Effect of chronic exposure to cadmium on serum lipid, lipoprotein and oxidative stress indices in male rats

Curcumin protects the testis against cadmium-induced histopathological damages and oxidative stress in mice

BACKGROUND

Cadmium is an environmental pollutant which can induce the overproduction of free radicals while suppressing the antioxidant defense system. Curcumin is considered a free-radical scavenger and a potent antioxidant. This study was conducted to investigate the effect of curcumin on serum antioxidant enzymes and histopathological changes in mice treated with cadmium.

METHODS

In this experimental study, adult mice were divided into four groups, namely, control, cadmium chloride (5 mg kg^-1), curcumin (100 mg kg^-1), and curcumin+cadmium chloride. The animals received curcumin 24 h prior to cadmium chloride injection. After 24 h, blood samples were collected and used to assess the levels of malondialdehyde (MDA), antioxidant enzymes activity (catalase, superoxide dismutase, and glutathione peroxidase), total glutathione, total thiol, and hydrogen peroxide. Histopathological evaluation was also performed for testicular tissue.

RESULTS

Mice treated with cadmium showed a significant (p < 0.001) decrease in the activity of antioxidant enzymes, serum amounts of total glutathione and total thiol, and the diameter of seminiferous tubules compared to the control group. This pollutant also significantly (p < 0.001) increased serum levels of MDA and hydrogen peroxide and the lumen diameter of seminiferous tubules compared to the control group. In the curcumin+cadmium group, curcumin significantly (p < 0.001) reversed the adverse effects of cadmium, compared to the cadmium group. In addition, curcumin alone significantly (p < 0.001) increased serum glutathione peroxidase activity and thiol content compared to the control group.

CONCLUSION

Curcumin, as a potent antioxidant, could compensate the adverse effects of cadmium on lipid and protein peroxidation, potentiated serum antioxidant defense system, and ameliorated some morphometrical parameters in the testis of cadmium-treated mice.

Resveratrol targeting the Wnt signaling pathway: A focus on therapeutic activities

Wingless-type MMTV integration site (Wnt) signaling pathway is considered as an important pathway regulating a variety of biological processes such as tissue formation and homeostasis, cell proliferation, cell migration, cell differentiation, and embryogenesis. Impairment in the Wnt signaling pathway is associated with pathological conditions, particularly cancer. So, modulation of this pathway can be considered as a promising strategy and several drugs have been developed in line with this strategy. Resveratrol (Res) is a naturally occurring nutraceutical compound exclusively found in different fruits and nuts such as grape, peanut, and pistachio. This compound has favorable biological and therapeutic activities such as antioxidant, anti-inflammatory, antitumor, hepatoprotective, cardioprotective, and antidiabetic. At the present review, we demonstrate how Res modulates Wnt signaling pathway to exert its pharmacological effects.

The role of arsenic in obesity and diabetes

As many individuals worlwide are exposed to arsenic, it is necessary to unravel the role of arsenic in the risk of obesity and diabetes. Therefore, the present study reviewed the effects of arsenic exposure on the risk and potential etiologic mechanisms of obesity and diabetes. It has been suggested that inflammation, oxidative stress, and apoptosis contribute to the pathogenesis of arsenic-induced diabetes and obesity. Though arsenic is known to cause diabetes through different mechanisms, the role of adipose tissue in diabetes is still unclear. This review exhibited the effects of arsenic on the metabolism and signaling pathways within adipose tissue (such as sirtuin 3 [SIRT3]- forkhead box O3 [FOXO3a], mitogen-activated protein kinase [MAPK], phosphoinositide-dependant kinase-1 [PDK-1], unfolded protein response, and C/EBP homologous protein [CHOP10]). Different types of adipokines involved in arsenic-induced diabetes are yet to be elucidated. Arsenic exerts negative effects on the white adipose tissue by decreasing adipogenesis and enhancing lipolysis. Some epidemiological studies have shown that arsenic can promote obesity. Nevertheless, few studies have indicated that arsenic may induce lipodystrophy. Arsenic multifactorial effects include accelerating birth and postnatal weight gains, elevated body fat content, glucose intolerance, insulin resistance, and increased serum lipid profile. Arsenic also elevated cord blood and placental, as well as postnatal serum leptin levels. The data from human studies indicate an association between inorganic arsenic exposure and the risk of diabetes and obesity. However, the currently available evidence is insufficient to conclude that low-moderate dose arsenic is associated with diabetes or obesity development. Therefore, more investigations are needed to determine biological mechanisms linking arsenic exposure to obesity and diabetes.

