The effects of cadmium exposure in the induction of inflammation

Evidence linking cadmium and/or lead exposure to immunomodulatory effects in mammals based upon an adverse outcome pathways approach, and research perspectives

For decades, studies have shown how exposure to non-essential trace metals such as lead (Pb) and cadmium (Cd) largely impact global wildlife. Ecoimmunotoxicology has emerged in the past two decades and focuses on the effects of pollutants on the immune system of free-ranging organisms. Adverse outcome pathways (AOPs) represent a conceptual approach to explore the mechanistic linkage between a molecular initiating event and adverse outcomes, potentially at all biological levels of organisation. The present paper proposes putative AOPs related to the effects of Cd, Pb, and the mixture Cd-Pb, on the immune system of mammals to address future questions in ecoimmunotoxicology. Molecular Initiating Events for both metals relate to entrance in cells through Ca2+ channels or bond to cell surfaces. Exposure to Cd, Pb and Cd-Pb share several similar Key Events (KEs), primarily an increase of oxidative stress (OS) in immune cells through production of reactive oxygen species. For both metals and the mixture, OS affects mitochondrial membranes, and induces apoptosis, ultimately decreasing immune cell number. Both metals affect innate immune system through nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) inflammatory signalling pathways, leading to an upregulation of inflammatory markers and mediators. Adaptive immune system is also affected by the exposure to both metals though a decrease of CD4+/CD8+ ratio, a decrease of MHCII, an inactivation of TH1 and TH2 response, and an inhibition of the humoral response mediated by various Ig. Mixture effects of Cd-Pb are less documented resulting in a more speculative AOP, but potential synergic and antagonistic effects were identified. According to our AOPs, further research in ecoimmunotoxicology of metals in free-ranging mammals should focus on KEs related to NF-κB/MAPK inflammatory signalling pathways, changes in CD4+/CD8+ ratio and MHCII complexes, and on AOs related to auto-immune disorders and on the effective increase of infection rate, particularly in case of exposure to metal mixtures.

Cadmium-induced augmentation of fungal translocation promotes systemic infection in mice via gut barrier disruption and immune dysfunction

Cadmium (Cd) disrupts the immune system and intestinal barrier, increasing infection risk and gut dysbiosis. Its impact on intestinal fungi, particularly the opportunistic pathogen Candida albicans, which can cause systemic infections in immunocompromised patients, is not well understood. Our study revealed that C. albicans exhibited high tolerance and maintained its morphogenetic switching in response to Cd. As C. albicans is not naturally found in the mouse gut, we attempted intestinal colonization of C. albicans-SC5314 strain using standard procedures. However, the intestinal fungal load decreased and was undetectable by 15th day. To assess the effects of sub-chronic Cd exposure, both oral and intravenous methods were used. Oral exposure to C. albicans (105 CFU/ml) resulted in a 10-fold increase in intestinal translocation in Cd-exposed mice (0.98 mg/kg) compared to controls. Cd exposure also downregulated intestinal tight junction proteins and increased FITC-dextran permeability, indicating that Cd disrupts the intestinal barrier and facilitates C. albicans translocation. Moreover, Cd-exposed mice showed significant morbidity and higher fungal loads in organs after intravenous non-lethal dose of C. albicans, along with a subdued cytokine response. These findings highlight the significant impact of Cd on fungal pathogenicity and immune response, pointing to the broader health risks of Cd exposure.

Chronic cadmium exposure to minimal-risk doses causes dysfunction of epididymal adipose tissue and metabolic disorders

Cadmium (Cd) is among the top seven most hazardous environmental contaminants. Minimal risk levels for daily exposure have been established, such as no observable adverse effect level (NOAEL) and lowest observable adverse effect level (LOAEL). Chronic exposure to Cd, at both NOAEL and LOAEL doses, causes toxicity in diverse tissues. However, Cd toxicity in adipose tissue, an endocrine and metabolic organ, remains relatively understudied. We aimed to investigate the potentially toxic effects of chronic Cd exposure (at NOAEL and LOAEL doses) on epidydimal adipose tissue of adult male Wistar rats. Ninety male Wistar rats were divided into three groups (n = 30): Control Cd-free, NOAEL, and LOAEL that received CdCl2 in drinking water for 15 days to 5 months. We evaluated over time zoometry, serum and adipose Cd concentration, redox balance, GLUT4 and Nrf2 expression, histology, leptin, adiponectin, adipose insulin resistance index, free fatty acids, and glucose tolerance. The higher dose group showed a more pronounced and sustained increase in serum and adipose tissue of Cd concentration. Zoometry was similarly affected in both Cd-exposed groups with adipocyte hypertrophy. The redox balance was maintained due to the augmenting of Nrf2 expression. Leptin concentration augmented, while adiponectin diminished. Adipose insulin resistance increased simultaneously to lipolysis and glucose intolerance despite high GLUT4 expression. In conclusion, this study provides strong evidence that chronic Cd exposure, even at minimal risk levels (LOAEL and NOAEL doses), has toxic effects, disrupting the function of epididymal adipose tissue and contributing to metabolic disorders.

Heavy Metals and Associated Risks of Wild Edible Mushrooms Consumption: Transfer Factor, Carcinogenic Risk, and Health Risk Index

This research aims to investigate the heavy metals (i.e., Cd, Cr, Cu, Ni, and Pb) in the fruiting bodies of six indigenous wild edible mushrooms including Agaricus bisporus, Agaricus campestris, Armillaria mellea, Boletus edulis, Macrolepiota excoriate, and Macrolepiota procera, correlated with various factors, such as the growth substrate, the sampling site, the species and the morphological part (i.e., cap and stipe), and their possible toxicological implications. Heavy metal concentrations in mushroom (228 samples) and soil (114 samples) were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In the first part of the study, the soil contamination (index of geo-accumulation, contamination factor, and pollution loading index) and associated risks (chronic daily dose for three exposure pathways-ingestion, dermal, and inhalation; hazard quotient of non-cancer risks and the carcinogenic risks) were calculated, while the phytoremediation capacity of the mushrooms was determined. At the end of these investigations, it was concluded that M. procera accumulates more Cd and Cr (32.528% and 57.906%, respectively), M. excoriata accumulates Cu (24.802%), B. edulis accumulates Ni (22.694%), and A. mellea accumulates Pb (18.574%), in relation to the underlying soils. There were statistically significant differences between the stipe and cap (i.e., in the cap subsamples of M. procera, the accumulation factor for Cd was five times higher than in the stipe subsamples). The daily intake of toxic metals related to the consumption of these mushrooms with negative consequences on human health, especially for children (1.5 times higher than for adults), was determined as well.

Attenuation of inflammation, oxidative stress and TGF-β1/Smad3 signaling and upregulation of Nrf2/HO-1 signaling mediate the protective effect of diallyl disulfide against cadmium nephrotoxicity

Heavy metals are toxic environmental pollutants with serious health effects on humans and animals. Cadmium (Cd) is known for its serious nephrotoxic effect and its toxicity involves oxidative stress (OS) and inflammation. Diallyl disulfide (DADS), a main constituent of garlic, exhibites cytoprotective and antioxidant activities. This study investigated the effect of DADS on OS, inflammation, and fibrosis induced by Cd in rat kidney, pointing to the involvement of transforming growth factor-β (TGF-β)/Smad3 and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling, and peroxisome proliferator-activated receptor gamma (PPARγ). Rats received DADS for 14 days and Cd on day 7 and blood and kidney samples were collected. Cd elevated serum creatinine, urea and uric acid, provoked kidney histopathological alterations and collagen deposition, increased kidney malondialdehyde (MDA) level, and decreased glutathione (GSH) and antioxidant enzymes. Nuclear factor-kappaB (NF-κB) p65, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, and CD68 were upregulated in Cd-administered rat kidney. DADS prevented kidney injury, mitigated OS, suppressed NF-κB, CD68 and pro-inflammatory mediators, and boosted antioxidants. DADS downregulated TGF-β1, Smad3 phosphorylation and Kelch-like ECH-associated protein-1 (Keap1), and increased Nrf2, HO-1, cytoglobin, and PPARγ. In conclusion, DADS protects the kidney against Cd toxicity by attenuating OS, inflammation, and TGF-β1/Smad3 signaling, and enhancement of Nrf2/HO-1 signaling, antioxidants, and PPARγ.

