Cadmium induces iron deficiency anemia through the suppression of iron transport in the duodenum

Association of blood trace metals with anemia in children aged 6-17 years old

BACKGROUND

Anemia significantly impacts children's health and quality of life, and may be influenced by the levels of various trace metals in the body. Current research on trace metals and anemia is mostly limited to single metals, and the association of multiple trace metals and their mixtures with anemia among children remains unclear.

METHODS

This study utilized cross-sectional data from the 2017-2020 National Health and Nutrition Examination Survey (NHANES), including 2208 children aged 6-17 years in the United States, who were tested for five trace metals: lead(Pb), mercury(Hg), cadmium(Cd), selenium(Se), and manganese(Mn). The study used logistic regression, quantile g-computation, and Bayesian kernel machine regression models to examine how these metals individually and collectively affect anemia and to identify significant influencing factors. Age-stratified analysis was also conducted to analyze the association of trace metals with anemia in different age groups.

RESULTS

Children with anemia had significantly higher blood Cd levels and significantly lower Se and Mn levels. In the univariate metal model, increasing Se levels was associated with decreased anemia risk. Mn was the main protective factor for anemia in school-age children, while Se was the main protective factor in adolescents. Both qgComp and BKMR models showed a negative association between mixed trace metal exposure and anemia. The age-specific analysis showed that the protective effect of trace metals was not as apparent in adolescents.

CONCLUSION

This research discovered that mixed trace metal exposure was associated with a reduced risk of anemia in children, with Se acting as a protective factor across all populations. Mn played a protective role in school-age children but may become a risk factor in adolescents.

Iron Metabolism, Calcium, Magnesium and Trace Elements: A Review

Iron (Fe) is fundamental to life on earth. In the human body, it is both essential and harmful if above threshold. A similar balance applies to other elements: calcium (Ca), magnesium (Mg), and trace elements including copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), mercury (Hg), and nickel (Ni). These elements share some proteins involved in the absorption and transport of Fe. Cu and Cd can inhibit Fe absorption, while excess of Fe may antagonize Cu metabolism and reduce ceruloplasmin (Cp). Excessive Fe can hinder Zn absorption and transferrin (Trf) can bind to both Zn and Ni. Ca is able to inhibit the divalent metal transporter 1 (DMT1) in a dose-dependent manner to reduce Fe absorption and low Mg concentrations can exacerbate Fe deficiency. Pb competitively inhibits Fe distribution and elevated Cd absorption reduces Fe uptake. Exposure to Hg is associated with higher ferritin concentrations and Ni alters intracellular Fe metabolism. Fe removal by phlebotomy in hemochromatosis patients has shown to increase the levels of Cd and Pb and alter the concentrations of trace elements in some types of anemia. Yet, the effects of chronic exposure of most trace elements remain poorly understood.

Machine learning identifies routine blood tests as accurate predictive measures of pollution-dependent poor cognitive function

Background

Several modifiable risk factors for dementia and related neurodegenerative diseases have been identified including education level, socio-economic status, and environmental exposures - however, how these population-level risks relate to individual risk remains elusive. To address this, we assess over 450 potential risk factors in one deeply clinically and demographically phenotyped cohort using random forest classifiers to determine predictive markers of poor cognitive function. This study aims to understand early risk factors for dementia by identifying predictors of poor cognitive performance amongst a comprehensive battery of imaging, blood, atmospheric pollutant and socio-economic measures.

Methods

Random forest modelling was used to determine significant predictors of poor cognitive performance in a cohort of 324 individuals (age 61.6 ± 4.8 years; 150 males, 174 females) without extant neurological disease. 457 features were assessed including brain imaging measures of volume and iron deposition, blood measures of anaemia, inflammation, and heavy metal levels, social deprivation indicators and atmospheric pollution exposure.

Results

Routinely assessed markers of anaemia including mean corpuscular haemoglobin concentration were identified as robust predictors of poor general cognition, where both extremes (low and high) were associated with poor cognitive performance. The strongest, most consistent predictors of poor cognitive performance were environmental measures of atmospheric pollution, in particular, lead, carbon monoxide, and particulate matter. Feature analysis demonstrated a significant negative relationship between low mean corpuscular haemoglobin concentration and high levels of atmospheric pollutants highlighting the potential of routinely assessed blood tests as a predictive measure of pollution-dependent cognitive functioning, at an individual level.