Cadmium exposure alters steroid receptors and proinflammatory cytokine levels in endothelial cells in vitro: a potential mechanism of endocrine disruptor atherogenic effect

BACKGROUND

Cadmium (Cd) is a widespread environmental pollutant that causes alterations in human health acting as endocrine disruptor. Recent data suggest that cardiovascular system might be a contamination target tissue, since Cd is found in atheromatic plaques. Thus, the purpose of this study was to evaluate the consequence of Cd exposure of endothelial cells in vitro to evaluate detrimental effect in vascular system by a potential sex-steroid hormone receptor-dependent mechanism(s).

METHODS

To this aim, Human Umbilical Vein Endothelial Cells (HUVECs) were cultured and exposed to several concentrations of cadmium chloride (CdCl₂) for different interval times.

RESULTS

CdCl₂ exposure of HUVECs induced a significant increase of ERβ and Cyp19a1 at both mRNA and protein levels, while a drastic dose-dependent decrease of AR expression level was observed after 24 h of exposure. On the contrary, an increase of PhAR^ser308 as well as a reduction of PhGSK-3β^ser9 and PhAKT^ser473 was detected after 1 h treatment. This effect was consistently reduced by GSK inhibition. Furthermore, CdCl₂ abolished DHT-induced cell proliferation in HUVECs suggesting an antagonist-like effect of Cd on AR-mediated signaling. Remarkable, after 6 h CdCl₂-treatment, a relevant increase in TNF-α, IL-6 and IL-8 mRNA was observed and this effect was blocked by the presence of an ERβ-selective antagonist. Moreover, Cd-induced TxR1 overexpression, likely, correlated with the activation of p38 MAPK/NF-κB pathway.

CONCLUSION

In conclusion, our study demonstrates for the first time that Cd alters sex-steroid hormone receptors level and activity likely affecting intracellular signaling linked to a proinflammatory state in endothelial cells. This alteration might possibly lead to endothelial cell injury and vascular dysfunction and could be a mechanism of gender-specific atherogenic damages induced by endocrine disruptors and, thus, induce atherogenic events with increased risk of cardiovascular diseases in individuals exposed to this endocrine disruptor.

Chronic cadmium exposure in Japanese quails perturbs serum biochemical parameters and enzyme activity

Cadmium is a heavy metal, toxic even in trace amounts and its biological function in the human body has not been described to date. It is assumed that cadmium manifests in dose-dependent genotoxic and cytotoxic effects on many organs and tissue types. In this study, we have analyzed the biochemical parameters in the serum of Japanese quails (Coturnix japonica) after chronic in vivo exposure to cadmium. Adult animals were exposed to cadmium in the form of CdCl₂ dissolved in water (0.20 mg/L) for 20 days. Significant differences between controls and exposed animals were found in 12 out of 13 analyzed biochemical parameters. Total bilirubin concentrations did not show any significant differences between the two groups. Exposure to cadmium has resulted in a significant increase in lactate dehydrogenase activity, sodium and chloride concentration, as well as significant reductions in total proteins, albumins, globulins, glucose, triglycerides, cholesterol, calcium concentration, and alkaline phosphatase activity. In this sense, chronic in vivo exposure to low doses of cadmium has induced severe changes in the levels of observed biochemical parameters and enzyme activity. Additionally, evident cytogenetic changes in the liver were also noted, where hepatocyte damage and even lack of organized nuclei, including nuclear fragmentation, clearly indicated ongoing apoptotic processes.

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 sub-chronic, low-dose cadmium exposure on kidney damage and potential mechanisms

Background

The present study was to investigate the potential mechanisms underlying the sub-chronic low-dose cadmium (Cd) exposure induced renal injury in rats.

Methods

Totally 40 male adult SD rats were randomly divided into four groups: control group, low-dose Cd group (1 mg/kg CdCl₂), moderate-dose Cd group (2.5 mg/kg) and high-dose Cd group (5 mg/kg).

