Lead Exposure Research Articles

Associations of insulin sensitivity and immune inflammatory responses with child blood lead (Pb) and PM2.5 exposure at an e-waste recycling area during the COVID-19 lockdown.

Fine particular matter (PM2.5) and lead (Pb) exposure can induce insulin resistance, elevating the likelihood of diabetes onset. Nonetheless, the underlying mechanism remains ambiguous. Consequently, we assessed the association of PM2.5 and Pb exposure with insulin resistance and inflammation biomarkers in children. A total of 235 children aged 3-7years in a kindergarten in e-waste recycling areas were enrolled before and during the Corona Virus Disease 2019 (COVID-19) lockdown. Daily PM2.5 data was collected and used to calculate the individual PM2.5 daily exposure dose (DED-PM2.5). Concentrations of whole blood Pb, fasting blood glucose, serum insulin, and high mobility group box 1 (HMGB1) in serum were measured. Compared with that before COVID-19, the COVID-19 lockdown group had lower DED-PM2.5 and blood Pb, higher serum HMGB1, and lower blood glucose and homeostasis model assessment of insulin resistance (HOMA-IR) index. Decreased DED-PM2.5 and blood Pb levels were linked to decreased levels of fasting blood glucose and increased serum HMGB1 in all children. Increased serum HMGB1 levels were linked to reduced levels of blood glucose and HOMA-IR. Due to the implementation of COVID-19 prevention and control measures, e-waste dismantling activities and exposure levels of PM2.5 and Pb declined, which probably reduced the association of PM2.5 and Pb on insulin sensitivity and diabetes risk, but a high level of risk of chronic low-grade inflammation remained. Our findings add new evidence for the associations among PM2.5 and Pb exposure, systemic inflammation and insulin resistance, which could be a possible explanation for diabetes related to environmental exposure.

Lead in umbilical cord blood and associated factors in Casablanca Morocco: A preliminary results

BackgroundLead is the most common toxic metal to which Moroccans are exposed. Given the susceptibility of the fetus to lead, it is crucial to assess prenatal lead exposure. However, in Morocco, no study has assessed prenatal exposure to lead. The main goals of the present study are to determine lead concentration in umbilical cord blood and identify risk factors for prenatal lead exposure in Casablanca, Morocco. MethodsTo achieve these purposes, 87 cord blood lead samples were collected from mothers-baby pairs from January to December 2019. Indeed, a structured questionnaire was used to collect socio-demographic characteristics, obstetric data, leisure, cultural habits, and environmental information. Cord blood lead level was analyzed by inductively coupled plasma-mass spectrometry. ResultsThe median lead concentration was 4.902 µg/dl with a minimum and maximum of 0.833 µg/dl and 23.593 µg/dl, respectively. A high proportion of the newborns (65.52 %) had cord blood lead levels above the Centers for Disease Control (CDC) allowable threshold limit (3.5 µg/dl). Statistical analysis was performed to assess the association between blood levels and the above factors. Lead levels in cord blood were significantly associated with the maternal educational level, anemia history, delivery mode, passive smoking during pregnancy as well as with the frequency of consumption of tea. ConclusionThis study provides the first data on lead levels in newborns. Cord blood lead levels were high in the majority of the participants, these results reinforce the need to establish health surveillance programs in Morocco.

Assessment of prevalence of elevated blood lead levels and risk factors among children and pregnant women in Bihar, India

BackgroundWhile modeled estimates and studies in contaminated areas indicate high lead exposure among children in Bihar, India, local data on lead exposure in the child population is limited. ObjectivesTo characterize lead exposure, and assess potential sources of lead exposure among a state-representative sample of children and their pregnant mothers residing in Bihar. MethodsBlood samples were collected from 697 children under five and 55 pregnant women from eight districts in Bihar. Blood lead levels were determined using capillary blood and a portable lead analyzer. Household demographics, home environment, behavior, and nutrition information were collected through computer-assisted personal interviews with primary caregivers. Logistic regression was used to assess associations between potential risk factors and elevated blood lead levels. ResultsMore than 90% of children and 80% of pregnant women reported blood lead levels ≥5 μg/dL. Living near a lead-related industry and pica behavior of eating soil were significantly associated with increased odds of having elevated blood lead levels. Additional risk factors for having a blood level ≥5 μg/dL included the use of skin lightning cream (aOR = 5.11, 95%CI: 1.62, 16.16) and the use of eyeliners (aOR = 2.81, 95%CI: 1.14, 6.93). Having blood lead levels ≥10 μg/dL was also significantly associated with the household member who had an occupation or hobby involving the use of lead (aOR = 1.75, 95%CI: 1.13, 2.72). DiscussionElevated blood lead levels were prevalent among children and pregnant women in Bihar, indicating the urgent need for a comprehensive lead poisoning prevention strategy.