Carcinogenic and non-carcinogenic risks caused by rice contamination with heavy metals and their effect on the prevalence of cardiovascular disease (Using machine learning)

INTRODUCTION

The safety and health of food products are essential in the food industry, and the risk of contamination from various contaminants must be evaluated. Exposure to HMs from the environment (especially food) causes various adverse effects on the body and increases the risk of cardiovascular disease (CVD).

MATERIAL AND METHOD

Volunteers in the study comprised both healthy individuals and those with CVD. Patients were chosen using a cohort database of CVD individuals. A random choice of samples was conducted. Medical information (individuals with CVD) related to the participants was obtained from the Hoveyzeh Cohort Study Center. CVD-HM relationships were assessed using various machine-learning techniques.

RESULT

Based on the results of the GAM statistics approach, the baseline levels (β) of As, Cd, and Cr in rice have been calculated to be 1.05, 1.19, and 1.11, respectively. Based on the investigation's results, rice acts as a mediator between high-magnitude actions and the prevalence of CVD. Eating rice increases the probability of CVD by 0.18 and raises As eating by 0.494. The results showed that rice consumption in the research area is not associated with non-carcinogenic and carcinogenic risk (CRs and ILCRs for both categories were less than 1∗10-6).

CONCLUSION

There was neither a carcinogenic nor non-carcinogenic threat to adults or children and many hazardous HMs existed at the accepted thresholds. A notable relationship was seen between rice contaminated with HM and CVD.

Unraveling the role of heavy metals xenobiotics in cancer: a critical review

Cancer is a multifaceted disease characterized by the gradual accumulation of genetic and epigenetic alterations within cells, leading to uncontrolled cell growth and invasive behavior. The intricate interplay between environmental factors, such as exposure to carcinogens, and the molecular cascades governing cell growth, differentiation, and survival contributes to cancer's development and progression. This review offers a comprehensive overview of key molecular targets and their roles in cancer development. Peroxisome proliferator-activated receptors are implicated in various cancers due to their role in regulating lipid metabolism, inflammation, and cell proliferation. Nuclear factor erythroid 2-related factor 2 protects cells from oxidative damage but can also promote tumor cell survival. Cytochrome P450 1B1 metabolizes exogenous and endogenous substances, and its increased expression is observed in several cancers. The constitutive androstane receptor regulates gene expression, and its dysregulation can lead to liver cancer. Transforming growth factor-beta 2 is involved in the development and progression of various cancers by dysregulating cell proliferation, differentiation, and migration. Chelation treatment has been investigated for removing heavy metals, while genetically altered immune cells show promise in treating specific cancers. Metal-organic frameworks and fibronectin targeting represent new directions in cancer treatment. While some heavy metals, such as arsenic, chromium, nickel, and cadmium, are known to have carcinogenic properties, others, like zinc, Copper, gold, bismuth, and silver, have many uses that highlight their potential as effective cancer control tactics. There are a variety of heavy metal-based technologies that show potential for improving cancer treatment methods, including targeted drug delivery, improved radiation, and diagnostic tools.

Potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in individuals with diabetes

Diabetes and its complications are major diseases that affect human health. Diabetic cardiovascular complications such as cardiovascular diseases (CVDs) are the major complications of diabetes, which are associated with the loss of cardiovascular cells. Pathogenically the role of ferroptosis, an iron-dependent cell death, and cuproptosis, a copper-dependent cell death has recently been receiving attention for the pathogenesis of diabetes and its cardiovascular complications. How exposure to environmental metals affects these two metal-dependent cell deaths in cardiovascular pathogenesis under diabetic and nondiabetic conditions remains largely unknown. As an omnipresent environmental metal, cadmium exposure can cause oxidative stress in the diabetic cardiomyocytes, leading to iron accumulation, glutathione depletion, lipid peroxidation, and finally exacerbate ferroptosis and disrupt the cardiac. Moreover, cadmium-induced hyperglycemia can enhance the circulation of advanced glycation end products (AGEs). Excessive AGEs in diabetes promote the upregulation of copper importer solute carrier family 31 member 1 through activating transcription factor 3/transcription factor PU.1, thereby increasing intracellular Cu+ accumulation in cardiomyocytes and disturbing Cu+ homeostasis, leading to a decline of Fe-S cluster protein and reactive oxygen species accumulation in cardiomyocytes mitochondria. In this review, we summarize the available evidence and the most recent advances exploring the underlying mechanisms of ferroptosis and cuproptosis in CVDs and diabetic cardiovascular complications, to provide critical perspectives on the potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in diabetic individuals.

Hormetic responses to cadmium exposure in wheat seedlings: insights into morphological, physiological, and biochemical adaptations

Cadmium is commonly recognized as toxic to plant growth, low-level Cd has promoting effects on growth performance, which is so-called hormesis. Although Cd toxicity in wheat has been widely investigated, knowledge of growth response to a broad range of Cd concentrations, especially extremely low concentrations, is still unknown. In this study, the morphological, physiological, and biochemical performance of wheat seedlings to a wide range of Cd concentrations (0-100 µΜ) were explored. Low Cd treatment (0.1-0.5 µM) improved wheat biomass and root development by enhancing the photosynthetic system and antioxidant system ability. Photosynthetic rate (Pn) was improved by 5.72% under lower Cd treatment (1 µΜ), but inhibited by 6.05-49.85% from 5 to 100 µΜ. Excessive Cd accumulation induced oxidative injury manifesting higher MDA content, resulting in lower photosynthetic efficiency, stunted growth, and reduction of biomass. Further, the contents of ascorbate, glutathione, non-protein thiols, and phytochelatins were improved under 5-100 µΜ Cd treatment. The ascorbate peroxidase activity in the leaf showed a hormetic dose-response characteristic. Correlation analysis and partial least squares (PLS) results indicated that antioxidant enzymes and metabolites were closely correlated with Cd tolerance and accumulation. The results of the element network, correlation analysis, and PLS showed a crucial role for exogenous Cd levels in K, Fe, Cu, and Mn uptake and accumulation. These results provided a deeper understanding of the hormetic effect of Cd in wheat, which would be beneficial for improving the quality of hazard and risk assessments.

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.

Unlocking the in vitro and in vivo antioxidant and anti-inflammatory activities of polysaccharide fractions from Lepidium sativum seed-coat mucilage

Inflammation coupled with oxidative stress contribute to the pathogenicity of various clinical disorders. Oxidative stress arises from an imbalance between production of reactive oxygen species (ROS) and antioxidant defense system, leading to cellular damages. The study investigated the antioxidant and anti-inflammatory effects of polysaccharides isolated from Lepidium sativum seed-coat mucilage. The water-soluble polysaccharides were extracted from mucilage and fractionated using gel permeation chromatography. The radical scavenging potential of various fractions was determined using DPPH, H2O2, and lipid peroxidation assays. The most effective EC50 was recorded for F53 (57.41 ± 1.34 μg/mL), followed by F20 (69.19 ± 0.61 μg/mL) and F52 (75.06 ± 0.45 μg/mL). In vitro anti-inflammatory effect was determined through human membrane stabilization assay while the in vivo effect was evaluated using a carrageenan-induced paw edema in mouse model where F53 demonstrated significant (P = 0.05) anti-inflammatory potential (92.60 % compared to diclofenac sodium 91.46 %). GC-MS analysis revealed the presence of galacturonic acid and glucuronic acid as main acidic monosaccharides along with varying quantities of rhamnose, arabinose, and maltose as prominent neutral monosaccharides. The study concludes that cress seed mucilage contains potent antioxidant and anti-inflammatory polysaccharides. Further studies on the mode of action of these polysaccharides could provide deeper insights into their potential use as antioxidant and anti-inflammatory agents.

Association of combined lead, cadmium, and mercury with systemic inflammation

Background

Exposure to environmental metals has been increasingly associated with systemic inflammation, which is implicated in the pathogenesis of various chronic diseases, including those with neurodegenerative aspects. However, the complexity of exposure and response relationships, particularly for mixtures of metals, has not been fully elucidated.

Objective

This study aims to assess the individual and combined effects of lead, cadmium, and mercury exposure on systemic inflammation as measured by C-reactive protein (CRP) levels, using data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018.

Methods

We employed Bayesian Kernel Machine Regression (BKMR) to analyze the NHANES 2017-2018 data, allowing for the evaluation of non-linear exposure-response functions and interactions between metals. Posterior Inclusion Probabilities (PIP) were calculated to determine the significance of each metal's contribution to CRP levels.

