Low-Level Cadmium Exposure and Atherosclerosis

Therapeutic Efficacy of Selenium Pre-treatment in Mitigating Cadmium-Induced Cardiotoxicity in Zebrafish (Danio rerio)

Cardiovascular diseases are a rampant public health threat. Environmental contaminants, such as Cadmium (Cd), a toxic metal, are risk factors for cardiovascular diseases. Given that human exposure to Cd is increasing, there is a need for therapies to ameliorate Cd toxicity. Selenium (Se), an essential trace element, has been proposed to rescue the effects of Cd toxicity, with mixed effects. Se's narrow therapeutic window necessitates precise dosing to avoid toxicity. Here, we assessed the effects of various waterborne Cd and Se concentrations and sequences on cardiac function using zebrafish (Danio rerio). We showed that Cd induced pericardial edemas and modified heart rates in zebrafish larvae in a concentration-dependent manner. To identify the therapeutic range of Se for Cd-induced cardiotoxicity, zebrafish embryos were treated with 0, 10, 50, 100, 150, or 200 μg/L Se for 1-4 days prior to exposure to 2.5 and 5 μg/L Cd. We found that a 50 µg/L Se pre-treatment before 2.5 μg/L Cd, but not 5 μg/L Cd, reduced the prevalence of pericardial edemas and ameliorated Cd-induced bradycardia in zebrafish. Zebrafish exposed to 10 and 50 μg/L of Se for up to 4 days showed typical heart morphology, whereas other Se-exposed and control fish presented pericardial edemas. Longer Se pre-treatment durations led to fewer incidences of pericardial edemas. Overall, this study highlights the importance of optimizing Se concentrations and pre-treatment periods to harness its protective effects against Cd-induced cardiotoxicity. These findings provide insights into potential therapeutic strategies for reducing Cd-related cardiovascular damage in humans.

Environmental Heavy Metal Exposure and Associated Cardiovascular Diseases in Light of the Triglyceride Glucose Index

Cardiovascular diseases (CVD), primarily ischemic heart disease and stroke, remain leading global health burdens. Environmental risk factors have a major role in the development of CVD, particularly exposure to heavy metals. The Triglyceride Glucose Index (TyG), a measure of insulin resistance and CVD risk, is the primary focus of this study, which summarizes the most recent findings on the effects of lead (Pb), arsenic (As), and cadmium (Cd) on CVD risk. A higher risk of CVD is correlated with an elevated TyG index, which has been linked to insulin resistance. Exposure to Cd is associated with disturbance of lipid metabolism and oxidative stress, which increases the risk of CVD and TyG. Exposure reduces insulin secretion and signaling, which raises the TyG index and causes dyslipidemia. Pb exposure increases the risk of CVD and TyG index via causing oxidative stress and pancreatic β-cell destruction. These results highlight the need of reducing heavy metal exposure by lifestyle and environmental modifications in order to lower the risk of CVD. To comprehend the mechanisms and create practical management plans for health hazards associated with heavy metals, more study is required.

Variety-dependent responses of common tobacco with differential cadmium resistance: Cadmium uptake and distribution, antioxidative activity, and gene expression

Cadmium (Cd), which accumulates in tobacco leaves, enters the human body through inhalation of smoke, causing harmful effects on health. Therefore, identifying the pivotal factors that govern the absorption and resistance of Cd in tobacco is crucial for mitigating the harmful impact of Cd. In the present study, four different Cd-sensitive varieties, namely, ZhongChuan208 (ZC) with resistance, ZhongYan100 (ZY), K326 with moderate resistance, and YunYan87 (YY) with sensitivity, were cultivated in hydroponic with different Cd concentrations (20 µM, 40 µM, 60 µM and 80 µM). The results indicated that plant growth was significantly decreased by Cd. Irrespective of the Cd concentration, ZC exhibited the highest biomass, while YY had the lowest biomass; ZY and K326 showed intermediate levels. Enzymatic (APX, CAT, POD) and nonenzymatic antioxidant (Pro, GSH) systems showed notable variations among varieties. The multifactor analysis suggested that the ZC and ZY varieties, with higher levels of Pro and GSH content, contribute to a decrease in the levels of MDA and ROS. Among all the Cd concentrations, ZC exhibited the lowest Cd accumulation, while YY showed the highest. Additionally, there were significant differences observed in Cd distribution and translocation factors among the four different varieties. In terms of Cd distribution, cell wall Cd accounted for the highest proportion of total Cd, and organelles had the lowest proportion. Among the varieties, ZC showed lower Cd levels in the cell wall, soluble fraction, and organelles. Conversely, YY exhibited the highest Cd accumulation in all tissues; K326 and ZY had intermediate levels. Translocation factors (TF) varied among the varieties under Cd stress, with ZC and ZY showing lower TF compared to YY and K326. This phenomenon mainly attributed to regulation of the NtNramp3 and NtNramp5 genes, which are responsible for the absorption and transport of Cd. This study provides a theoretical foundation for the selection and breeding of tobacco varieties that are resistant to or accumulate less Cd.

