Kidney Dysfunction and Hypertension: Role for Cadmium, P450 and Heme Oxygenases?

Coenzyme Q10 Attenuates Kidney Injury Induced by Titanium Dioxide Nanoparticles and Cadmium Co-exposure in Rats

This study examined the possible defensive role of coenzyme Q10 (CQ10) against the impact of cadmium (Cd) and titanium dioxide nanoparticle (TNP) exposure on rat kidneys. Distilled water (1 mL/rat), corn oil (1 mL/rat), 10 mg CQ10/kg b.wt, 50 mg TNP/kg b.wt, 5 mg Cd/kg b.wt, TNP + Cd, or TNP + Cd + CQ10 was administered orally to seven groups of 70 male Sprague Dawley rats for 60 days. The findings demonstrated that TNP and/or Cd exposure considerably raised serum levels of several renal damage products, disturbed electrolyte balance including sodium, potassium, and calcium, decreased antioxidant enzyme concentration in the kidneys, and elevated malondialdehyde. In addition, rats exposed to TNP and/or Cd had significantly higher levels of renal titanium and Cd. In addition, rats exposed to TNP and/or Cd showed significant histopathological lesions and collagen deposition as revealed by H and E and Masson trichrome staining, respectively. The kidneys were severely damaged by the combined effects of TNP and Cd, although CQ10 greatly mitigated these effects. According to the study, exposure to TNP and Cd can damage the kidneys' function and structure, especially when combined. However, CQ10 can protect against TNP and Cd's nephrotoxic effects.

Heavy metal contamination in Sungai Petani, Malaysia: a wastewater-based epidemiology study

The aim of this study was to investigate the use of wastewater-based epidemiology (WBE) to estimate heavy metal exposure in Sungai Petani, Malaysia. Atomic absorption spectroscopy was used to detect copper (Cu), nickel (Ni), zinc (Zn), iron (Fe), and cadmium (Cd) in wastewater from eight sewage treatment facilities in Sungai Petani in January 2022. The heavy metal concentrations were measured in both influent and effluent, and the mean concentrations in the wastewater were found to be in the following order: Fe > Ni > Zn > Cd > Cu, with a 100% detection frequency. The results of WBE estimation showed that Fe, Ni, and Zn had the highest estimated per population exposure levels, while Cd had the lowest. Compared to a similar study conducted in Penang, Malaysia, all metals except Cu were found to have higher concentrations in Sungai Petani, even though it is a non-industrial district. These findings highlight the importance of addressing heavy metal contamination in Sungai Petani and implementing effective risk management and prevention strategies.

Evaluation of cadmium and mercury on cardiovascular and neurological systems: Effects on humans and fish

Chemicals are at the top of public health concerns and metals have received much attention in terms of toxicological studies. Cadmium (Cd) and mercury (Hg) are among the most toxic heavy metals and are widely distributed in the environment. They are considered important factors involved in several organ disturbances. Heart and brain tissues are not among the first exposure sites to Cd and Hg but they are directly affected and may manifest intoxication reactions leading to death. Many cases of human intoxication with Cd and Hg showed that these metals have potential cardiotoxic and neurotoxic effects. Human exposure to heavy metals is through fish consumption which is considered as an excellent source of human nutrients. In the current review, we will summarize the most known cases of human intoxication with Cd and Hg, highlight their toxic effects on fish, and investigate the common signal pathways of both Cd and Hg to affect heart and brain tissues. Also, we will present the most common biomarkers used in the assessment of cardiotoxicity and neurotoxicity using Zebrafish model.

The effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city

Background

This study investigated the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city.

Methods

We conducted a retrospective longitudinal study of male firefighters who completed the regular health checkups, including a health examination survey and blood cadmium measurements. We followed them for 3 years. To investigate the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension, we estimated the short-term (model 1) and long-term (model 2) effects of exposure and hypothesized a reversed causal pathway model (model 3) for sensitivity analysis. Sequential conditional mean models were fitted using generalized estimating equations, and the odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated for hypertension for log-transformed (base 2) blood cadmium levels and quartiles.

Results

Using the lowest category of dispatch frequency as a reference, we observed that the highest category showed an increase in blood cadmium levels of 1.879 (95% CI: 0.673, 3.086) μg/dL and 0.708 (95% CI: 0.023, 1.394) μg/dL in models 2 and 3, respectively. In addition, we observed that doubling the blood cadmium level significantly increased the odds of hypertension in model 1 (OR: 1.772; 95% CI: 1.046, 3.003) and model 3 (OR: 4.288; 95% CI: 1.110, 16.554). Using the lowest quartile of blood cadmium levels as a reference, the highest quartile showed increased odds of hypertension in model 1 (OR: 2.968; 95% CI: 1.121, 7.861) and model 3 (OR: 33.468; 95% CI: 1.881, 595.500).

Conclusions

We found that dispatch frequency may affect blood cadmium levels in male firefighters, and high blood cadmium levels may influence hypertension in a dose-response manner.

Fashionable Co-operative Sensing of Bivalent Zn2+ and Cd2+ in Attendance of OAc- by Use of Simple Sensor: Exploration of Molecular Logic Gate and Docking Studies

The Schiff-base probe H₂VL [6,6'-((1E,1'E)-hydrazine-1,2 diylidenebis(methanylylidene))bis(2-methoxyphenol)] is synthesized and structurally characterized by single crystal X-ray diffraction (SCXRD). H₂VL is able to detect selectively acetate ion (OAc-) colorimetrically over other anions with 1:1 co-ordination. The detection limit is found to be 4.93 µM. On the other hand, fluorescence intensity of the receptor is drastically enhanced with Zn²⁺ and Cd²⁺ in the presence of acetate as counter anion. N, N-Dimethyl formamide (DMF) or Dimethylsulphoxide (DMSO) and acetate (OAc-) was the best solvent and counter anion for Zn²⁺/Cd²⁺ -sensing compared with other solvents and anions, respectively. Detection limit for Zn²⁺ and Cd²⁺ are calculated to be 1.94 µM and 1.99 µM, respectively. The strong selective emissive behavior could be attributed to the CHEF (chelation-enhanced fluorescence) process. According to the changes in output emission intensity in DMSO in response to the set of ions (Zn²⁺, Cd²⁺ and OAc¯) as input variables, the function of 3-input multifunctional molecular logic circuits has been demonstrated. The molecular docking studies of H₂VL with DNA and BSA are also performed to confirm its possible bioactivity.

Cadmium-Induced Kidney Injury: Oxidative Damage as a Unifying Mechanism

Cadmium is a nonessential metal that has heavily polluted the environment due to human activities. It can be absorbed into the human body via the gastrointestinal tract, respiratory tract, and the skin, and can cause chronic damage to the kidneys. The main site where cadmium accumulates and causes damage within the nephrons is the proximal tubule. This accumulation can induce dysfunction of the mitochondrial electron transport chain, leading to electron leakage and production of reactive oxygen species (ROS). Cadmium may also impair the function of NADPH oxidase, resulting in another source of ROS. These ROS together can cause oxidative damage to DNA, proteins, and lipids, triggering epithelial cell death and a decline in kidney function. In this article, we also reviewed evidence that the antioxidant power of plant extracts, herbal medicines, and pharmacological agents could ameliorate cadmium-induced kidney injury. Finally, a model of cadmium-induced kidney injury, centering on the notion that oxidative damage is a unifying mechanism of cadmium renal toxicity, is also presented. Given that cadmium exposure is inevitable, further studies using animal models are warranted for a detailed understanding of the mechanism underlying cadmium induced ROS production, and for the identification of more therapeutic targets.

Associations between urinary heavy metal concentrations and blood pressure in residents of Asian countries

BACKGROUND

Previous studies have suggested that exposures to heavy metals (arsenic, cadmium, lead, and selenium) may be associated with differences in blood pressure. However, the findings of these studies have been inconsistent. This study was performed to examine the associations between urinary heavy metal concentrations and blood pressure among residents of four Asian countries (Bangladesh, Indonesia, Nepal, and Vietnam).

