Independent, combine and interactive effects of heavy metal exposure on dyslipidemia biomarkers: A cross-sectional study in northeastern China

Metal mixture exposures and serum lipid levels in childhood: the Rhea mother-child cohort in Greece

BACKGROUND

Growing evidence suggests that cardiovascular disease develops over the lifetime, often beginning in childhood. Metal exposures have been associated with cardiovascular disease and important risk factors, including dyslipidemia, but prior studies have largely focused on adult populations and single metal exposures.

OBJECTIVE

To investigate the individual and joint impacts of multiple metal exposures on lipid levels during childhood.

METHODS

This cross-sectional study included 291 4-year-old children from the Rhea Cohort Study in Heraklion, Greece. Seven metals (manganese, cobalt, selenium, molybdenum, cadmium, mercury, and lead) were measured in whole blood using inductively coupled plasma mass spectrometry. Serum lipid levels included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. To determine the joint and individual impacts of child metal exposures (log2-transformed) on lipid levels, Bayesian kernel machine regression (BKMR) was employed as the primary multi-pollutant approach. Potential effect modification by child sex and childhood environmental tobacco smoke exposure was also evaluated.

RESULTS

BKMR identified a positive association between the metal mixture and both total and LDL cholesterol. Of the seven metals examined, selenium (median 90.6 [IQR = 83.6, 96.5] µg/L) was assigned the highest posterior inclusion probability for both total and LDL cholesterol. A difference in LDL cholesterol of 8.22 mg/dL (95% CI = 1.85, 14.59) was observed when blood selenium was set to its 75th versus 25th percentile, holding all other metals at their median values. In stratified analyses, the positive association between selenium and LDL cholesterol was only observed among boys or among children exposed to environmental tobacco smoke during childhood.

IMPACT STATEMENT

Growing evidence indicates that cardiovascular events in adulthood are the consequence of the lifelong atherosclerotic process that begins in childhood. Therefore, public health interventions targeting childhood cardiovascular risk factors may have a particularly profound impact on reducing the burden of cardiovascular disease. Although growing evidence supports that both essential and nonessential metals contribute to cardiovascular disease and risk factors, such as dyslipidemia, prior studies have mainly focused on single metal exposures in adult populations. To address this research gap, the current study investigated the joint impacts of multiple metal exposures on lipid concentrations in early childhood.

Human Health Effects of Oral Exposure to Chromium: A Systematic Review of the Epidemiological Evidence

The toxicity and carcinogenicity of hexavalent chromium via the inhalation route is well established. However, a scientific debate has arisen about the potential effects of oral exposure to chromium on human health. Epidemiological studies evaluating the connection between ingested chromium and adverse health effects on the general population are limited. In recent years, a wealth of biomonitoring studies has emerged evaluating the associations between chromium levels in body fluids and tissues and health outcomes. This systematic review brings together epidemiological and biomonitoring evidence published over the past decade on the health effects of the general population related to oral exposure to chromium. In total, 65 studies were reviewed. There appears to be an inverse association between prenatal chromium exposure and normal fetal development. In adults, parameters of oxidative stress and biochemical alterations increase in response to chromium exposure, while effects on normal renal function are conflicting. Risks of urothelial carcinomas cannot be overlooked. However, findings regarding internal chromium concentrations and abnormalities in various tissues and systems are, in most cases, controversial. Environmental monitoring together with large cohort studies and biomonitoring with multiple biomarkers could fill the scientific gap.

Joint and interactive effects of metal mixtures on liver damage: Epidemiological evidence from repeated-measures study

BACKGROUND

The impact of heavy metals on liver function has been examined in numerous epidemiological studies. However, these findings lack consistency and longitudinal validation.

METHODS

In this study, we conducted three follow-up surveys with 426 participants from Northeast China. Blood and urine samples were collected, along with questionnaire information. Urine samples were analyzed for concentrations of four metals (chromium [Cr], cadmium [Cd], lead [Pb], and manganese [Mn]), while blood samples were used to measure five liver function indicators (alanine aminotransferase [ALT], aspartate aminotransferase [AST], albumin [ALB], globulin [GLB], and total protein [TP]). We utilized a linear mixed-effects model (LME) to explore the association between individual heavy metal exposure and liver function. Joint effects of metal mixtures were investigated using quantile g-computation and Bayesian kernel machine regression (BKMR). Furthermore, we employed BKMR and Marginal Effect models to examine the interaction effects between metals on liver function.