Conclusions

Taken together, these data demonstrate how routine, inexpensive medical testing and local authority initiatives could help to identify and protect at-risk individuals. These findings highlight the potential to identify individuals for targeted, cost effective medical and social interventions to improve population cognitive health.

A Ratiometric Fluorescence Probe for Visualized Detection of Heavy Metal Cadmium and Application in Water Samples and Living Cells

Heavy metal cadmium (II) residuals have inflicted severe damage to human health and ecosystems. It has become imperative to devise straightforward and highly selective sensing methods for the detection of Cd2+. In this work, a ratiometric benzothiazole-based fluorescence probe (BQFA) was effortlessly synthesized and characterized using standard optical techniques for the visual detection of Cd2+ with a change in color from blue to green, exhibiting a significant Stokes shift. Moreover, the binding ratio of BQFA to Cd2+ was established as 1:1 by the Job's plot and was further confirmed by FT-IR and 1HNMR titrations. The ratiometric fluorescence response via the ICT mechanism was confirmed by DFT calculations. Furthermore, the limit of detection for detecting Cd2+ was determined to be 68 nM. Furthermore, it is noteworthy that BQFA showed good performance in real water samples, paper strips, smartphone colorimetric identification, and cell imaging.

Iron Administration Partially Ameliorates Cadmium-Induced Oxidative Damage in the Liver and Kidney of Rats

The protective effect of Fe against Cd-induced toxicity in the liver and kidney of rats during concurrent administration of both metals was investigated in this study. Fifty female rats (130-150 g) were distributed into five groups of 10 rats each (n = 10): Group I (control), received normal saline solution; Group II (1.2 mg CdCl2/kg b.w.); Group III (1.2 mg CdCl2 + 0.25 mg FeCl2/kg b.w.); Group IV (1.2 mg CdCl2 + 0.75 mg FeCl2/kg b.w.); and Group V (1.2 mg CdCl2 + 1.5 mg FeCl2/kg b.w.). Administration of both tested substances lasted for 47 days. Cd was injected intraperitoneally once a week, while Fe was administered to the Cd-exposed animals by oral gavage thrice weekly. The animals were killed at the end of the study, their blood was collected, and their liver and kidneys were harvested for biochemical and histological analysis. Following Cd administration, the kidney and liver showed a significant increase in Cd concentration, while Fe concentration in the kidney decreased. However, cotreatment with Fe decreased Cd concentration in the kidney and liver and increased Fe concentration in the kidney but not the liver, and the effect was more pronounced in the higher than lower doses. In the kidney, cotreatment with Fe especially at higher doses inhibited Cd-induced lipid peroxidation and plasma uric acid concentration. In the liver, lipid peroxidation which Cd did not alter was found to be elevated after cotreatment with the highest dose Fe. Inflammatory cell infiltrations of the central vein and renal tubular and glomeruli injury induced by Cd were not obviated by Fe cotreatment. It seems that both tissues respond differently to the concurrent administration of these metals and that Fe protected the kidney against oxidative injury-induced by Cd but not histopathological changes in both tissues.

A multi-domain snail metallothionein increases cadmium resistance and fitness in Caenorhabditis elegans

Metallothioneins (MTs) are a family of mostly low-molecular weight, cysteine-rich proteins capable of specific metal-ion binding that are involved in metal detoxification and homeostasis, as well as in stress response. In contrast to most other animal species which possess two-domain (bidominial) MTs, some gastropod species have evolved Cd2+-selective multidomain MTs (md-MTs) consisting of several concatenated β3 domains and a single C-terminal β1 domain. Each domain contains three-metal ion clusters and binds three metal ions. The terrestrial snail Alinda biplicata possesses, among other MT isoforms, an md-MT with nine β3 domains and a C-terminal β1 domain (termed 10md-MT), capable of binding up to 30 Cd2+ ions per protein molecule. In the present study, the Alinda biplicata 10md-MT gene and a truncated version consisting of one β3 domain and a single C-terminal β1 domain (2d-MT) were introduced into a Caenorhabditis elegans knock-out strain lacking a native MT gene (mtl-1). The two snail MT constructs consistently increased Cd2+ resistance, and partially improved morphological, life history and physiological fitness traits in the nematode model host Caenorhabditis elegans. This highlights how the engineering of transgenic Caenorhabditis elegans strains expressing snail MTs provides an enhancement of the innate metal detoxification mechanism and in doing so provides a platform for enhanced mechanistic toxicology.