Therapeutic Efficacy of Selenium Pre-treatment in Mitigating Cadmium-Induced Cardiotoxicity in Zebrafish (Danio rerio)

Cardiovascular diseases are a rampant public health threat. Environmental contaminants, such as Cadmium (Cd), a toxic metal, have been linked to increased risk for cardiovascular diseases. Given that human exposure to Cd is increasing overtime, there is a need to develop new therapies to ameliorate Cd toxicity. Selenium (Se), an essential trace element, has been proposed to rescue the effects of Cd toxicity, with mixed effects. Se's narrow therapeutic window necessitates precise dosing to avoid toxicity. Here, we assessed the effects of various waterborne Cd and Se concentrations and sequences on cardiac function using zebrafish (Danio rerio). We showed that Cd induced pericardial edemas and modified heart rates in a concentration-dependent manner. To identify the therapeutic range of Se for Cd-induced cardiotoxicity, zebrafish embryos were treated with 0, 10, 50, 100, 150, or 200 μg/L Se for 1-4 days prior to exposure to Cd at 2.5, and 5 μg/L. We found that a 50 μg/L Se pre-treatment prior to Cd at 2.5 μg/L, but not at 5 μg/L, reduced the prevalence of pericardial edemas and ameliorated Cd-induced bradycardia in zebrafish. Embryos exposed to 10 and 50 μg/L of Se showed typical heart morphology, whereas other Se-exposed and Se-deficient fish presented pericardial edemas. Longer Se pre-treatment durations led to fewer incidences of pericardial edemas. Overall, this study highlights the importance of optimizing Se concentration and pre-treatment periods to harness its protective effects against Cd-induced cardiotoxicity. These findings provide insights into potential therapeutic strategies for reducing Cd-related cardiovascular damage in humans.

Translational toxicology of metal(loid) species: linking their bioinorganic chemistry in the bloodstream to organ damage onset

The quantification of arsenic, mercury, cadmium and lead in the human bloodstream is routinely used today to assess exposure to these toxic metal(loid)s, but the interpretation of the obtained data in terms of their cumulative health relevance remains problematic. Seemingly unrelated to this, epidemiological studies strongly suggest that the simultaneous chronic exposure to these environmental pollutants is associated with the etiology of autism, type 2 diabetes, irritable bowel disease and other diseases. This from a public health point of view undesirable situation urgently requires research initiatives to establish functional connections between human exposure to multiple toxic metal(loid) species and adverse health effects. One way to establish causal exposure-response relationships is a molecular toxicology approach, which requires one to unravel the biomolecular mechanisms that unfold after individual toxic metal(loid)s enter the bloodstream/organ nexus as these interactions ultimately determine which metabolites impinge on target organs and thus provide mechanistic links to diseases of unknown etiology. In an attempt to underscore the importance of the toxicological chemistry of metal(loid)s in the bloodstream, this review summarizes recent progress into relevant bioinorganic processes that are implicated in the etiology of adverse organ-based health effects and possibly diseases. A better understanding of these bioinorganic processes will not only help to improve the regulatory framework to better protect humans from the adverse effects of toxic metal(loid) species, but also represents an important starting point for the development of treatments to ameliorate pollution-induced adverse health effects on human populations, including pregnant women, the fetus and children.

Low-dose cadmium induces lymphangiogenesis through activation of the STAT3 signaling pathway

Cadmium (Cd) is a widespread environmental toxicant that poses significant threat to public health. After intake, Cd is distributed throughout the body via blood and lymphatic circulation. However, the effect of Cd on lymphatic vessels has not been revealed. In this study, mice were exposed to 10 μM cadmium chloride through drinking water immediately after corneal alkali burn. In vivo analyses showed that Cd treatment enhances the alkali burn-induced corneal lymphangiogenesis, which is characterized by increased expression of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), prospero-related homeobox 1 (PROX-1) and vascular endothelial growth factor receptor 3 (VEGFR3). In vitro, the proliferation and migration of human dermal lymphatic endothelial cells (HDLECs) are increased by 1 μM Cd treatment, while inhibited by 10 μM Cd treatment. At a concentration of 1 μM, Cd specifically induces phosphorylation of signal transducer and activator of transcription 3 (STAT3), but has no effect on the MAPK, AKT, or NF-κB signaling pathway. In the presence of the STAT3 inhibitor STATTIC, Cd fails to induce HDLECs proliferation and migration. In addition, Cd upregulates VEGFR3 expression and its gene promoter activity in a STAT3-dependent manner. Our study suggests that low-dose Cd promotes lymphangiogenesis through activation of the STAT3 signaling pathway.