Results

The PIP results highlighted mercury's significant contribution to CRP levels (PIP = 1.000), followed by cadmium (PIP = 0.6456) and lead (PIP = 0.3528). Group PIP values confirmed the importance of considering the metals as a collective group in relation to CRP levels. Our BKMR analysis revealed non-linear relationships between metal exposures and CRP levels. Univariate analysis showed a flat relationship between lead and CRP, with cadmium having a positive relationship. Mercury exhibited a U-shaped association, indicating both low and high exposures as potential risk factors for increased inflammation. Bivariate analysis confirmed this relationship when contaminants were combined with lead and cadmium. Analysis of single-variable effects suggested that cadmium and lead are associated with higher values of the h function, a flexible function that takes multiple metals and combines them in a way that captures the complex and potentially nonlinear relationship between the metals and CRP. The overall exposure effect of all metals on CRP revealed that exposures below the 50th percentile exposure level are associated with an increase in CRP levels, while exposures above the 60th percentile are linked to a decrease in CRP levels.

Conclusions

Our findings suggest that exposure to environmental metals, particularly mercury, is associated with systemic inflammation. These results highlight the need for public health strategies that address the cumulative effects of metal exposure and reinforce the importance of using advanced statistical methods to understand the health impact of environmental contaminants. Future research should focus on the mechanistic pathways of metal-induced inflammation and longitudinal studies to ascertain the long-term effects of these exposures.

Co-exposure effects of urinary polycyclic aromatic hydrocarbons and metals on lung function: mediating role of systematic inflammation

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) and metals were associated with decreased lung function, but co-exposure effects and underlying mechanism remained unknown.

METHODS

Among 1,123 adults from National Health and Nutrition Examination Survey 2011-2012, 10 urinary PAHs, 11 urinary metals, and peripheral white blood cell (WBC) count were determined, and 5 lung function indices were measured. Least absolute shrinkage and selection operator, Bayesian kernel machine regression, and quantile-based g-computation were used to estimate co-exposure effects on lung function. Mediation analysis was used to explore mediating role of WBC.

RESULTS

These models demonstrated that PAHs and metals were significantly associated with lung function impairment. Bayesian kernel machine regression models showed that comparing to all chemicals fixed at median level, forced expiratory volume in 1 s (FEV1)/forced vital capacity, peak expiratory flow, and forced expiratory flow between 25 and 75% decreased by 1.31% (95% CI: 0.72%, 1.91%), 231.62 (43.45, 419.78) mL/s, and 131.64 (37.54, 225.74) mL/s respectively, when all chemicals were at 75th percentile. In the quantile-based g-computation, each quartile increase in mixture was associated with 104.35 (95% CI: 40.67, 168.02) mL, 1.16% (2.11%, 22.40%), 294.90 (78.37, 511.43) mL/s, 168.44 (41.66, 295.22) mL/s decrease in the FEV1, FEV1/forced vital capacity, peak expiratory flow, and forced expiratory flow between 25% and 75%, respectively. 2-Hydroxyphenanthrene, 3-Hydroxyfluorene, and cadmium were leading contributors to the above associations. WBC mediated 8.22%-23.90% of association between PAHs and lung function.

CONCLUSIONS

Co-exposure of PAHs and metals impairs lung function, and WBC could partially mediate this relationship. Our findings elucidate co-exposure effects of environmental mixtures on respiratory health and underlying mechanisms, suggesting that focusing on highly prioritized toxicants would effectively attenuate adverse effects.

Curcumin Treatment Ameliorates Hepatic Insulin Resistance Induced by Sub-chronic Oral Exposure to Cadmium LOAEL Dose via NF-κB and Nrf2 Pathways

Cadmium (Cd) is a global pollutant, and its accumulation in the liver causes oxidative stress, inflammation, insulin resistance (IR), and metabolic complications. This study investigated whether curcumin treatment could alleviate hepatic IR in Wistar rats exposed to sub-chronic cadmium and explored the underlying molecular pathways. Male Wistar rats were divided into a control group (standard normocaloric diet + cadmium-free water) and a cadmium group (standard normocaloric diet + drinking water with 32.5 ppm CdCl2) for 30 days. Oral glucose tolerance, insulin response, and IR were assessed using mathematical models. Liver tissue was analyzed for markers of oxidative stress, inflammation, and key regulatory pathways, including NF-κB, Nrf2, MAPKs (JNK and p38), and the IRS1-Akt pathway. We established an effective curcumin dose of 250 mg/kg for 5 days orally. Results demonstrated that after 30 days of exposure, cadmium accumulated in the liver, inducing an oxidative and inflammatory state. This was characterized by increased expression of NF-κB, JNK, and p38, along with diminished Nrf2 expression, hepatic IR, hyperglycemia, and hyperinsulinemia. Curcumin treatment effectively alleviated these metabolic disorders by restoring the balance between NF-κB and Nrf2 in the liver, modulating the MAPK pathway, and, consequently, improving oxidative and inflammatory balance. In conclusion, this study suggests that cadmium induces hepatic IR through an imbalance between NF-κB and Nrf2 signaling pathways. Curcumin treatment appears to improve these pathways, thereby ameliorating hepatic IR.

Heavy metal stress and mitogen activated kinase transcription factors in plants: Exploring heavy metal-ROS influences on plant signalling pathways

Due to their stationary nature, plants are exposed to a diverse range of biotic and abiotic stresses, of which heavy metal (HM) stress poses one of the most detrimental abiotic stresses, targeting diverse plant processes. HMs instigate the overproduction of reactive oxygen species (ROS), and to mitigate the adverse effects of ROS, plants induce multiple defence mechanisms. Besides the negative implications of overproduction of ROS, these molecules play a multitude of signalling roles in plants, acting as a central player in the complex signalling network of cells. One of the ROS-associated signalling mechanisms is the mitogen-activated protein kinase (MAPK) cascade, a signalling pathway which transduces extracellular stimuli into intracellular responses. Plant MAPKs have been implicated in signalling involved in stress response, phytohormone regulation, and cell cycle cues. However, the influence of various HMs on MAPK activation has not been well documented. In this review, we address and summarise several aspects related to various HM-induced ROS signalling. Additionally, we touch on how these signals activate the MAPK cascade and the downstream transcription factors that influence plant responses to HMs. Moreover, we propose a workflow that could characterise genes associated with MAPKs and their roles during plant HM stress responses.

Lysine-63-linked polyubiquitination: a principal target of cadmium carcinogenesis

Cadmium is an environmental pollutant that constitutes a major danger to human health. It is considered a definite human carcinogen. The lung and kidney are the most sensitive organs for cancer development, and we recently provided the first evidence of direct upregulation of lysine-63-linked polyubiquitination by cadmium, particularly in response to environmentally relevant concentrations. Investigations of K63 polyubiquitination have greatly progressed, and various strategies have been reported for studying this molecular process in different biological systems under both physiological and stress conditions. Furthermore, the mechanisms underlying cadmium-induced accumulation of K63-polyubiquitinated proteins in lung and renal cells continue to be of interest given the unknown mechanism involved in the carcinogenesis of this metal. Cadmium is persistent within the cytosol and induces oxidative stress, which continuously damages proteins and causes K63 polyubiquitination, leading to the regulation/activation of different cellular signaling pathways. The aim of this review was to perform a critical analysis of the knowledge about K63 polyubiquitination induced by cadmium and its effect on selective autophagy, CYLD, the NF-KB pathway and Hif-1α. We also report data obtained in different experimental studies using cadmium, highlighting similarities in the induction of the ubiquitination system. A more detailed discussion will concern the role of K63 polyubiquitination in cadmium-exposed renal proximal convoluted tubules and lung cells since they are suitable model systems that are extremely sensitive to environmental stress, and cadmium is one of the most carcinogenic metals to which humans are exposed. We ultimately concluded that K63 polyubiquitination may be the origin of cadmium carcinogenesis in the lung and kidney.

Graphical Abstract

Pathways of cadmium carcinogenesis: Cadmium mimics zinc and induces Lysine-63-linked polyubiquitination, which promotes three intracellular processes: (1) accumulation of ubiquitinated proteins, (2) stabilization of hypoxic inducible factor-1α and (3) activation of the nuclear factor-kappaB pathway, which results in the blockade of selective autophagy, angiogenesis, inflammation and cell proliferation.