Results

From the 3^rd week, the body weight of rats in moderate-dose and high-dose declined significantly as compared to the control group (P<0.05); the liver to body weight ratio increased, the volumes of 24-hour urine and drinking-water decreased markedly (P<0.05), the BUN, SCr and β₂-MG increased significantly, but the Fe²⁺ concentration decreased markedly as compared to the control group (P<0.05); the serum MDA and SOD₁ content contents increased, but the serum SOD₂ and CAT contents decreased significantly in Cd-treated groups (P<0.05); Renal injury deteriorated with the increase in Cd dose; swelling glomeruli showed stenotic renal-tubules, and epithelial-cell-necrosis, shedding and accumulation in the lumen, massive infiltrated inflammatory cells and interstitial hyperaemia were observed; The mitochondria in renal-tubular-epithelial-cells displayed swelling, deformation and vacuolation; the renal ROS content increased in Cd-exposure-groups; the renal SOD₁ expression increased but the expression of SOD₂ and CAT decreased (P<0.05). The Bcl-2 expression decreased, but Bax expression and Bax/Bcl-2 ratio increased significantly in a Cd-dose dependent manner.

Conclusions

Cd may cause renal injury in a dose dependent manner, which may be ascribed to the disordered Fe²⁺ absorption, redox imbalance and apoptosis in the kidney.

NMR-based lipidomics of fish from a metal(loid) contaminated wetland show differences consistent with effects on cellular membranes and energy storage

Metals and metalloids are priority contaminants due to their non-degradable and bioaccumulative nature, and their ability to regulate and perturb diverse physiological processes in various species. Metal(loid)s are known to cause oxidative stress through production of reactive oxygen species (ROS), thus related endpoints like lipid peroxidation (LPO) have received considerable attention as biomarkers of exposure. However, the implications of metal(loid) toxicity including LPO on actual lipid profiles of species inhabiting contaminated systems are poorly understood. Here we applied Nuclear Magnetic Resonance (NMR) spectroscopy for untargeted lipidomics of mosquitofish (Gambusia holbrooki) collected from reference and metal(loid)-contaminated wetlands. We measured a range of trace elements in water and fish using inductively coupled plasma - mass spectrometry (ICP-MS), and interpreted site differences in the lipid profiles of mosquitofish in the context of known physiological responses to sub-lethal metal(loid) exposure. Results indicate deregulation of cellular membrane lipids (i.e., glycerophospholipids, cholesterol and sphingolipids) and increased energy storage molecules (i.e., triacylglycerols and fatty acids) in fish from the contaminated wetland. These responses are consistent with the recognised induction of oxidative stress pathways in organisms exposed to metal(loid)s and could also be symptomatic of mitochondrial dysfunction and endocrine disruption. It is difficult to attribute metal(loid)s as the sole factor causing differences between wetlands, and a more controlled experimental approach is therefore warranted to further explore mechanistic pathways. Nevertheless, our study highlights the benefits of untargeted ¹H NMR-based lipidomics as a relatively fast and simple approach for field-scale assessment and monitoring of organisms inhabiting metal(loid) contaminated environments.

Impact of maternal low-level cadmium exposure on glucose and lipid metabolism of the litter at different ages after weaning

Cadmium (Cd) is a metal which may participate in the development of type II diabetes even if Cd exposure levels are mild. However, experimental studies focusing on daily environmentally relevant doses are scarce, particularly for glucose metabolism of the offspring of chronically exposed mothers. The aim is to measure the impact of maternal low level Cd exposure on glucose and lipid metabolism of offspring. Female rats were exposed to 0, 50 or 500 μg.kg^-1.d^-1 of CdCl₂, 21 days before mating and during 21 days of gestation and 21 days of lactation. Pups exposure was organized in 3 groups (control, Cd1, Cd2) according to renal dams' Cd burden. Parameters of glucose and lipid metabolisms were measured for the pups on post-natal day 21, 26 and 60. Maternal Cd exposure led to significant amounts of Cd in the liver and kidney of pups. At weaning, insulin secretion upon glucose stimulation was unchanged, but the removal of circulating glucose was slower for pups born from the lowest impregnated dams (Cd1). Five days after, glucose tolerance of all groups was identical. Thus, this loss of insulin sensitivity was reversed, in part by increased adiponectin secretion for the Cd1 group. Furthermore, pups from dams accumulating the highest levels of Cd (Cd2) exhibited a compensatory increased insulin pancreatic secretion, together with increased circulating non-esterified fatty acids, indicating the establishment of insulin resistance, 2 months after birth. This study has demonstrated the influence of maternal exposure to low levels of Cd on glucose homeostasis in the offspring that might increase the risk of developing type II diabetes later in life.