Cerebellar ferroptosis of hypertension mice following lead exposure

Exploring the changes in cerebellar ferroptosis in hypertensive mice after lead exposure. Twenty-five healthy C57 male mice were selected to construct a hypertensive model by intraperitoneal injection of angiotensin II(Ang II) at a concentration of 0.05 mg/kg for 7 consecutive days. After a systolic blood pressure of 140 mmHg, 20 hypertensive mice were randomly divided into a hypertensive control group and a hypertensive lead exposure group. Twenty C57 mice with normal blood pressure were randomly divided into a blood pressure normal control group and a blood pressure normal lead exposure group. The mice in the normal blood pressure control group and the hypertensive control group drank water freely. Mice in the lead exposure group with normal blood pressure and the lead exposure group with hypertension drank lead acetate water containing 250 mg/L. Ang II was injected intraperitoneally every two days in the hypertensive control group and hypertensive lead exposed group mice. Each group of mice was poisoned for 12 weeks. Using open field experiments and balance beam experiments to detect motor dysfunction in mice. Using a reagent kit to detect the levels of divalent iron(Fe~(2+)), malondialdehyde(MDA), and glutathione(GSH) in the cerebellum of different groups of mice. Western blot was used to determine the protein expression of member 11 of the solute carrier family 7(SLC7A11), glutathione peroxidase 4(GPX4), nuclear receptor coactivator 4(NCOA4), microtubule associated protein 1 light chain 3B(LC3B), and ferritin heavy chain 1(FTH1) in mouse cerebellar tissue. The result of the open field experiment showed that the activity distance(1013.04 cm) of mice in the hypertensive lead exposure group was significantly lower than that of the hypertensive control group(1351.18 cm) and the lead exposure group with normal blood pressure(1287.35 cm). And the lead exposure group with hypertension also extended the time through the balance beam, which was 29.40 seconds(P<0.05). In addition, the Fe~(2+)content in the cerebellum of mice in the hypertensive lead exposure group was 3.33 μmol/g prot, which was 1.54 times that of the hypertensive control group and 1.14 times that of the lead exposure group with normal blood pressure. The MDA content was 4.71 nmol/mg prot, higher than that of the hypertensive control group and the lead exposure group with normal blood pressure. The GSH content was 5.36 μmol/g prot, lower than that of the hypertensive control group and the lead exposure group with normal blood pressure(P<0.05). Western blot result showed that compared with the hypertensive control group and the lead exposure group with normal blood pressure, the protein expression of SLC7A11 and GPX4 in the hypertensive lead exposure group was significantly reduced(P<0.05). In addition, compared with the control group with normal blood pressure, the expression of NCOA4 and LC3B proteins in the cerebellum of mice in the hypertension control group and lead exposure group with normal blood pressure increased, while the expression of FTH1 protein decreased(P<0.05). The expression of NCOA4 and LC3B proteins in the hypertensive lead exposure group was higher than that in the hypertensive control group and the lead exposure group with normal blood pressure, while the expression of FTH1 protein decreased(P<0.05). Lead exposure can exacerbate iron death in the cerebellar tissue of hypertensive mice, and iron autophagy may be involved in its occurrence and development.

A Snapshot of Lead in Consumer Products Across Four US Jurisdictions.