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

Effects of postweaning cadmium exposure on socioemotional behaviors in adolescent male mice

Exposure to cadmium (Cd), a toxic heavy metal classified as an environmental endocrine disruptor, can exert significant toxicity in both animals and humans. However, the potential effects of Cd exposure on socioemotional behaviors are still poorly understood, as are the underlying mechanisms. In the present study, employing a series of behavioral tests as well as 16 S rRNA sequencing analysis, we investigated the long-term effects of Cd exposure on socioemotional behaviors and their associated mechanisms in mice based on the brain-gut interaction theory. The results showed that postweaning exposure to Cd reduced the ability to resist depression, decreased social interaction, subtly altered sexual preference, and changed the composition of the gut microbiota in male mice during adolescence. These findings provided direct evidence for the deleterious effects of exposure to Cd in the postweaning period on socioemotional behaviors later in adolescence, and suggested that these effects of Cd exposure may be linked to changes in the gut microbiota.

Metabolome analysis to investigate the effect of heavy metal exposure and chemoprevention agents on toxic injury caused by a multi-heavy metal mixture in rats

Heavy metal pollution is a significant threat to both the environment and living organisms. This is especially vital considering the persistent and cumulative nature of heavy metal exposure, which can lead to severe and chronic health consequences for individuals. Therefore, implementing effective treatments is critical to addressing the serious public health issues posed by heavy metal pollution. In this study, nontargeted metabolomics was carried out to investigate the metabolic changes associated with long-term low-dose intake of mixed heavy metal pollutants (MHMPs) in liver, kidney, and plasma samples of Sprague-Dawley (SD) rats with and without treatment to reveal the underlying toxic effects of MHMPs and the effects of chemoprevention agents, including epigallocatechin-3-gallate (EGCG), trisodium citrate dihydrate (TCD), and glutathione (GSH). In the liver, kidney, and plasma, we observed a total of 21, 69, and 16 metabolites, respectively, exhibiting significant differences (P < 0.05, fold change >1.2 or <0.83, and VIP ≥ 1) between the control group and the mixture group. The findings demonstrated that exposure to MHMPs leads to the dysregulation of numerous metabolic pathways, with a particular emphasis on purine metabolism and aminoacyl-tRNA biosynthesis with upregulated renal purine metabolites and downregulated hepatic purine metabolites as well as renal aminoacyl-tRNA biosynthesis-related metabolites. However, the application of chemical protectants was shown to partially restore the metabolic alterations induced by MHMPs, particularly purine metabolism-related metabolites, including hepatic adenine and renal adenine, guanine, guanosine, adenosine monophosphate (AMP), and hypoxanthine. In addition, liver adenosine, kidney inosine and L-phenylalanine were considered the main regulated sites based on their significant correlations with multiple heavy metals. Our study provides crucial insights into the toxicological mechanisms of heavy metal pollution and has the potential to guide the development of effective preventive strategies.

Involvement of toxic metals and PCBs mixture in the thyroid and male reproductive toxicity: In silico toxicogenomic data mining

Toxicological research is mostly limited to considering the effects of a single substance, even though the real exposure of people is reflected in their daily exposure to many different chemical substances in low-doses. This in silico toxicogenomic study aims to provide evidence for the selected environmental (organo)metals (lead, cadmium, methyl mercury) + polychlorinated biphenyls mixture involvement in the possible alteration of thyroid, and male reproductive system function, and furthermore to predict the possible toxic mechanisms of the environmental cocktail. The Comparative Toxicogenomic Database, GeneMANIA online software, and ToppGene Suite portal were used as the main tools for toxicogenomic data mining and gene ontology analysis. The results show that 35 annotated common genes between selected chemicals and endocrine system diseases can interact on the co-expression level. Our study highlighted the disruption of the cytokines, the cell's response to oxidative stress, and the influence of the transcription factors as the potential core of toxicological mechanisms of the discussed mixture's effects. The connected toxicological effects of the tested mixture were abnormal sperm cells, a disrupted level of testosterone, and thyroid hormones. The core mechanisms of these effects were inflammation, oxidative stress, disruption of androgen receptor signaling, and the alteration of the FOXO3-Keap-1/NRF2-HMOX1-NQO1 pathway signaling most likely controlled by the co-expression of overlapped genes among used chemicals. This in silico research can be used as a potential core for the determination of biomarkers that can be monitored in future further in vitro and in vivo experiments.