RESULTS

The LME results demonstrated a significant association between urinary heavy metals (Cr, Cd, Pb, and Mn) and liver function markers. BKMR results indicated positive associations between heavy metal mixtures and ALT, AST, and GLB, and negative associations with ALB and TP, which were consistent with the g-comp results. Synergistic effects were observed between Cd-Cr on ALT, Mn-Cr and Cr-Pb on ALB, while an antagonistic effect was found between Mn-Pb and Mn-Cd on ALB. Additionally, synergistic effects were observed between Mn-Cr on GLB and Cd-Cr on TP. Furthermore, a three-way antagonistic effect of Mn-Pb-Cr on ALB was identified.

CONCLUSION

Exposure to heavy metals (Cr, Cd, Mn, Pb) is associated with liver function markers, potentially leading to liver damage. Moreover, there are joint and interaction effects among these metals, which warrant further investigation at both the population and mechanistic levels.

Associations of urinary zinc exposure with blood lipid profiles and dyslipidemia: Mediating effect of serum uric acid

The relationship between zinc (Zn) exposure and abnormal blood lipids including dyslipidemia is contentious. Serum uric acid (SUA) has been reported to be correlated to both Zn exposure and dyslipidemia. The underlying mechanisms of Zn exposure associated with blood lipids and the mediating effects of SUA remain unclear. Therefore, this study analyzed the data from Chinese 2110 adults (mean age: 59.0 years old) in rural areas across China to explore the associations of Zn exposure with blood lipid profiles and dyslipidemia, and to further estimate the mediating effects of SUA in these relationships. The study data showed that urinary Zn was associated with increased levels of blood lipid components triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C). Moreover, an increased risk of dyslipidemia was observed in the study participants who had higher urinary Zn levels. Compared with the first quartile, the fourth quartile of urinary Zn concentration corresponded to the increase of TG (β = 0.20, 95 % CI: 0.12, 0.28), LDL-C (β = 0.06, 95 % CI: 0.01, 0.10) and dyslipidemia risk (OR = 2.16, 95 % CI: 1.50, 3.10), respectively. Elevated urinary Zn was also associated with higher levels of SUA and hyperuricemia risk. The SUA levels were positively related to total cholesterol (TC), TG, LDL-C levels and dyslipidemia risk. Mediation analyses revealed that SUA mediated 31.75 %, 46.16 % and 19.25 % of the associations of urinary Zn with TG, LDL-C levels and dyslipidemia risk, respectively. The subgroup and sensitivity analyses confirmed the positive associations between urinary Zn and blood lipid profiles and the mediating effect of SUA. The national population-based study further enhanced our understanding of the associations between Zn exposure and blood lipid profiles and mediating effect of SUA among generally healthy, middle-aged, and elderly individuals.

Association of multiple blood metals and systemic atherosclerosis: A cross-sectional study in the CAD population

BACKGROUND

Coronary atherosclerotic disease (CAD) is often accompanied by peripheral atherosclerosis, resulting in a higher risk of ischemia and cardiovascular death. Exposure to metals is associated with atherosclerotic plaques at specific sites. However, less is known about the effects of mixed metals on systemic atherosclerotic burden in CAD patients.

OBJECTIVES

To investigate the association of metal mixtures with systemic atherosclerotic burden in a CAD population.

METHODS

A cross-sectional study including 1562 CAD patients from Southwest China was conducted. The levels of 10 blood metals were measured via inductively coupled plasma spectrometry. More than one vessel with a stenosis ≥50% vessel diameter was defined as CAD. Carotid and lower limb atherosclerosis was assessed by using ultrasound, and coronary atherosclerosis was quantified via arterial angiography. Systemic atherosclerosis was scored according to the presence or absence of lesions at the three sites and the total number of lesions. To investigate the combined impacts and interaction effects of metals, Bayesian kernel machine regression was used. Weighted quantile regression was used to identify the contributions of the metals.

RESULTS

Significant overall associations of mixed metals with systemic atherosclerotic burden were found. These positive overall associations were mainly driven by Cd, Cu and Pb in systemic atherosclerosis. The main contributing factors were As and Cu for coronary atherosclerosis as well as Cd, Cu and Pb for carotid and lower limb atherosclerosis. Cd and Pb or Cr can interact, and Pb interacts with age, sex and alcohol.

CONCLUSIONS

In CAD patients, exposure to combinations of metals was highly positively associated with systemic atherosclerotic burden. These significant trends were more pronounced in the peripheral arteries and carotid arteries. Controlling environmental metal exposure can contribute to reducing systemic atherosclerosis in CAD patients.