Following the removal of lead from gasoline, paint and pipes were thought to be the main sources of lead exposure in the United States. However, consumer products, such as certain spices, ceramic and metal cookware, traditional health remedies, and cultural powders, are increasingly recognized as important sources of lead exposure across the United States. This paper reviews data from four US jurisdictions that conduct in-home investigations for children with elevated blood lead levels (BLLs) to examine the prevalence of lead exposures associated with consumer products, in comparison with housing-related sources. Authors reviewed investigation data (2010-2021) provided by California, Oregon, New York City, and King County, Washington, and compared the extent of lead exposures associated with housing-related vs. consumer products-related sources. The proportion of investigations identifying consumer products-related sources of lead exposure varied by jurisdiction (range: 15%-38%). A review of US CDC and US FDA alerts and New York City data indicates that these types of lead-containing products are often sourced internationally, with many hand carried into the United States during travel. Based on surveillance data, we believe that US immigrant and refugee communities are at an increased risk for lead exposures associated with these products. To engage health authorities, there is a need for evidentiary data. We recommend implementing a national product surveillance database systematically tracking data on consumer products tested by childhood lead poisoning prevention programs. The data repository should be centralized and accessible to all global stakeholders, including researchers and governmental and nongovernmental agencies, who can use these data to inform investigations. Effectively identifying and addressing the availability of lead-containing consumer products at their source can focus resources on primary prevention, reducing lead exposures for users abroad and in the United States. https://doi.org/10.1289/EHP14336.

Management of the Work Environment to Reduce Blood Lead (BLL) Levels in the Assay Laboratory

Assay Laboratory in PT Freeport Indonesia's Concentrating Division, especially for conducting fire assay. Litharge (lead oxide) is a reagent used to test mineral levels; the content of precious metals is called Au. Although lead exposure is low, prolonged exposure to lead could accumulate in the human system, resulting in poisoning or toxicity. This study aimed to determine the effect of work environment management in assay laboratories on reducing blood lead levels during fire assay analysis. This research is a quantitative cohort study. The sampling technique used is purposive sampling. Data analysis techniques are used in different tests. Data collection was conducted using laboratory tests to take blood samples once a year regularly for every worker working in the assay laboratory. Based on the results of the different tests, a T value of 5,638 was obtained with a Sig value of 0.011 (α˂5%), so it can be concluded that there was a decrease in blood Pb levels in workers before and after managing the work environment. Recommended exposure standards are floor exposure values for laboratories (other than fire test laboratories) not to exceed 2.2 mg/m2 (200 μg/ft2) and surface in dining areas not to exceed 0.43 mg/m2 (40 μg/ft2). Improving working environment conditions by procuring a laundry system and lockers, procuring more than one laboratory coat, procuring sinks in every corner of the laboratory, and having special soap for washing hands has proven to be able to reduce Pb exposure rates in assay laboratories from 2019 to 2022.

Ripe Musa sapientum Peels Exhibit Neuroprotection Against Lead Acetate-Induced Brain Damage in Wistar Rats

Objective: Human health has continued to be at risk from lead exposure. This study explored the antioxidative potential of ethanol extract of ripe Musa sapientum peels to protect against lead acetate-induced neuronal insult in female wistar rats. Methods: Thirty adult female rats (120-160 g) were randomly divided into six groups (n = 5): Group 1 (control group) received 10 mL/kg of distilled water; Group 2 received 100 mg/kg lead acetate. Group 3 received 2.5 mg/kg of donepezil. Groups 4 to 6 received 100, 200, and 400 mg/kg ethanol extract of ripe M sapientum, respectively, via oral gavage. Groups 2 to 5 were co-treated with 100 mg/kg lead acetate for 21 days. Neurobehavioral parameter, biochemical and histological analyses of the hippocampus were determined. Recognition memory was evaluated using Novel Object Recognition Test. Results: There was a significant ( p < 0.05) increase in total exploration, discrimination index, and percentage alternation in the ethanol extract M sapientum-treated groups compared with the lead acetate-induced group. M sapientum ethanol extract and dopamine significantly ( p < 0.05) reduced acetylcholinesterase enzyme (AChE) and malondialdehyde (MDA) activities in a dose-dependent manner and significantly ( p < 0.05) increased superoxide dismutase activity (SOD) dose dependently, respectively. In the histopathological analysis of the hippocampal area, there were mild vacuolation (V), mild degeneration as well as mild granular cell atrophy in the treated groups, suggesting that M sapientum may have neuroprotective properties. Conclusion: Ethanol extract of ripe M sapientum peels enhanced cognitive functions and may be beneficial in preventing neurodegenerative disorders via antioxidant mechanism.