Increased Cadmium Load, Vitamin D Deficiency, and Elevated FGF23 Levels as Pathophysiological Factors Potentially Linked to the Onset of Acute Lymphoblastic Leukemia: A Review

The preventability of acute lymphocytic leukemia during childhood is currently receiving great attention, as it is one of the most common cancers in children. Among the known risk factors so far are those affecting the development of gut microbiota, such as a short duration or absence of breastfeeding, cesarean section, a diet lacking in short-chain fatty acids (SCFAs), the use of antibiotics, absence of infection during infancy, and lack of pets, among other factors. Namely, it has been shown that iron deficiency anemia (IDA) and lack of vitamin D may cause intestinal dysbiosis, while at the same time, both increase the risk of hematological malignancies. The presence of IDA and vitamin D deficiency have been shown to lead to a decreased proportion of Firmicutes in stool, which could, as a consequence, lead to a deficit of butyrate. Moreover, children with IDA have increased blood concentrations of cadmium, which induces systemic inflammation and is linked to the onset of an inflammatory microenvironment in the bone marrow. Finally, IDA and Cd exposure increase fibroblast growth factor 23 (FGF23) blood levels, which in turn suppresses vitamin D synthesis. A lack of vitamin D has been associated with a higher risk of ALL onset. In brief, as presented in this review, there are three independent ways in which IDA increases the risk of acute lymphocytic leukemia (ALL) appearance. These are: intestinal dysbiosis, disruption of vitamin D synthesis, and an increased Cd load, which has been linked to systemic inflammation. All of the aforementioned factors could generate the appearance of a second mutation, such as ETV6/RUNX1 (TEL-AML), leading to mutation homozygosity and the onset of disease. ALL has been observed in both IDA and thalassemia. However, as IDA is the most common type of anemia and the majority of published data pertains to it, we will focus on IDA in this review.

Bi-component sensing platform for the detection of Cd2+, Fe2+and Fe3+ ions

The ability of N-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)isonicotinamide (naphydrazide) or 2,6-pyridinedicarboxylic acid (2,6-H2pdc) individually or as a bi-component system in distinguishing and detecting Fe3+ or Fe2+ and Cd2+ ions was investigated. The use of these molecules as single or bi-component analytes in absorption or emission spectroscopy studies showed that under specific conditions each had their own merits for specific purposes. UV-visible spectroscopic studies of 2,6-H2pdc for assessing the interactions with ferrous and ferric ions showed characteristic distinctions. The detection limit for Fe3+ analysed through UV-visible spectroscopy using naphydrazide was 0.46 μM, whereas it was 1.28 μM using 2,6-H2pdc. Naphydrazide together with Fe3+ allowed distinguishing Cd2+ ions from Zn2+ and Fe2+ ions. The bi-component system was useful for the selective detection of Cd2+ ions using fluorescence spectroscopy, with a detection limit for Cd2+ ions of 18.31 μM. The presence of Fe2+ and Cd2+ ions in a solution of the bi-component had resulted white-light emission. An analogous compound N,N'-(1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-2,7(1H,3H,6H,8H)-diyl)diisonicotinamide (binaphydrazide) was found unsuitable for such detections. Two 2,6-pyridinedicarboxylate Fe3+ complexes possessing protonated naphydrazide or binaphydrazide were prepared and characterised. These complexes were also found unsuitable for the detection of the said ions in solution. Electrochemical studies with the bi-component system showed that cyclic voltammograms could distinguish Fe3+ or Fe2+ from Cd2+ ions.

Evaluation of the Potential Cytoprotective Effect of Melatonin in Comparison with Vitamin E and Trolox against Cd2+-Induced Toxicity in SH-SY5Y, HCT 116, and HepG2 Cell Lines

Cadmium (Cd) toxicity poses a significant threat to cellular health, leading to oxidative stress and cell damage. Antioxidant agents, particularly those of natural origin, have been studied as a potential alternative for mitigating heavy metal toxicity. This study aimed to evaluate the cytoprotective effects of the antioxidant melatonin (MLT) in comparison with Vitamin E (VitE) and Trolox against Cd2+-induced cellular toxicity. The MTT assay was employed to assess cell viability in neuronal SH-SY5Y, colorectal HCT 116, and hepatic HepG2 cell lines. The results showed that all three antioxidants offered some level of protection against Cd toxicity, with Vitamin E proving to be the most effective. MLT also demonstrated a substantial cytoprotective effect, especially at the highest Cd concentration of 30 µM. These findings suggest that MLT, alongside Vit E and Trolox, could be valuable in mitigating the detrimental effects of Cd exposure by reducing the oxidative stress in these cellular models.