METHODS

This cross-sectional study examined 1899 adults in four Asian countries. Urinary concentrations of heavy metals were measured by inductively coupled plasma mass spectrometry. A questionnaire survey was administered regarding individual characteristics. Anthropometric measurements (height and weight) were performed. Systolic and diastolic blood pressures were measured after a short rest. Multiple linear regression models were applied to investigate associations between urinary heavy metal concentrations and blood pressure after adjustments for age, sex, and body mass index.

RESULTS

The geometric means of the urinary concentrations of arsenic, cadmium, lead, and selenium were 84.6, 0.885, 2.09, and 16.5 μg/g creatinine, respectively. The urinary arsenic concentrations were slightly higher than those typically reported in non-polluted populations, while urinary cadmium, lead, and selenium concentrations were equivalent or slightly lower. The urinary lead concentrations were positively associated with both systolic and diastolic blood pressure, but urinary selenium concentrations were negatively associated with them.

CONCLUSIONS

Variations in the urinary concentrations of lead and selenium were associated with blood pressure at low levels of exposure/intake.

Cadmium-induced hypertension is associated with renal myosin light chain phosphatase inhibition via increased T697 phosphorylation and p44 mitogen-activated protein kinase levels

Dietary intake of the heavy metal cadmium (Cd²⁺) is implicated in hypertension, but potassium supplementation reportedly mitigates hypertension. This study aims to elucidate the hypertensive mechanism of Cd²⁺. Vascular reactivity and protein expression were assessed in Cd²⁺-exposed rats for 8 weeks to determine the calcium-handling effect of Cd²⁺ and the possible signaling pathways and mechanisms involved. Cd²⁺ induced hypertension in vivo by significantly (p < 0.001) elevating systolic blood pressure (160 ± 2 and 155 ± 1 vs 120 ± 1 mm Hg), diastolic blood pressure (119 ± 2 and 110 ± 1 vs 81 ± 1 mm Hg), and mean arterial pressure (133 ± 2 and 125 ± 1 vs 94 ± 1 mm Hg) (SBP, DBP, and MAP, respectively), while potassium supplementation protected against elevation of these parameters. The mechanism involved augmentation of the phosphorylation of renal myosin light chain phosphatase targeting subunit 1 (MYPT1) at threonine 697 (T697) (2.58 ± 0.36 vs 1 ± 0) and the expression of p44 mitogen-activated protein kinase (MAPK) (1.78 ± 0.20 vs 1 ± 0). While acetylcholine (ACh)-induced relaxation was unaffected, 5 mg/kg b.w. Cd²⁺ significantly (p < 0.001) attenuated phenylephrine (Phe)-induced contraction of the aorta, and 2.5 mg/kg b.w. Cd²⁺ significantly (p < 0.05) augmented sodium nitroprusside (SNP)-induced relaxation of the aorta. These results support the vital role of the kidney in regulating blood pressure changes after Cd²⁺ exposure, which may be a key drug target for hypertension management. Given the differential response to Cd²⁺, it is apparent that its hypertensive effects could be mediated by myosin light chain phosphatase (MLCP) inhibition via phosphorylation of renal MYPT1-T697 and p44 MAPK. Further investigation of small arteries and the Rho-kinase/MYPT1 interaction is recommended.

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 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.

Heavy metal content of rice meals sold in a Nigerian market population with a high prevalence of hypertension

Context

Some market populations in Nigeria have been shown to have high prevalence of hypertension. Current evidence includes environmental pollutants such as heavy metals as risk factors for hypertension.

Aim

To study the heavy metal content of rice meals sold in a market population with a high prevalence of hypertension.

Settings and Design

This was a descriptive, cross-sectional study conducted in Ogbete market in Enugu, Southeast Nigeria.

Subjects and Methods

Five different cooked rice meals were obtained from 25 locations of the market. The rice meals included jollof rice, white rice and tomato stew, fried rice, white rice and vegetable sauce, and white rice and palm oil stew (ofeakwu). Accompanying protein (meat, fish, and egg) and vegetable salad were excluded. Similar rice meals were homogenized and analyzed in triplicates using spectrophotometric methods for mercury, copper, cadmium, lead, and arsenic determination.

Statistical Analysis Used

The mean concentrations of the heavy metals were compared using analysis of variance, and P < 0.05 was considered statistically significant.

Results

Twenty-five rice dishes were evaluated, five of each kind. Arsenic content ranged from 503 to 550 mg/kg and was comparable across the five rice dishes (P = 0.148). Copper was significantly highest (16767 mg/kg) in the white rice and tomato stew dish (P < 0.001), while mercury was significantly highest (33 mg/kg) in white rice and ofeakwu (P < 0.001). Jollof rice had the highest cadmium content (23 mg/kg), which was statistically significant (P = 0.021). Lead was not found in any of the rice dishes.

Conclusions

Risk factors such as heavy metals may play a role in the high prevalence of hypertension observed in market populations, and rice meals may be a major source of these heavy metals.

Cadmium exposure activates NADPH oxidase, renin-angiotensin system and cyclooxygenase 2 pathways in arteries, inducing hypertension and vascular damage

Exposure to high concentrations of cadmium (Cd), widely used in many industries and found in air, food and contaminated water, is not uncommon. Cd damages the cardiovascular system, but the vascular mechanisms involved are not fully understood. This study investigated the mechanisms involved in cardiovascular damage after exposure to high Cd concentrations. Three-month-old male Wistar rats were treated intraperitoneally for 14 days with distilled water (Untreated group) or 1 mg/kg cadmium chloride (Cd group). We investigated the systolic blood pressure (SBP) and vascular reactivity of mesenteric resistance arteries (MRA) and the aorta by analysing contractile and relaxation responses in the absence and presence of the endothelium; we also evaluated pathways involved in vascular tone regulation. Superoxide anion production, COX-2 protein expression and in situ detection of COX-2, AT-1, and NOX-1 were evaluated. Oxidative status, creatinine level and angiotensin-converting enzyme (ACE) activity in plasma were also evaluated. Fourteen-day exposure to a high Cd concentration induced hypertension associated with vascular dysfunction in MRA and the aorta. In both vessels, there was increased participation of cyclooxygenase 2 (COX2), angiotensin II type 1 (AT1) receptor and NOX1. MRA also presented endothelial dysfunction, denoted by impaired acetylcholine-mediated relaxation. All vascular changes were accompanied by increased reactive oxygen species production and COX2, NOX1 and AT1 receptor expression in vascular tissue. Overall, high Cd concentrations induced cardiovascular damage: hypertension, endothelial dysfunction and vascular damage in conductance and resistance arteries, NADPH oxidase, renin-angiotensin system and COX2 pathway activation.

Relationship between low-level lead, cadmium and mercury exposures and blood pressure in children and adolescents aged 8-17 years: An exposure-response analysis of NHANES 2007-2016

This study investigated whether low-level blood and urinary lead, cadmium and mercury exposures were associated with blood pressure (BP) in children and adolescents. Data from National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016 for children and adolescents aged 8-17 years (n = 7076) were analyzed. Outcome variables were systolic BP, diastolic BP and high BP status. High BP was defined as: self-reported antihypertensive medication usage or a diagnosis of hypertension; classified as having elevated BP/hypertension according to 2017 AAP guidelines. Multivariable linear and logistic regressions models were performed and stratified by race/ethnicity and gender. Blood lead was negatively associated with diastolic BP among blacks, and positively associated with diastolic BP among whites. For a two-fold increase of blood lead concentration, the change in diastolic BP was -1.59 mm Hg (95% CI: -3.04 to -0.16 mm Hg) among blacks and 1.38 mm Hg (95% CI: 0.40 to 2.36 mm Hg) among whites. No significant associations between either systolic BP or diastolic BP with urinary lead were observed. The inverse associations between blood lead and high BP were found in females, Mexican Americans and other Hispanics. No associations between blood cadmium and BP were observed, except in other Hispanics. Urinary cadmium levels were inversely correlated with systolic BP, diastolic BP and high BP in all participants and in men. When compared to the lowest quartile of urinary cadmium levels, participants with a urinary cadmium level ≥ 0.12 μg/L had 0.48 (95% CI: 0.29-0.78) times and 0.53 (95% CI: 0.30-0.94) times reduced odds of having high BP in all participants and in men, respectively. No associations between either blood mercury or urinary mercury with systolic BP were observed. Significant inverse associations were found between blood total mercury and methyl mercury with diastolic BP in all participants and in men. Future prospective studies are warranted to confirm these findings.