Lead exposure estimation through a physiologically based toxicokinetic model using human biomonitoring data and comparison with scenario-based exposure assessment: A case study in Korean adults

Pb toxicity is linked to cardiovascular and nephrotoxicity issues. Exposure to this heavy metal can occur through food and drinking water. Therefore, this study aimed to evaluate Pb exposure and assess health risks in Korean adults using a physiologically based toxicokinetic (PBTK) model. Human blood Pb concentrations were monitored using the Korean National Environmental Health Survey (KoNEHS) Cycle 4. The average Pb exposure in Korean adults was 0.520 μg/kg bw/day. The PBTK results were compared with scenario-based results from the 2021 risk assessment report of five heavy metals, including Pb, conducted by the MFDS. Exposure determined through reverse dosimetry was approximately two times higher than scenario-based exposure (0.264 μg/kg bw/day). The higher exposure levels obtained during PBTK analysis may be attributed to sustained exposure within historically more contaminated living environments and the long half-life of Pb. These findings suggest that the PBTK-based method can quantify aggregated exposure levels in the body over time, potentially serving as a complementary tool to address the constraints of scenario-based assessment methods for integrated risk assessment. Moreover, this model is convenient and cost-effective compared with scenario-based exposure estimation. These findings can facilitate the application of model for tracking continuous national changes in hazardous substance levels.

Childhood blood-lead level predicts lower general, non-selective hippocampal subfield volumes in midlife

Millions of adults and children are exposed to high levels of lead, a neurotoxicant, each year. Recent evidence suggests that lead exposure may precipitate neurodegeneration, particularly if the exposure occurs early or late in life, with unique alterations to the structure or function of specific subfields of the hippocampus, a region involved in memory and Alzheimer’s disease. It has been proposed that specific hippocampal subfields may thus be useful biomarkers for lead-associated neurological disease. We turned to a population-representative New Zealand birth cohort where the extent of lead exposure was not confounded by social class (the Dunedin Study; born 1972–1973 and followed to age 45) to test the hypothesis that early life lead exposure (blood-lead level at age 11 years) is associated with smaller MRI-assessed gray matter volumes of specific subfields of the hippocampus at age 45 years. Among the 508 Dunedin Study members with childhood lead data and adult MRI data passing quality control (93.9 % of those with lead data who attended the age-45 assessment wave, 240[47.2 %] female), childhood blood-lead levels ranged from 4 to 31 µg/dL (M[SD]=10.9[4.6]). Total hippocampal volumes were lower among adults with higher childhood blood-lead levels (b=-102.6 mm3 per 5 ug/dL-unit greater blood-lead level, 95 %CI: −175.4 to −29.7, p=.006, β=-.11), as were all volumes of the 24 hemisphere-specific subfields of the hippocampus. Of these 24 subfields, 20 demonstrated negative lead-associations greater than β=-.05 in size, 14 were statistically significant after adjustment for multiple comparisons (pFDR<.05), and 9 remained significant after adjustment for potential confounders and multiple comparisons. Children exposed to lead demonstrate smaller volumes across all subfields of the hippocampus in midlife. The hypothesis that lead selectively impairs specific subfields of the hippocampus, or that specific subfields may be markers for lead-associated neurological disease, requires further evaluation.

Histological of the Epididymis after Lead (Plumbum) Exposure in Albino Mice Mus musculus

Histological of the Epididymis after Lead (Plumbum) Exposure in Albino Mice Mus musculus

Ecological and Health Risk Assessment of Nitrates and Heavy Metals in the Groundwater of the Alluvial Area of the Danube River near Kostolac Basin, Serbia

Water-quality indicators and trace elements were measured in the alluvial area of the Kostolac Basin, Serbia. The results revealed that the groundwater was naturally neutral, with a mean conductance of 920.10 μs/cm. The primary factors contributing to the decline in the groundwater quality in the researched area were electrical conductivity (EC), NO3−, SO42−, Cd, and Pb; the water samples were deemed unfit for human consumption and the water was classified as having impaired quality. A Pearson correlation matrix, a principal component analysis (PCA), and a cluster analysis (CA) were applied to identify the pollution source and factors controlling the groundwater quality and the results indicated that both natural and anthropogenic factors influenced the groundwater of the studied area. The Nemerow pollution index indicated medium to high pollution levels along with the degree of contamination. A health risk evaluation was conducted to determine the non-carcinogenic risks posed by nitrates and heavy metals from oral consumption and skin contact in the researched area. Nearly all monitoring sites had hazard quotients (HQs) below 1, suggesting that potential concerns might be negligible. However, children showed the highest exposure levels, with HQs for nitrates at 2.26 and for lead (Pb) at 2.515. No carcinogenic risk from oral lead (Pb) exposure was found in any sample.