Physical activity attenuates the association between blood cadmium exposure and cardiovascular disease: findings from the National Health and Nutrition Examination Survey 2007-2018

Existing studies could not separate the effects of heavy metal exposure on cardiovascular disease (CVD) risk from those caused by physical activity (PA). The possible interactive effect of heavy metal exposure and PA on the risk of CVD remains still unknown. We enrolled a total of 12,280 participants in 2007-2018 cycles of the U.S. National Health and Nutrition Examination Survey (NHANES) and discovered that both low blood concentrations of Cd and Pb were positively correlated with increased prevalence of CVD and subtypes, with a stronger association for blood Cd than Pb. Negative dose-response relationships between PA and the prevalence of CVD and subtypes were identified. Participants with inactive and active PA had lower risk of CVD than those having no PA, with multivariate adjusted ORs 0.8 (95% CI: 0.69, 0.94) and 0.76 (95% CI: 0.68, 0.85), respectively. The only evidence for negative interaction between regular PA and blood Cd concentrations was found with regard to the prevalence of CVD and subtypes, indicating that regular PA could well modify the adverse effect of blood Cd on CVD risk. We demonstrate for the first time to date that PA may have a beneficial effect against the hazardous impact of Cd exposure on elevated CVD risk, emphasizing the necessity to promote a healthy lifestyle with active PA.

Cadmium, von Willebrand factor and vascular aging

Vascular aging is a major contributing factor to cardiovascular disease. The aged blood vessels, characterized by vascular wall thickening and stiffening, are instigated by endothelial cell dysfunction induced by oxidative stress and inflammation. von Willebrand Factor (vWF) is a glycoprotein known for its role in coagulation, and plasma levels of vWF are increased with age. Elevated vWF promotes thrombosis, atherosclerotic plaque formation, inflammation and proliferation of vascular smooth muscle cells. Cadmium (Cd) is an environmental pollutant associated with increased morbidity and mortality of cardiovascular disease. At low concentrations, Cd activates pro-survival signaling in endothelial cells, however enhances intima-media thickness and atherogenesis. A non-cytotoxic dose of Cd also increases endothelial vWF expression and secretion in vivo and in vitro. In this review, we summarize the molecular mechanisms underlying vWF-promoted vascular aging-associated pathologies and Cd-induced vWF expression. In addition, we propose that exposure to low-dose Cd is a risk factor for vascular aging, through elevation of plasma vWF.

Effects of cadmium on transcription, physiology, and ultrastructure of two tobacco cultivars

Cadmium (Cd) is one of the most toxic heavy metal pollutants worldwide. Tobacco is an important cash crop; however, the accumulation of Cd in its biomass is very high. Cadmium may enter the body of smokers with contaminated tobacco and the surrounding environment via smoke. Therefore, it is important to understand the mechanisms of Cd accumulation and tolerance in tobacco plants, especially in the leaves. In this study, the effects of Cd on the growth, accumulation, and biochemical indices of two tobacco varieties, K326 (Cd resistant) and NC55 (Cd sensitive), were studied through transcriptomic and physiological experiments. Transcriptome and physiological analyses showed differences in the expression of Cd transport and Cd resistance related genes between NC55 and K326 under Cd stress. The root meristem cells of NC55 were more severely damaged. The antioxidant enzyme activity, ABA and ZT content, chlorophyll content, photosynthetic rate, and nitrogen metabolism enzyme activity in K326 leaves were higher than in NC55. These data elucidate the mechanisms of low Cd accumulation and high Cd tolerance in K326 leaves and provide a theoretical basis for cultivating tobacco varieties with low Cd accumulation and high Cd resistance.

Ascorbic acid attenuates cadmium-induced myocardial hypertrophy and cardiomyocyte injury through Nrf2 signaling pathways comparable to resveratrol

Chronic cadmium (Cd) exposure severely affects the structural integrity of the heart, leading to cardiovascular disease. This study investigates the protective role of ascorbic acid (AA) and resveratrol (Res) in cellular defense against Cd-induced cardiomyocyte damage and myocardial hypertrophy in H9c2 cardiomyocytes. Experimental results showed that AA and Res treatment significantly increased cell viability, reduced ROS production, attenuated lipid peroxidation, and increased antioxidant enzyme activity in Cd-induced H9c2 cells. AA and Res decreased the mitochondrial membrane permeability and protected the cells from Cd induced cardiomyocyte damage. This also suppressed the pathological hypertrophic response triggered by Cd, which increased the cell size of cardiomyocytes. Gene expression studies revealed that cells treated with AA and Res decreased the expression of hypertrophic genes ANP (two-fold), BNP (one-fold) and β- MHC (two-fold) compared to Cd exposed cells. AA and Res promoted the nuclear translocation of Nrf2 and increased the expression of antioxidant genes (HO-1, NQO1, SOD and CAT) during Cd mediated myocardial hypertrophy. This study proves that AA and Res play a significant role in improving Nrf2 signaling, thereby reversing stress-induced injury, and facilitating the regression of myocardial hypertrophy.

Independent association of blood cadmium with subclinical lower extremity atherosclerosis: An observational study based on dose-response analysis

BACKGROUND

Atherosclerosis is an increasingly public health issue globally. Previous studies have showed a causal link between heavy metal exposure and atherosclerosis. However, the association of cadmium concentration with subclinical lower extremity atherosclerosis (SLEA) remains unclear.

AIMS

To investigate the association of blood cadmium with SLEA and its extent, and further analyze the potential dose-response relationship.