Association Between Multiple Metal(loid)s Exposure and Blood Lipid Levels: Evidence from a Cross-Sectional Study of Southeastern China

Exposure to essential and toxic metals occurs simultaneously as a mixture in real-life. However, there is no consensus regarding the effects of co-exposure to multiple metal(loid)s (designated hereafter metals) on blood lipid levels. Thus, blood concentrations of six human essential metals and five toxic metals in 720 general populations from southeastern China were simultaneously determined as a measure of exposure. In addition, quantile g-computation, Bayesian kernel machine regression, elastic net regression, and generalized linear model were used to investigate both the joint and individual effects of exposure to this metal mixture on human blood lipid levels. The significant positive joint effect of exposure to this metal mixture on serum total cholesterol (TC) levels, rather than on serum triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, Castelli risk index I, Castelli risk index II, atherogenic coefficient, and non-HDL-C levels, was found. In addition, the positive effect may be primarily driven by selenium (Se), lead (Pb), and mercury (Hg) exposure. In addition, on the effect of TC levels, the synergistic effect between Pb and Hg and the antagonistic effect between Se and Pb were identified. Our finding suggests that combined exposure to this metal mixture may affect human blood lipid levels. Therefore, reducing exposure to heavy metals, such as Pb and Hg, should be a priority for the general population. In addition, Se supplementation should also be considered with caution.

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.

Occurrence of 8 trace elements in Rhizoma Cibotii from China and exposure assessment

The contamination of trace elements in Chinese edible herbs has attracted worldwide concern over the world. The objective of the present study was to investigate the occurrence and exposure assessment of eight trace elements in Rhizoma Cibotii from China. For this purpose, the method of inductively coupled plasma mass spectrometry was employed to detect the contamination levels of target trace elements in 58 Rhizoma Cibotii samples. The results demonstrated that the trace elements of Cr, Ni, Cu, Zn, and Pb were detected in all analyzed samples; the occurrence frequencies of As, Se, and Cd were 98.3%, 96.6%, and 98.3%, respectively. The highest mean levels were found in Zn (17.32 mg/kg), followed by Pb (8.50 mg/kg) and Cu (3.51 mg/kg). For a further step, one-way ANOVA was used to compare the difference of eight elements levels among groups, and Pearson's correlation analysis was used to explore the correlation between elements in Rhizoma Cibotii. A strong positive correlation between Zn and Cd was observed by Pearson's correlation analysis, which indicated that the possible presence of Cd contamination in Rhizoma Cibotii. Based on the contamination levels, the mean exposure of individual element and the health risks of eight trace elements in Rhizoma Cibotii were estimated by health risk assessment models. The calculated HQ values were less than 1, indicating that the contamination of trace elements in Rhizoma Cibotii did not pose significant health risks to human. In conclusion, the study provided baseline information on the contamination levels of trace elements in Rhizoma Cibotii. Moreover, it is necessary to monitor the trend of trace elements levels in Rhizoma Cibotii, which will be useful for ingredient control and human health protection.

Integration of transcriptomics and metabolomics analysis for unveiling the toxicological profile in the liver of mice exposed to uranium in drinking water

Uranium is a contaminate in the underground water in many regions of the world, which poses health risks to the local populations through drinking water. Although the health hazards of natural uranium have been concerned for decades, the controversies about its detrimental effects continue at present since it is still unclear how uranium interacts with molecular regulatory networks to generate toxicity. Here, we integrate transcriptomic and metabolomic methods to unveil the molecular mechanism of lipid metabolism disorder induced by uranium. Following exposure to uranium in drinking water for twenty-eight days, aberrant lipid metabolism and lipogenesis were found in the liver, accompanied with aggravated lipid peroxidation and an increase in dead cells. Multi-omics analysis reveals that uranium can promote the biosynthesis of unsaturated fatty acids through dysregulating the metabolism of arachidonic acid (AA), linoleic acid, and glycerophospholipid. Most notably, the disordered metabolism of polyunsaturated fatty acids (PUFAs) like AA may contribute to lipid peroxidation induced by uranium, which in turn triggers ferroptosis in hepatocytes. Our findings highlight disorder of lipid metabolism as an essential toxicological mechanism of uranium in the liver, offering insight into the health risks of uranium in drinking water.

Elevated serum lead and cadmium levels associated with increased risk of dyslipidemia in children aged 6 to 9 years in Shenzhen, China

Exposure to heavy metals can influence on metabolism, but studies have not fully evaluated young children. We investigated the association between levels of serum lead (Pb), cadmium (Cd), chromium (Cr), and arsenic (As) and risk of dyslipidemia in children. A total of 4513 children aged 6 to 9 years at 19 primary schools in Shenzhen were enrolled. Overall, 663 children with dyslipidemia were matched 1:1 with control by sex and age, and levels of serum Pb, Cd, Cr, and As were detected by inductively coupled plasma-mass spectrometry. Demographic characteristics and lifestyle were covariates in the logistic regression to determine the association of heavy metal levels with risk of dyslipidemia. Serum Pb and Cd levels were significantly higher in children with dyslipidemia than controls (133.08 vs. 84.19 μg/L; 0.45 vs. 0.29 μg/L; all P < 0.05), but this association was not found in Cr and As. We found significant upward trends for the odds ratios (ORs) of dyslipidemia associated with increasing quartiles of Pb and Cd levels (highest quartile of serum Pb OR 1.86, 95% confidence interval (CI) 1.46-2.38; Cd OR 2.51, 95% CI 1.94-3.24). Elevated serum Pb and Cd levels were associated with increased risk of dyslipidemia among children.

