Cadmium exposure is accompanied by increased prevalence and future growth of atherosclerotic plaques in 64-year-old women

Combined exposure to multiple metals on abdominal aortic calcification: results from the NHANES study

Exposure to metals increases the risk of many diseases and has become a public health concern. However, few studies have focused on the effect of metal on abdominal aortic calcification (AAC), especially the combined effects of metal mixtures. In this study, we aim to investigate the combined effect of metals on AAC risk and determine the key components in the multiple metals. We tried to investigate the relationship between multiple metal exposure and AAC risk. Fourteen urinary metals were analyzed with five statistical models as follows: generalized linear regression, weighted quantile sum regression (WQS), quantile g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) models. A total of 838 participants were involved, of whom 241 (28.8%) had AAC. After adjusting for covariates, in multiple metal exposure logistic regression, cadmium (Cd) (OR = 1.364, 95% CI = 1.035-1.797) was positively associated with AAC risk, while cobalt (Co) (OR = 0.631, 95% CI = 0.438-0.908) was negatively associated with AAC risk. A significant positive effect between multiple metal exposure and AAC risk was observed in WQS (OR = 2.090; 95% CI = 1.280-3.420, P < 0.01), Qgcomp (OR = 1.522, 95% CI = 1.012-2.290, P < 0.05), and BKMR models. It was found that the positive association may be driven primarily by Cd, lead (Pb), uranium (U), and tungsten (W). Subgroups analysis showed the association was more significant in participants with BMI ≥ 25 kg/m2, abdominal obesity, drinking, and smoking. Our study shows that exposure to multiple metals increases the risk of AAC in adults aged ≥ 40 years in the USA and that Cd, Pb, U, and W are the main contributors. The association is stronger in participants who are obese, smoker, or drinker.

Interactive effects of cadmium and titanium dioxide nanoparticles on hepatic tissue in rats: Ameliorative role of coenzyme 10 via modulation of the NF-κB and TNFα pathway

This study investigated the effect of oral dosing of titanium dioxide nanoparticles (TNPs) and cadmium (Cd2+) on rat liver and the potential protective role of coenzyme Q10 (CQ10) against TNPs and Cd2+-induced hepatic injury. Seventy male Sprague Dawley rats were divided into seven groups and orally given distilled water, corn oil, CQ10 (10 mg/kg b.wt), TNPs (50 mg/kg b.wt), Cd2+ (5 mg/kg b.wt), TNPs + Cd2+, or TNPs + Cd2++CQ10 by gastric gavage for 60 successive days. The results showed that individual or mutual exposure to TNPs and Cd2+ significantly increased the serum levels of various hepatic enzymes and lipids, depleted the hepatic content of antioxidant enzymes, and increased malondialdehyde. Moreover, the hepatic titanium and Cd2+ content were increased considerably in TNPs and/or Cd2+-exposed rats. Furthermore, marked histopathological perturbations with increased immunoexpression of tumor necrosis factor-alpha and nuclear factor kappa B were evident in TNPs and/or Cd2+-exposed rats. However, CQ10 significantly counteracted the damaging effect of combined exposure of TNPs and Cd2+ on the liver. The study concluded that TNPs and Cd2+ exposure harm hepatic function and its architecture, particularly at their mutual exposure, but CQ10 could be a candidate protective agent against TNPs and Cd2+ hepatotoxic impacts.

Exposure to metals among Electronic Nicotine Delivery System (ENDS) users in the PATH study: A longitudinal analysis

BACKGROUND

Few studies have evaluated Electronic Nicotine Delivery Systems (ENDS) in longitudinal studies, as a potential source of metals which may have carcinogenic, neurotoxic, and cardiotoxic effects. We evaluated metal body burden by ENDS use status in a longitudinal population-based national survey.

METHODS

We used the Population Assessment of Tobacco and Health (PATH) Study wave 1 (2013-2014), wave 2 (2014-2015), and wave 3 (2015-2016) adult data to assess urinary concentrations of seven metals among (1) ENDS only users who never used any nonelectronic tobacco products (n = 50), (2) ENDS only users who were former users of any nonelectronic tobacco products (n = 123) and (3) Never users (n = 1501) of any tobacco product.

RESULTS

Among ENDS only users who never used any nonelectronic tobacco products (n = 50), the geometric mean ratios (GMRs) of Cd and Pb were 1.25 (95%CI: 1.09-1.42) and 1.19 (95%CI: 1.05-1.34), respectively, compared to never users after adjustment for PATH Study wave, age, sex, race/ethnicity, education, region, secondhand smoke at home and work, and cannabis and other substance use. After the same adjustment, the corresponding GMRs were 1.48 (95%CI: 1.32-1.67) and 1.43 (95%CI: 1.28-1.60) for ENDS only users who were former users of any nonelectronic tobacco products (n = 123). No difference was observed in urinary concentrations of other metals comparing ENDS users to never users of any tobacco product.

DISCUSSION

ENDS users show higher urinary levels of Cd and Pb, including lifetime exclusive ENDS users compared to never users of any tobacco product. These findings are limited by the small sample size and could be related to underreporting of past combustible tobacco use or other factors. Metals typical of ENDS such as nickel and chromium unfortunately are not available in PATH. Studies assessing metal exposure associated with long term lifetime exclusive ENDS use (≥5 years) with larger sample size are needed.

Arsenic, polycyclic aromatic hydrocarbons, and metal exposure and risk assessment of stroke

Globally, stroke is one of the primary causes of morbidity and mortality. In the USA, stroke is a major cause of death and disability. Limited studies assessed the impact of polycyclic aromatic hydrocarbons, arsenic, and other metal exposure and their association with the risk of stroke. This study aimed to assess different arsenic species, including total arsenic; two types of organic arsenic, i.e., arsenobetaine and arsenocholine; four types of inorganic arsenic, i.e., arsenic acid, arsenous acid, dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA); six types of urinary polycyclic aromatic hydrocarbon (PAH) compounds, i.e., 1-hydroxynaphthalene, 1-hydroxyphenanthrene, 1-hydroxypyrene, 2-hydroxynaphthalene, 2-hydroxyfluorene, and 3-hydroxyfluorene; and fourteen types of metals from urine specimen, i.e., manganese, cadmium, lead, mercury, barium, cobalt, strontium, molybdenum, cesium, thallium, antimony, tin, tungsten, and uranium and their association with those who reported having been told they had had a stroke by a medical professional. The National Health and Nutrition Examination Survey (NHANES) data used in this study include three data cycles from 2011-2016. In this study, data from a total of 5537 males and females who are aged 20 years and older were analyzed using logistic modeling of the complex weighted survey design. R version 3.6.3 software was used to conduct the analyses. Four species of urinary PAHs, including the third quantiles of 1-hydroxynaphthalene [odds ratio (OR): 2.327, 95% confidence interval (CI): 0.961-5.632], 2-hydroxynaphthalene [OR: 2.449, 95% CI: 1.067-5.622], and 3-hydroxyfluorene [OR: 2.289, 95% CI: 1.077-4.861] and the second quantiles of 3-hydroxyfluorene [OR: 2.201, 95% CI: 1.115, 4.346] and 1-hydroxypyrene [OR: 2.066, 95% CI: 1.037, 4.114], showed a positive correlation with increased odds of stroke. Among metals, the third (3rd) [OR: 3.566, 95% CI: 1.370, 9.280] and fourth (4th) [OR: 2.844, 95% CI: 0.947, 8.543] quantiles of urinary manganese showed a positive correlation with increased odds of stroke.