Association between breakfast skipping and blood levels of lead and cadmium in children and adolescents aged 6-17 years: Results from the National Health and Nutrition Examination Survey 2013-2018

INTRODUCTION

Previous research suggests that fasting increases lead absorption in the gastrointestinal tract, and that regularly eating meals may reduce blood lead. However, there is insufficient evidence linking breakfast status and blood-metal levels in children. We assessed the cross-sectional association between breakfast consumption status and children and adolescent's blood levels of lead and cadmium. We also explored blood hemoglobin, serum ferritin, and age group as potential effect modifiers of these associations.

METHODS

This analysis included children and adolescents aged 6-17 years who participated in the National Health and Nutrition Examination Survey (NHANES) cycles 2013-2018 with complete data on breakfast consumption status (consumers vs. skippers), blood metals, and covariates (N=3722). Blood metal variables were log-transformed. Crude and covariate-adjusted, survey-weighted linear regression models were conducted for each blood metal outcome. Potential effect modification was explored using stratification.

RESULTS

Overall fewer participants reported skipping breakfast (n=719) than eating breakfast (n=3003). Mean (SE) concentrations of blood lead and cadmium (µg/L) were 0.63 (0.01) µg/dL and 0.13 (0.00) µg/L, respectively. Children and adolescents who skipped breakfast were more likely to be female (51.2%), older (mean 12.2 years, SE = 0.1), have a higher body mass index (mean 22.8 kg/m2, SE = 0.2), and a lower income-poverty ratio (mean 1.7, SE = 0.1) than breakfast consumers. No associations between breakfast consumption and any of the blood metals were found. When stratified by age (≤ 10, 11-13, and 14-17 years), children aged 11-13 years who consumed breakfast had lower log-transformed blood lead levels [β = -0.14 µg/L; 95% CI: (-0.25, -0.03)] compared to children of the same age who skipped breakfast.

CONCLUSION

Children 11-13 years-old who were breakfast consumers had lower blood lead levels compared to children of the same age who skipped breakfast. Our results support that encouraging breakfast consumption among school-age children may contribute to lower blood lead levels.

Integrating Transcriptomics and Proteomics to Characterize the Intestinal Responses to Cadmium Exposure Using a Piglet Model

Cadmium (Cd) is a heavy metal element with a wide range of hazards and severe biotoxicity. Since Cd can be easily accumulated in the edible parts of plants, the exposure of humans to Cd is mainly through the intake of Cd-contaminated food. However, the intestinal responses to Cd exposure are not completely characterized. Herein, we simulated laboratory and environmental Cd exposure by feeding the piglets with CdCl2-added rice and Cd-contaminated rice (Cdcr) contained diet, as piglets show anatomical and physiological similarities to humans. Subsequent analysis of the metal element concentrations showed that exposure to the two types of Cd significantly increased Cd levels in piglets. After verifying the expression of major Cd transporters by Western blots, multi-omics further expanded the possible transporters of Cd and found Cd exposure causes wide alterations in the metabolism of piglets. Of significance, CdCl2 and Cdcr exhibited different body distribution and metabolic rewiring, and Cdcr had stronger carcinogenic and diabetes-inducing potential. Together, our results indicate that CdCl2 had a significant difference compared with Cdcr, which has important implications for a more intense study of Cd toxicity.

Multilevel Regulation of Membrane Proteins in Response to Metal and Metalloid Stress: A Lesson from Yeast