Commercially available mouthguards: Unearthing trace elements for the first time

The use of mouthguards is advocated by the American Dental Association for orofacial injury prevention and teeth protection. However, the chemical environment in the mouth may cause harmful substances within the mouthguard's polymer material to leach out and be absorbed by the user. Considering this, the present study for the first time analyzed commercially available mouthguards and disclosed the presence of trace elements. Specifically, an analytical method was developed based on closed-vessel microwave-assisted digestion and plasma-based atomic spectrometry for determining toxic trace elements in mouthguard samples. Initially, 75 elements were assessed and, thereafter, quantified cadmium (Cd), copper (Cu) and lead (Pb) in each sample by inductively coupled plasma mass spectrometry (ICP-MS). Method validation was carried out by analyzing a certified reference material of Low-Density Polyethylene, and by addition and recovery experiments. Results for copper were further validated by ICP optical emission spectrometry (ICP-OES). While most samples exhibited elemental levels beneath the method's limit of quantification, Cd, Cu and Pb were detected in four samples. Remarkably, one sample had Cu levels exceeding safe limits by 109 times, highlighting potential toxicity risks. This initial research underscores the need for stricter contamination control in mouthguard materials to minimize potentially health hazards.

Cadmium promoted LPS-induced inflammation through TLR4/IκBα/NFκ-B signaling by increasing ROS-mediated incomplete autophagy

Cadmium (Cd) exposure is considered as non-infectious stressor to human and animal health. Recent studies suggest that the immunotoxicity of low dose Cd is not directly apparent, but disrupts the immune responses when infected with some bacteria or virus. But how Cd alters the adaptive immunity organ and cells remains unclear. In this study, we applied lipopolysaccharide (LPS, infectious stressor) to induced inflammation in spleen tissues and T cells, and investigated the effects after Cd exposure and the underlying mechanism. Cd exposure promoted LPS-induced the expressions of the inflammatory factors, induced abnormal initiation of autophagy, but blocked autophagic flux. The effects Cd exposure under LPS activation were reversed by the autophagy promoter Rapamycin. Under LPS activation conditions, Cd also induced oxidative stress by increasing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and reducing total antioxidant capacity (T-AOC) activity. The increased superoxide dismutase (SOD) activity after Cd exposure might be a negative feedback or passive adaptive regulation of oxidative stress. Cd-increased autophagic flux inhibition and TNF-α expression were reversed by ROS scavenger α-tocopherol (TCP). Furthermore, under LPS activation condition, Cd promoted activation of toll-like receptor 4 (TLR4)/IκBα/NFκ-B signaling pathway and increased TLR4 protein stability, which were abolished by the pretreatment of Rapamycin. The present study confirmed that, by increasing ROS-mediated inhibiting autophagic degradation of TLR4, Cd promoted LPS-induced inflammation in spleen T cells. This study identified the mechanism of autophagy in Cd-aggravated immunotoxicity under infectious stress, which could arouse public attention to synergistic toxicity of Cd and bacterial or virus infection.

Cadmium modulates intestinal Wnt/β-catenin signaling ensuing intestinal barrier disruption and systemic inflammation

The intricate architecture of the intestinal epithelium, crucial for nutrient absorption, is constantly threatened by environmental factors. The epithelium undergoes rapid turnover, which is essential for maintaining homeostasis, under the control of intestinal stem cells (ISCs). The central regulator, Wnt/β-catenin signaling plays a key role in intestinal integrity and turnover. Despite its significance, the impact of environmental factors on this pathway has been largely overlooked. This study, for the first time, investigates the influence of Cd on the intestinal Wnt signaling pathway using a mouse model. In this study, male BALB/c mice were administered an environmentally relevant Cd dose (0.98 mg/kg) through oral gavage to investigate the intestinal disruption and Wnt signaling pathway. Various studies, including histopathology, immunohistochemistry, RT-PCR, western blotting, ELISA, intestinal permeability assay, and flow cytometry, were conducted to study Cd-induced changes in the intestine. The canonical Wnt signaling pathway experienced significant downregulation as a result of sub-chronic Cd exposure, which caused extensive damage throughout the small intestine. Increased intestinal permeability and a skewed immune response were also observed. To confirm that Wnt signaling downregulation is the key driver of Cd-induced gastrointestinal toxicity, mice were co-exposed to LiCl (a recognized Wnt activator) and Cd. The results clearly showed that the harmful effects of Cd could be reversed, which is strong evidence that Cd mostly damages the intestine through the Wnt/β-catenin signalling axis. In conclusion, this research advances the current understanding of the role of Wnt/β catenin signaling in gastrointestinal toxicity caused by diverse environmental pollutants.

Co-exposure to PVC microplastics and cadmium induces oxidative stress and fibrosis in duck pancreas

PVC microplastics (PVC-MPs) are environmental pollutants that interact with cadmium (Cd) to exert various biological effects. Ducks belong to the waterfowl family of birds and therefore are at a higher risk of exposure to PVC-MPs and Cd than other animals. However, the effects of co-exposure of ducks to Cd and PVC-MPs are poorly understood. Here, we used Muscovy ducks to establish an in vivo model to explore the effects of co-exposure to 1 mg/L PVC-MPs and 50 mg/kg Cd on duck pancreas. After 2 months of treatment with 50 mg/kg Cd, pancreas weight decreased by 21 %, and the content of amylase and lipase increased by 25 % and 233 %. However, exposure to PVC-MPs did not significantly affect the pancreas. Moreover, co-exposure to PVC-MPs and Cd worsened the reduction of pancreas weight and disruption of pancreas function compared to exposure to either substance alone. Furthermore, our research has revealed that exposure to PVC-MPs or Cd disrupted mitochondrial structure, reduced ATP levels by 10 % and 18 %, inhibited antioxidant enzyme activity, and increased malondialdehyde levels by 153.8 % and 232.5 %. It was found that exposure to either PVC-MPs or Cd can induce inflammation and fibrosis in the duck pancreas. Notably, co-exposure to PVC-MPs and Cd exacerbated inflammation and fibrosis, with the content of IL-1, IL-6, and TNF-α increasing by 169 %, 199 %, and 98 %, compared to Cd exposure alone. The study emphasizes the significance of comprehending the potential hazards linked to exposure to these substances. In conclusion, it presents promising preliminary evidence that PVC-MPs accumulate in duck pancreas, and increase the accumulation of Cd. Co-exposure to PVC-MPs and Cd disrupts the structure and function of mitochondria and promotes the development of pancreas inflammation and fibrosis.

Association between Combined Metals and PFAS Exposure with Dietary Patterns: A Preliminary Study

Background

The global burden of chronic diseases has been increasing, with evidence suggesting that diet and exposure to environmental pollutants, such as per- and polyfluoroalkyl substances (PFAS) and heavy metals, may contribute to their development. The Dietary Inflammatory Index (DII) assesses the inflammatory potential of an individual's diet. However, the complex interplay between PFAS, heavy metals, and DII remains largely unexplored.

Objective

The goal of this cross-sectional study was to investigate the associations between diet operationalized as the DII with individual and combined lead, cadmium, mercury, perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) exposures using data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018.

Methods

Descriptive statistics, a correlational analysis, and linear regression were initially used to assess the relationship between the variables of interest. We subsequently employed Bayesian kernel Machine regression (BKMR) to analyze the data to assess the non-linear, non-additive, exposure-response relationships and interactions between PFAS and metals with the DII.

Results

The multi-variable linear regression revealed significant associations between the DII and cadmium and mercury. Our BKMR analysis revealed a complex relationship between PFAS, metal exposures, and the DII. In our univariate exposure-response function plot, cadmium and mercury exhibited a positive and negative linear relationship, respectively, which indicated a positive and negative relationship across the spectrum of exposures with the DII. In addition, the bivariate exposure-response function between two exposures in a mixture revealed that cadmium had a robust positive relationship with the DII for different quantiles of lead, mercury, PFOA, and PFOS, indicating that increasing levels of cadmium are associated with the DII. Mercury's bivariate plot demonstrated a negative relationship across all quantiles for all pollutants. Furthermore, the posterior inclusion probability (PIP) results highlighted the consistent importance of cadmium and mercury with the inflammatory potential of an individual's diet, operationalized as the DII in our study, with both showing a PIP of 1.000. This was followed by PFOS with a PIP of 0.8524, PFOA at 0.5924, and lead, which had the lowest impact among the five environmental pollutants, with a PIP of 0.5596.

Conclusion

Our study suggests that exposures to environmental metals and PFAS, particularly mercury and cadmium, are associated with DII. These findings also provide evidence of the intricate relationships between PFAS, heavy metals, and the DII. The findings underscore the importance of considering the cumulative effects of multi-pollutant exposures. Future research should focus on elucidating the mechanistic pathways and dose-response relationships underlying these associations in a study that examines causality, which will enable a deeper understanding of the dietary risks associated with environmental pollutants.