METHODS

Blood cadmium concentration was measured using inductively coupled plasma mass spectrometry. SLEA and its extent were assessed by ultrasound diagnosis system. Multivariate models were applied to evaluate the association of blood cadmium with SLEA and its extent. Restricted cubic splines were performed to explore the potential dose-response relationship.

RESULTS

This observational study consisted of 1664 participants from cardiovascular outpatient, with an average age of 62.4 years and 1218 (73.2%) men. When blood cadmium was included as a categorical variable in multivariate models, logistic regression analysis showed that high quartile in blood cadmium was an independent risk factor of SLEA (OR = 2.704, 95%CI 1.866-3.919). After log-transformed for SLEA extent parameters, linear regression analysis indicated that high quartile in blood cadmium was significantly associated with higher Crouse score (GMR = 1.21, 95%CI 1.15-1.28), plaque maximum thickness (GMR = 1.13, 95%CI 1.09-1.18) and diseased vessel count (GMR = 1.14, 95%CI 1.10-1.19), respectively. When blood cadmium was used as a continuous variable in restricted cubic splines, the dose-response relationship presented a positive progression in SLEA (P = 0.302), plaque maximum thickness (P = 0.145) and diseased vessel count (P = 0.055) apparently that did not deviate from linearity.

CONCLUSIONS

Blood cadmium exhibited an independent association with SLEA, and this dose-response relationship was progressive without significant departure from linearity.

Informer-Based Safety Risk Prediction of Heavy Metals in Rice in China

Focused supervision and early warning of heavy metal (HM)-contaminated rice areas can effectively protect people's livelihood security and maintain social stability. To improve the accuracy of risk prediction, an Informer-based safety risk prediction model for HMs in rice is constructed in this paper. First, based on the national sampling data and residential consumption statistics of rice, we construct a dataset of evaluation indicators that can characterize the level of rice safety risk so as to form a safety risk space. Second, based on the K-medoids clustering algorithm, we classify the rice safety risk space into levels. Finally, we use the Informer neural network model to predict the safety risk indicators of rice in each province so as to predict the safety risk level. This study compares the prediction accuracy of a self-constructed dataset of rice safety risk assessment indicators. The experimental results show that the prediction precision of the method proposed in this paper reaches 99.17%, 91.77%, and 91.33% for low, medium, and high risk levels, respectively. The model provides technical support and a scientific basis for screening the time and area of HM contamination of rice, which needs focus.

Phenotypic aging mediates the association between blood cadmium and depression: a population-based study

Depression is a serious public health problem today, especially in middle-aged and older adults. Although the etiology of the disease has not been fully elucidated, environmental factors are increasingly not negligible. Cadmium is widely used in industrial production. The general population may be chronically exposed to low doses of cadmium. This study aimed to investigate the association between blood cadmium and depression and to explore the mediating role of aging indicators in this process. We conducted a cross-sectional study on blood cadmium (N = 7195, age ≥ 20 years) using data from the 2007-2010 National Health and Nutrition Examination Survey (NHANES). Aging indicators (biological and phenotypic age) are calculated by combining multiple biochemical and/or functional indicators. To determine the relationship between blood cadmium concentrations and depressive symptoms, we used weighted multivariate logistic regression and restricted cubic spline functions and employed mediation analysis to explore the possible mediating effects of aging indicators in the process. We found a significant positive association between blood cadmium and depression with an odds ratio (OR) and 95% confidence interval (CI): 1.22 (1.04,1.43). Restricted cubic spline analysis found a linear positive association between blood cadmium and depression. In the fully covariate-adjusted model, we found a positive association between blood cadmium and biological age and phenotypic age with β and 95% CI: 1.02 (0.65, 1.39) and 2.35 (1.70, 3.01), respectively. In the mediation analysis, we found that phenotypic age mediated 21.32% of the association between blood cadmium and depression. These results suggest that even exposure to low doses of cadmium can increase the risk of depression and that this process may be mediated by phenotypic aging.

Development and application of an evidence-based directed acyclic graph to evaluate the associations between metal mixtures and cardiometabolic outcomes

Objectives

Specifying causal models to assess relationships among metal mixtures and cardiometabolic outcomes requires evidence-based models of the causal structures; however, such models have not been previously published. The objective of this study was to develop and evaluate a directed acyclic graph (DAG) diagraming metal mixture exposure and cardiometabolic outcomes.

Methods

We conducted a literature search to develop the DAG of metal mixtures and cardiometabolic outcomes. To evaluate consistency of the DAG, we tested the suggested conditional independence statements using linear and logistic regression analyses with data from the San Luis Valley Diabetes Study (SLVDS; n=1795). We calculated the proportion of statements supported by the data and compared this to the proportion of conditional independence statements supported by 1,000 DAGs with the same structure but randomly permuted nodes. Next, we used our DAG to identify minimally sufficient adjustment sets needed to estimate the association between metal mixtures and cardiometabolic outcomes (i.e., cardiovascular disease, fasting glucose, and systolic blood pressure). We applied them to the SLVDS using Bayesian kernel machine regression, linear mixed effects, and Cox proportional hazards models.