Effect of Lead Exposure and Lifestyle Factors on Methylation Index Markers Among Pb-Exposed Workers.

S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) and the ratio of SAM and SAH in Pb-exposed workers need to be assessed. In this study, we investigated the effects of Pb exposure on SAM, SAH, and methylation index (MI) in Pb-exposed workers with contemplation of lifestyle factors. Blood lead levels (BLLs), SAM, SAH, MI, and lifestyle factors were assessed in 338 male Pb-exposed workers. BLLs are estimated by ICP-OES method. SAM and SAH levels in serum were determined by ELISA method. The MI was calculated using SAM and SAH individual values. The lifestyle factors were collected using standard questionnaire. Levels of SAM and MI were significantly decreased with increased age, experience > 5 years, habits of tobacco chewing, smoking, alcohol consumption, and BLLs 10-30, 30-50, and > 50 µg/dL. Levels of SAH were significantly increased with increased age, habits of tobacco chewing and smoking, and BLLs 10-30, 30-50, and > 50 µg/dL. The association between BLLs and methylation index markers (SAM and MI) was reported as negative and significant. The association between BLLs and SAH was noted positive and significant. The influence of BLLs and lifestyle factors on SAM was noted at 12%, SAH at 35%, and MI at 27%, respectively. The highest percentage of influence was noted in SAH, followed by MI and SAM. In the workers exposed to Pb, lifestyle factors resulted in decreased SAM and MI and increased SAH levels. Adaptation of healthy lifestyle factors, personal hygiene practices, and use of PPE were suggested to minimize the reduction of methylation index markers.

Nucleic acid aptamers protect against lead (Pb(II)) toxicity

Lead (Pb(II)) is a pervasive heavy metal toxin with many well-established negative effects on human health. Lead toxicity arises from cumulative, repeated environmental exposures. Thus, prophylactic strategies to protect against the bioaccumulation of lead could reduce lead-associated human pathologies. Here we show that DNA and RNA aptamers protect C. elegans from toxic phenotypes caused by lead. Reproductive toxicity, as measured by brood size assays, is prevented by co-feeding of animals with DNA or RNA aptamers. Similarly, lead-induced neurotoxicity, measured by behavioral assays, are also normalized by aptamer feeding. Further, cultured human HEK293 and primary murine osteoblasts are protected from lead toxicity by transfection with DNA aptamers. The osteogenic development, which is decreased by lead exposure, is maintained by prior transfection of lead-binding DNA aptamers. Aptamers may be an effective strategy for the protection of human health in the face of increasing environmental toxicants.

Assessment of occupational exposure to lead among workers engaged in a city bus garage in Addis Ababa, Ethiopia: a comparative cross-sectional study

BackgroundLead is one of the most nonessential toxic heavy metal agents found in automotive garages. The occupational exposure of garage workers to lead commonly poses acute and chronic health risks that can be prevented. In Ethiopia, there have been limited studies on lead exposure among garage workers, who overemphasize exposure to lead. This study aimed to assess occupational blood lead levels and associated factors in garage workers using a cross-sectional comparative design.MethodsA comparative cross-sectional study design was used to compare the occupational blood lead levels of 36 randomly selected garage workers and 34 office workers who were matched by age and sex. Blood specimens were collected by trained medical laboratory experts. The collected blood samples were tested in a certified laboratory using a microwave plasma atomic emission spectrometry (MP-AES) device at a wavelength of 405.78 nm. Excel and SPSS Version 26 were used for data management and analysis, respectively.ResultsThe mean (SD) age of the exposed group was 39.0 (7.5) years, whereas the mean age of the unexposed group was 38.0 (6.1) years. The occupational mean (SD) blood-lead-level in the exposed groups was 29.7 (12.2) µg/dl, compared to 14.8 (9.9) µg/dl among the unexposed groups. The mean blood-lead level among the exposed workers was significantly different from that among the unexposed workers (P < 0.01). Of all the study participants, only 22.2% of the exposed groups had blood lead levels higher than the World Health Organization’s recommended limit of 40 µg/dl. The main significant predictors of occupational blood-lead-level exposure among workers were extra working hours, service years, and having a previous (prior) employment history in a garage. The occupations of the two groups did not significantly differ in terms of blood-lead levels (p > 0.05).ConclusionsThe BLL of the Garage workers was significantly greater than that of the Non-Garage workers. Hence, it is advised that garage management should encourage workers to use exposure prevention methods, such as washing their hands before eating and taking showers after the completion of work, by providing regular occupational safety training.