Cadmium Exposure: Mechanisms and Pathways of Toxicity and Implications for Human Health

Cadmium (Cd), a prevalent environmental contaminant, exerts widespread toxic effects on human health through various biochemical and molecular mechanisms. This review encapsulates the primary pathways through which Cd inflicts damage, including oxidative stress induction, disruption of Ca2+ signaling, interference with cellular signaling pathways, and epigenetic modifications. By detailing the absorption, distribution, metabolism, and excretion (ADME) of Cd, alongside its interactions with cellular components such as mitochondria and DNA, this paper highlights the extensive damage caused by Cd2+ at the cellular and tissue levels. The role of Cd in inducing oxidative stress-a pivotal mechanism behind its toxicity-is discussed with emphasis on how it disrupts the balance between oxidants and antioxidants, leading to cellular damage and apoptosis. Additionally, the review covers Cd's impact on signaling pathways like Mitogen-Activated Protein Kinase (MAPK), Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), and Tumor Protein 53 (p53) pathways, illustrating how its interference with these pathways contributes to pathological conditions and carcinogenesis. The epigenetic effects of Cd, including DNA methylation and histone modifications, are also explored to explain its long-term impact on gene expression and disease manifestation. This comprehensive analysis not only elucidates the mechanisms of Cd toxicity but also underscores the critical need for enhanced strategies to mitigate its public health implications.

Nano-Selenium Alleviates Cd-Induced Chronic Colitis through Intestinal Flora

BACKGROUND

Cadmium (Cd) is an environmental contaminant that poses risks to human and animal health. Selenium (Se), a beneficial element, alleviates the detrimental consequences of colitis and Cd toxicity. Se is found in food products as both inorganic Se (sodium selenite) and organic Se (typically Se-enriched yeast). Nano-selenium (nano-Se; a novel form of Se produced through the bioreduction of Se species) has recently garnered considerable interest, although its effects against Cd-induced enterotoxicity are poorly understood. The aim of this study was to investigate the impact of nano-selenium on mitigating cadmium toxicity and safeguarding the integrity of the intestinal barrier.

METHODS

For a total of two cycles, we subjected 6-week-old C57 mice to chronic colitis by exposing them to Cd and nano-selenium for two weeks, followed by DSS water for one week.

RESULTS

The application of nano-selenium mitigated the intensity of colitis and alleviated inflammation in the colon. Nano-selenium enhanced the diversity of the intestinal flora, elevated the concentration of short-chain fatty acids (SCFAs) in feces, and improved the integrity of the intestinal barrier.

CONCLUSIONS

In summary, nano-Se may reduce intestinal inflammation by regulating the growth of intestinal microorganisms and protecting the intestinal barrier.

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.

Urinary cadmium concentration is associated with the severity and clinical outcomes of COVID-19: a bicenter observational cohort study

BACKGROUND

Cadmium and nickel exposure can cause oxidative stress, induce inflammation, inhibit immune function, and therefore has significant impacts on the pathogenesis and severity of many diseases. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can also provoke oxidative stress and the dysregulation of inflammatory and immune responses. This study aimed to assess the potential associations of cadmium and nickel exposure with the severity and clinical outcomes of patients with coronavirus disease 2019 (COVID-19).

METHODS

We performed a retrospective, observational, bicenter cohort analysis of patients with SARS-CoV-2 infection in Taiwan between June 2022 and July 2023. Cadmium and nickel concentrations in blood and urine were measured within 3 days of the diagnosis of acute SARS-CoV-2 infection, and the severity and clinical outcomes of patients with COVID-19 were analyzed.

RESULTS

A total of 574 patients were analyzed and divided into a severe COVID-19 group (hospitalized patients) (n = 252; 43.9%), and non-severe COVID-19 group (n = 322; 56.1%). The overall in-hospital mortality rate was 11.8% (n = 68). The severe COVID-19 patients were older, had significantly more comorbidities, and significantly higher neutrophil/lymphocyte ratio, C-reactive protein, and interleukin-6 than the non-severe COVID-19 patients (all p < 0.05). Blood and urine cadmium and urine nickel concentrations were significantly higher in the severe COVID-19 patients than in the non-severe COVID-19 patients. Among the severe COVID-19 patients, those in higher urine cadmium/creatinine quartiles had a significantly higher risk of organ failure (i.e., higher APACHE II and SOFA scores), higher neutrophil/lymphocyte ratio, lower PaO2/FiO2 requiring higher invasive mechanical ventilation support, higher risk of acute respiratory distress syndrome, and higher 60-, 90-day, and all-cause hospital mortality (all p < 0.05). Multivariable logistic regression models revealed that urine cadmium/creatinine was independently associated with severe COVID-19 (adjusted OR 1.643 [95% CI 1.060-2.547], p = 0.026), and that a urine cadmium/creatinine value > 2.05 μg/g had the highest predictive value (adjusted OR 5.349, [95% CI 1.118-25.580], p = 0.036).

CONCLUSIONS

Urine cadmium concentration in the early course of COVID-19 could predict the severity and clinical outcomes of patients and was independently associated with the risk of severe COVID-19.

Potential pathological mechanisms and pharmacological interventions for cadmium-induced miscarriage

The prevalence of cadmium (Cd) contamination has emerged as a significant global concern. Exposure to Cd during pregnancy is associated with adverse pregnancy outcomes, including miscarriage. However, there is currently a lack of comprehensive summaries on Cd-induced miscarriage. Therefore, it is imperative to further strengthen research into in vivo studies, clinical status, pathological mechanisms, and pharmacological interventions for Cd-induced miscarriage. This study systematically presents the current knowledge on animal models and clinical trials investigating Cd exposure-induced miscarriage. The underlying mechanisms involving oxidative stress, inflammation, endocrine disruption, and placental dysfunction caused by Cd-induced miscarriage are also extensively discussed. Additionally, potential drug interventions such as melatonin, vitamin C, and vitamin E are highlighted for their pharmacological role in mitigating adverse pregnancy outcomes induced by Cd.

Could the gut microbiota be capable of making individuals more or less susceptible to environmental toxicants?

Environmental toxicants are chemical substances capable to impair environmental quality and exert adverse effects on humans and other animals. The main routes of exposure to these pollutants are through the respiratory tract, skin, and oral ingestion. When ingested orally, they will encounter trillions of microorganisms that live in a community - the gut microbiota (GM). While pollutants can disrupt the GM balance, GM plays an essential role in the metabolism and bioavailability of these chemical compounds. Under physiological conditions, strategies used by the GM for metabolism and/or excretion of xenobiotics include reductive and hydrolytic transformations, lyase and functional group transfer reactions, and enzyme-mediated functional transformations. Simultaneously, the host performs metabolic processes based mainly on conjugation, oxidation, and hydrolysis reactions. Thus, due to the broad variety of bacterial enzymes present in GM, the repertoire of microbial transformations of chemicals is considered a key component of the machinery involved in the metabolism of pollutants in humans and other mammals. Among pollutants, metals deserve special attention once contamination by metals is a worldwide problem, and their adverse effects can be observed even at very low concentrations due to their toxic properties. In this review, bidirectional interaction between lead, arsenic, cadmium, and mercury and the host organism and its GM will be discussed given the most recent literature, presenting an analysis of the ability of GM to alter the host organism's susceptibility to the toxic effects of heavy metals, as well as evaluating the extent to which interventions targeting the microbiota could be potential initiatives to mitigate the adverse effects resulting from poisoning by heavy metals. This study is the first to highlight the overlap between some of the bacteria found to be altered by metal exposure and the bacteria that also aid the host organism in the metabolism of these metals. This could be a key factor to determine the beneficial species able to minimize the toxicity of metals in future therapeutic approaches.