Results

From the 42 articles included in the review, we developed an evidence-based DAG with 74 testable conditional independence statements (43 % supported by SLVDS data). We observed evidence for an association between As and Mn and fasting glucose.

Conclusions

We developed, tested, and applied an evidence-based approach to analyze associations between metal mixtures and cardiometabolic health.

Interspecies differences in mammalian susceptibility to legacy POPs and trace metals using skin fibroblast cells

The susceptibility to trace metals and legacy POPs is different between terrestrial and marine mammals. In this study, we established the first cell line from Indo-Pacific finless porpoises and compared the cellular responses of skin fibroblast cells from Pygmy killer whales, Pantropic spotted dolphins, Indo-Pacific finless porpoises, mice, and humans following exposure to copper, methylmercury, cadmium, PCB126, PCB153, and BDE47 to better understand the interspecies sensitivities of mammals to chemical pollutants. We conducted a risk assessment by comparing no-observed effect concentrations (NOEC), lowest-observed effect concentrations (LOEC), and half maximal effective concentrations (EC50) from cell viability assays and previously reported pollutant body burdens in mammals. Based on the in vitro data, Indo-Pacific finless porpoises were more sensitive to copper and methylmercury than other mammals. PCB153 exposure reduced cell viability in all mammals except humans, while PCB126 was more potent, with 13.33 μg/mL exposure reducing cell viability in all mammals. In contrast, BDE47 exposure reduced cell viability only in terrestrial mammals in addition to pantropic spotted dolphin. Based on the in vitro data and the natural context of metal concentrations, both methylmercury and cadmium posed a higher risk to cetaceans than human, while copper posed a lower risk to cetaceans. All three legacy POPs (PCB126, PCB153, and BDE47) posed minor risk to cetaceans for short-term exposure. This study demonstrated that a species-specific in vitro model may provide more accurate information on the potential risk of pollutants to mammals. However, due to the bioamplification of POPs and their potential impact on the endocrine system and immune system of cetaceans, risk assessment with long-term exposure with more in vitro models should be further studied.

Mitochondrial disruption in isolated human monocytes: an underlying mechanism for cadmium-induced immunotoxicity

Cadmium (Cd) is an immunotoxic metal frequently found in the environment. The in vitro study undertaken here evaluated the immunotoxic effects of Cd in isolated human peripheral blood monocytes (hPBM). The results of the studies of exposures to varying doses of Cd (0, 0.1, 1, 10, and 100 µM, as cadmium dichloride [CdCl₂]) for 3, 6, 12, 24, 48, and 72 hr showed the test agent was cytotoxic to the cells in time- and concentration-related manners. Thereafter, using only those doses found to not cause extreme cell lethality a 48-hr period, the impact of 0.1 or 1 µM CdCl₂ on the cells was evaluated. Functionally, CdCl₂ treatment led to time- and concentration-related decreases in hPBM phagocytic activities as well as in the ability of the cells to form/release cytokines (including tumor necrosis factor [TNF]-α and interleukin [IL]-6 and -8). The CdCl₂ also led to significantly decreased ATP production (in part, via inhibition of mitochondrial complexes I and III) as well as in mitochondrial membrane potentials (MMP) and oxygen consumption rates (OCR; associated with parallel increases in cell lactate production) in the cells. In addition, CdCl₂ treatment resulted in significant increases in mitochondrial membrane fluidity (MMF) and cell unsaturated fatty acid content. Based on the results here, one might conclude that some of the effects that arose during the CdCl₂-induced dysfunction of the isolated hPBM (i.e. changes phagocytic activity, cytokine formation/secretion) could have evolved secondary to CdCl₂-induced disruptions of hPBM cell bioenergetics - an effect that itself was a culmination of an overall toxicity from CdCl₂ upon the mitochondria within these cells.

Urinary metals as influencing factors of coronary heart disease among a population in Guangzhou, China