In the face of flourishing industrialization and global trade, heavy metal and metalloid contamination of the environment is a growing concern throughout the world. The widespread presence of highly toxic compounds of arsenic, antimony, and cadmium in nature poses a particular threat to human health. Prolonged exposure to these toxins has been associated with severe human diseases, including cancer, diabetes, and neurodegenerative disorders. These toxins are known to induce analogous cellular stresses, such as DNA damage, disturbance of redox homeostasis, and proteotoxicity. To overcome these threats and improve or devise treatment methods, it is crucial to understand the mechanisms of cellular detoxification in metal and metalloid stress. Membrane proteins are key cellular components involved in the uptake, vacuolar/lysosomal sequestration, and efflux of these compounds; thus, deciphering the multilevel regulation of these proteins is of the utmost importance. In this review, we summarize data on the mechanisms of arsenic, antimony, and cadmium detoxification in the context of membrane proteome. We used yeast Saccharomyces cerevisiae as a eukaryotic model to elucidate the complex mechanisms of the production, regulation, and degradation of selected membrane transporters under metal(loid)-induced stress conditions. Additionally, we present data on orthologues membrane proteins involved in metal(loid)-associated diseases in humans.

Environmental cadmium exposure perturbs systemic iron homeostasis via hemolysis and inflammation, leading to hepatic ferroptosis in common carp (Cyprinus carpio L.)

Cadmium (Cd) pollution is considered a pressing challenge to eco-environment and public health worldwide. Although it has been well-documented that Cd exhibits various adverse effects on aquatic animals, it is still largely unknown whether and how Cd at environmentally relevant concentrations affects iron metabolism. Here, we studied the effects of environmental Cd exposure (5 and 50 μg/L) on iron homeostasis and possible mechanisms in common carp. The data revealed that Cd elevated serum iron, transferrin saturation and iron deposition in livers and spleens, leading to the disruption of systemic iron homeostasis. Mechanistic investigations substantiated that Cd drove hemolysis by compromising the osmotic fragility and inducing defective morphology of erythrocytes. Cd concurrently exacerbated hepatic inflammatory responses, resulting in the activation of IL6-Stat3 signaling and subsequent hepcidin transcription. Notably, Cd elicited ferroptosis through increased iron burden and oxidative stress in livers. Taken together, our findings provide evidence and mechanistic insight that environmental Cd exposure could undermine iron homeostasis via erythrotoxicity and hepatotoxicity. Further investigation and ecological risk assessment of Cd and other pollutants on metabolism-related effects is warranted, especially under the realistic exposure scenarios.

Cadmium induces microcytosis and anisocytosis without anaemia in hypertensive rats

Dietary cadmium (Cd2+) intake is implicated in the pathogenesis of hypertension and anaemia, but there is a paucity of information on the haematological changes in hypertensive conditions. This study, therefore, aims to evaluate the effects of Cd2+ on blood pressure (BP) and haematological indices in the Sprague-Dawley rat model. Three cohorts (n = 10 each) of control and Cd2+-fed male Sprague-Dawley rats were selected. Cd2+-exposed rats received 2.5 or 5 mg/kg b.w. cadmium chloride via gavage thrice-weekly for eight weeks, while control animals received tap water. BP and flow were measured non-invasively from rat tails twice-weekly using a CODA machine, while weights were measured thrice-weekly. Haematological indices were assessed using the Cell-Dyn Emerald Haematology Analyzer. Data were reported as mean ± SEM, and statistically analyzed using One-Way Analysis of Variance. Bonferroni post hoc test was used for multiple comparisons. Cd2+-exposure induced hypertension by significantly (p < 0.05) elevating systolic, diastolic, and mean arterial BPs, pulse pressure, and heart rate (HR), and increased (p < 0.05) blood flow. Mean cell volume (MCV) and haemoglobin (MCH) were significantly (p < 0.05) reduced, and red cell distribution width (RDW) significantly (p < 0.01) increased by exposure to 5 mg/kg b.w. Cd2+. Haemoglobin concentration (MCHC), haematocrit, haemoglobin, red blood cell, platelet, mean platelet volume, and white blood cell counts were unaffected by Cd2+-exposure. Cd2+ induced hypertension, microcytosis, hypochromicity, and anisocytosis without anaemia, which may be precursor to microcytic anaemia and coronary artery disease. This study is important in Cd2+-exposed environments and warrants further investigations.