Association of urinary metal concentrations with blood pressure and serum hormones in Spanish male adolescents

OBJECTIVE

To examine the association of urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), lead (Pb), manganese (Mn), and chromium (Cr) with blood pressure (BP) and serum hormone levels in male adolescents.

METHODS

Participants were selected from the INMA (Environment and Childhood)-Granada cohort at their follow-up visit when aged 15-17 years. Metal concentrations were measured in urine samples using inductively coupled plasma mass spectrometry. Outcomes were BP measurements (systolic, diastolic, and pulse pressure) recorded during the visit and concurrent serum levels of thyroid hormones, sex hormones, and adrenal hormones. Associations were assessed by regression analysis in a sub-sample of 133 boys with available data on urinary metals, outcomes, and relevant covariates.

RESULTS

Models simultaneously adjusted for all metals and other potential confounders showed that urinary As and Cd were both associated with slight elevations in systolic BP (0.70 mmHg, 95%CI = 0.11; 1.29 and 1.47, 95%CI = 0.30; 2.63, respectively, per each 50% increase in metal concentrations), and urinary As was also associated with an increased risk of elevated systolic BP (≥120 mmHg) (OR = 1.28, 95%CI = 1.04; 1.56). The presence of detectable levels of 4 and 5 versus 2-3 non-essential metals (As, Cd, Hg, Ni, Pb) per boy was associated with elevations in systolic BP of 5.84 mmHg (95%CI = 0.40; 11.3) and 7.01 mmHg (95%CI = 1.01; 13.0), respectively (p-trend = 0.05). Significant associations were also found between Hg and increased testosterone and luteinizing hormone (LH) and decreased thyroid-stimulating hormone (TSH); between the combination of As and Hg and increased LH and insulin-like growth factor 1; between Cr and decreased TSH; and between Cd and increased adrenocorticotropic hormone.

CONCLUSIONS

These findings suggest that combined exposure to toxic metals, especially As and Cd, may contribute to BP elevation in male adolescents and that exposure to Hg, As, Cd, and Cr may affect their hormone levels.

Urinary metal/metalloid levels in relation to hypertension among occupationally exposed workers

Occupational exposure to metals can have an adverse effect on the cardiovascular system. However, epidemiological studies of the associations of metals expose with hypertension among occupationally exposed workers were limited. The aim of this study was to investigate the potential association between urinary metal levels and the risk of hypertension among molybdenum miners and iron and steel foundry workers. The cross-sectional study had 395 participants. Urinary metal levels were determined by inductively coupled plasma mass spectrometry. Log-binomial regression model and two-piece-wise regression model were applied to assess the dose-response relationship between metal exposure and hypertension. We observed that increased prevalence ratios for hypertension among the quartile of urinary concentrations of molybdenum, arsenic and lead were positive (all P for trend <0.05). Compared with the lowest quartiles, participants in the highest quartiles of molybdenum, arsenic and lead had a 2.58-fold, 4.30-fold and 4.85-fold increased probability of having hypertension, respectively. In the threshold effect analyses, we found the relationship was nonlinear between urinary molybdenum, cobalt, cadmium, arsenic and lead concentrations and the prevalence of hypertension. In addition, Pb, Mo, As and Co may have joint effect, and a strong positive correlation with the prevalence of hypertension. Conversely, the association between the joint effect of Cd, Pb and Mo versus the prevalence of hypertension is not significant. We provide reference levels of molybdenum, cobalt, cadmium, arsenic and lead that can be used to assess the effects of occupational metal exposure on hypertension.

Urinary Metal Concentrations and the Incidence of Hypertension Among Adult Residents Along the Yangtze River, China

Metals from the natural environment have potential hypertension effects. However, relevant studies on this topic are few. A total of 1358 adults aged 18-74 years from Chizhou, Maanshan, and Tongling of Anhui Province participated in the baseline study from 2014 to 2015. The follow-up study was performed from 2016 to 2017. Inductively coupled plasma optical emission spectrometry (7000 DV) was used to measure urinary Cr, Mn, Fe, Cu, and Zn of residents. Urinary concentrations of Cd determined via TAS-900 atomic absorption spectrophotometry at 228.8 nm wavelength. A total of 275 hypertension cases were identified. After adjusting for sociodemographic factors and risk factors for hypertension, four metals (Cd, Cr, Cu, and Mn) were significantly associated with hypertension in the single-metal model. Upon including all metals in the same model, the hazard ratios of the highest quartiles Cd and Cu compared with the reference group were 1.42 (95% confidence interval [CI] 1.09-2.02) and 1.56 (95% CI 1.16-2.09) for cases of hypertension. Our findings suggested that high levels of Cd and Cu might increase the incidence of hypertension. Further studies involving larger population should be conducted to confirm these findings.

Cadmium in Human Diseases: It's More than Just a Mere Metal

Cadmium (Cd), poisoning has been reported from all around the World, causing many deaths annually. Cd is a toxic heavy metal, and is widely present in environment. It has been reported that chronic Cd exposure is associated with kidney disease, osteoporosis, cardiovascular diseases and cancer. Smoking causes exposure to significantly higher Cd levels in humans. Tobacco smoke transports Cd into the lungs. Blood then transport it to the rest of the body where it increases effects by potentiating Cd that is already present from Cd-rich food. Other high exposures of Cd can occur with people, who live near hazardous waste sites, or factories that release Cd into the air and people who work in the metal refinery industry. Breathing of Cd can severely damage the lungs and may even cause death. Multiple studies have shown an association between environmental exposure to hazardous chemicals including toxic metals and obesity, diabetes, and metabolic syndrome. At the same time, the existing data on the impact of Cd exposure on obesity and diabetes are contradictory. On the converse, results of epidemiologic studies linking Cd exposure and Osteoporosis, overweight or obesity are far less consistent and even conflicting, also depending on differences in exposure levels. In turn, laboratory studies demonstrated that Cd adversely affects adipose tissue physiopathology through several mechanisms, thus contributing to increased insulin resistance and enhancing diabetes. However, intimate biological mechanisms linking Cd exposure with human diseases are still to be adequately investigated. Therefore, the aim of the present review was to explore the impact of Cd exposure and status on the risk of Cd in human diseases.

Blood Pressure and Lipid Profile in Automechanics in Relation to Lead Exposure

Context

Elevated blood pressure and alterations in lipid and lipoproteins play a major role in the development and progression of cardiovascular diseases.

Aim

This study is aimed at determining the blood pressure and lipid profile in automechanics.

Settings and Design

A total of 120 male subjects between 18 and 55 years of age comprised 60 automechanics and 60 age-matched occupationally unexposed control subjects in Emene, Enugu State, Nigeria.

Subjects and Methods

Four milliliters of fasting blood samples was collected from all subjects, 2 mL of blood was dispensed into K₂-EDTA vacutainer tube for blood lead analysis, while the other 2 mL was dispensed into plain vacutainer tube, allowed to retract, centrifuged, and the serum used for serum lipid profile analysis. Blood pressure was measured using aneroid sphygmomanometer.

Statistical Analysis

Statistical Package for Social Sciences (SPSS) version 21.0 was used for data analysis.

Results

Automechanics had significantly higher values of systolic and diastolic blood pressures compared with the controls. Serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglyceride (TG) were also significantly higher in the automechanics compared with the controls (P < 0.05); serum high-density lipoprotein cholesterol (HDL-C) level, however, did not differ significantly between the two groups (P > 0.05). Blood lead level showed a significant positive correlation (P < 0.05) with systolic and diastolic blood pressures, serum TC, LDL-C, VLDL-C, and TG, with no significant correlation with serum HDL-C (P > 0.05) in the automechanics and no correlation in the controls.

Conclusion

The result of this study indicates that blood pressure is elevated and lipid profile altered in automechanics which suggests that these groups of workers are prone to increased risk of developing hypertension and cardiovascular disorders due to occupational exposure to lead.