Selenium attenuated food borne cadmium-induced intestinal inflammation in red swamp crayfish (Procambarus clarkii) via regulating PI3K/Akt/NF-κB pathway

Selenium (Se), an indispensable micronutrient for living organisms, has been extensively studied for its heavy metal-detoxifying properties in diverse biological systems and tissues. Nevertheless, it is not entirely certain whether Se can effectively protect against Cadmium (Cd)-induced gut inflammation, especially in aquatic animals. In this study, we employed various approaches, including transcriptome profiling, histological examinations, assessment of antioxidant enzyme activities, and analysis of gut microbiota composition to investigate the effects on crayfish growth and intestinal health after exposure to dietary Cd (15 mg kg-1 diet) and Se (15 mg kg-1 diet) individually or in combination for 8 weeks. The results revealed that dietary Cd exposure resulted in reduced body weight and survival rates, along with an increased occurrence of intestinal inflammation. Nevertheless, Se supplementation proved effective in mitigating the adverse effects of Cd on growth and gut health. Se exhibited a remarkable ability to counteract the disruption of gut antioxidant abilities induced by dietary Cd, as evidenced by the observed increases in ROS and MDA contents, decrease in GSH levels, and inhibition of antioxidative enzyme activities. At the concentration of 6 mg kg-1 in the diet, Se was found beneficial for maintaining gut microbiota richness and diversity. Among them, Flavobacterium, Thermomonas, and Chloronema displayed a weak negative correlation with the rate of gut inflammation. Meanwhile, the levels of short chain fatty acids (SCFAs), including acetic acid (AA) and butanoic acid (BA), showed a significant increase in the Se-Cd group compared to the Cd-only group. Furthermore, transcriptome analysis exhibited significant responses of the PI3K/Akt and NF-κB pathways following crayfish exposure to dietary Se and Cd, either separately or in combination. In short, this study provides a new evidence regarding the molecular mechanisms through which Se could regulate the PI3K/Akt and NF-κB pathways, either directly or indirectly via ROS and SCFAs, thereby alleviating Cd-induced gut inflammation in crayfish.

Cadmium exposure exacerbates immunological abnormalities in a BTBR T+ Itpr3tf/J autistic mouse model by upregulating inflammatory mediators in CD45R-expressing cells

Autism spectrum disorder (ASD) is a neurodevelopmental illness characterized by behavior, learning, communication, and social interaction abnormalities in various situations. Individuals with impairments usually exhibit restricted and repetitive actions. The actual cause of ASD is yet unknown. It is believed, however, that a mix of genetic and environmental factors may play a role in its development. Certain metals have been linked to the development of neurological diseases, and the prevalence of ASD has shown a positive association with industrialization. Cadmium chloride (Cd) is a neurotoxic chemical linked to cognitive impairment, tremors, and neurodegenerative diseases. The BTBR T+ Itpr3tf/J (BTBR) inbred mice are generally used as a model for ASD and display a range of autistic phenotypes. We looked at how Cd exposure affected the signaling of inflammatory mediators in CD45R-expressing cells in the BTBR mouse model of ASD. In this study, we looked at how Cd affected the expression of numerous markers in the spleen, including IFN-γ, IL-6, NF-κB p65, GM-CSF, iNOS, MCP-1, and Notch1. Furthermore, we investigated the effect of Cd exposure on the expression levels of numerous mRNA molecules in brain tissue, including IFN-γ, IL-6, NF-κB p65, GM-CSF, iNOS, MCP-1, and Notch1. The RT-PCR technique was used for this analysis. Cd exposure increased the number of CD45R+IFN-γ+, CD45R+IL-6+, CD45R+NF-κB p65+, CD45R+GM-CSF+, CD45R+GM-CSF+, CD45R+iNOS+, and CD45R+Notch1+ cells in the spleen of BTBR mice. Cd treatment also enhanced mRNA expression in brain tissue for IFN-γ, IL-6, NF-κB, GM-CSF, iNOS, MCP-1, and Notch1. In general, Cd increases the signaling of inflammatory mediators in BTBR mice. This study is the first to show that Cd exposure causes immune function dysregulation in the BTBR ASD mouse model. As a result, our study supports the role of Cd exposure in the development of ASD.

Protective potential of thymoquinone against cadmium, arsenic, and lead toxicity: A short review with emphasis on oxidative pathways

Heavy metals are among the most important environmental pollutions used in various industries. Their extensive use has increased human susceptibility to different chronic diseases. Toxic metal exposure, especially cadmium, arsenic, and lead, causes oxidative damages, mitochondrial dysfunction, and genetic and epigenetic modifications. Meanwhile, thymoquinone (TQ) is an effective component of Nigella sativa oil that plays an important role in preventing the destructive effects of heavy metals. The present review discusses how TQ can protect various tissues against oxidative damage of heavy metals. This review is based on the research reported about the protective effects of TQ in the toxicity of heavy metals, approximately the last 10 years (2010-2021). Scientific databases, including Scopus, Web of Science, and PubMed, were searched using the following keywords either alone or in combination: cadmium, arsenic, lead, TQ, and oxidative stress. TQ, as a potent antioxidant, can distribute to cellular compartments and prevent oxidative damage of toxic metals. However, depending on the type of toxic metal and the carrier system used to release TQ in biological systems, its therapeutic dosage range may be varied.

Environmental pollution and nutritional quality modulate immune response of the wood mouse (Apodemus sylvaticus) through hormonal disturbances

Cadmium (Cd) and lead (Pb) are known to enhance immune cell damages and to decrease cellular immunity, promoting higher susceptibility to infectious diseases. Selenium (Se) is an essential element involved in immunity and reactive oxygen species scavenging. This study aimed at evaluating how Cd and Pb and low nutritional (Se) quality modulate immune response to a bacterial lipopolysaccharide (LPS) challenge in wood mice (Apodemus sylvaticus). Mice were trapped near a former smelter in northern France in sites of High or Low contamination. Individuals were challenged immediately after capture or after five days of captivity, fed a standard or a Se-deficient diet. Immune response was measured with leukocyte count and plasma concentration of TNF-α, a pro-inflammatory cytokine. Faecal and plasma corticosterone (CORT), a stress-hormone involved in anti-inflammatory processes, was measured to assess potential endocrine mechanisms. Higher hepatic Se and lower faecal CORT were measured in free-ranging wood mice from High site. LPS-challenged individuals from High site showed steeper decrease of circulating leukocytes of all types, higher TNF-α concentrations, and a significant increase of CORT, compared to individuals from Low site. Challenged captive animals fed standard food exhibited similar patterns (decrease of leukocytes, increase of CORT, and detectable levels of TNF-α), with individuals from lowly contaminated site having higher immune responses than their counterparts from highly polluted site. Animals fed Se-deficient food exhibited lymphocytes decrease, no CORT variation, and average levels of TNF-α. These results suggest (i) a higher inflammatory response to immune challenge in free-ranging animals highly exposed to Cd and Pb, (ii) a faster recovery of inflammatory response in animals lowly exposed to pollution when fed standard food than more exposed individuals, and (iii) a functional role of Se in the inflammatory response. The role of Se and mechanisms underlying the relationship between glucocorticoid and cytokine remain to be elucidated.

Review of cadmium toxicity effects on fish: Oxidative stress and immune responses

Cadmium (Cd) in aquatic environments can cause environmental toxicity to fish and induce oxidative stress owing to an excessive production of reactive oxygen species in fish bodies. Fish have developed various antioxidant systems to protect themselves from reactive oxygen species; thus, a change in antioxidant responses in fish can be a criterion for evaluating oxidative stress resulting from Cd exposure. Because Cd exposure may be recognized as an exogenous substance by a fish body, it may lead to the stimulation or suppression of its immune system. Various immune responses can be assessed to evaluate Cd toxicity in fish. This review aimed to identify the impacts of Cd exposure on oxidative stress and immunotoxicity in fish as well as identify accurate indicators of Cd toxicity in aquatic ecosystems.

Pomegranate peel extract, N-Acetylcysteine and their combination with Ornipural alleviate Cadmium-induced toxicity in rats

Cadmium is a major environmental pollutant and a highly toxic metal. It was aimed to determine the effects of pomegranate peel extract (PPE), N-acetylcysteine (NAC) alone and along with Ornipural on cadmium-induced toxicity. Forty-six Wistar Albino male rats were divided into 6 groups and the groups were formed into healthy control, Cadmium group (5 mg/kg/day, oral), Cadmium + Pomegranate peel extract (500 mg/kg, oral), Cadmium + N-acetylcysteine (100 mg/kg, oral), Cadmium + Pomegranate peel extract (500 mg/kg, oral) + Ornipural (1 mL/kg, subcutaneous) and Cadmium + N-acetylcysteine (100 mg/kg, oral) + Ornipural (1 mL/kg, subcutaneous). Cadmium accumulated heavily in both liver and kidney tissue. The administration of N-acetylcysteine and pomegranate peel extract alone reduced cadmium levels in both tissues. N-acetylcysteine treatment prevented the increase in ALT and MDA levels by cadmium damage. N-acetylcysteine + Ornipural treatment inhibited the increase in liver 8-OHdG level in the liver. N-acetylcysteine and N-acetylcysteine + Ornipural treatments prevented the reduced serum MMP2 level. N-acetylcysteine and Pomegranate peel extract + Ornipural treatments significantly reduced the increased liver iNOS level in the liver. In conclusion, NAC therapy may be a successful treatment option for cadmium toxicity. However, further research is needed on the effects of PPE and Ornipural combinations for the treatment of cadmium toxicity. In future studies, various doses of these treatment options (with chelators) should be investigated for cadmium toxicity.