Association between urinary cadmium level and subclinical myocardial injury in the general population without cardiovascular disease aged ≥ 50 years

Cadmium (Cd) is a toxic heavy metal linked to an increased risk of cardiovascular disease (CVD). But the relationship between urinary Cd (U-Cd) and electrocardiographic subclinical myocardial injury (SC-MI) in older people is unclear. This study evaluated the connection between U-Cd and SC-MI in people who did not have CVD. The study involved 4269 participants from the National Health and Nutrition Examination Survey III(NHANES III) aged ≥ 50 years and had no history of CVD. The relationship between U-Cd and cardiac infarction/injury score (CIIS) was assessed by multivariable linear regression. Whether U-Cd and SC-MI were correlated was determined by multivariate logistic regression, restricted cubic spline, and subgroup analysis. There was a significant association between U-Cd and CIIS (β, 1.04, 95% confidence interval (CI): 0.39-1.69; P = 0.003) in the highest quartile and fully adjusted model. After adjusting for relevant confounders, multivariable logistic regression showed that participants in the highest quartile of U-Cd had a greater chance of having SC-MI than those in the first ( OR (95% CI), 1.37(1.13,1.66), P for trend = 0.003), and this relationship was especially strong among hypertensive participants. And a positive linear correlation between U-Cd and the prevalence of SC-MI was shown by restricted cubic spline analysis. U-Cd may be a novel risk element for SC-MI because it is independently and linearly linked to CIIS and SC-MI.

Association of metal exposure with arterial stiffness in Chinese adults

BACKGROUND

Arterial stiffness is an important indicator of cardiovascular aging. However, studies assessing the association between metal exposure and arterial stiffness are limited.

OBJECTIVE

The aim of this study was to investigate the independent and joint associations of metal exposure with arterial stiffness.

METHODS

This cross-sectional study recruited 2982 Chinese adults from August 2018 to March 2019 in Wuhan, China. The concentrations of 20 urinary metals were determined using inductively coupled plasma mass spectrometer. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). We used generalized linear model (GLM) to estimate the association of single metal exposure with baPWV. We used weighted quantile sum (WQS) regression to estimate the association of metal mixture with baPWV.

RESULTS

In GLM regression analysis, each doubling of urinary copper (Cu) and chromium (Cr) concentrations were associated with 6.48 (95 % CI: 2.51-10.45) cm/s and 3.78 (95 % CI: 0.42-7.14) cm/s increase in baPWV, respectively. In WQS regression analysis, each unit increase in WQS index of the metal mixture was associated with a 9.10 (95 % CI: 2.39-15.82) cm/s increase in baPWV. Cu, Zn, and Cr were the dominant urinary metals associated with baPWV.

CONCLUSION

Metal exposure, both individually and in mixture, was associated with an increased risk of arterial stiffness. Our findings may provide a target for preventative strategies against cardiovascular aging.

Cadmium contributes to atherosclerosis by affecting macrophage polarization

Chronic cadmium (Cd) exposure contributes to the progression of atherosclerosis, but the direct role of Cd and its mechanisms in atherosclerosis remains incompletely understood. Atherosclerosis is a chronic inflammatory disease promoting macrophage polarization to M1 phenotype and producing pro-inflammations that are vital in regulating the inflammatory response. Herein, through a case-control study, we found that Cd exposure may promote the occurrence of carotid plaque via inflammation, where interleukin-6 (IL-6) may play an important role. We also combined in vivo and in vitro experiments to explore the underlying mechanism of Cd-promoted plaque formation and the production of IL-6. With or without cadmium chloride (CdCl₂) fed ApoE^-/- mouse and treated RAW264.7 cells, we found Cd accumulated in the aortas which significantly increased the plaque area in atherosclerotic mice, macrophage accumulation, and lipid accumulation, and Cd promoted M1 phenotype macrophage polarization reflected by the increased expression of CD86 which produced tumor necrosis factor-α (TNF-α) and IL-6. However, the influences on M2 phenotype and anti-inflammatory cytokines interleukin-4 (IL-4) and interferon-γ (IFN-γ) were non-significant. Moreover, we found that JAK2/STAT3 pathway was greatly activated in the plaques and CdCl₂-treated macrophages. The inhibition of JAK2/STAT3 substantially reversed the Cd-stimulated macrophage M1 phenotype macrophage polarization and the expression of pro-inflammatory cytokines including TNF-α and IL-6. Altogether, Cd intensifies atherosclerosis by modulating macrophage polarization via JAK2/STAT3 to up-regulated the expression of IL-6.

Seasonal variation, contribution and dynamics of trace elements in the drainage basin and estuary of the Serinhaém river, BA

In the present study a mass balance calculation was used to quantify trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, Ti, V and Zn) fluxes exported from the Serinhaém River estuary to the Atlantic Ocean. The studied elements exportation in the particulate fraction showed higher fluxes in the first sampling campaign and a high export rate to the Atlantic Ocean during this period. The physical-chemical parameters showed the highest values in sampling campaign 1. These variations are probably the cause of the different trace elements behavior in fluvial and estuarine areas, where removal and addition processes between particulate and dissolved phases took place, affecting distribution coefficient and fluxes to the Atlantic Ocean. EPA ecosystems present values in accordance with Brazilian legislation for pristine areas, however, monitoring programs must be carried out in the region, to avoid future environmental problems.

Associations with Blood Lead and Urinary Cadmium Concentrations in Relation to Mortality in the US Population: A Causal Survival Analysis with G-Computation

Using the parametric g-formula, we estimated the 27-year risk of all-cause and specific causes of mortality under different potential interventions for blood lead (BLLs) and urinary cadmium (UCd) levels. We used data on 14,311 adults aged ≥20 years enrolled in the NHANES-III between 1988 and 1994 and followed up through 31 Dec 31 2015. Time and cause of death were determined from the National Death Index records. We used the parametric g-formula with pooled logistic regression models to estimate the relative and absolute risk of all-cause, cardiovascular, and cancer mortality under different potential threshold interventions for BLLs and UCd concentrations. Median follow-up was 22.5 years. A total of 5167 (36%) participants died by the end of the study, including 1550 from cardiovascular diseases and 1135 from cancer. Increases in BLLs and creatinine-corrected UCd levels from the 5th to the 95th percentiles were associated with risk differences of 4.17% (1.54 to 8.77) and 6.22% (4.51 to 12.00) for all-cause mortality, 1.52% (0.09 to 3.74) and 1.06% (-0.57 to 3.50) for cardiovascular disease mortality, and 1.32% (-0.09 to 3.67) and 0.64% (-0.98 to 2.80) for cancer mortality, respectively. Interventions to reduce historical exposures to lead and cadmium may have prevented premature deaths, especially from cardiovascular disease.