Effects of hydroxyapatite@poly-lactide-co-glycolide nanoparticles combined with Pb and Cd on liver and kidney parenchyma after the reconstruction of mandibular bone defects

Reconstruction of bone defects with the use of biomaterials based on hydroxyapatite (HAp) has been a popular approach in medicine and dentistry. Most often the process of new bone formation is analyzed with the focus only on the region of the reconstructed defect. The effects of the therapy on distant organs have been rarely reported in the literature, especially not in synergy with the exposure to other bioactive chemicals. In this study, reconstruction of the mandibular bone in vivo using poly-lactide-co-glycolide-coated HAp (HAp/PLGA) nanoparticles was monitored with a simultaneous histopathological analysis of distant organs, specifically kidney and liver parenchyma. Heavy metals are among the most prominent environmental pollutants and have a high affinity for the crystal lattice of HAp, where they get incorporated by replacing calcium ions. Lead (Pb) and cadmium (Cd) are two such metals that can be found in food, water and air, but are most commonly present in cigarette smoke, the frequent contaminant of hospital settings in the developing world. The influence of their presence in the repaired bone on the content of calcium (Ca) in the reconstructed bone defect was analyzed, along with the histopathological changes in liver and kidneys. A study performed on 24 female Wistar rats demonstrated that the reconstruction of mandibular bone defects using HAp/PLGA particles induced an increase in the content of Ca in the newly created bone without causing any pathological changes to the liver and the kidneys. The presence of Pb and Cd in the defects reconstructed with HAp/PLGA nanoparticles impeded the regenerative process and led to a severe and irreversible damage to the liver and kidney parenchyma.

Cadmium affects blood pressure and negatively interacts with obesity: Findings from NHANES 1999-2014

Inconsistencies are noted regarding the association between cadmium exposure and blood pressure/hypertension and the interaction between cadmium and body mass index (BMI). This study aims to clarify these inconsistencies in a large sample (n = 32,791) of adults age ≥20 years from eight cycles of the US National Health Examination and Nutrition Survey (NHANES, 1999-2014). The cadmium levels in blood (BCd) and urine (UCd) were used as exposure biomarker. Multiple-linear/logistic regression models were built and stratified by sex, ethnicity and BMI category. The interaction between BCd and BMI was assessed on additive and multiplicative scales. A twofold increase in BCd was associated with 0.54 mm Hg (95% CI: 0.49, 0.58) and 0.05 mm Hg (95% CI: 0.04, 0.06) increases in the systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively, in black women. The SBP and DBP increased by 0.92 mm Hg (95% CI: 0.73, 1.11) and 0.85 mm Hg (95% CI: 0.65, 1.05), respectively, in Mexican-Am women. Significant associations were found between BCd and hypertension in them (systolic risk per twofold BCd, OR = 1.31; 95% CI: 1.07, 1.61; and diastolic risk per twofold BCd, OR = 1.55; 95% CI: 1.17, 2.05). UCd was significantly associated with hypertension in all individuals (OR = 1.14 per twofold; 95% CI: 1.07, 1.21). The associations between cadmium exposure and blood pressure/hypertension showed some discrepancies across BMI categories. A negative interaction was observed between BCd and obesity with regard to their effects on systolic hypertension (RERI = -0.30; 95% CI: -0.56, -0.03; ratio of ORs = 0.55; 95% CI: 0.35, 0.89). Our findings provided evidence for the effect of cadmium on blood pressure and the prevalence of hypertension in American adults. The associations showed discrepancies by sex and ethnicity. The negative interaction between cadmium exposure and obesity influenced systolic hypertension risk.

Genome-wide Transcriptional Analysis of Oxidative Stress-related Genes and Pathways Induced by CdTe aqQDs in Mice

Objective: Quantum dots (QDs) has widely applied in the field of science, whose potential toxic effect has increasingly become a focus concern we need pay attention to in public health. The purpose of this article was to explore the toxicity mechanism with oxidative damage from treatment with QDs at the molecular level through a gene microarray.

Methods: Mice were administered aqueously synthesized cadmium telluride QDs (CdTe aqQDs) via intravenous tail injection of a 2 µmol/kg solution (based on the molar mass of Cd), and their kidneys were collected at 1 day in strict accordance with the programs used for treated mice. We determined the hierarchical clustering of expression ratios, enriched gene ontology (GO) terms and signaling pathways through gene microarray analysis and bioinformatics analysis in kidney tissue and screened the key enzyme genes, which were verified by real-time quantitative polymerase chain reaction (real-time qPCR).

Results: Compared to control group, 459 lncRNAs (197 down-regulated and 262 up-regulated) and 256 mRNAs (103 down-regulated and 153 up-regulated) were differentially expressed. According to biological processes in enriched GO terms, the response to a redox state played a significant role in the biological processes involved altered genes. Pathway analysis showed that the signaling pathways that involved cytochrome P450 (CYP450) enzymes had a close relationship with QDs. Among these signaling pathways, gene expression profiling revealed that selected differentially expressed mRNAs (CYP19A1, CYP1B1, CYP11A1, CYP11B2, and CYP17A1 in the kidney and CYP19A1 and CYP1B1 in the liver) were validated by real-time qPCR, resulting in expression levels of CYP11A1, CYP11B2 and CYP17A1 in the kidney and CYP19A1 and CYP1B1 in the liver that were significantly increased, however in expression levels of CYP19A1 and CYP1B1 compared with control group in the kidney, there was no significant difference.

Conclusions: Our results provide a foundation for and potential insight into the role of CYP450-related genes in QD-induced oxidative stress. QDs may produce a great deal of reactive oxygen species (ROS) by promoting high expression of CYP450 enzymes and accumulating steroid hormones, which may be an important toxicity mechanism for mediating oxidative stress and tissue damage.

Associations of environmental exposure to metals with the risk of hypertension in China

Hypertension contributes largely to the global burden of disease and mortality. Environmental exposure to metals might be a causative factor for hypertension, but the association remains unclear. The present case-control study of 502 hypertension patients and 502 healthy participants aimed to evaluate the potential relationships between the concentrations of 20 metal in urine and the risk of hypertension in a Chinese population. Multivariate logistic analyses adjusted for potential confounders were performed separately considering the effects of single and multi-metal. We found the increasing trends of urinary Fe, Co, Ni, Cu, Zn and Sr quartiles and the decreasing trends of urinary V and Rb quartiles with the ORs for hypertension. These dose-response associations were confirmed in the RCS models and remained robust in the multi-metal model. Urinary Hg quartiles were positively associated with the risk of hypertension in the models of single-metal and multi-metal. Urinary Cd quartiles were inversely associated with the risk of hypertension in the multi-metal model. Besides, modification effects of gender, BMI and smoking status on the associations of the exposure to various metals with the risk of hypertension were also suggested in the subgroup analysis. Our findings suggest that environmental exposure to V, Fe, Co, Ni, Cu, Zn, Rb, Sr, Cd and Hg might be related with the prevalence of hypertension. Further studies with prospective design should be conducted to confirm these findings.

Cadmium body burden, hypertension, and changes in blood pressure over time: results from a prospective cohort study in American Indians

American Indian communities are at greater risk of hypertension and cardiovascular disease than the general US population and are exposed to greater cadmium levels. However, cadmium's effect on blood pressure is unclear. This study assesses the association between baseline urinary cadmium and longitudinal changes in blood pressure in American Indian communities. Cadmium was measured in 3047 baseline urine samples from Strong Heart Study participants from three geographic areas. Longitudinal changes in blood pressure across three study visits (1989-1999) were modeled using linear mixed models by baseline log urinary cadmium to creatinine ratio. Hypertension risk was evaluated using interval-censored survival analysis. Higher levels of urinary cadmium at baseline were associated with faster rates of increase in diastolic and systolic blood pressure (P [trend] = .001 and .02, respectively). The estimated change in diastolic and systolic blood pressures per year was 0.18 mm Hg (0.05-0.31) and 0.62 mm Hg (0.37-0.87) in the upper quintile of cadmium level compared with -0.11 mm Hg (-0.24 to 0.02) and 0.21 mm Hg (-0.04 to 0.46) in the lowest, respectively. A one-unit increase in log-transformed urinary cadmium was associated with 10% greater hypertension risk (95% confidence interval: 1.01-1.20). In conclusion, blood pressure of individuals with greater baseline levels of urinary cadmium increased at a faster rate relative to those with lower levels.