Protective Effects of Curcumin Against Nephrotoxic Agents

BACKGROUND

Curcumin is the one of the main phenolic ingredients in curcuma species rhizome. Curcuma species have traditionally been used for the treatment of diabetes, cardiovascular, and renal diseases.

METHODS

The present study was designed to review the scientific literature on the protective effects of curcumin against nephrotoxic agents.

RESULTS

Studies have shown the protective effects of curcumin against nephrotoxic agents such as gallic acid, glucose, tartrazine, streptozotocin, lead, cadmium, fluoride, maleate, malathion, nicotine, cisplatin, gentamicin, and methotrexate. However, further investigations are needed to determine the efficacy of curcumin as an antidote agent due to the lack of clinical trial studies. Therefore, it is recommended to conduct clinical trials in humans to confirm these effects.

CONCLUSION

The current review indicated that curcumin may be effective against nephrotoxicity by modulating oxidative stress and inflammatory responses.

Impairment of learning and memory of mice offspring at puberty, young adulthood, and adulthood by low-dose Cd exposure during pregnancy and lactation via GABAAR α5 and δ subunits

Cadmium (Cd) is a pervasive carcinogen and environmental endocrine disruptor. We studied the changes in learning and memory of offspring mice, whose mothers were exposed to 10 mg Cd/L via the drinking water during pregnancy and lactation period, as well as the changes of testosterone and estrogen levels, serum Cd levels, the histopathological changes and the changes in the mRNA and protein levels of different subunits of γ-aminobutyric acid receptor subtype A subunits (G_ABA_ARs) in the hippocampus at the prepuberty, puberty, young adult, and adult stages. At birth, Cd had no obvious effect on mice offspring as statistically accessed based on their body weight, body length, and tail length (all p > 0.05). After grouped, the serum Cd levels increased in the three exposed groups more than in the normal control group at stages (all p < 0.05). Only serum estradiol of female offspring at age 7 weeks was significantly decreased compared with other groups (all p < 0.05). Histopathological results showed that the arrangement of the cells in hippocampal CA1 area of mice offspring was significantly sparse in the exposed groups compared with the control group. At 5 and 7 weeks, two Cd-exposed groups showed prolonged escape latency and exploring time for the platform compared with the normal group in the Morris water maze (all p < 0.05). Only increased protein expression of GABA_ARα5 was found in the Cd group at these two ages. At age 12 weeks, similar impaired learning and memory of female mice, and decreased protein expression of GABA_ARδ was found in Cd-exposed groups. Collectively, low-dose Cd had no effect on the growth of mice offspring but affected their learning and memory, especially female offspring, at puberty, young adulthood, and adulthood through changed structure in the hippocampal CA1 area and protein expression of GABA_ARα5 and GABA_ARδ.

Urinary cadmium concentrations and metabolic syndrome in U.S. adults: The National Health and Nutrition Examination Survey 2001-2014

BACKGROUND

Low to moderate acute cadmium exposure has been associated with increased risk of chronic diseases, such as cardiovascular and kidney disease. Little is known about the association between urinary cadmium levels-an indicator of longer-term exposure-and metabolic syndrome (MetS).

METHODS

We analysed data from 3982 participants aged 20-<80 years of the National Health and Nutrition Examination Survey 2001-2014. Urinary cadmium levels were measured and adjusted for creatinine using spot urine samples. Cadmium levels were evaluated in quintiles (Q). MetS was defined by National Cholesterol Education Program's Adult Treatment Panel III report criteria. Prevalence odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariable logistic regression accounting for complex survey design, while adjusting for potential confounders and stratifying by sex and smoking status.

RESULTS

In the overall study population, there was a marginal inverse association between urinary cadmium and MetS (adj. OR for Q5 versus Q1: 0.7; 95% CI: 0.5-1.0). Sex stratified models were similar. When examining individual components of MetS, participants with higher levels of urinary cadmium had decreased odds of abdominal obesity (adj. OR for Q5 versus Q1 0.4; 95% CI: 0.3-0.6), but increased odds for low HDL (adj. OR for Q5 versus Q1 2.1; 95% CI: 1.4-3.1). Among current smokers, higher urinary cadmium was associated with increased odds of MetS, hypertension, and low HDL even after accounting for serum cotinine-a marker of smoking intensity.