Troubled waters? The disproportionate impact of lead water pollution: Evidence from three American communities

&lt;p&gt;Although water is considered essential to life and an important natural resource, disadvantaged communities, such as low-income and minority communities, are disproportionately burdened by lead exposure in drinking water. In this paper, we highlight case studies that have received national press coverage as well as recent examples of community lead poisoning hazards that are still ongoing across various regions of the US. We show through these three case studies of Flint, Michigan, Washington, D.C., and Birmingham, Alabama, that the severity and frequency of this pervasive public health problem are highly concentrated in minority and low-income populations, and thus they bear the brunt of the socio-economic impacts. We identify the use of sensors to improve detection of hazardous materials and decrease inequities in drinking water contamination. To address water-related equity issues, we call for a sustainable community capacity approach that consists of shared governance between those who live in a community and stakeholders, such as businesses and health services, who have vested interests in it. We conclude by highlighting ways that a community could build collective social capital, safeguarding its environment from lead poisoning through health literacy education. Promoting water literacy is highly significant since water knowledge is crucial towards achieving water sustainability and equity.&lt;/p&gt;

Association between Combined Metals and PFAS Exposure with Dietary Patterns: A Preliminary Study.

The global burden of chronic diseases has been increasing, with evidence suggesting that diet and exposure to environmental pollutants, such as per- and polyfluoroalkyl substances (PFAS) and heavy metals, may contribute to their development. The Dietary Inflammatory Index (DII) assesses the inflammatory potential of an individual's diet. However, the complex interplay between PFAS, heavy metals, and DII remains largely unexplored. The goal of this cross-sectional study was to investigate the associations between diet operationalized as the DII with individual and combined lead, cadmium, mercury, perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) exposures using data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018. Descriptive statistics, a correlational analysis, and linear regression were initially used to assess the relationship between the variables of interest. We subsequently employed Bayesian kernel Machine regression (BKMR) to analyze the data to assess the non-linear, non-additive, exposure-response relationships and interactions between PFAS and metals with the DII. The multi-variable linear regression revealed significant associations between the DII and cadmium and mercury. Our BKMR analysis revealed a complex relationship between PFAS, metal exposures, and the DII. In our univariate exposure-response function plot, cadmium and mercury exhibited a positive and negative linear relationship, respectively, which indicated a positive and negative relationship across the spectrum of exposures with the DII. In addition, the bivariate exposure-response function between two exposures in a mixture revealed that cadmium had a robust positive relationship with the DII for different quantiles of lead, mercury, PFOA, and PFOS, indicating that increasing levels of cadmium are associated with the DII. Mercury's bivariate plot demonstrated a negative relationship across all quantiles for all pollutants. Furthermore, the posterior inclusion probability (PIP) results highlighted the consistent importance of cadmium and mercury with the inflammatory potential of an individual's diet, operationalized as the DII in our study, with both showing a PIP of 1.000. This was followed by PFOS with a PIP of 0.8524, PFOA at 0.5924, and lead, which had the lowest impact among the five environmental pollutants, with a PIP of 0.5596. Our study suggests that exposures to environmental metals and PFAS, particularly mercury and cadmium, are associated with DII. These findings also provide evidence of the intricate relationships between PFAS, heavy metals, and the DII. The findings underscore the importance of considering the cumulative effects of multi-pollutant exposures. Future research should focus on elucidating the mechanistic pathways and dose-response relationships underlying these associations in a study that examines causality, which will enable a deeper understanding of the dietary risks associated with environmental pollutants.