Structural–functional aberrations of erythrocytes in the northern red-backed vole (Clethrionomys rutilus Pallas, 1779) that inhabits the zone of influence of the copper smelter (the Middle Ural)

Red blood cell parameters were assessed in a natural population of the northern red-backed vole (Clethrionomys rutilus Pallas, 1779) in the zone of influence of the Kirovgrad Copper Smelter along a gradient of pollution by heavy metals (Cu, Zn, Cd, and Pb) at three catching sites (polluted [Imp] and controls [Bg-1, and Bg-2]). The difference of the smelter area (Imp group of voles) from both background groups (Bg-1 and Bg-2) was proven by means of a set of 13 parameters in univariate and multivariate analyses. Among the detected erythrocyte disturbances, we noted the following: a decrease in activities of Na⁺,K⁺-ATPase and antioxidant enzymes (SOD, GSH-Px, and CAT); an increase in the concentration of lipid peroxidation products, in osmotic fragility, and in intravascular hemolysis; interruption of carbohydrate metabolism; and lowered oxygen-carrying capacity. A higher load of Cd (p = 0.0009) and possibly Pb (p = 0.054) in the Imp animals was confirmed by quantitation of heavy metals in the liver. Most erythrocyte parameters (11 out of 13) covaried with individual Cd load by obeying a semilogarithmic dependence; such a relation was not found for Cu, Zn, and Pb. A decrease in the growth rate of structural and functional erythrocyte aberrations ("resistance improvement") with increasing cadmium load is probably due to compensatory enhancement of the synthesis of metallothioneins in the liver and kidneys and hence a greater proportion of Cd bound to metallothioneins. Problems of differences/similarities in Cd-associated reactivity among the animals are discussed too, taking into account the catching sites (polluted [Imp] and controls [Bg-1, and Bg-2]) and reproductive-age (i.e., immature underyearlings, mature underyearlings, and individuals that overwintered). The persistence of differences in erythrocyte status observed by us between the Imp and background groups after normalization to Cd load may be due to the action of other (unexamined) adverse factors and calls for further ecotoxicological studies.

[Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment]

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

A systematic review of adverse health effects associated with oral cadmium exposure

Scientific data characterizing the adverse health effects associated with dietary cadmium (Cd) exposure were identified in order to make informed decisions about the most appropriate toxicological reference value (TRV) for use in assessing dietary Cd exposure. Several TRVs are available for Cd and regulatory organizations have used epidemiologic studies to derive these reference values; however, risk of bias (RoB) evaluations were not included in the assessments. We performed a systematic review by conducting a thorough literature search (through January 4, 2020). There were 1714 references identified by the search strings and 328 studies identified in regulatory assessments. After applying the specific inclusion and exclusion criteria, 208 studies (Human: 105, Animal: 103) were considered eligible for further review and data extraction. For the epidemiologic and animal studies, the critical effects identified for oral Cd exposure from the eligible studies were a decrease in bone mineral density (BMD) and renal tubular degeneration. A RoB analysis was completed for 49 studies (30 epidemiological and 19 animal) investigating these endpoints. The studies identified through the SR that were considered high quality and low RoB (2 human and 5 animal) can be used to characterize dose-response relationships and inform the derivation of a Cd TRV.

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.

A review of environmental metabolism disrupting chemicals and effect biomarkers associating disease risks: Where exposomics meets metabolomics

Humans are exposed to an ever-increasing number of environmental toxicants, some of which have gradually been elucidated to be important risk factors for metabolic diseases, such as diabetes and obesity. These metabolism-sensitive diseases typically occur when key metabolic and signaling pathways were disrupted, which can be influenced by the exposure to contaminants such as endocrine disrupting chemicals (EDCs), along with genetic and lifestyle factors. This promotes the concept and research on environmental metabolism disrupting chemicals (MDCs). In addition, identifying endogenous biochemical markers of effect linked to disease states is becoming an important tool to screen the biological targets following environmental contaminant exposure, as well as to provide an overview of toxicity risk assessment. As such, the current review aims to contribute to the further understanding of exposome and human health and disease by characterizing environmental exposure and effect metabolic biomarkers. We summarized MDC-associated metabolic biomarkers in laboratory animal and human cohort studies using high throughput targeted and nontargeted metabolomics techniques. Contaminants including heavy metals and organohalogen compounds, especially EDCs, have been repetitively associated with metabolic disorders, whereas emerging contaminants such as perfluoroalkyl substances and microplastics have also been found to disrupt metabolism. In addition, we found major limitations in the effective identification of metabolic biomarkers especially in human studies, toxicological research on the mixed effect of environmental exposure has also been insufficient compared to the research on single chemicals. Thus, it is timely to call for research efforts dedicated to the study of combined effect and metabolic alterations for the better assessment of exposomic toxicology and health risks. Moreover, advanced computational and prediction tools, further validation of metabolic biomarkers, as well as systematic and integrative investigations are also needed in order to reliably identify novel biomarkers and elucidate toxicity mechanisms, and to further utilize exposome and metabolome profiling in public health and safety management.

The preferential accumulation of cadmium ions among various tissues in mice

Cadmium (Cd) is hazardous to human health because of its toxicity and long half-life of clearance. Many studies have explored the relationship between chronic Cd exposure and different human diseases. However, most of the studies limited the study targets of Cd toxicity to two or three organ systems. The goal of this study was to establish a mouse model of Cd accumulation in most organ systems and to particularly investigate the potential toxic effects of Cd to the cardiovascular system. Mice were divided into three groups: the control group, Cd-100 group, and Cd-200 group. In the control group, Cd was detected in the kidney, lung, liver, heart and urine but was undetectable in the aorta, intestine, thigh bone, spinal bone and serum. Upon chronic exposure in the Cd-100 and Cd-200 groups, Cd accumulated in all tissues, with a dramatic increase in concentration. We confirmed that Cd could accumulate significantly in the heart and aorta upon chronic exposure. This finding might help to explain the potential toxic effects of Cd on these organs. In addition, the calcium concentration in the bones and kidney declined when the exposure to Cd increased. This finding aligned with the negative effects of Cd on bony mineralization and the potential direct toxic effects of Cd on bones. The impacts of Cd on the cardiovascular system were explored. Histologically, chronic Cd exposure led to myocytes hypertrophy and myocardial architecture disarray in the Cd-100 group compared to those in the control group. Our research confirms that Cd can accumulate in all of the organs studied upon chronic exposure, and suggests that the toxicity of Cd accumulation may play important roles in mediating the pathophysiologic effects in these target organs, especially the bone and heart.

Environmental Contaminants Acting as Endocrine Disruptors Modulate Atherogenic Processes: New Risk Factors for Cardiovascular Diseases in Women?