A review of important heavy metals toxicity with special emphasis on nephrotoxicity and its management in cattle

Toxicity with heavy metals has proven to be a significant hazard with several health problems linked to it. Heavy metals bioaccumulate in living organisms, pollute the food chain, and possibly threaten the health of animals. Many industries, fertilizers, traffic, automobile, paint, groundwater, and animal feed are sources of contamination of heavy metals. Few metals, such as aluminum (Al), may be eliminated by the elimination processes, but other metals like lead (Pb), arsenic (As), and cadmium (Ca) accumulate in the body and food chain, leading to chronic toxicity in animals. Even if these metals have no biological purpose, their toxic effects are still present in some form that is damaging to the animal body and its appropriate functioning. Cadmium (Cd) and Pb have negative impacts on a number of physiological and biochemical processes when exposed to sub-lethal doses. The nephrotoxic effects of Pb, As, and Cd are well known, and high amounts of naturally occurring environmental metals as well as occupational populations with high exposures have an adverse relationship between kidney damage and toxic metal exposure. Metal toxicity is determined by the absorbed dosage, the route of exposure, and the duration of exposure, whether acute or chronic. This can lead to numerous disorders and can also result in excessive damage due to oxidative stress generated by free radical production. Heavy metals concentration can be decreased through various procedures including bioremediation, pyrolysis, phytoremediation, rhizofiltration, biochar, and thermal process. This review discusses few heavy metals, their toxicity mechanisms, and their health impacts on cattle with special emphasis on the kidneys.

Disturbed Ratios between Essential and Toxic Trace Elements as Potential Biomarkers of Acute Ischemic Stroke

Background: Cadmium (Cd) and lead (Pb) are known to be two of the metal contaminants that pose the greatest potential threat to human health. The purpose of this research study was to compare the levels of toxic metals (Cd, Pb) in patients with acute ischemic stroke (AIS), with a control group in Podlaskie Voivodeship, Poland. The study also aimed to assess the correlations between toxic metals and clinical data in AIS patients, and to assess the potential effect of smoking. Materials and methods: The levels of mineral components in the collected blood samples were assessed by means of atomic absorption spectrometry (AAS). Results: The Cd blood concentration was significantly higher in AIS patients as compared to the control group. We found that the molar ratios of Cd/Zn and Cd/Pb were significantly higher (p < 0.001; p < 0.001, respectively), when the molar ratios of Se/Pb, Se/Cd, and Cu/Cd were significantly lower (p = 0.01; p < 0.001; p < 0.001, respectively), in AIS patients as compared to control subjects. However, there were no considerable fluctuations in relation to the blood Pb concentration or molar ratios of Zn/Pb and Cu/Pb between our AIS patients and the control group. We also found that patients with internal carotid artery (ICA) atherosclerosis, particularly those with 20–50% ICA stenosis, had higher concentrations of Cd and Cd/Zn, but lower Cu/Cd and Se/Cd molar ratios. In the course of our analysis, we observed that current smokers among AIS patients had significantly higher blood-Cd concentrations, Cd/Zn and Cd/Pb molar ratios, and hemoglobin levels, but significantly lower HDL-C concentrations, Se/Cd, and Cu/Cd molar ratios. Conclusions: Our research has shown that the disruption of the metal balance plays a crucial role in the pathogenesis of AIS. Furthermore, our results broaden those of previous studies on the exposure to Cd and Pb as risk factors for AIS. Further investigations are necessary to examine the probable mechanisms of Cd and Pb in the onset of ischemic stroke. The Cd/Zn molar ratio may be a useful biomarker of atherosclerosis in AIS patients. An accurate assessment of changes in the molar ratios of essential and toxic trace elements could serve as a valuable indicator of the nutritional status and levels of oxidative stress in AIS patients. It is critical to investigate the potential role of exposure to metal mixtures in AIS, due to its public health implications.

Endocrine disrupting chemicals: A promoter of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder. With the improvement in human living standards, the prevalence of NAFLD has been increasing in recent years. Endocrine-disrupting chemicals (EDCs) are a class of exogenous chemicals that simulate the effects of hormones in the body. There has been growing evidence regarding the potential effects of EDCs on liver health, especially in NAFLD. This paper aims to summarize the major EDCs that contribute to the growing burden of NAFLD and to raise public awareness regarding the hazards posed by EDCs with the objective of reducing the incidence of NAFLD.