Environmental exposure to metals and the risk of hypertension: A cross-sectional study in China

Metal pollution is a severe environmental issue in China, which has been recently linked with the risk of hypertension. However, relevant epidemiological studies are limited. The present exploratory study was conducted to assess the associations of environmental exposure to metals with the odds of hypertension as well as blood pressure (BP) levels using urine samples in a Chinese general population. From May 2016 to April 2017, a total of 823 eligible participants were consecutively enrolled in our study in Wuhan, China. Hypertension was defined as systolic BP (SBP) of ≥140 mmHg or diastolic BP (DBP) of ≥90 mmHg, a self-reported physician diagnosis, or current use of antihypertensive medication. We used urine samples as biomarkers to reflect the levels of environmental exposure to 20 metals. Multivariable regression models were applied to assess the potential association. Multi-metal models were conducted to investigate the impacts of co-exposure to various metals. Based on the results from various models, positive trends for increased odds of hypertension with increasing quartiles of vanadium (V), iron (Fe), zinc (Zn) and selenium (Se) were suggested. Compared with those in the lowest quartiles, participants in the highest quartiles of V, Fe, Zn and Se had a 4.4-fold, 4.9-fold, 4.2-fold and 2.5-fold increased odds of having hypertension, respectively. High urinary Hg level was found to increase the levels of DBP. Individuals in the highest group of Hg were found to have a 4.3 mmHg higher level of DBP. Our findings suggest that environmental exposure to V, Fe, Zn, Se and Hg might increase the risk of hypertension or elevate the levels of BP. These findings warrant further prospective studies in a larger population.

Serum levels of lead, mercury and cadmium in relation to coronary artery disease in the elderly: A cross-sectional study

BACKGROUND

There is a continuing attempt to identify novel factors that can predict the risk of cardiovascular disease beyond the established coronary risk factors. It has been suggested that serum levels of lead, mercury and cadmium are associated with the risk of coronary artery disease (CAD). In the present study, we aimed to evaluate serum concentrations of lead (s-Pb), mercury (s-Hg) and cadmium (s-Cd) in patients with CAD in comparison with those of healthy individuals. The correlation between serum levels of these heavy metals and lipid profile parameters was also investigated.

METHODS

In this case-control study, we included 65 patients (35 females) aged 50-70 years with angiographically-documented CAD and 65 healthy controls (43 female) matched for sex, age and place of residence. Serum concentrations of heavy metals were determined using graphite furnace atomic absorption (GFAA). Serum lipids were measured using routine enzymatic methods.

RESULTS

It was observed that the mean concentration of s-Pb (12.54 ± 8.41 vs. 5.89 ± 4.44 μg/L, p < 0.05) and s-Cd (0.938 ± 0.72 vs. 0.448 ± 0.30, p < 0.05; CI: 95%) and s-Hg (10.14 ± 5.06 vs. 6.11 ± 5.66, p < 0.05) were significantly higher in CAD patients compared with control subjects. The same result was also obtained after adjustment for cardiovascular risk factors including age, dyslipidemia, diabetes mellitus and hypertension (p < 0.05). The mean concentration of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and TC:HDL-C ratio were significantly higher in CAD patients (p < 0.05). There was no significant association between serum metal concentrations with TC, HDL-C and TC:HDL-C ratio (p > 0.05).

CONCLUSIONS

The present results showed that serum levels of heavy metals are associated with the presence of CAD. Long-term exposure to trace levels of Pb, Cd and Hg may play a role in the development of coronary atherosclerotic plaques.

Involvement of Notch1 signaling in malignant progression of A549 cells subjected to prolonged cadmium exposure

Cadmium exposure is known to increase lung cancer risk, but the underlying molecular mechanisms in cadmium-stimulated progression of malignancy are unclear. Here, we examined the effects of prolonged cadmium exposure on the malignant progression of A549 human lung adenocarcinoma cells and the roles of Notch1, hypoxia-inducible factor 1α (HIF-1α), and insulin-like growth factor 1 receptor (IGF-1R)/Akt/extracellular signal-regulated kinase (ERK)/p70 S6 kinase 1 (S6K1) signaling pathways. Exposing A549 cells to 10 or 20 μm cadmium chloride (CdCl2) for 9-15 weeks induced a high proliferative potential, the epithelial-mesenchymal transition (EMT), stress fiber formation, high cell motility, and resistance to antitumor drugs. Of note, the CdCl2 exposure increased the levels of the Notch1 intracellular domain and of the downstream Notch1 target genes Snail and Slug. Strikingly, siRNA-mediated Notch1 silencing partially suppressed the CdCl2-induced EMT, stress fiber formation, high cell motility, and antitumor drug resistance. In addition, we found that prolonged CdCl2 exposure induced reduction of E-cadherin in BEAS-2B human bronchial epithelial cells and antitumor drug resistance in H1975 human tumor-derived non-small-cell lung cancer cells depending on Notch1 signaling. Moreover, Notch1, HIF-1α, and IGF-1R/Akt/ERK/S6K1 activated each other to induce EMT in the CdCl2-exposed A549 cells. These results suggest that Notch1, along with HIF-1α and IGF-1R/Akt/ERK/S6K1 signaling pathways, promotes malignant progression stimulated by prolonged cadmium exposure in this lung adenocarcinoma model.

Microphthalmia-associated transcription factor ensures the elongation of axons and dendrites in the mouse frontal cortex

Long interspersed element-1 (LINE-1) is a mammalian transposable element, and its genomic insertion could cause neurological disorders in humans. Incidentally, LINE-1 is present in intron 3 of the microphthalmia-associated transcription factor (Mitf) gene of the black-eyed white mouse (Mitf^mi-bw allele). Mice homozygous for the Mitf^mi-bw allele show the white coat color with black eye and deafness. Here, we explored the functional consequences of the LINE-1 insertion in the Mitf gene using homozygous Mitf^mi-bw mice on the C3H background (C3H-bw mice) or on the C57BL/6 background (bw mice). The open-field test showed that C3H-bw mice moved more irregularly in an unfamiliar environment during the 20-min period, compared to wild-type mice, suggesting the altered emotionality. Moreover, C3H-bw mice showed the lower serum creatinine levels, which may reflect the creatine deficiency. In fact, morphologically abnormal neurons and astrocytes were detected in the frontal cortex of bw mice. The immunohistochemical analysis of bw mouse tissues showed the lower intensity for expression of guanidinoacetate methyltransferase, a key enzyme in creatine synthesis, in neurons of the frontal cortex and in glomeruli and renal tubules. Thus, Mitf may ensure the elongation of axons and dendrites by maintaining creatine synthesis in the frontal cortex.

Association of Blood Pressure with Exposure to Lead and Cadmium: Analysis of Data from the 2008-2013 Korean National Health and Nutrition Examination Survey

We examined the association of blood pressure with blood levels of cadmium, lead, and their combination in a representative sample of adults from South Korea (Korean National Health and Nutrition Examination Survey, 2008-2013). This cross-sectional study enrolled subjects who were at least 19 years-old, completed a health examination survey, and had blood measurements of lead and cadmium. We estimated the adjusted mean differences in diastolic and systolic blood pressure associated with doubling of blood lead and cadmium by regression of blood pressure against log₂-transformed blood metals and their tertiles after covariate adjustment. Adjusted odds ratios for hypertension and prehypertension were calculated for log₂-transformed blood levels of lead and cadmium and their tertiles. In the general population of Korea, blood lead level was associated with increased BP and risk of hypertension. Blood cadmium levels had a stronger association with elevated blood pressure and risk of hypertension than blood lead levels, and these associations remained significant after statistical adjustment for blood lead. The combination of blood lead and cadmium was more strongly associated with elevated blood pressure than exposure to each individual metal. In females, there was a stronger relationship between blood pressure and blood levels of these metals by analyzing interaction model. After adjustment for confounding factors, there were significant associations of blood pressure with the level of blood lead, cadmium, and their combination in adults from South Korea.