The cardiovascular system is highly sensitive to toxic metal exposure and trace element dysregulation. However, previous findings relating to metal exposure and coronary heart disease (CHD) have partially been conflicting and difficult to exhibit the combined effect of metal mixtures. This case-control study investigated urinary concentrations of ten metal/metalloids among clinically-diagnosed CHD patients and healthy adults during May to December 2021 in Guangzhou, China. We found that cadmium (Cd) status in urine from CHD patients was remarkably higher than its reference, while chromium (Cr), nickel (Ni), copper (Cu) and selenium (Se) concentrations were lower (p < 0.05). Spearman correlation analysis showed that urinary arsenic (As) and Se were highly correlated (r_s=0.830, p < 0.001), indicating their similar sources. Principal component analysis (PCA) exhibited denser distribution of Cd-Sn in cases than in controls. Logistic regression analysis exhibited significant associations between urinary Cd (adjusted OR: 1.965, 95% CI: 1.222-3.162), Se (0.787, 95% CI: 0.695-0.893), Ni (0.493, 95% CI: 0.265-0.916) and CHD risk. Quantile g-computation showed negative joint effect of metal mixtures on CHD (adjusted OR: 0.383, 95% CI: 0.159-0.932) (p < 0.05), suggesting the need for supplementing essential trace elements. The negative partial effect was primarily attributed to Se and Ni, while positive partial effect was mainly due to tin (Sn) and Cd. Nevertheless, we also found a quantile increase of Cd-Sn level was negatively correlated with 8.26% (95% CI: 3.44-13.08%) decrease of high-density lipoprotein cholesterol (p < 0.001), and 71.2% of the joint effect attributed to Cd. Based on random forest, Se, Cd and Ni were found to be the dominant influencing factors of CHD. The role of Ni in CHD is yet to be uncovered, while excessive Cd exposure and low Se status among CHD patients need to be mitigated.

An Ultrasensitive and Selective Determination of Cadmium Ions at ppt Level Using an Enzymic Membrane with Colorimetric and Electrochemical Detection

Cadmium ions (Cd²⁺) are extremely toxic heavy metal pollutants found in the environment, and which endanger human health. Therefore, it is critical to develop a sensitive and simple method for rapidly detecting Cd²⁺ in water samples. Herein, an enzymic membrane was developed based on an easy and rapid immobilization method of horseradish peroxidase (HRP), for determination of Cd²⁺ in drinking water. Hence, for the first time, an enzymic membrane was applied for the detection of Cd²⁺ without being pretreated. In the first format, the inhibition of horseradish peroxidase was performed using a colorimetric microplate reader. Under optimal conditions, the achieved limit of detection was 20 ppt. In addition, an electrochemical biosensor was developed, by combining the enzymic membrane with screen printed electrodes, which showed a linear calibration range between 0.02–100 ppb (R² = 0.990) and a detection limit of 50 ppt. The use of this enzymic membrane proved to be advantageous when reversible inhibitors such as the copper ion (Cu²⁺) were present in water samples, as Cu²⁺ can interfere with Cd²⁺ and cause erroneous results. In order to alleviate this problem, a medium exchange procedure was used to eliminate Cu²⁺, by washing and leaving only cadmium ions as an irreversible inhibitor for identification. The use of this membrane proved to be a simple and rapid method of immobilizing HRP with a covalent bond.

Higher Blood Cadmium Concentration Is Associated With Increased Likelihood of Abdominal Aortic Calcification

Aims

This study aimed to evaluate the association between blood cadmium concentration (BCC) and abdominal aortic calcification (AAC) in adults aged ≥40 years in the United States.

Methods

Data were obtained from the 2013–2014 National Health and Nutrition Examination Survey (NHANES). Participants without data about BCC and AAC scores were excluded. BCC was directly measured using inductively coupled plasma mass spectrometry (ICP–MS). AAC scores were quantified by the Kauppila scoring system, and severe AAC was defined as an AAC score &gt;6. Weighted multivariable regression analysis and subgroup analysis were conducted to explore the independent relationship between cadmium exposure with AAC scores and severe AAC.

Results

A total of 1,530 participants were included with an average BCC of 0.47 ± 0.02 μg/L and AAC score of 1.40 ± 0.10 [mean ± standard error (SE)]. The prevalence of severe AAC was 7.96% in the whole subjects and increased with the higher BCC tertiles (Tertile 1: 4.74%, Tertile 2: 9.83%, and Tertile 3: 10.17%; p = 0.0395). We observed a significant positive association between BCC and the AAC score (β = 0.16, 95% CI: 0.01~0.30) and an increased risk of severe AAC [odds ratio (OR) = 1.45; 95% CI: 1.03~2.04]. Subgroup analysis and interaction tests revealed that there was no dependence for the association between BCC and AAC.

Conclusion

Blood cadmium concentration was associated with a higher AAC score and an increased likelihood of severe AAC in adults in the United States. Cadmium exposure is a risk factor for AAC, and attention should be given to the management of blood cadmium.

Cadmium exposure and growth differentiation factor-15 (GDF-15) levels in non-smoking older adults

BACKGROUND

Cadmium (Cd) exposure is a risk factor for cardiovascular disease (CVD); however, understanding the effects of Cd at the cellular level remains incomplete. Since growth differentiation factor-15 (GDF-15) is a cytokine produced in many cell types in response to tissue injury and inflammation that may capture several pathways between Cd and CVD, this study examined the relationship between blood Cd levels and serum GDF-15 concentrations in community-dwelling older adults.