Cadmium Induces Kidney Iron Deficiency and Chronic Kidney Injury by Interfering with the Iron Metabolism in Rats

Cadmium (Cd) is a common environmental pollutant and occupational toxicant that seriously affects various mammalian organs, especially the kidney. Iron ion is an essential trace element in the body, and the disorder of iron metabolism is involved in the development of multiple pathological processes. An iron overload can induce a new type of cell death, defined as ferroptosis. However, whether iron metabolism is abnormal in Cd-induced nephrotoxicity and the role of ferroptosis in Cd-induced nephrotoxicity need to be further elucidated. Sprague Dawley male rats were randomly assigned into three groups: a control group, a 50 mg/L CdCl2-treated group, and a 75 mg/L CdCl2-treated group by drinking water for 1 month and 6 months, respectively. The results showed that Cd could induce renal histopathological abnormalities and dysfunction, disrupt the mitochondria's ultrastructure, and increase the ROS and MDA content. Next, Cd exposure caused GSH/GPX4 axis blockade, increased FTH1 and COX2 expression, decreased ACSL4 expression, and significantly decreased the iron content in proximal tubular cells or kidney tissues. Further study showed that the expression of iron absorption-related genes SLC11A2, CUBN, LRP2, SLC39A14, and SLC39A8 decreased in proximal tubular cells or kidneys after Cd exposure, while TFRC and iron export-related gene SLC40A1 did not change significantly. Moreover, Cd exposure increased SLC11A2 gene expression and decreased SLC40A1 gene expression in the duodenum. Finally, NAC or Fer-1 partially alleviated Cd-induced proximal tubular cell damage, while DFO and Erastin further aggravated Cd-induced cell damage. In conclusion, our results indicated that Cd could cause iron deficiency and chronic kidney injury by interfering with the iron metabolism rather than typical ferroptosis. Our findings suggest that an abnormal iron metabolism may contribute to Cd-induced nephrotoxicity, providing a novel approach to preventing kidney disease in clinical practice.

Challenges and Recommendations in Assessing Potential Endocrine-Disrupting Properties of Metals in Aquatic Organisms

New tools and refined frameworks for identifying and regulating endocrine-disrupting chemicals (EDCs) are being developed as our scientific understanding of how they work advances. Although focus has largely been on organic chemicals, the potential for metals to act as EDCs in aquatic systems is receiving increasing attention. Metal interactions with the endocrine system are complicated because some metals are essential to physiological systems, including the endocrine system, and nonessential metals can have similar physiochemical attributes that allow substitution into or interference with these systems. Consequently, elevated metal exposure could potentially cause endocrine disruption (ED) but can also cause indirect effects on the endocrine system via multiple pathways or elicit physiologically appropriate compensatory endocrine-mediated responses (endocrine modulation). These latter two effects can be confused with, but are clearly not, ED. In the present study, we provide several case studies that exemplify the challenges encountered in evaluating the endocrine-disrupting (ED) potential of metals, followed by recommendations on how to meet them. Given that metals have multiple modes of action (MOAs), we recommend that assessments use metal-specific adverse outcome pathway networks to ensure that accurate causal links are made between MOAs and effects on the endocrine system. We recommend more focus on establishing molecular initiating events for chronic metal toxicity because these are poorly understood and would reduce uncertainty regarding the potential for metals to be EDCs. Finally, more generalized MOAs such as oxidative stress could be involved in metal interactions with the endocrine system, and we suggest it may be experimentally efficient to evaluate these MOAs when ED is inferred. These experiments, however, must provide explicit linkage to the ED endpoints of interest. Environ Toxicol Chem 2023;42:2564-2579. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Long-Term Exposure to Cadmium Causes Hepatic Iron Deficiency through the Suppression of Iron-Transport-Related Gene Expression in the Proximal Duodenum

Cadmium (Cd) is an environmental pollutant that damages various tissues. Cd may cause a depletion of iron stores and subsequently an iron deficiency state in the liver. However, the molecular mechanism of decreased iron accumulation in the liver induced by long-term exposure to Cd is unknown. In this study, we investigated the hepatic accumulation of iron and the proximal duodenal expression of the genes involved in iron transport using mice chronically exposed to Cd. Five-week-old female C57BL/6J mice were fed a diet containing 300 ppm Cd for 12, 15, 19 and 21 months. The iron concentration in the liver was markedly decreased by Cd. Among iron-transport-related genes in the proximal duodenum, the gene expression of HCP1 and Cybrd1 was significantly decreased by Cd. HCP1 is an influx transporter of heme iron. Cybrd1 is a reductase that allows non-heme iron to enter cells. The expression of iron-transport-related genes on the duodenal basolateral membrane side was hardly altered by Cd. These results suggest that long-term exposure to Cd suppresses the expression of HCP1 and Cybrd1 in the proximal duodenum, resulting in reduced iron absorption and iron accumulation in the liver.

