Increased blood lead level induces oxidative stress and alters the antioxidant status of spray painters

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 association of lead exposure with blood pressure and hypertension: a mediation analyses of estimated glomerular filtration rate

The link between lead and blood pressure was debatable, and whether it was mediated by renal function was unknown. The purpose was to investigate the relationship between blood lead concentrations and blood pressure and hypertension, as well as the mediating role of estimated glomerular filtration rate (eGFR) in this relationship. Participants aged 18 were recruited from the National Health and Nutrition Examination Survey (1999-2014) and provided with lead and blood pressure data. Multivariate linear and logistic regression, stratification, interaction tests, and a restricted cubic spline curve were used to assess the association of blood lead with systolic/diastolic blood pressure (SBP/DBP) and hypertension, and mediation effect analysis was used to investigate the role of eGFR in this relationship. A total of 20,073 subjects were enrolled, and among them, 9837 (49.01%) were male and 7800 (38.86%) were hypertensive patients. Multivariate linear and logistic regression analysis showed that blood lead levels were significantly associated with SBP (β = 3.14, 95%CI: 2.03, 4.25; P < 0.001), DBP (β = 3.50, 95%CI: 2.69, 4.30; P < 0.001), and hypertension (OR = 1.29, 95%CI: 1.09, 1.52; P = 0.0026). In comparison to the lowest blood lead quartile, the highest lead group was significantly associated with SBP (= 2.55, 95%CI: 1.66, 3.44; P = 0.0001), DBP (= 2.60, 95%CI: 1.95, 3.24; P = 0.0001), and hypertension (OR = 1.26, 95%CI: 1.10, 1.45; P = 0.0007). Mediation analysis showed that the proportion of blood lead mediated for SBP, DBP, and hypertension was 3.56% (95%CI: 0.42%, 7.96%; P = 0.0320), 6.21% (95%CI: 4.02%, 9.32%; P < 0.0001), and 17.39% (95%CI: 9.34%, 42.71%; P < 0.0001), respectively. Adjusted restricted cubic spline curves presented a non-linear correlation of blood lead levels with DBP (P-non-linearity < 0.001), linear with SBP (P-non-linearity = 0.203), and hypertension (P-non-linearity = 0.763). Our findings demonstrated that blood lead levels were non-linear with DBP, but linear with SBP and hypertension, and this relationship was mediated by eGFR.

Metabolic and genetic derangement: a review of mechanisms involved in arsenic and lead toxicity and genotoxicity

Urbanisation and industrialisation are on the rise all over the world. Environmental contaminants such as potentially toxic elements (PTEs) are directly linked with both phenomena. Two PTEs that raise greatest concern are arsenic (As) and lead (Pb) as soil and drinking water contaminants, whether they are naturally occurring or the consequence of human activities. Both elements are potential carcinogens. This paper reviews the mechanisms by which As and Pb impair metabolic processes and cause genetic damage in humans. Despite efforts to ban or limit their use, due to high persistence both continue to pose a risk to human health, which justifies the need for further toxicological research.

Serum klotho and its associations with blood and urine cadmium and lead across various stages of glomerular function: data for US adults aged 40-79 years

Exposures to cadmium and lead can cause oxidative stress, leading to tissue damage resulting in kidney and cardiovascular diseases. The antiaging protein klotho, on the other hand, is known to act as an anti-oxidative agent. How klotho homeostasis interacts with exposure to cadmium and lead has not been reported. Thus, this study was carried to investigate associations of serum klotho with blood and urine cadmium and lead in US adults aged 40-79 years across stages of eGFR-based kidney function and albuminuria defined as urinary albumin/creatinine ratio of > 30 mg/g creatinine. As long as the kidney function was normal (eGFR ≥ 90 mL/min/1.73 m²) or near normal (60 ≤ eGFR < 90 mL/min/1.73 m²), there was no evidence of an association between cadmium exposure and klotho concentrations irrespective of the presence/absence of albuminuria. During kidney dysfunction (15 ≤ eGFR < 60 mL/min/1.73 m²), 10% increases in blood cadmium concentrations resulted in decreases in klotho concentrations between 0.27 and 0.84%. In addition, during severe kidney dysfunction (15 ≤ eGFR < 45 mL/min/1.73 m²), a positive association between urine cadmium and serum klotho concentrations was observed. In the absence of albuminuria and when kidney function was normal or near normal, 10% increases in blood lead concentrations were observed to be associated with modest decreases between 0.28% and 0.37% in serum klotho concentrations. Similar results were observed between the concentrations of urine lead and serum klotho during kidney dysfunction.

Accelerated apoptosis, oxidative stress, and cholinergic inflammation in blood of metalworkers

Metalworkers are exposed to numerous chemicals in their workplace environment, such as solvents, heavy metals, and metalworking fluids, that have a negative impact on their health. Furthermore, there is an increase in the prevalence of chronic diseases among metalworkers; however, the molecular mechanisms involved in this increased predisposition to chronic diseases are unclear. Considering that occupational exposure represents a potential risk for metalworkers, the aim of this study was to measure biomarkers of oxidative stress, inflammation, and cytotoxicity in the peripheral blood of metalworkers from Southern Brazil. The study included 40 metalworkers and 20 individuals who did not perform activities with any recognized exposure to chemical substances, such as those working in administration, commerce, and education, as controls. Cellular and molecular biomarkers as leukocyte viability, intracellular production of reactive species, mitochondrial mass and membrane potential and plasma lipid peroxidation, sulfhydryl groups, total antioxidant capacity, and butyrylcholinesterase activity were evaluated in the blood of metalworkers and controls. Metalworkers were found to have higher rates of apoptosis, increased production of reactive species, and increased mitochondrial potential and mass in leukocytes associated with decreased antioxidant defenses and increased activity of the butyrylcholinesterase enzyme in their plasma. It can be concluded that cytotoxicity, oxidative stress, and inflammation are involved in the multiplicity of health outcomes related to chemical exposure in the metalworking industry.

MOLECULAR MECHANISMS OF LEAD NEUROTOXICITY

Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.