Metabolomics: a promising tool for deciphering metabolic impairment in heavy metal toxicities

Heavy metals are the metal compounds found in earth's crust and have densities higher than that of water. Common heavy metals include the lead, arsenic, mercury, cadmium, copper, manganese, chromium, nickel, and aluminum. Their environmental levels are consistently rising above the permissible limits and they are highly toxic as enter living systems via inhalation, ingestion, or inoculation. Prolonged exposures cause the disruption of metabolism, altered gene and/or protein expression, and dysregulated metabolite profiles. Metabolomics is a state of the art analytical tool widely used for pathomolecular inv22estigations, biomarkers, drug discovery and validation of biotransformation pathways in the fields of biomedicine, nutrition, agriculture, and industry. Here, we overview studies using metabolomics as a dynamic tool to decipher the mechanisms of metabolic impairment related to heavy metal toxicities caused by the environmental or experimental exposures in different living systems. These investigations highlight the key role of metabolomics in identifying perturbations in pathways of lipid and amino acid metabolism, with a critical role of oxidative stress in metabolic impairment. We present the conclusions with future perspectives on metabolomics applications in meeting emerging needs.

Asperuloside attenuates cadmium-induced toxicity by inhibiting oxidative stress, inflammation, fibrosis and apoptosis in rats

This present study investigated the protective effects of asperuloside (ASP) against cadmium-induced nephrocardiac toxicity. Rats were treated with 50 mg/kg of ASP for five weeks and CdCl2 (5 mg/kg, p.o., once daily) during the last 4 weeks of ASP treatment. The serum levels of blood urea nitrogen (BUN), creatinine (Scr), aspartate transaminase (AST), creatine kinase-MB (CK-MB), troponin T (TnT) and lactate dehydrogenase (LDH) were evealuted. Oxido-inflammatory parameters were detected via malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-1beta (IL-1β) and nuclear factor kappa B (NF-κB). Additionally, the cardiorenal levels of caspase 3, transforming growth factor-β (TGF-β), α-smooth muscle actin (α-SMA), collagen IV and Bcl2 were measured by ELISA or immunohistochemical assays. The results indicated that ASP significantly decreased Cd-instigated oxidative stress, serum BUN, Scr, AST, CK-MB, TnT and LDH as well as histopathological alterations. Furthermore, ASP notably attenuated Cd-induced cardiorenal and apoptosis and fibrosis by reducing caspase 3 and TGF-β levels, as well as reducing the stain intensity of a-SMA and collagen IV, while increasing Bcl2 intensity. These results revealed that ASP attenuated Cd induced cardiac and renal toxicity which may be attributed to reducing oxidative stress, inflammation, fibrosis and apoptosis.

Polystyrene exacerbates cadmium-induced mitochondrial damage to lung by blocking autophagy in mice

Cadmium (Cd) is an environmental heavy metal, and its accumulation is harmful to animal and human health. The cytotoxicity of Cd includes oxidative stress, apoptosis, and mitochondrial histopathological changes. Furthermore, polystyrene (PS) is a kind of microplastic piece derived from biotic and abiotic weathering courses, and has toxicity in various aspects. However, the potential mechanism of action of Cd co-treated with PS is still poorly unclear. The objective of this study was to investigate the effects of PS on Cd-induced histopathological injury of mitochondria in the lung of mice. In this study, the results have showed that Cd could induce the activity of oxidative enzymes of the lung cells in mice, increasing the content of partial microelement and the phosphorylation of inflammatory factor NF-κB p65. Cd further destroys the integrity of mitochondria by increasing the expression of apoptotic protein and blocking the autophagy. In addition, PS solely group aggravated the lung damage in mice, especially mitochondrial toxicity, and played a synergistic effect with Cd in lung injury. However, how PS can augment mitochondrial damage and synergism with Cd in lung of mice requiring further exploration. Therefore, PS was able to exacerbate Cd-induced mitochondrial damage to the lung in mice by blocking autophagy, and was associated with the apoptosis.

Quantum dots are time bomb: Multiscale toxicological study

The use of quantum dots has spread widely into many applications. Works on the study of quantum dots on living organisms have had conflicting results on toxicity. There are no full-scale long-term toxicological studies with multiple administration of quantum dots. Understanding the toxicity of quantum dots is still limited. Here we present data on the effects of quantum dots on animals. In this work for the first time, it is shown that at a single administration of quantum dots in the body they have moderate species-specific toxicity, but repeated administration of quantum dots for 14 days even in the amount of 0.5 mg/kg leads to a delayed not completely irreversible hematotoxic effect, delayed irreversible disorders of barrier function of the liver, irreversible nephrotoxic effect, and to pathological changes in the thymus, kidneys and spleen. Administration of quantum dots in the amount of 2.5 mg/kg for 14 days leads to irreversible changes in the lungs, liver, spleen, kidneys and thyroid gland. This phenomenon is based on immunological reactions. On the one hand, these data confirm that quantum dots at a single administration can show relatively low toxicity. On the other hand, they cause to a delayed irreversible organ and tissue damage when repeatedly administered to the body even in small quantities. This study demonstrates that quantum dots are not as low in toxicity as previously thought to be and pose a serious risk when entering living organisms. Detecting and treating poisoning using standard methods of diagnosis and treatment of heavy metal poisoning may not be effective. This study demonstrates that toxic effects of quantum dots on a living body are quite complex and cannot be generalized based on previously reported assumptions.

A Mixture of Multi-Strain Probiotics (Lactobacillus Rhamnosus, Lactobacillus Helveticus, and Lactobacillus Casei) had Anti-Inflammatory, Anti-Apoptotic, and Anti-Oxidative Effects in Oxidative Injuries Induced By Cadmium in Small Intestine and Lung

INTRODUCTION

Cadmium (Cd) produces severe oxidative stress, which can result in serious clinical consequences and tissue injury. The aim of the present survey was to investigate the protective effects of native Iranian probiotics (Lactobacillus rhamnosus, L. helveticus, and L. casei) against cadmium (Cd)-induced toxicity against the small intestine and lung at histopathological and biochemical levels.

MATERIALS AND METHODS

Twenty-one adult male Wistar rats were randomized into three groups of seven rats (control, Cd-treated (3 mg/kg), and concomitant Cd and mix probiotic treatment for 30 days). Histological alterations were appraised via hematoxylin & eosin, Trichrome Masson, and PAS staining. The qRT-PCR technique was applied to assess the expression of pro-apoptotic, anti-apoptotic, and pro-inflammatory genes. Antioxidant enzymes activity was measured via ZellBio kits.

RESULTS

Probiotic-treated rats displayed low production of lipid peroxides, reduced malondialdehyde (MDA) level, and elevated contents of superoxide dismutase (SOD) and catalase (CAT) enzymes compared with Cd-treated rats. The results of qRT-PCR demonstrated the up-regulation of Bax, p53, and caspase 3 and down-regulation of Bcl2, TNF-α, and IL-6 genes in both the intestine and lungs of mix probiotic-treated rats compared with Cd-treated animals. Histopathological findings revealed that the probiotic formulation improved Cd-triggered tissue damage in the intestine and lungs.

CONCLUSION

The strong cytoprotective benefits of Iranian probiotics against Cd-induced tissue injury observed in this study may be due to their anti-inflammatory and antioxidant properties. Therefore, additional clinical and experimental research is required to explain the precise mechanisms of probiotics' beneficial impacts and underline their potential therapeutic use.