Combined Protective Effects of Quercetin, Rutin, and Gallic Acid against Cadmium-Induced Testicular Damages in Young-Adult Rats

Cadmium (Cd) is a toxic metal that damages several tissues of animals and humans including the testis. The ameliorative effects of quercetin (QUE), rutin (RUT), and gallic acid (GAL) at 20 mg kg-1 body weight alone or in combination against testicular injury induced by Cd (24 mg kg-1 body weight) in male Wistar rats were evaluated in this study. Forty-two (42) rats were randomly grouped into six (6) groups: (1) vehicle control group, (2) Cd group, (3) RUT+Cd group, (4) GAL+Cd group, (5) QUE+Cd group, and (6) RUT+GAL+QUE+Cd group. At the end of the oral gavage of the tested chemicals, the rats were sacrificed, blood samples were collected, and testes were harvested and processed for biochemical assays. Cd exposure damaged the testis (smaller epithelium thickness and spermatogenesis index and sloughing of the epithelium); increased lipid peroxidation, glutathione S-transferase activity, and DNA fragmentation; and diminished glutathione reductase activity and serum testosterone level 40 days posttreatment. Treatment with the phenolics separately or in combination attenuated the effect of Cd on serum testosterone, glutathione reductase and glutathione S-transferase activities, lipid peroxidation, and percent fragmented DNA. The increased nitric oxide concentration in the QUE+Cd group was attenuated to control values in the combined (RUT+GAL+QUE+Cd) exposure group. Coadministration of the phenolics appears to have more substantial protective effects than their single effects against Cd-induced testicular DNA damage, glutathione S-transferase activity, and the recovery of testosterone levels and spermatogenesis index. Overall, the tested phenolics can reduce testicular damage more efficiently in their combined form than individual administration.

Biological Effects of Human Exposure to Environmental Cadmium

Cadmium (Cd) is a toxic metal for the human organism and for all ecosystems. Cd is naturally found at low levels; however, higher amounts of Cd in the environment result from human activities as it spreads into the air and water in the form of micropollutants as a consequence of industrial processes, pollution, waste incineration, and electronic waste recycling. The human body has a limited ability to respond to Cd exposure since the metal does not undergo metabolic degradation into less toxic species and is only poorly excreted. The extremely long biological half-life of Cd essentially makes it a cumulative toxin; chronic exposure causes harmful effects from the metal stored in the organs. The present paper considers exposure and potential health concerns due to environmental cadmium. Exposure to Cd compounds is primarily associated with an elevated risk of lung, kidney, prostate, and pancreatic cancer. Cd has also been linked to cancers of the breast, urinary system, and bladder. The multiple mechanisms of Cd-induced carcinogenesis include oxidative stress with the inhibition of antioxidant enzymes, the promotion of lipid peroxidation, and interference with DNA repair systems. Cd²⁺ can also replace essential metal ions, including redox-active ones. A total of 12 cancer types associated with specific genes coding for the Cd-metalloproteome were identified in this work. In addition, we summarize the proper treatments of Cd poisoning, based on the use of selected Cd detoxifying agents and chelators, and the potential for preventive approaches to counteract its chronic exposure.

Ferroptosis as a mechanism of non-ferrous metal toxicity

Ferroptosis is a recently discovered form of regulated cell death, implicated in multiple pathologies. Given that the toxicity elicited by some metals is linked to alterations in iron metabolism and induction of oxidative stress and lipid peroxidation, ferroptosis might be involved in such toxicity. Although direct evidence is insufficient, certain pioneering studies have demonstrated a crosstalk between metal toxicity and ferroptosis. Specifically, the mechanisms underlying metal-induced ferroptosis include induction of ferritinophagy, increased DMT-1 and TfR cellular iron uptake, mitochondrial dysfunction and mitochondrial reactive oxygen species (mitoROS) generation, inhibition of Xc-system and glutathione peroxidase 4 (GPX4) activity, altogether resulting in oxidative stress and lipid peroxidation. In addition, there is direct evidence of the role of ferroptosis in the toxicity of arsenic, cadmium, zinc, manganese, copper, and aluminum exposure. In contrast, findings on the impact of cobalt and nickel on ferroptosis are scant and nearly lacking altogether for mercury and especially lead. Other gaps in the field include limited studies on the role of metal speciation in ferroptosis and the critical cellular targets. Although further detailed studies are required, it seems reasonable to propose even at this early stage that ferroptosis may play a significant role in metal toxicity, and its modulation may be considered as a potential therapeutic tool for the amelioration of metal toxicity.