The co-induced effects of molybdenum and cadmium on the mRNA expression of inflammatory cytokines and trace element contents in duck kidneys

The aims of this study were determining the co-induced effects of dietary Cadmium (Cd) and high intake of Molybdenum (Mo) on renal toxicity in ducks. 240 healthy 11-day-old ducks were randomly divided into 6 groups, which were treated with Mo or/and Cd at different doses added to the basal diet for 120 days. Ducks of control group were fed with basal diet, LMo and HMo groups were fed with 15mg/kg Mo and 100mg/kg Mo respectively; ducks of Cd group were provided with 4mg/kg Cd which was added into basal diet. Two combination groups were treated with 15mg/kg Mo+4mg/kg Cd and 100mg/kg Mo+4mg/kg Cd respectively. On days 30, 60, 90 and 120, the mRNA expression levels of inflammatory cytokines and contents of trace elements were detected. In addition, transmission electron microscopic examination was used for ultrastructural studies. The results indicated that the mRNA expression levels of tumor necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB), and cyclooxygenase-2 (COX-2) showed an upward tendency in treatment groups in comparison with control group, and in the later period of the experiment it showed a significant rise in joint groups compared with the Mo and Cd group (P<0.01); the contents of copper (Cu) and iron (Fe) decreased in joint groups in the later period (P<0.05) while the contents of Mo and Cd significantly increased (P<0.01); zinc (Zn) and selenium (Se) concentration had a slight downtrend in treated groups, but showed no significant difference (P>0.05). The ultrastructural analysis showed that kidney tissues were severely injured in joint groups on day 120. These results suggested that the combination of Mo and Cd could aggravate damages to the kidney. In addition, dietary of Mo or/and Cd caused the decrease of Cu, Fe, Zn, and Se contents, inflammatory response and pathological lesions whose mechanism is somehow linked with Mo and Cd deposition in kidney.

A blood pressure-associated variant of the SLC39A8 gene influences cellular cadmium accumulation and toxicity

Genome-wide association studies have revealed a relationship between inter-individual variation in blood pressure and the single nucleotide polymorphism rs13107325 in the SLC39A8 gene. This gene encodes the ZIP8 protein which co-transports divalent metal cations, including heavy metal cadmium, the accumulation of which has been associated with increased blood pressure. The polymorphism results in two variants of ZIP8 with either an alanine (Ala) or a threonine (Thr) at residue 391. We investigated the functional impact of this variant on protein conformation, cadmium transport, activation of signalling pathways and cell viability in relation to blood pressure regulation. Following incubation with cadmium, higher intracellular cadmium was detected in cultured human embryonic kidney cells (HEK293) expressing heterologous ZIP8-Ala391, compared with HEK293 cells expressing heterologous ZIP8-Thr391. This Ala391-associated cadmium accumulation also increased the phosphorylation of the signal transduction molecule ERK2, activation of the transcription factor NFκB, and reduced cell viability. Similarly, vascular endothelial cells with the Ala/Ala genotype had higher intracellular cadmium concentration and lower cell viability than their Ala/Thr counterpart following cadmium exposure. These results indicate that the ZIP8 Ala391-to-Thr391 substitution has an effect on intracellular cadmium accumulation and cell toxicity, providing a potential mechanistic explanation for the association of this genetic variant with blood pressure.

Oxidative Stress and Cardiovascular Dysfunction Associated with Cadmium Exposure: Beneficial Effects of Curcumin and Tetrahydrocurcumin

Cadmium (Cd) is a non-essential heavy metal with high toxicity potential. Humans are exposed to Cd present in diet, polluted air, and cigarette smoke. Cd exposure has been associated with increased risk of chronic diseases, including hypertension, atherosclerosis, diabetes, and nephropathy, all of which could be attributable to dysfunctional endothelial and smooth muscle cells. Cd toxicity is correlated with increased reactive oxygen formation and depletion of antioxidants, resulting in an oxidative stress. Chelation of Cd has proved useful in the removal of the Cd burden. However, several chelating agents cause side effects in clinical usage. Recent studies have shown that the antioxidant compounds curcumin and tetrahydrocurcumin can alleviate vascular dysfunction and high blood pressure caused by Cd toxicity. In chronic Cd exposure, these antioxidants protect vascular endothelium by increasing nitric oxide (NO•) bioavailability and improving vascular function. Antioxidant activity against Cd intoxication results directly and/or indirectly through free radical scavenging, metal chelation, enhanced expression of the antioxidant defense system, regulation of inflammatory enzymes, increase in NO• bioavailability, and reduction of gastrointestinal absorption and tissue Cd accumulation. This review summarizes current knowledge of Cd-induced oxidative stress and cardiovascular dysfunction and a possible protective effect conferred by the antioxidants curcumin and tetrahydrocurcumin.

The stress response of human proximal tubule cells to cadmium involves up-regulation of haemoxygenase 1 and metallothionein but not cytochrome P450 enzymes

Enzymes of the cytochrome P450 (CYP) super-family are implicated in cadmium (Cd) -induced nephrotoxicity, however, direct evidence is lacking. This study investigated the endogenous expression of various CYP proteins together with the stress-response proteins, heme oxygenase-1 (HO-1) and metallothionein (MT) in human kidney sections and in cadmium-exposed primary cultures of human proximal tubular epithelial cells (PTC). By immunohistochemistry, the CYP members 2B6, 4A11 and 4F2 were prominently expressed in the cortical proximal tubular cells and to a lesser extent in distal tubular cells. Low levels of CYPs 2E1 and 3A4 were also detected. In PTC, in the absence of Cd, CYP2E1, CYP3A4, CYP4F2 and MT were expressed, but HO-1, CYP2B6 and CYP4A11 were not detected. A range of cadmium concentrations (0-100μM) were utilized to induce stress conditions. MT protein was further induced by as little as 0.5μM cadmium, reaching a 6-fold induction at 20μM, whereas for HO-1, a 5μM cadmium concentration was required for initial induction and at 20μM cadmium reached a 15-fold induction. The expression of CYP2E1, CYP3A4, and CYP4F2 were not altered by any cadmium concentrations tested at 48h. Cadmium caused a reduction in cell viability at concentrations above 10μM. In conclusion although cultured PTC, do express CYP proteins, (CYP2E1, CYP3A4, and CYP4F2), Cd-induced cell stress as indicted by induction of HO-1 and MT does not alter expression of these CYP proteins at 48h.

The Co-Induced Effects of Molybdenum and Cadmium on the Trace Elements and the mRNA Expression Levels of CP and MT in Duck Testicles

To investigate the chronic toxicity of molybdenum (Mo) and cadmium (Cd) on the trace elements and the mRNA expression levels of ceruloplasmin (CP) and metallothionein (MT) in duck testicles, 120 healthy 11-day-old male ducks were randomly divided into six groups with 20 ducks in each group. Ducks were treated with the diet containing different dosages of Mo or Cd. The source of Mo and Cd was hexaammonium molybdate ([(NH4)6Mo7O24·4H2O]) and cadmium sulfate (3CdSO4·8H2O), respectively, in this study. After being treated for 60 and 120 days, ten male birds in each group were randomly selected and euthanized and then testicles were aseptically collected for determining the mRNA expression levels of MT and CP, antioxidant indexes, and contents of trace elements in the testicle. In addition, testicle tissues at 120 days were subjected to histopathological analysis with the optical microscope. The results showed that co-exposure to Mo and Cd resulted in an increase in malondialdehyde (MDA) level while decrease in xanthine oxidase (XOD) and catalase (CAT) activities. The mRNA expression level of MT gene was upregulated while CP was decreased in combination groups. Contents of Mo, copper (Cu), iron (Fe), and zinc (Zn) decreased in combined groups while Cd increased in Cd and combined groups at 120 days. Furthermore, severe congestion, low sperm count, and malformation were observed in low dietary of Mo combined with Cd group and high dietary of Mo combined with Cd group. Our results suggested that Mo and Cd might aggravate testicular degeneration synergistically through altering the mRNA expression levels of MT and CP, increasing lipid peroxidation through inhibiting related enzyme activities and disturbing homeostasis of trace elements in testicles. Interaction of Mo and Cd may have a synergistic effect on the testicular toxicity.