The number of aged individuals is increasing worldwide, rendering essential the comprehension of pathophysiological mechanisms of age-related alterations, which could facilitate the development of interventions contributing to “successful aging” and improving quality of life. Cardiovascular diseases (CVD) include pathologies affecting the heart or blood vessels, such as hypertension, peripheral artery disease and coronary heart disease. Indeed, age-associated modifications in body composition, hormonal, nutritional and metabolic factors, as well as a decline in physical activity are all involved in the increased risk of developing atherogenic alterations that raise the risk of CVD development. Several factors have been reported to play a role in the alterations observed in muscle and endothelial cells and that lead to increased CVD, such as genetic pattern, smoking and unhealthy lifestyle. Moreover, a difference in the risk of these diseases in women and men has been reported. Interestingly, in the past decades attention has been focused on a potential role of several pollutants that disrupt human health by interfering with hormonal pathways, and more specifically in non-communicable diseases such as obesity, diabetes and CVD. This review will focus on the potential alteration induced by Endocrine Disruptors (Eds) in the attempt to characterize a potential role in the cellular and molecular mechanisms involved in the atheromatous degeneration process and CVD progression.

Toxic Metals and Subclinical Atherosclerosis in Carotid, Femoral, and Coronary Vascular Territories: The Aragon Workers Health Study

OBJECTIVE

Studies evaluating the association of metals with subclinical atherosclerosis are mostly limited to carotid arteries. We assessed individual and joint associations of nonessential metals exposure with subclinical atherosclerosis in 3 vascular territories. Approach and Results: One thousand eight hundred seventy-three Aragon Workers Health Study participants had urinary determinations of inorganic arsenic species, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten. Plaque presence in carotid and femoral arteries was determined by ultrasound. Coronary Agatston calcium score ≥1 was determined by computed tomography scan. Median arsenic, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten levels were 1.83, 1.98, 0.27, 1.18, 0.05, 9.8, 0.03, 0.66, and 0.23 μg/g creatinine, respectively. The adjusted odds ratio (95% CI) for subclinical atherosclerosis presence in at least one territory was 1.25 (1.03-1.51) for arsenic, 1.67 (1.22-2.29) for cadmium, and 1.26 (1.04-1.52) for titanium. These associations were driven by arsenic and cadmium in carotid, cadmium and titanium in femoral, and titanium in coronary territories and mostly remained after additional adjustment for the other relevant metals. Titanium, cadmium, and antimony also showed positive associations with alternative definitions of increased coronary calcium. Bayesian Kernel Machine Regression analysis simultaneously evaluating metal associations suggested an interaction between arsenic and the joint cadmium-titanium exposure.

CONCLUSIONS

Our results support arsenic and cadmium and identify titanium and potentially antimony as atherosclerosis risk factors. Exposure reduction and mitigation interventions of these metals may decrease cardiovascular risk in individuals without clinical disease.

Multifactorial Screening Reveals New Insight into Early Cadmium Exposure and Garlic Interactions in Dicentrarchus labrax

Environmental pollutants and especially metal trace elements remain an unmitigated threat to the overall life support system. Their chemical stability and accumulation pattern in the ecosystem make them a persistent hazard. This study aims to characterize the early cadmium (Cd) histological and hematological alterations and their corresponding plasma indicators in the Mediterranean sea bass (Dicentrarchus labrax). We also assessed garlic potential to prevent cadmium toxicity. For this purpose, 200 fish of 55 g mean weight were separated into 3 cylindroconical fiberglass tanks of 500-L capacity, each with a stocking density of 4 kg m-3. The fish were regularly hand-fed 0% (control group), 2%, and 6% garlic-supplemented diets to apparent satiation twice a day for 1 month. At the end of the experiment, we injected 22.2 mM cadmium (CdCl2) intraperitoneally to the experimental groups and a placebo solution (9% NaCl) to the control groups; liver, kidney, heart, and blood tissue alterations were monitored with a full screening of their plasmatic indicators, 24 h before and 48 h after Cd injection. Subsequently, whole blood count and blood smears were performed to follow up on Cd-induced vascular damages. Our data showed that Cd induced thrombotic thrombocytopenic purpura, leading to widespread bleeding and cellular alterations in the targeted tissues. These alterations were associated with an obvious normochromic normocytic anemia in favor of microangiopathic hemolytic anemia. Cd injection has also seriously inhibited the overall enzymatic activities triggering a metabolic shift. Although garlic supplementation had little effect on cadmium-induced alterations, it significantly reduced biomass dispersion. Our data is the first evidence of the cadmium versatile toxicity involving vascular alterations as a central and a leading cause of the overall parenchymal lesions. Cd toxicity was associated with a specific enzymatic signature, which must be considered during the interpretation.

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.

Cadmium induces triglyceride levels via microsomal triglyceride transfer protein (MTTP) accumulation caused by lysosomal deacidification regulated by endoplasmic reticulum (ER) Ca2+ homeostasis

Cadmium (Cd) exposure induced lipid metabolic disorder with changes in lipid composition, as well as triglyceride (TG) levels. Liver is the main organ maintaining body TG level and previous studies suggested that Cd exposure might increase TG synthesis but reduce TG uptake in liver. However, the effects of Cd exposure on TG secretion from liver and underlying mechanism are still unclear. In the present study, the data revealed that Cd exposure increased TG levels in the HepG2 cells and the cultured medium by increasing the expression of microsomal triglyceride transfer protein (MTTP), which was abrogated by siRNA knockdown of MTTP. MTTP was synergistically accumulated after Cd exposure or treated with proteasome inhibitor MG132 and lysosome inhibitor chloroquine (CQ), which suggested the Cd increased MTTP protein stability by inhibiting both the proteasome and the lysosomal protein degradation pathways. In addition, our results demonstrated that Cd exposure inhibited the lysosomal acidic degradation pathway through disrupting endoplastic reticulum (ER) Ca2+ homeostasis. Cd-induced MTTP protein and TG levels were significantly reduced by pretreatments of BAPTA/AM chelation of intracellular Ca2+, 2-APB inhibition of ER Ca2+ release channel inositol 1,4,5-trisphosphate receptor (IP3R) and CDN1163 activation of ER Ca2+ reuptake pump sarcoplasmic reticulum Ca2+-ATPase (SERCA). These results suggest that Cd-induced ER Ca2+ release impaired the lysosomal acidity, which associated with MTTP protein accumulation and contributed to increased TG levels.

Cadmium and cardiovascular disease: An overview of pathophysiology, epidemiology, therapy, and predictive value

Cadmium is a widely distributed toxic heavy metal that has been associated with many diseases including chronic renal dysfunction, osteomalacia, acute heart failure, secondary hypertension, and atherosclerosis. Although several studies have suggested that cadmium may affect multiple systems by inducing lipid per oxidation in cells and disturbing the antioxidant system, the mechanism by which cadmium affects the cardiovascular system remains unclear. Recent studies on heart failure and acute myocardial infarction have shown that cadmium has good predictive ability for mortality in patients with cardiovascular disease. In this study, we briefly review the role of cadmium in cardiovascular disease, which may prompt further studies to investigate the potential association between cadmium and mortality in patients with cardiovascular disease.

