workers. Lead intoxication was characterized by high blood lead concentration, high lipid peroxidation and low activity of delta-aminolevulinic acid dehydratase (δ-ALAD). Relevantly, we found a loss of DNA repair capacity related with down-regulation of a set of specific DNA repair genes, showing specifically, for the first time, the role of Ape1 down regulation at transcriptional and protein levels in workers exposed to lead. Additionally, using a functional assay we found an impaired function of Ape1 that correlates with high blood lead concentration and lipid peroxidation. Taken together, these data suggest that occupational exposure to lead could decrease DNA repair capacity, inhibiting the function of Ape1, as well other repair genes through the regulation of the ZF-transcription factor, promoting the genomic instability.