Lead specifically declines tyrosine hydroxylase activity to induce the onset of Parkinson's disease through disrupting dopamine biosynthesis in fly models

Parkinson's disease (PD) is one of the fastest-growing neurodegenerative diseases and has been linked to the exposure to numerous environmental neurotoxins. Although lead (Pb) exposure has been related to the development of PD, the molecular target of Pb to cause the onset of PD is insufficiently investigated. Herein, we explored the effects of Pb exposure on behavior, pathophysiology, and gene expression of wild-type (WT) fly (Drosophila melanogaster) by comparison with its PD model. After exposure to Pb, the WT flies showed PD-like locomotor impairments and selective loss of dopaminergic (DAergic) neurons, displaying similar phenotypes to fly PD model (PINK1). Transcriptomic analysis showed the similarity in gene expression profiles between Pb treatment WT flies and PINK1 mutant flies. Moreover, Pb exposure resulted in endogenous dopamine deficits in WT flies. Analyses of gene expression and enzyme activity confirmed that Pb exposure reduced tyrosine hydroxylase (TH) activity and led to failure of dopamine synthesis. Furthermore, molecular dynamics simulation confirmed that Pb was adsorbed by TH and subsequently inhibited the enzymatic activity. Exogenous injection of L-dopa and melatonin could partially rescue the pathological phenotypes of Pb-exposed flies and PD fly model. Antagonist injection of microRNA-133, which negatively regulated the expression of TH gene, ultimately rescued in the manifestation of PD phenotypes in flies. Involvement of TH overexpression mutants of fly strongly promoted the resistance to Pb exposure and rescued both behavior and the number of DAergic neurons. Therefore, our study elucidates the Pb molecular target in dopamine pathway and mechanism underlying the risks of Pb exposure on the occurrence of PD at environmentally-relevant concentrations.

Assessment of lead contamination in soil and tap water in daycare facilities in Addis Ababa: implications for children's health

ABSTRACT In recent years, lead poisoning has been recognized as a serious environmental health problem throughout the world, particularly, for children in developing countries. The objective of the study was to investigate the lead level in the water and soil of daycare facilities in Addis Ababa. Graphite furnaces atomic absorption spectrometry was used to analyze the concentration of lead in soil and tap water of 28 daycare centers. The result indicated that the mean levels of lead in soil and water were 0.00237 mg/g and 8.26 μg/L, respectively, which are below the permissible values of 0.1 mg/g and 10 μg/L according to WHO standards. The blood lead levels and exposure to lead in children were calculated using the integrated exposure uptake biokinetic model as per United States Environmental Protection Agency (USEPA) guidelines. The mean blood lead level was 1.78 μg/dL, and the model also predicted that 6.497% of the children in the city may have blood lead levels above the Center for Disease Control recommended reference value of 3.5 μg/dL. Even if the values were below the reference, there is no safe blood lead level since even a small amount can have adverse effects on children.

Assessing the multi-dimensional impact of lead-induced toxicity on collembola found in maize fields: From oxidative stress to genetic disruptions

The prolonged exposure of agricultural soils to heavy metals from wastewater, particularly in areas near industrial facilities, poses a significant threat to the well-being of living organisms. The World Health Organization (WHO) has established standard permissible limits for heavy metals in agricultural soils to mitigate potential health hazards. Nevertheless, some agricultural fields continue to be irrigated with wastewater containing industrial effluents. This study aimed to assess the concentration of lead in soil samples collected from agricultural fields near industrial areas. Subsequently, we determined the lethal concentration (LC50) of lead (Pb) and other heavy metals for two Collembola species, namely Folsomia candida, a standard organism for soil ecotoxicity tests, and comparing it with Proisotoma minuta. The research further examined the toxic effects of lead exposure on these two species, revealing depletion in the energy reservoirs and alterations in the tissue histology of both organisms. The study revealed that lead can induce genotoxic damage as it evidently has moderate binding affinity with the ct-DNA and hence can cause DNA fragmentation and the formation of micronuclei. Elevated lipid peroxidation (LPO) levels and protein carbonylation levels were observed, alongside a reduction in antioxidant enzymes (CAT, SOD & GPx). These findings suggest that lead disrupts the balance between oxidants and the antioxidant enzyme system, impairing defense mechanisms and consequential derogatory damage within microarthropods. The investigation elucidates a complex network of various signaling pathways compromised as a result of lead toxicity. Hence, it presents a novel perspective that underscores the pressing necessity for implementing an integrated risk assessment framework at the investigated site.

Exogenous Application of Thiamine and Nicotinic Acid Improves Tolerance and Morpho-physiological Parameters of Lens culinaris Under Lead (Pb) Exposure

Exogenous Application of Thiamine and Nicotinic Acid Improves Tolerance and Morpho-physiological Parameters of Lens culinaris Under Lead (Pb) Exposure