The endocrine disruptor cadmium: a new player in the pathophysiology of metabolic diseases

Cadmium (Cd), a highly toxic heavy metal, is found in soil, environment and contaminated water and food. Moreover, Cd is used in various industrial activities, such as electroplating, batteries production, fertilizers, while an important non-occupational source is represented by cigarette smoking, as Cd deposits in tobacco leaves. Since many years it is clear a strong correlation between Cd body accumulation and incidence of many diseases. Indeed, acute exposure to Cd can cause inflammation and affect many organs such as kidneys and liver. Furthermore, the attention has focused on its activity as environmental pollutant and endocrine disruptor able to interfere with metabolic and energy balance of living beings. Both in vitro and in vivo experiments have demonstrated that the Cd-exposure is related to metabolic diseases such as obesity, diabetes and osteoporosis even if human studies are still controversial. Recent data show that Cd-exposure is associated with atherosclerosis, hypertension and endothelial damage that are responsible for cardiovascular diseases. Due to the large environmental diffusion of Cd, in this review, we summarize the current knowledge concerning the role of Cd in the incidence of metabolic and cardiovascular diseases.

Cadmium and cardiovascular disease: An overview of pathophysiology, epidemiology, therapy, and predictive value

Cadmium is a widely distributed toxic heavy metal that has been associated with many diseases including chronic renal dysfunction, osteomalacia, acute heart failure, secondary hypertension, and atherosclerosis. Although several studies have suggested that cadmium may affect multiple systems by inducing lipid per oxidation in cells and disturbing the antioxidant system, the mechanism by which cadmium affects the cardiovascular system remains unclear. Recent studies on heart failure and acute myocardial infarction have shown that cadmium has good predictive ability for mortality in patients with cardiovascular disease. In this study, we briefly review the role of cadmium in cardiovascular disease, which may prompt further studies to investigate the potential association between cadmium and mortality in patients with cardiovascular disease.

Cadmium Exposure and Coronary Artery Atherosclerosis: A Cross-Sectional Population-Based Study of Swedish Middle-Aged Adults

BACKGROUND

The general population is ubiquitously exposed to the toxic metal cadmium through the diet and smoking. Cadmium exposure is associated with increased morbidity and mortality in myocardial infarction and stroke. Atherosclerosis is the main underlying mechanism of myocardial infarction. However, associations between cadmium and coronary artery atherosclerosis have not been examined.

OBJECTIVES

Our study sought to examine the hypothesis that blood cadmium (B-Cd) is positively associated with coronary artery calcification, as a measure of coronary artery atherosclerosis in the population-based Swedish SCAPIS study.

METHODS

Our analysis included 5,627 individuals (51% women), age 50-64 y, enrolled from 2013 to 2018. The coronary artery calcium score (CACS) was obtained from computed tomography. Blood cadmium was determined by inductively coupled plasma mass spectrometry (ICP-MS). Associations between B-Cd and coronary artery calcium score (CACS Agatston score) were evaluated using prevalence ratios (PRs) in models adjusted for sex, age, smoking, hypertension, diabetes, low-density cholesterol/high-density cholesterol ratio, and family history.

RESULTS

The median B-Cd concentration was 0.24μg/L. The prevalence of positive coronary artery calcium (CACS>0) was 41% and the prevalence of CACS≥100 was 13%. Relative to the lowest quartile (Q) of B-Cd (<0.16μg/L), the highest quartile (median 0.63μg/L) was associated with a small but significant increase in CACS>0 (PR 1.1; 95% CI: 1.0, 1.3), and a greater relative increase in CACS≥100 (PR 1.6; 95% CI: 1.3, 2.0). When restricted to 2,446 never-smokers, corresponding PRs were 1.1 (95% CI 0.9, 1.3) for CACS>0 (63 cases in Q4) and 1.7 (95% CI 1.1, 2.7) for CACS≥100 (17 cases in Q4).

DISCUSSION

Blood cadmium in the highest quartile was associated with CACS in a general population sample with low to moderate cadmium exposure. This supports the hypothesis that atherosclerosis is an important mechanism underlying the associations between cadmium and incident cardiovascular disease. The findings suggest that public health measures to reduce cadmium exposure are warranted. https://doi.org/10.1289/EHP8523.

Effects of myricetin against cadmium-induced neurotoxicity in PC12 cells

Cadmium (Cd) is one of the most prevalent toxic metals widely found in the environment. Cd induces toxicity and apoptosis in various organs and cells. The nervous system is one of the primary organs targeted by Cd. Cd toxicity is correlated with induction of severe oxidative stress. Myricetin, a natural product, has been found to exert protective effects against various disease conditions. The present study aimed to evaluate the potential protective effects of myricetin on Cd-induced neurotoxicity in PC12 cells. The cells were pretreated with myricetin in the absence and presence of Cd. The viability of cells was assessed using the MTT assay. Markers of oxidative stress were investigated by the lipid peroxidation (LPO), glutathione (GSH) content, and total antioxidant capacity (TAC). Moreover, activation of caspase 3 was examined by Western blot analysis. Myricetin could significantly enhance the viability of PC12 cells. Pretreatment of the cells with myricetin, prior to Cd exposure, showed a significant decrease in the levels of LPO whereas GSH and TAC levels were increased. In addition, the activity of caspase-3 was notably prevented by myricetin. These findings revealed that myricetin has protective effects on Cd-induced neurotoxicity in PC12 cells, which can be linked to its antioxidant potential, inhibition of LPO, and prevention of caspase-3 activation.

Multiple metals exposure and arterial stiffness: A panel study in China

Chronic exposure to metals has been linked to arterial stiffness. However, the effects of exposure to multiple metals on arterial stiffness have rarely been studied. We aimed to investigate the associations of 23 urinary metals with arterial stiffness in a panel study of 127 Chinese adults with 3 repeated visits. Urinary metal measurements were conducted once a day for 4 consecutive days of each visit. Brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI) were measured in health examinations during each visit. Linear mixed models, least absolute shrinkage and selection operator (LASSO) penalized regression models, and generalized linear models were applied to investigate the associations between multiple metals and arterial stiffness parameters. The odds ratio (OR) for peripheral arterial disease (PAD) was examined using generalized estimating equations. After adjusting for potential covariates and other metals, we found ABI reductions were associated with one unit increase in 4-day average (lag 0-3 day) of ln-transformed urinary titanium (Ti) [β = -0.019 (SE = 0.010), P = 0.045], and cobalt (Co) [β = -0.012 (SE = 0.006), P = 0.048], whereas no significant associations were observed for baPWV at different lag days. Stratified analyses revealed that urinary Ti was inversely related to ABI among never-smokers or in the winter. In addition, the current day or 4-day average of ln-transformed urinary Ti was associated with an increased OR of 1.94 (95% CI: 1.28, 2.92) or 3.30 (95% CI: 1.64, 6.63) for PAD, respectively. Our study showed significant associations of exposure to Ti and Co with arterial stiffness. Particularly, Ti may increase the risk of PAD.

Chronic cadmium exposure and cardiovascular disease in adults

Chronic cadmium exposure and its effect on cardiovascular-related markers were explored in the cross-sectional study of U.S. adults using the National Health and Nutrition Examination Survey (NHANES) 2007-2010 data. Cardiovascular-related markers, such as LDL cholesterol mg/dL (LDL-C), non-HDL cholesterol mg/dL (non-HDL-C), triglycerides mg/dL (TG), c-reactive protein mg/dL (CRP), and gamma-glutamyl transferase U/L (GGT) were explored in relation to urine cadmium level µg/L (UCL). The variables and their relation to UCL µg/L were explored both as continuous and categorical variables using linear and logistic regression models and basic descriptive statistics. Geometric Mean values of the markers of interest were statistically significantly more elevated in middle-aged adults (45-65 years) as compared to younger adults (18-44 years). In linear regression analysis, CRP mg/dL, LDL-C mg/dL, non-HDL-C mg/dL, and GGT U/L levels were significantly associated with UCLs mg/dL after adjusting for confounding variables. In binary logistic regression models, young and middle-aged adults chronically exposed to cadmium were significantly more likely to have elevated CRP mg/dL levels. This study suggests that chronic exposure to cadmium alters cardiovascular-related markers in middle-aged adults more so than younger adults, which calls for early public health intervention to limit cadmium exposure in the U.S.