CONCLUSIONS

Higher levels of urinary cadmium, a marker of long term exposure, were not associated with an increased risk of MetS in the overall study population. However, higher urine cadmium was associated with altered MetS components. Current smokers were the most vulnerable group, with higher long-term cadmium exposure being associated with increased risk of MetS, low HDL, and hypertension.

The effect of repeated cadmium oral exposure on the level of sex hormones, estrous cyclicity, and endometrium morphometry in female rats

Cadmium (Cd) is regarded as a potential endocrine disruptor. However, the exact mechanism by which this metal may interfere with the reproductive system has not yet been elucidated. The present study aimed to investigate the effect of subacute Cd oral administration at daily doses of 0.09, 1.8, and 4.5 mgCd/kg b.w. and the impact of Cd on sex hormones (estradiol (E2) and progesterone (P)) in the plasma and uterus, as well as on estrous cyclicity and histopathological changes in uterine and ovary in female rats after terminating the exposure and after a prolonged observation period (3 months). Moreover, Cd bioaccumulation in the uterine and brain tissue of rats was analyzed. The study revealed that oral Cd exposure induced changes in the plasma levels of steroid hormones: decrease in E2 and increase in P after the highest dose of Cd. Probably, for the first time, it was evidenced that circulation sex hormone disturbances in Cd-exposed rats caused irregular estrous cycle, persisting for 3 months after exposure termination; no alterations in these hormone levels in uterine tissue were noted. Cd did not induce estradiol-like hyperplasia of endometrium, but resulted in endometrial edema irrespective of the dose, and caused damage of the ovaries after the highest dose. In summary, subacute oral exposure of female rats to Cd may lead to long-term disturbances in reproductive system.

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.

Impact of oral cadmium intoxication on levels of different essential trace elements and oxidative stress measures in mice: a response to dose

The study evaluated the effect of oral intoxication of cadmium and the possible causes of oxidative stress and its preferential accumulation in different organs as well as sub-sequential effects in mice. Twenty-four Swiss albino male mice were divided into three groups viz., normal control group without cadmium chloride (CdCl₂), whereas a daily dose of 0.5 and 1.2 mg of CdCl₂ was orally administered for a period of a week to dose group 1 (DG-1) and dose group 2 (DG-2), respectively. A significant increase in the severity of cadmium toxicity was observed in animals as evidenced by aggravation in liver enzymes viz., serum alanine aminotransferase and aspartate transaminase, whereas lower levels of antioxidative stress markers in liver and kidney tissues of treated mice were observed as compared to normal control group. A significant depletion of calcium levels in liver tissues of DG-1 (217.36 ± 1.73 μg/g of wet tissues) and DG-2 (186.41 ± 1.56 μg/g of wet tissues) groups, along with Cd accumulation, was observed. To summarize, the current study would increase our understanding with respect to dose-dependent absorption of Cd and its toxicity led to mortality as well as adverse health effects in the body of mice. Graphical abstract ᅟ.

Polyphenols isolated from virgin coconut oil attenuate cadmium-induced dyslipidemia and oxidative stress due to their antioxidant properties and potential benefits on cardiovascular risk ratios in rats

OBJECTIVE

Literature has confirmed the pathogenic role of cadmium (Cd) and its exposure in the induction of dyslipidemia implicated in the development and increasing incidence of cardiovascular diseases. The current study explored whether polyphenolics isolated from virgin coconut oil (VCO) prevent Cd-induced dyslipidemia and investigate the underlying mechanism of action, in rats.

MATERIALS AND METHODS

Rats were pretreated with VCO polyphenols (10, 20 and 50 mg/kg body weight; orally) 2 weeks prior to concurrent Cd administration (5 mg/kg) for 5 weeks. Subsequently, serum concentrations of lipid and lipoprotein cholesterol and cardiovascular risk ratios were determined. Hepatic activities of superoxide dismutase (SOD) and catalase (CAT) as well as reduced glutathione (GSH) and malondialdehyde (MDA) contents were analyzed.

RESULTS

Sub-chronic Cd administration significantly increased the serum levels of total cholesterol, triglycerides, low density lipoprotein cholesterol and very low density lipoprotein cholesterol while markedly reduced high density lipoprotein cholesterol. Hepatic activities of SOD and CAT as well as GSH content were suppressed by Cd, whereas MDA level was obviously increased. The co-administration of VCO polyphenol with Cd remarkably restored lipid profile and cardiovascular risk ratios and stabilized antioxidant defense systems comparable to control group.