Combined Effect of Blood Cadmium and Lead Levels on Coronary Heart Disease Prediction Risk in Korean Men

This study was designed to investigate the combined effects of cadmium (Cd) and lead (Pb) on 10-year coronary heart disease (CHD) risk calculated using the Framingham risk score. The heavy metal data set of the Korean National Health and Nutrition Examination Survey IV and V (2008-2010) was analyzed. The 10-year CHD risk was significantly associated with the log-transformed blood Cd and Pb levels in Korean men. For the highest quartile of Cd and Pb, the odds ratio (OR) of the intermediate risk and beyond for CHD (10-year risk ≥10%) compared to the lowest quartile was 6.870 (Cd, 95% confidence interval [CI]: 4.58-10.30) and 3.127 (Pb, 95% CI: 2.09-4.69) after adjusting for confounders, respectively. The adjusted OR of the intermediate risk and beyond for CHD (10-year risk ≥10%) in the fourth quartile of both Cd and Pb was 12.2 (95% CI: 8.0-18.5) compared to the reference group (first and second quartiles of Cd and Pb). However, the association between log-transformed blood Cd and Pb and the 10-year CHD risk was not significant in Korean women.

Serum metabolomics study and eicosanoid analysis of childhood atopic dermatitis based on liquid chromatography-mass spectrometry

Atopic dermatitis (AD) is the most common inflammatory skin disease in children. In the study, ultra high performance liquid chromatography-mass spectrometry was used to investigate serum metabolic abnormalities of AD children. Two batch fasting sera were collected from AD children and healthy control; one of them was for nontargeted metabolomics analysis, the other for targeted eicosanoids analysis. AD children were divided into high immunoglobulin E (IgE) group and normal IgE group. On the basis of the two analysis approaches, it was found that the differential metabolites of AD, leukotriene B4, prostaglandins, conjugated bile acids, etc., were associated with inflammatory response and bile acids metabolism. Carnitines, free fatty acids, lactic acid, etc., increased in the AD group with high IgE, which revealed energy metabolism disorder. Amino acid metabolic abnormalities and increased levels of Cytochrome P450 epoxygenase metabolites were found in the AD group with normal IgE. The results provided a new perspective to understand the mechanism and find potential biomarkers of AD and may provide a new reference for personalized treatment.

Low serum zinc is associated with elevated risk of cadmium nephrotoxicity

BACKGROUND

Despite animal evidence suggests that zinc modulates cadmium nephrotoxicity, limited human data are available.

OBJECTIVE

To test the hypothesis that low serum zinc concentrations may increase the risk of cadmium-mediated renal dysfunction in humans.

METHODS

Data from 1545 subjects aged 20 or older in the National Health and Nutrition Examination Survey (NHANES), 2011-2012 were analyzed. Renal function was defined as impaired when estimated glomerular filtration rate (eGFR) fell below 60 ml/min/1.73 m(2) and/or the urinary albumin-to-creatinine ratio surpassed 2.5 in men and 3.5mg/mmol in women.

RESULTS

Within the study cohort, 117 subjects had reduced eGFR and 214 had elevated urinary albumin. After adjusting for potential confounders, subjects with elevated blood cadmium (>0.53 μg/L) were more likely to have a reduced eGFR (odds ratio [OR]=2.21, 95% confidence interval [CI]: 1.09-4.50) and a higher urinary albumin (OR=2.04, 95% CI: 1.13-3.69) than their low cadmium (<0.18 μg/L) peers. In addition, for any given cadmium exposure, low serum zinc is associated with elevated risk of reduced eGFR (OR=3.38, 95% CI: 1.39-8.28). A similar increase in the odds ratio was observed between declining serum zinc and albuminuria but failed to reach statistical significance. Those with lower serum zinc/blood cadmium ratios were likewise at a greater risk of renal dysfunction (p<0.01).

CONCLUSIONS

This study results suggest that low serum zinc concentrations are associated with an increased risk of cadmium nephrotoxicity. Elevated cadmium exposure is global public health issue and the assessment of zinc nutritional status may be an important covariate in determining its effective renal toxicity.

Lead and cadmium in public health in Nigeria: physicians neglect and pitfall in patient management

Low-level heavy metals exposure may contribute much more toward the causation of chronic disease and impaired functioning than previously thought. Among the suggested preventive and intervention measures for the control of renal diseases are the reduction in the exposure to heavy metals. Although these indicate knowledge and awareness of possible role of some heavy metals in the etiogenesis of some chronic diseases by Nigerian Physicians, heavy metal assay as diagnostic guide in patient management is often omitted in most healthcare settings. This is a synoptic capture of the increased incidence and prevalence of some metabolic disorders where heavy metals may be implicated. A search of the terms heavy metal exposure, source, toxicity, metabolic disorders, poisoning in Nigeria, in bibliographical databases (in English language) such as PubMed, Scopus, Google Scholar, and Africa Journal Online (AJOL) digital library was conducted. Leaded gasoline, refuse dumping, absence of poison information centers, and poor record keeping characterize environmental health in Nigeria. Lead and cadmium are of most significant public health importance in Nigeria. The recognition and inclusion of heavy metals assays in the diagnosis of metabolic disorders may ensure early diagnosis and improve management.

Cadmium exposure and clinical cardiovascular disease: a systematic review

Mounting evidence supports that cadmium, a toxic metal found in tobacco, air and food, is a cardiovascular risk factor. Our objective was to conduct a systematic review of epidemiologic studies evaluating the association between cadmium exposure and cardiovascular disease. Twelve studies were identified. Overall, the pooled relative risks (95% confidence interval) for cardiovascular disease, coronary heart disease, stroke, and peripheral arterial disease were: 1.36 (95% CI: 1.11, 1.66), 1.30 (95% CI: 1.12, 1.52), 1.18 (95% CI: 0.86, 1.59), and 1.49 (95% CI: 1.15, 1.92), respectively. The pooled relative risks for cardiovascular disease in men, women and never smokers were 1.29 (1.12, 1.48), 1.20 (0.92, 1.56) and 1.27 (0.97, 1.67), respectively. Together with experimental evidence, our review supports the association between cadmium exposure and cardiovascular disease, especially for coronary heart disease. The number of studies with stroke, heart failure (HF) and peripheral arterial disease (PAD) endpoints was small. More studies, especially studies evaluating incident endpoints, are needed.

Growth, bioluminescence and shoal behavior hormetic responses to inorganic and/or organic chemicals: a review

A biphasic dose response, termed hormesis, is characterized by beneficial effects of a chemical at a low dose and harmful effects at a high dose. This biphasic dose response phenomenon has the potential to strongly alter toxicology in a broad range. The present review focuses on the progress of research into hormetic responses in terms of growth (in plants, birds, algae and humans), bioluminescence, and shoal behavior as end points. The paper describes how both inorganic and organic chemicals at a low dose show stimulatory responses while at higher doses are inhibitory. The article highlights how factors such as symbiosis, density-dependent factors, time, and contrasting environmental factors (availability of nutrients, temperature, light, etc.) affect both the range and amplitude of hormetic responses. Furthermore, the possible underlying mechanisms are also discussed and we suggest that, for every end point, different hormetic mechanisms may exist. The occurrences of varying interacting receptor systems or receptor systems affecting the assessment of hormesis for each endpoint are discussed. The present review suggests that a hormetic model should be adopted for toxicological evaluations instead of the older threshold and linear non-threshold models.

Cadmium exposure and incident peripheral arterial disease

BACKGROUND

Cadmium has been associated with peripheral arterial disease (PAD) in cross-sectional studies, but prospective evidence is lacking. Our goal was to evaluate the association of urine cadmium concentrations with incident PAD in a large population-based cohort.

METHODS AND RESULTS

A prospective cohort study was performed with 2864 adult American Indians 45 to 74 years of age from Arizona, Oklahoma, and North and South Dakota who participated in the Strong Heart Study from 1989 to 1991 and were followed through 2 follow-up examination visits in 1993 to 1995 and 1997 to 1999. Participants were free of PAD, defined as an ankle brachial index <0.9 or >1.4 at baseline, and had complete baseline information on urine cadmium, potential confounders, and ankle brachial index determinations in the follow-up examinations. Urine cadmium was measured using inductively coupled plasma mass spectrometry and corrected for urinary dilution by normalization to urine creatinine. Multivariable-adjusted hazard ratios were computed using Cox-proportional hazards models for interval-censored data. A total of 470 cases of incident PAD, defined as an ankle brachial index <0.9 or >1.4, were identified. After adjustment for cardiovascular disease risk factors including smoking status and pack-years, the hazard ratio comparing the 80th to the 20th percentile of urine cadmium concentrations was 1.41 (1.05-1.81). The hazard ratio comparing the highest to the lowest tertile was 1.96 (1.32-2.81). The association persisted after excluding participants with ankle brachial index >1.4 only as well as in subgroups defined by sex and smoking status.