Nutraceuticals: A New Challenge against Cadmium-Induced Testicular Injury

Cadmium (Cd) is a widespread heavy metal and a ubiquitous environmental toxicant. For the general population, the principal causes of Cd exposure are cigarette smoking, air pollution and contaminated water and food consumption, whereas occupational exposure usually involves humans working in mines or manufacturing batteries and pigments that utilize Cd. The aim of the present review is to evaluate recent data regarding the mechanisms of Cd-induced testicular structural and functional damages and the state of the art of the therapeutic approaches. Additionally, as the current literature demonstrates convincing associations between diet, food components and men's sexual health, a coherent nutraceutical supplementation may be a new valid therapeutic strategy for both the prevention and alleviation of Cd-induced testicular injury. The toxic effects on testes induced by Cd include many specific mechanisms, such as oxidative stress, inflammation and apoptosis. As no specific therapy for the prevention or treatment of the morbidity and mortality associated with Cd exposure is available, the development of new therapeutic agents is requested. Dietary strategies and the use of nutraceuticals, particularly abundant in fresh fruits, beans, vegetables and grains, typical of the Mediterranean diet, are recommended against Cd-induced testicular injury.

Gender Difference in the Associations among Heavy Metals with Red Blood Cell Hemogram

This study aimed to investigate gender differences in the association between heavy metals and hemograms including hemoglobin (Hgb), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). A health survey of 2447 participants was conducted in southern Taiwan between June 2016 and September 2018. Seven heavy metals were measured: blood lead (Pb), urine nickel (Ni), urine chromium (Cr), urine manganese, urine arsenic (As), urine copper and urine cadmium (Cd). The results show that in females, Pb and Ni were significantly negatively associated with Hgb. In addition, As and Cd were significantly positively, and Pb and Ni were significantly negatively, associated with MCV, in males and females, respectively. The interactions between gender and Ni and gender and Cd in MCV were statistically significant. Further, Pb, in males, and Pb, Ni and Cr, in females, were significantly negatively associated with MCHC. In conclusion, in females, associations of red blood cell (RBC) hemograms with heavy metals such as Pb and Ni were found. In males, heavy metals such as Pb, As and Cd were found to associate with RBC hemograms. Further research is warranted to discuss the mechanism behind these associations.

Correlation of the iron level in the bristles of Kemerovo pigs with macro- and essential microelements

Correlation data analysis of the iron content with macro- and essential microelements, as well as on the group of chemical elements interrelated with the Fe level in pig bristles are presented. The studies were carried out of the Kemerovo region on six-month-old pigs of the Kemerovo breed. Chemical analysis of swine bristle samples was carried out using atomic absorption spectrometry. The data were processed using of the program R. Only positive relationships were established between the iron content and the chemical elements of the bristle, as well as the group of chemical elements associated with the Fe level in the bristle. Most of the connections are explained by comparing the data obtained with the research of other scientists on the topic.

A comparative study of the phenotype with kainic acid-induced seizure in DBA/2 mice from three different sources

The kainic acid-induced seizure mouse model is widely used in epilepsy research. In this study, we applied kainic acid to the subcutaneous injections of three different sources of DBA/2 mice to compare and evaluate the seizure response. The three mouse sources consisted of DBA/2Kor1 (Korea FDA source), DBA/2A (USA source), and DBA/2 (Japan source), and were purchased from different vendors. To compare the responses of DBA/2 mice to kainic acid injections, we examined the survival rate, seizure phenotype scoring, and behavioral changes. We also evaluated brain lesions using histopathological analysis. Following the administration of kainic acid, almost half of the cohort survived, and the seizure phenotype displayed a moderate level of sensitivity (2 ~ 4 out of 6). In the histopathologic analysis, there was no change in morphological features, and levels of glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba-1) increased in the kainic acid-treated groups. However, there was no difference in the neuronal nuclei (NeuN) expression level. All the data showed that the responses in the kainic acid-treated group were similar across the three strains. In conclusion, our results suggest that the three sources of DBA/2 mice (DBA/2Kor1, DBA/2A, and DBA/2B) have similar pathological responses to kainic acid-induced seizures.