CONCLUSION

This is the first study presenting that polyphenols isolated from VCO prevent Cd-induced lipid abnormalities and cardiovascular risk ratios by improving antioxidant defense systems.

Cadmium exposure exacerbates severe hyperlipidemia and fatty liver changes in zebrafish via impairment of high-density lipoproteins functionality

Cadmium (Cd) is a heavy metal with several toxicities that have destructive effect on most organ systems. However, its toxic effects on human lipoproteins are largely remained unknown especially in hyperlipidemic zebrafish model. Treatment of human high-density lipoprotein (HDL) with cadmium chloride (CdCl₂, final 12 and 24μM) caused spontaneous formation of multimeric apoA-I as well as increased production of glycated extent products. Cd-HDL₃ accelerated uptake of oxidized LDL (oxLDL) into macrophages and induced severe senescence in human dermal fibroblast (HDF) cells. Microinjection of Cd-HDL₃ into zebrafish embryos resulted in acute embryonic toxicity with high mortality. Exposure of zebrafish embryos to water containing CdCl₂ (final 12 and 24μM) caused early embryonic death along with increased production of oxidized products and impairment of skeletal development. Consumption of CdCl₂ (12 and 24μM) by zebrafish for 4weeks resulted in severe elevation of plasma total cholesterol (TC) and triglyceride (TG) levels as well as cholesteryl ester (CE) transfer activity. Furthermore, consumption of CdCl₂ resulted in acceleration of fatty liver changes and increased production of reactive oxygen species (ROS). In conclusion, CdCl₂ caused structural modification of HDL₃ and impaired the beneficial functions of HDL₃, including anti-oxidation, anti-atherosclerosis, and anti-senescence effects. Consumption of CdCl₂ also resulted in exacerbated hyperlipidemia and fatty liver changes in zebrafish via enhancement of cholesteryl ester transfer protein (CETP) activity.

Cadmium Exposure Is Associated with Monocyte Count and Monocyte to HDL Ratio, a Marker of Inflammation and Future Cardiovascular Disease in the Male Population

Cadmium is a heavy metal that humans can be exposed to the in environment and occupation, and its relationship with cardiovascular diseases has been reported. in various reports. Epidemiological studies have also been associated with various inflammatory markers of cardiovascular diseases. In this study, we examined the relationship between monocyte count and monocyte to high density lipoprotein (HDL) ratio (MHR) and blood cadmium, which are one of the inflammatory markers of cardiovascular diseases. Data from a total of 733 male fire officers who received a health checkup at a hospital for one year in 2016 were analyzed. Populations were classified into 4 groups according to the quartile of blood cadmium and general characteristics were described. The relationship between monocyte count, MHR and cadmium in blood was statistically analyzed by linear regression analysis. In the univariate analysis and multivariate analysis, monocyte count was significantly higher in the second, third and fourth quartile groups than in the first quartile of cadmium, and the linear trend was significant. In univariate and multivariate analysis, MHR was significantly higher in the third and fourth quartile groups than in the first quartile group, and the linear trend was also significant. This study showed the significant relationship between blood cadmium and monocyte count and MHR among male fire officers. This was also statistically significant in the model adjusted for possible confounders and other cardiovascular risk factors and showed a linear trend.

PM2.5-bound metal metabolic distribution and coupled lipid abnormality at different developmental windows

Atmospheric fine particulate matter (PM_2.5) is a serious threat to human health. As a toxicant constituent, metal leads to significant health risks in a population, but exposure to PM_2.5-bound metals and their biological impacts are not fully understood. In this study, we determined the metal contents of PM_2.5 samples collected from a typical coal-burning city and then investigated the metabolic distributions of six metals (Zn, Pb, Mn, As, Cu, and Cd) following PM_2.5 inhalation in mice in different developmental windows. The results indicate that fine particles were mainly deposited in the lung, but PM_2.5-bound metals could reach and gather in secondary off-target tissues (the lung, liver, heart and brain) with a developmental window-dependent property. Furthermore, elevations in triglycerides and cholesterol levels in sensitive developmental windows (the young and elderly stages) occurred, and significant associations between metals (Pb, Mn, As and Cd) and cholesterol in the heart, brain, liver and lung were observed. These findings suggest that PM_2.5 inhalation caused selective metal metabolic distribution in tissues with a developmental window-dependent property and that the effects were associated with lipid alterations. This provides a foundation for the underlying systemic toxicity following PM_2.5 exposure based on metal components.