Smoking-induced risk of future cardiovascular disease is partly mediated by cadmium in tobacco: Malmö Diet and Cancer Cohort Study

BACKGROUND

Smoking is a strong risk factor for cardiovascular disease (CVD) and causes exposure to cadmium, which is a pro-atherosclerotic metal. Cadmium exposure has also been shown to increase the risk of CVD, even after adjustment for smoking. Our hypothesis was that part of the risk of CVD in smokers may be mediated by cadmium exposure from tobacco smoke. We examined this hypothesis in a mediation analysis, trying to assess how much of the smoking-induced CVD risk could be explained via cadmium.

METHODS

We used prospective data on CVD (incidence and mortality) in a Swedish population-based cohort of 4304 middle-aged men and women (the Malmö Diet and Cancer Study). Blood cadmium was analyzed in base-line samples from 1991, and clinical events were followed up for 16-19 years based on registry data. Mediation analysis was conducted to evaluate the indirect effect (via cadmium) of smoking on CVD. Survival was analyzed by the accelerated failure time (AFT) model and the Aalen additive hazard model.

RESULTS

The mean blood cadmium level in the study population was 0.43 μg/L (median 0.24 μg/L) and increased with recent and current smoking. As expected, shorter survival time (AFT model) and higher incidence rate (Aalen model) were found in current smokers for all CVD outcomes and this effect seemed to be partly mediated by cadmium. For the sum of acute myocardial infarction, bypass grafts and percutaneous coronary intervention, and death in ischemic heart disease, about half of the increased risk of such events in current smokers was mediated via cadmium, with similar results for the AFT and Aalen models.

CONCLUSIONS

Cadmium plays an important role in smoking-induced CVDs. This provides evidence for mechanisms and is of importance for both individuals and policy makers.

Chronic Cadmium Exposure Accelerates the Development of Atherosclerosis and Induces Vascular Dysfunction in the Aorta of ApoE-/- Mice

Cadmium exposure is related to cardiovascular diseases, including hypertension, atherosclerosis, increased oxidative stress, endothelial dysfunction, and specific biochemical changes induced by this metal. Thus, we aimed to investigate whether cadmium exposure induces endothelial dysfunction, accelerates atherosclerotic plaque formation in the aorta, and enhances oxidative stress in apolipoprotein E knockout (ApoE^-/-) mice. Experiments were performed in 14-week-old male wild-type and ApoE^-/- mice. ApoE^-/- mice received cadmium (CdCl₂ 100 mg/L in drinking water for 28 days) or vehicle (distilled water). After treatment, vascular reactivity to phenylephrine, acetylcholine, and sodium nitroprusside was analyzed using isolated aorta. Bone marrow cells were isolated to assess the production of nitric oxide and reactive oxygen and nitrogen species. ApoE^-/- cadmium-treated mice had higher cholesterol levels than non-exposed mice. Cadmium exposure decreased the vasodilatation response to acetylcholine in aortic ring of ApoE^-/- mice, though no changes in phenylephrine or sodium nitroprusside responses were observed. L-NAME reduced vasodilator responses to acetylcholine; this effect was lower in ApoE^-/- cadmium-treated mice, suggesting reduction in nitric oxide (NO) bioavailability. Moreover, in bone marrow cells, cadmium decreased cytoplasmic levels of NO and increased superoxide anions, hydrogen peroxide, and peroxynitrite in ApoE^-/- mice. Morphological analysis showed that cadmium exposure increased plaque deposition in the aorta by approximately 3-fold. Our results suggest that cadmium exposure induces endothelial dysfunction in ApoE^-/- mice. Moreover, cadmium increased total cholesterol levels, which may promote the early development of atherosclerosis in the aorta of ApoE^-/- mice. Our findings support the hypothesis that cadmium exposure might increase the risk of atherosclerosis.

Protective Effects of Quercetin Against Cadmium Chloride-Induced Oxidative Injury in Goat Sperm and Zygotes

Quercetin, a plant-derived flavonoid, is frequently used as an antioxidant for efficient anti-oxidative capacity. However, whether quercetin has protective effects on goat sperm and preimplantation embryos against Cd²⁺-induced oxidative injury is still unclear. So, we researched the influence of quercetin on goat sperm and zygotes respectively under the oxidative stress induced by Cd²⁺. In our study, quercetin decreased the malonaldehyde (MDA) and reactive oxygen species (ROS) levels caused by Cd²⁺ in goat sperm (p < 0.05), which facilitated sperm characteristics including motility, survival rates, membrane integrity, and mitochondria activity during storage in vitro and subsequent embryo development (p < 0.05). Moreover, in goat zygotes, quercetin decreased peroxidation products including ROS, MDA, and carbonyl through preserving or maintaining mitochondrial function, gene expression, and anti-oxidative products such as glutathione peroxidase, superoxide dismutase, and catalase, which ameliorated subsequent embryo development and embryo quality (p < 0.05). Taken together, these results suggest that quercetin protects both goat sperm and preimplantation embryos from Cd²⁺-induced oxidative stress.

Partial Mediation by Cadmium Exposure of the Association Between Tobacco Smoking and Atherosclerotic Plaques in the Carotid Artery

Exposure to cadmium confers increased cardiovascular risk. Tobacco smoke contains cadmium, which, hypothetically, may mediate parts of the tobacco-associated risk of developing atherosclerotic plaques. Baseline data from the Swedish Malmö Diet and Cancer cohort (1991-1996) were used to test this hypothesis. Mediation analysis was used to examine associations between smoking and blood cadmium levels and the prevalence of ultrasound-assessed carotid atherosclerotic plaques. The total association with smoking status (never smokers, 2 categories of former smokers, and current smokers) was split into direct and indirect association, and the proportion mediated was estimated. The adjusted estimated plaque prevalence was approximately 27% among never smokers. We identified both a direct and an indirect pathway between smoking and carotid plaques; the indirect association, through cadmium, was observed among current smokers and former smokers who had quit smoking less than 15 years before. For current smokers, the prevalence ratio for plaque was 1.5, with 60%-65% of the association with smoking being mediated through cadmium. Recent former smokers had a prevalence ratio of 1.3, and 40%-45% was mediated through cadmium. Long-time former smokers had a prevalence ratio of 1.2, but none of the association was mediated through cadmium. In conclusion, about two-thirds of the proatherosclerotic association with smoking was mediated by cadmium.