METHODS

Cd and GDF-15 were measured in 1942 non-smoking individuals aged 65+ with no previous history of CVD. The association of Cd with GDF-15 was evaluated in linear regression models that adjusted for sociodemographic, lifestyle and biological risk factors, inflammatory biomarkers (IL-6, C-reactive protein and neutrophil to lymphocyte ratio), and markers of vascular damage (NTproBNP and cTnT-hs).

RESULTS

Geometric mean Cd exposure was 0.11 μg/L (0.09 in never- and 0.15 in former-smokers) and geometric mean GDF-15 was 1186.21 pg/mL (1182.67 in never- and 1191.66 in former-smokers). In multivariable analyses, we found a dose-response association between Cd levels and GDF-15: adjusted mean percentage differences in GDF-15 (95% confidence interval) per 2-fold increase in Cd concentrations in the overall non-smoking population and in never smokers were, respectively, 2.54% (1.01, 4.06) and 2.50% (0.47, 4.54). In spline regression, the dose-response relationship was progressive over the range of Cd concentrations with no significant departures from linearity.

CONCLUSIONS

Cd exposure may be related to enhanced GDF-15 expression. Future studies with repeated GDF-15 measurements should confirm the present findings to better understand the biological mechanisms underlying this association.

Impacts of Environmental Insults on Cardiovascular Aging

PURPOSE OF REVIEW

With cardiovascular disease (CVD) being the top cause of deaths worldwide, it is important to ensure healthy cardiovascular aging through enhanced understanding and prevention of adverse health effects exerted by external factors. This review aims to provide an updated understanding of environmental influences on cardiovascular aging, by summarizing epidemiological and mechanistic evidence for the cardiovascular health impact of major environmental stressors, including air pollution, endocrine-disrupting chemicals (EDCs), metals, and climate change.

RECENT FINDINGS

Recent studies generally support positive associations of exposure to multiple chemical environmental stressors (air pollution, EDCs, toxic metals) and extreme temperatures with increased risks of cardiovascular mortality and morbidity in the population. Environmental stressors have also been associated with a number of cardiovascular aging-related subclinical changes including biomarkers in the population, which are supported by evidence from relevant experimental studies. The elderly and patients are the most vulnerable demographic groups to majority environmental stressors. Future studies should account for the totality of individuals' exposome in addition to single chemical pollutants or environmental factors. Specific factors most responsible for the observed health effects related to cardiovascular aging remain to be elucidated.

Increased serum levels of cadmium are associated with an elevated risk of cardiovascular disease in adults

Previous studies have determined the effects of exposure to certain heavy metals on cardiovascular disease (CVD); however, the association between cadmium exposure and CVD in adults remains unclear. The relationship between serum levels of cadmium and the risk of CVD was studied by analyzing available data from 38,223 different participants of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2016. After adjusting for all covariates, we found that higher serum cadmium concentrations were positively related to both the overall risk of CVD (odds ratio (OR): 1.45; 95% confidence interval (CI): 1.22, 1.72; p for trend <0.001) and the risks of its subtypes, including congestive heart failure, coronary heart disease, heart attack, and stroke. Elevated cadmium levels were associated with increased levels of lipids and inflammatory factors, including blood triglycerides, total cholesterol, white blood cells (WBCs), and C-reactive protein (CRP). Our study provided epidemiological evidence that cadmium may increase the risk of CVD by elevating blood lipids and inflammation.

Review of cadmium exposure and smoking-independent effects on atherosclerotic cardiovascular disease in the general population

BACKGROUND

Exposure to cadmium (Cd) via food and smoking is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Blood and urine levels of Cd are established biomarkers of exposure.

OBJECTIVES

To review (1) the smoking-independent associations between Cd exposure and ASCVD, including the possible presence of a nonlinear dose-response relationship with Cd exposure and (2) the causal effects of Cd exposure on different stages of atherosclerosis.

METHODS

Narrative review.

RESULTS

Cd confers increased risk of ASCVD and asymptomatic atherosclerosis in the carotid and coronary arteries above B-Cd >0.5 μg/L or U-Cd >0.5 μg/g creatinine, but it has not been shown below a threshold of these exposure levels. Adjustment for smoking does not exclude the possibility of residual confounding, but several studies in never-smoking cohorts have shown associations between Cd and ASCVD, and experimental studies have demonstrated pro-atherosclerotic effects of Cd. Cd accumulates in arterial walls and atherosclerotic plaques, reaching levels shown to have proatherosclerotic effects. Suggested early effects are increased subendothelial retention of atherogenic lipoproteins, which become oxidized, and endothelial dysfunction and damage with increased permeability for monocytes, which in the intima turn to macrophages and then to foam cells. Later, Cd may contribute to plaque rupture and erosion by endothelial apoptosis and degradation of the fibrous cap. Finally, by having prothrombotic and antifibrinolytic effects, the CVD risk may be further increased.

CONCLUSIONS

There is strong evidence that Cd causes ASCVD above a suggested exposure level via mechanisms in early as well as the late stages of atherosclerotic disease.