CONCLUSIONS

Urine cadmium, a biomarker of long-term cadmium exposure, was independently associated with incident PAD, providing further support for cadmium as a cardiovascular disease risk factor.

Emerging roles of cadmium and heme oxygenase in type-2 diabetes and cancer susceptibility

Many decades after an outbreak of severe cadmium poisoning, known as Itai-itai disease, cadmium continues to pose a significant threat to human health worldwide. This review provides an update on the effects of this environmental toxicant cadmium, observed in numerous populations despite modest exposure levels. In addition, it describes the current knowledge on the link between heme catabolism and glycolysis. It examines novel functions of heme oxygenase-2 (HO-2) that protect against type 2-diabetes and obesity, which have emerged from diabetic/obese phenotypes of the HO-2 knockout mouse model. Increased cancer susceptibility in type-2 diabetes has been noted in several large cohorts. This is a cause for concern, given the high prevalence of type-2 diabetes worldwide. A lifetime exposure to cadmium is associated with pre-diabetes, diabetes, and overall cancer mortality with sex-related differences in specific types of cancer. Liver and kidney are target organs for the toxic effects of cadmium. These two organs are central to the maintenance of blood glucose levels. Further, inhibition of gluconeogenesis is a known effect of heme, while cadmium has the propensity to alter heme catabolism. This raises the possibility that cadmium may mimic certain HO-2 deficiency conditions, resulting in diabetic symptoms. Intriguingly, evidence has emerged from a recent study to suggest the potential interaction and co-regulation of HO-2 with the key regulator of glycolysis: 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4). HO-2 could thus be critical to a metabolic switch to cancer-prone cells because the enzyme PFKFB and glycolysis are metabolic requirements for cell proliferation and resistance to apoptosis.

NTPDase and 5'-nucleotidase activities from synaptosomes and platelets of rats exposed to cadmium and treated with N-acetylcysteine

The purpose of the present investigation was to evaluate the hydrolysis of adenine nucleotides on synaptosomes and platelets obtained from rats exposed to cadmium (Cd) and treated with N-acetylcysteine (NAC). Rats received Cd (2 mg/kg) and NAC (150 mg/kg) by gavage every other day for 30 days. Animals were divided into four groups (n = 4-6): control/saline, NAC, Cd, and Cd/NAC. The results of this study demonstrated that NTPDase and 5'-nucleotidase activities were increased in the cerebral cortex synaptosomes of Cd-poisoned rats, and NAC co-treatment reversed these activities to the control levels. In relation to hippocampus synaptosomes, no differences on the NTPDase and 5'-nucleotidase activities of Cd-poisoned rats were observed and only the 5'-nucleotidase activity was increased by the administration of NAC per se. In platelets, Cd-intoxicated rats showed a decreased NTPDase activity and no difference in the 5'-nucleotidase activity; NAC co-treatment was inefficient in counteracting this undesirable effect. Our findings reveal that adenine nucleotide hydrolysis in synaptosomes and platelets of rats were altered after Cd exposure leading to a compensatory response in the central nervous system and acting as a modulator of the platelet activity. NAC was able to modulate the purinergic system which is interesting since the regulation of these enzymes could have potential therapeutic importance. Thus, our results reinforce the importance of the study of the ecto-nucleotidases pathway in poisoning conditions and highlight the possibility of using antioxidants such as NAC as adjuvant against toxicological conditions.

Association of blood cadmium with hypertension in the Korean general population: analysis of the 2008-2010 Korean National Health and Nutrition Examination Survey data

INTRODUCTION

We present data from the Korean National Health and Nutrition Examination Survey 2008-2010 regarding the association between blood cadmium levels and blood pressure in a representative sample of the adult South Korean population.

METHODS

We restricted the analysis to participants ≥20 years of age who completed the health examination survey, including blood cadmium measurements (n = 5,919). We performed multivariate linear regression analyses to estimate adjusted mean differences in diastolic and systolic blood pressure associated with doubling of, or quartiles of, cadmium levels after covariate adjustment. We calculated odds ratios (ORs) for hypertension and prehypertension for log-transformed blood cadmium levels and quartiles thereof after covariate adjustment.

RESULTS

We observed a twofold increase in blood cadmium associated with 0.755 and 1.007 mmHg increases in diastolic pressure in women and men, respectively. We observed 2.243 and 1.975 mmHg increases in diastolic pressure in women and men, respectively, in the highest compared with the lowest quartile of blood cadmium. Systolic pressure showed results similar to those of diastolic pressure. Based on ORs, a doubling of blood cadmium resulted in 18.6% and 31.5% increases in the risk of hypertension in women and men, respectively. Doubling of blood cadmium resulted in a 23.5% and 22.9% increase in the risk of prehypertension in women and men, respectively.

CONCLUSION

We found a significant association between blood cadmium levels and elevated blood pressure regardless of the type of variable (continuous or categorical) in women and men with a lower blood cadmium level compared to previous Korean studies. This study also showed that blood cadmium levels were robust risk factors for prehypertension in both women and men.

Expression of metallothionein isoforms in peripheral blood leukocytes from Thai population residing in cadmium-contaminated areas

Metallothionein (MT) is a group of proteins with high cadmium (Cd) affinity and with a potential role in Cd transportation and detoxification. The aim of the present study was to investigate the relationship between MT (MT-1A, MT-2A, and MT-3 isoforms) gene expression level in peripheral blood leukocytes and Cd-associated renal injury in non-occupational exposed Thai population. The study was conducted in adult subjects residing in Cd-contaminated areas of Mae Sot District, Thailand. The basal levels of MT-1A, MT-2A, and MT-3 mRNA expression were determined in leukocytes by quantitative RT-PCR. MT-1A and MT-2A expressions, particularly MT-1A, were found to be significantly increased with elevated levels of blood and urinary Cd levels. In subjects with high urinary Cd levels, negative correlations between MT-1A and microalbumin, and between MT-2A and β(2)-MG, were observed. These results suggest that MT gene expression may reflect susceptibility of the exposed population to Cd-induced renal dysfunction. MT-1A mRNA expression in leukocytes might be developed as a potential biomarker of Cd exposure and Cd-induced renal dysfunction.

Comparative metal distribution in scalp hair of Pakistani and Irish referents and diabetes mellitus patients

BACKGROUND

The essential metals, chromium (Cr), magnesium (Mg), manganese (Mn) and zinc (Zn), are necessary for many metabolic processes and their homeostasis is crucial for life. The toxic metals, cadmium (Cd) and lead (Pb), have no beneficial role in human metabolism. The aim of this study was to investigate the levels of Cd, Cr, Mg, Mn, Pb, and Zn in scalp hair samples of type 2 diabetes mellitus patients of both genders, ages ranging from 30 to 50 y, and belong to urban areas of Ireland and Pakistan. For comparison purposes, age matched non-diabetic subjects of both countries were selected as referents.

METHODS

The concentrations of metals in scalp hair samples were measured by inductively coupled plasma atomic emission spectrophotometer and atomic absorption spectrophotometer after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked by conventional wet-acid-digestion method and using certified reference materials.

RESULTS

The mean values of Cd and Pb were significantly higher in scalp hair samples of both Pakistani and Irish diabetic patients as compared to referents of both countries (P<0.001). In contrast, lower Cr, Mg, Mn, and Zn (P<0.01) concentrations were detected in scalp hair derived from patients with type 2 diabetes versus healthy subjects of both countries.

CONCLUSION

This study showed that, increased toxic elements and decreased essential elements are associated with diabetes mellitus. Therefore, these elements may play a role in the development and pathogenesis of diabetes mellitus.