Cadmium and atherosclerosis: A review of toxicological mechanisms and a meta-analysis of epidemiologic studies

Cadmium has been proposed to be the one of the factors of atherosclerosis development, although the existing data are still controversial. The primary objective of the present study is the review and the meta-analysis of studies demonstrating the association between Cd exposure and atherosclerosis as well as review of the potential mechanisms of such association. We performed a systematic search in the PubMed-Medline database using the MeSH terms cadmium, cardiovascular disease, atherosclerosis, coronary artery disease, myocardial infarction, stroke, mortality and humans up through December 20, 2017. Elevated urinary Cd levels were associated with increased mortality for cardiovascular disease (HR = 1.34, 95% CI: 1.07-1.67) as well as elevated blood Cd levels (HR = 1.78, 95% CI: 1.24-2.56). Analysis restricted to never smokers showed similar, though more imprecise, results. Consistently, we also observed an association between Cd exposure markers (blood and urine) and coronary heart disease, stroke, and peripheral artery disease. Moreover, Cd exposure was associated with atherogenic changes in lipid profile. High Cd exposure was associated with higher TC levels (OR = 1.48, 95% CI: 1.10-2.01), higher LDL-C levels (OR = 1.31, 95% CI 0.99-1.73) and lower HDL-C levels (OR = 1.96, 95% CI: 1.09-3.55). The mechanisms of atherogenic effect of cadmium may involve oxidative stress, inflammation, endothelial dysfunction, enhanced lipid synthesis, up-regulation of adhesion molecules, prostanoid dysbalance, as well as altered glycosaminoglycan synthesis.

Cadmium, Carotid Atherosclerosis, and Incidence of Ischemic Stroke

Background

Exposure to cadmium has been associated with carotid plaques, inflammation in carotid plaques, and increased risk of ischemic stroke. This study examined the separate and interacting effects of blood cadmium levels and carotid plaques on the risk of incident ischemic stroke.

Methods and Results

Cadmium levels were measured in 4156 subjects (39.2% men; mean±SD age 57.3±5.9 years) without history of stroke, from the Malmö Diet and Cancer cohort. The right carotid artery was examined using B‐mode ultrasound examination at baseline. Incidence of ischemic stroke was monitored over a mean follow‐up of 16.7 years. Carotid plaque was present in 34.5% of participants. Cadmium was significantly higher in subjects with plaque (mean±SD: 0.53±0.58 μg/L versus 0.42±0.49 μg/L; P<0.001). A total of 221 subjects had ischemic stroke during the follow‐up. Incidence of ischemic stroke was associated both with carotid plaque (hazard ratio 1.44, 95% confidence interval, 1.09–1.90, P=0.009) and cadmium (hazard ratio for quartile [Q] 4 versus Q1–3: 1.95, confidence interval, 1.33–2.85, P=0.001), after adjustment for risk factors. There was a significant interaction between cadmium and plaque with respect to risk of ischemic stroke (P=0.011). Adjusted for risk factors, subjects with plaque and cadmium in Q4 had a hazard ratio of 2.88 (confidence interval, 1.79–4.63) for ischemic stroke, compared with those without plaque and cadmium in Q1 to Q3.

Conclusions

Cadmium was associated with incidence of ischemic stroke, both independently and in synergistic interaction with carotid plaques. This supports the hypothesis that cadmium promotes vulnerability of carotid plaques, thereby increasing the risk of rupture and ischemic stroke.

Declining exposures to lead and cadmium contribute to explaining the reduction of cardiovascular mortality in the US population, 1988-2004

Background

Lead and cadmium exposures have markedly declined in the USA following the implementation of large-scale public health policies and could have contributed to the unexplained decline in cardiovascular mortality in US adults. We evaluated the potential contribution of lead and cadmium exposure reductions to explain decreasing cardiovascular mortality trends occurring in the USA from 1988-94 to 1999-2004.

Methods

Prospective study in 15 421 adults ≥40 years old who had participated in the National Health and Nutrition Examination Survey 1988-94 or 1999-2004. We estimated the amount of change in cardiovascular mortality over time that can be independently attributed to the intermediate pathway of changes in blood lead and urine cadmium concentrations.

Results

There was a 42.0% decrease in blood lead and a 31.0% decrease in urine cadmium concentrations. The cardiovascular mortality rate ratio [95% confidence intervals (CIs)] associated with a doubling of metal levels was 1.19 (1.07, 1.31) for blood lead and 1.20 (1.09, 1.32) for urine cadmium. The absolute reduction in cardiovascular deaths comparing 1999-2004 to 1988-94 was 230.7 deaths/100 000 person-years, in models adjusted for traditional cardiovascular risk factors. Among these avoided deaths, 52.0 (95% CI 8.4, 96.7) and 19.4 (4.3, 36.4) deaths/100 000 person-years were attributable to changes in lead and cadmium, respectively.

Conclusions

Environmental declines in lead and cadmium exposures were associated with reductions in cardiovascular mortality in US adults. Given the fact that lead and cadmium remain associated with cardiovascular disease at relatively low levels of exposure, prevention strategies that further minimize exposure to lead and cadmium may be needed.

Toxicity of cadmium and its health risks from leafy vegetable consumption

Cadmium (Cd) is a highly toxic heavy metal and has spread widely in the environment in recent decades. This review summarizes current knowledge about Cd contamination of leafy vegetables, its toxicity, exposure, health risks, and approaches to reducing its toxicity in humans. Leafy vegetable consumption has been identified as a dominant exposure pathway of Cd in the human body. An overview of Cd pollution in leafy vegetables as well as the main sources of Cd is given. Notable estimated daily intakes and health risks of Cd exposure through vegetable consumption for humans are revealed in occupational exposure areas and even in some reference areas. Vegetable consumption is one of the most significant sources of exposure to Cd, particularly in occupational exposure regions. Therefore, numerous approaches have been developed to minimize the accumulation of Cd in leafy vegetables, among which the breeding of Cd pollution-safe cultivars is one of the most effective tools. Furthermore, dietary supplements from leafy vegetables perform positive roles in alleviating Cd toxicity in humans with regard to the effects of essential mineral elements, vitamins and phytochemicals taken into the human body via leafy vegetable consumption.

Assessment of cadmium-induced nephrotoxicity using a kidney-on-a-chip device

Cadmium (Cd) is a common environmental pollutant. Its effects on human health have attracted great attention. The kidney is the organ that is the most affected by Cd exposure. Thus, it is highly desirable to develop a reliable model to evaluate Cd-induced nephrotoxicity in vitro. We present a kidney-on-a-chip with three compartmentalized culture chambers to examine Cd-induced nephrotoxicity. The culture and collection channels represent the capillary and the glomerular capsule sides of the glomerular filtration barrier, respectively. Isolated primary rat glomerular endothelial cells (GECs) were cultured on the side surface of the middle gel channel. The integrated GEC layer demonstrated the selective permeability of the renal barrier. Therefore, it was further utilized to study the nephrotoxicity induced by Cd exposure at different concentrations. Cd induced significant cytotoxicity and disrupted the expression of tight junction protein ZO-1 in a dose-dependent manner. Moreover, Cd exposure increased the permeability of the endothelial layer to large molecules, immunoglobulin G and albumin. These results facilitate the understanding of the underlying mechanism of kidney dysfunction and glomerular disease. This is the first study on Cd-induced nephrotoxicity using primary GECs in a microfluidic device. The kidney-on-a-chip device enables direct visualization and quantitative analysis of GEC responses to Cd in real time. It may provide a micro-scale platform based on the human system for nephrotoxicity testing under varying environmental exposure.

Cadmium exposure is associated with soluble urokinase plasminogen activator receptor, a circulating marker of inflammation and future cardiovascular disease

BACKGROUND

Diet and smoking are the main sources of cadmium exposure in the general population. Cadmium increases the risk of cardiovascular diseases, and experimental studies show that it induces inflammation. Blood cadmium levels are associated with macrophages in human atherosclerotic plaques. Soluble urokinase-type plasminogen activator receptor (suPAR) is an emerging biomarker for cardiovascular events related to inflammation and atherosclerotic plaques. The aim was to examine whether blood cadmium levels are associated with circulating suPAR and other markers of inflammation.

METHODS

A population sample of 4648 Swedish middle-aged women and men was examined cross-sectionally in 1991-1994. Plasma suPAR was assessed by ELISA, leukocytes were measured by standard methods, and blood cadmium was analysed by inductively coupled plasma mass spectrometry. Prevalent cardiovascular disease, ultrasound-assessed carotid plaque occurrence, and several possible confounding factors were recorded.

RESULTS

After full adjustment for risk factors and confounding variables, a 3-fold increase in blood cadmium was associated with an 10.9% increase in suPAR concentration (p<0.001). In never-smokers, a 3-fold increase in blood cadmium was associated with a 3.7% increase in suPAR concentration (p<0.01) after full adjustment. Blood cadmium was not associated with C-reactive protein, white blood cell count and Lp-PLA2 but with neutrophil/lymphocyte ratio in one of two statistical models.

CONCLUSIONS

Exposure to cadmium was associated with increased plasma suPAR in the general population, independently of smoking and cardiovascular disease. These results imply that cadmium is a possible cause for raised levels of this inflammatory marker.

Interrelation of Cadmium, Smoking, and Cardiovascular Disease (from the National Health and Nutrition Examination Survey)

Cadmium biomarker levels are associated with both cigarette smoking and cardiovascular disease. In this cross-sectional survey, we explore whether the association between cadmium and cardiovascular disease differs between cigarette smoking states. A cross-sectional analysis using the National Health and Nutrition Examination Survey in 2003 to 2012 was performed accounting for the nationally representative complex sampling design. All participants 45 to 79 years old with blood and urinary cadmium levels were included (n = 12,511). We explored the inter-relationships of blood and urine cadmium levels with cigarette smoking and a composite cardiovascular outcome that included self-reported myocardial infarction or stroke or both. We used multivariable logistic regressing models to further adjust for age, income, gender, hypercholesterolemia, body mass index, diabetes, smoking intensity, and time period of smoking cessation. Of the 12,511 participants, 1,330 (8.5%) had previous myocardial infarction or stroke or both. The crude prevalence ratio (PR) comparing those in the lowest tertile of blood cadmium with those in the highest tertile for the composite outcome was 1.73 (95% confidence interval [CI] 1.49 to 2.01). After adjustment for age, gender, income, self-reported diabetes, self-reported hypercholesterolemia, body mass index, and smoking status, the PR was 1.54 (95% CI 1.30 to 1.84). The adjusted PRs for each smoking subgroup were 1.54 (95% CI 1.09 to 2.18) for never-smokers, 1.57 (95% CI 1.11 to 2.23) for current smokers, and 1.31 (95% CI 0.96 to 1.78) for former smokers. These descriptive data from a nationally representative sample suggest that cadmium is related to cardiovascular outcomes even after adjustment for smoking status.

Blood Cadmium Levels and Incident Cardiovascular Events during Follow-up in a Population-Based Cohort of Swedish Adults: The Malmö Diet and Cancer Study

BACKGROUND

Cadmium exposure may increase the risk of cardiovascular disease. The only published longitudinal study on cadmium and incident cardiovascular disease was performed in American Indians with relatively high cadmium exposure.

OBJECTIVES

Our aim was to examine the association between blood cadmium at baseline and incident cardiovascular events in a population-based study of Swedish men and women with cadmium levels similar to those of most European and U.S.

METHODS

A Swedish population-based cohort (n = 6,103, age 46-67 years) was recruited between 1991 and 1994. After we excluded those with missing data on smoking, 4,819 participants remained. Acute coronary events, other major cardiac events, stroke, and cardiovascular mortality were followed until 2010. Associations with blood cadmium (estimated from cadmium in erythrocytes) were analyzed using Cox proportional hazards regression including potential confounders and important cardiovascular risk factors.

RESULTS

Hazard ratios for all cardiovascular end points were consistently increased for participants in the 4th blood cadmium quartile (median, 0.99 μg/L). In models that also included sex, smoking, waist circumference, education, physical activity, alcohol intake, serum triglycerides, HbA1c, and C-reactive protein, the hazard ratios comparing the highest and lowest quartiles of exposure were 1.8 (95% CI: 1.2, 2.7) for acute coronary events, and 1.9 (1.3, 2.9) for stroke. Hazard ratios in never-smokers were consistent with these estimates.

CONCLUSIONS

Blood cadmium in the highest quartile was associated with incident cardiovascular disease and mortality in our population-based samples of Swedish adults. The consistent results among never-smokers are important because smoking is a strong confounder. Our findings suggest that measures to reduce cadmium exposures are warranted, even in populations without unusual sources of exposure.

CITATION

Barregard L, Sallsten G, Fagerberg B, Borné Y, Persson M, Hedblad B, Engström G. 2016. Blood cadmium levels and incident cardiovascular events during follow-up in a population-based cohort of Swedish adults: the Malmö Diet and Cancer Study. Environ Health Perspect 124:594-600; http://dx.doi.org/10.1289/ehp.1509735.

Zinc diethyldithiocarbamate as an inducer of metallothionein in cultured vascular endothelial cells

Vascular endothelial cells are in direct contact with blood. Inorganic zinc is thought to be incapable of inducing metallothionein, which protects cells from heavy metal toxicity and oxidative stress, in vascular endothelial cells. Here, we aimed to further characterize the induction of metallothionein in vascular endothelial cells. Our results confirmed that inorganic zinc could not induce metallothionein in vascular endothelial cells. Moreover, ZnSO4 could not activate both the metal response element (MRE) transcription factor 1 (MTF-1)/MRE and Nrf2/antioxidant response element (ARE) pathways and was incapable of inducing metallothionein. In addition, bis(L-cysteinato)zincate(II), a zinc complex that activates the MTF-1/MRE pathway, increased MRE promoter activity but failed to induce metallothionein, suggesting that vascular endothelial metallothionein was not induced only by activation of the MTF-1/MRE pathway. Further analysis of a library of zinc complexes showed that zinc(II) bis(diethyldithiocarbamate) activated the MTF-1/MRE pathway but not the Nrf2/ARE pathway, increased MT-1A, MT-1E, and MT-2A mRNA levels, and induced metallothionein proteins. These data indicated that zinc complexes may be excellent tools to analyze metallothionein induction in vascular endothelial cells.