Adaptive plastic responses to metal contamination in a multistress context: a field experiment in fish

Wild populations often differ in their tolerance to environmental stressors, but intraspecific variability is rarely taken into account in ecotoxicology. In addition, plastic responses to multiple stressors have rarely been investigated in realistic field conditions. In this study, we compared the responses to metal contamination of gudgeon populations (Gobio occitaniae) differing in their past chronic exposure to metal contamination, using a reciprocal transplant experiment and an immune challenge mimicking a parasite attack to test for potential effects of multiple stressors across biological levels. We measured fish survival and traits involved in metal bioaccumulation, oxidative stress, immunity, cell apoptosis, and energy management to decipher underpinning physiological mechanisms across biological levels (i.e., gene expression, cell, organism). Fish from the two replicate High Contamination sites had higher survival when transferred into contaminated sites, suggesting a local adaptation to the contaminated site, possibly explained by higher levels of detoxification and antioxidant capacity but with potential higher apoptosis costs compared to their naïve counterparts. We found no evidence of co- or maladaptation to the immune stressor, suggesting no specific costs to face pathogens. In the emerging field of evolutionary ecotoxicology, this study underlines the need to consider intraspecific variability to better understand the effects of pollution in heterogeneous populations.

Pancreas-Liver-Adipose Axis: Target of Environmental Cadmium Exposure Linked to Metabolic Diseases

Cadmium has been well recognized as a critical toxic agent in acute and chronic poisoning cases in occupational and nonoccupational settings and environmental exposure situations. Cadmium is released into the environment after natural and anthropogenic activities, particularly in contaminated and industrial areas, causing food pollution. In the body, cadmium has no biological activity, but it accumulates primarily in the liver and kidney, which are considered the main targets of its toxicity, through oxidative stress and inflammation. However, in the last few years, this metal has been linked to metabolic diseases. The pancreas-liver-adipose axis is largely affected by cadmium accumulation. Therefore, this review aims to collect bibliographic information that establishes the basis for understanding the molecular and cellular mechanisms linked to cadmium with carbohydrate, lipids, and endocrine impairments that contribute to developing insulin resistance, metabolic syndrome, prediabetes, and diabetes.

The protective mechanism of a novel polysaccharide from Lactobacillus-fermented Nostoc commune Vauch. on attenuating cadmium-induced kidney injury in mice

A novel polysaccharide (NCVP-F) from Lactobacillus-fermented Nostoc commune Vauch. was obtained to investigate its underlying mechanism in cadmium-induced kidney injury. Results indicated that in comparison with NCVP, NCVP-F with lower molecular weight of 365.369 kDa, exhibited higher mole percentage of Man and Glc-UA, whereas slightly lower mole percentage of other monosaccharides. NCVP-F is a α-pyran polysaccharide similar to NCVP. Meanwhile, NCVP-F can more effectively alleviate hepatorenal injury (ALT, AST, TG, BUN and SCr) and kidney tissue lesions in Cd-injured mice model by increasing antioxidant enzyme activity (SOD, GSH and GSH-Px), inhibiting cytokines levels (IL-6, IL-1β, TNF-α and IL-18). In addition, NCVP-F effectively inhibited apoptosis proteins (Bax, cytochrome c, a-caspase-9 and a-caspase-3) and enhanced anti-apoptotic protein (Bcl-2) probably via activating PI3K/AKT/mTOR pathway in the Cd-injury kidney. Furthermore, 16S rRNA sequencing results indicated that NCVP-F better enriched Lachnospiraceae, reduced Muribaculaceae, Alloprevotella and Blautia to regulate Cd-induced gut microbiota disorders, which was probably down-regulated 7 pathways including apoptosis and lipopolysaccharide biosynthesis, and up-regulated 63 pathways, such as carbohydrate metabolism and lipid metabolism. This study suggested that applying functional NCVP-F prepared by biotransformation with low molecular weight might be more beneficial.

The Impact of Long-Term Clinoptilolite Administration on the Concentration Profile of Metals in Rodent Organisms

Heavy metals are dangerous systemic toxicants that can induce multiple organ damage, primarily by inducing oxidative stress and mitochondrial damage. Clinoptilolite is a highly porous natural mineral with a magnificent capacity to eliminate metals from living organisms, mainly by ion-exchange and adsorption, thus providing detoxifying, antioxidant and anti-inflammatory medicinal effects. The in vivo efficiency and safety of the oral administration of clinoptilolite in its activated forms, tribomechanically activated zeolite (TMAZ) and Panaceo-Micro-Activated (PMA) zeolite, as well as the impact on the metallic biodistribution, was examined in healthy female rats. Concentration profiles of Al, As, Cd, Co, Pb, Ni and Sr were measured in rat blood, serum, femur, liver, kidney, small and large intestine, and brain using inductively coupled plasma mass spectrometry (ICP-MS) after a 12-week administration period. Our results point to a beneficial effect of clinoptilolite materials on the concentration profile of metals in female rats supplemented with the corresponding natural clinoptilolite materials, TMAZ and PMA zeolite. The observed decrease of measured toxicants in the kidney, femur, and small and large intestine after three months of oral intake occurred concomitantly with their most likely transient release into the bloodstream (serum) indicative of a detoxification process.

Zinc oxide nanoparticles mediated biostimulant impact on cadmium detoxification and in silico analysis of zinc oxide-cadmium networks in Zea mays L. regulome

Cadmium (Cd) toxicity can significantly limit plant growth and development. To eliminate the toxic effects of Cd stress, we intended to evaluate the biochemical mediated physiological responses in maize treated with biostimulant and zinc oxide nanoparticles (ZnPs). In silico analysis exhibited that the maize treated with Cd stress (200 μM) had an adverse impact on CAT1, CAT2, CAT3 and gor1 proteins, which are influential in managing the machinery of redox homeostasis. While maize inoculated with bacteria-based biostimulant and ZnPs (10 ppm) showed prominently improved biomass, chlorophyll a, b and carotenoid content. We found a significant increase in the total sugar, protein, proline content and antioxidants under the effect of Cd stress. However, these parameters are further enhanced by applying biostimulants and ZnPs. Declined lipid peroxidation and membrane solubilization index under the effect of biostimulant and ZnPs was observed. Furthermore, these treatments improved maize's zinc, copper, sodium, magnesium, iron, potassium and calcium content. Based on these results, an antagonistic relationship between Zn and Cd uptake that triggered efficient Cd detoxification in maize shoot was found. Scanning electron micrography showed distorted leaf structure of the Cd stressed plants while the biostimulant and ZnPs reduced the structural cell damage of maize leaves. In silico study showed that ZnO positively regulates all protein interactors, including GRMZM2G317386_P01 (Metallo endo proteinase 1-MMP), GRMZM2G110220_P01 (Metallo endo proteinase 5-MMP), GRMZM2G103055_P01 (Alpha-amylase) and GRMZM2G006069_P01 (Zn-dependent exo peptidase superfamily) proteins which are involved in energy generating processes, channels formation, matrix re-localization and stress response. This suggests that ZnO offers an ideal role with protein interactors in maize. Our findings depict that these treatments, i.e., biostimulant and ZnPs alone, are efficient enough to exhibit Cd remediation potential in maize; however, their combination showed synergistic effects.

Plasma microRNA expression and immunoregulatory cytokines in an Indian population occupationally exposed to cadmium

Following its accumulation in the body, cadmium (Cd) exposure is associated with devastating effects on multiple organ system of the human body. The immune system is one of the sensitive targets for Cd-induced toxicity. Recently, studies have demonstrated a significant role of Cd in inducing epigenetic alterations. With this background, the present study was planned to study the changes in candidate microRNA (miRNA) expression associated with immune regulation in occupationally Cd-exposed workers. One hundred individuals involved in welding and metal handicraft manufacturing, while 80 apparently healthy subjects without any prior history of occupational exposure were recruited for the study. Blood Cd level was determined by atomic absorption spectrometry. Serum cytokine levels were measured using an enzyme-linked immunosorbent assay and serum miRNA expression of candidate miRNAs (miR-146a, miR-210, and miR-222) were determined by real-time polymerase chain reaction. The median Cd level (2.40 μg/L) in the occupationally exposed workers was significantly higher than the nonexposed subjects (0.90 μg/L). Among the cytokines, interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-α) were significantly higher while IL-2 and IL-10 were significantly lower in the exposed. The expression level of miR-146a and miR-222 were significantly different between the groups with the former showing downregulation and later showing upregulation. Correlation analysis revealed a positive and negative association of miR-222 and miR-146a with blood cadmium level, IL-17 as well as TNF-α, respectively. Furthermore, the in-silico analysis revealed a significant role of the studied miRNAs in various cellular and genetic pathways. The findings of the present study demonstrate significant involvement of Cd-induced alteration in miRNAs in varied immune regulatory changes in exposed individuals.

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

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

ROS and ERK Pathway Mechanistic Approach on Hepatic Insulin Resistance After Chronic Oral Exposure to Cadmium NOAEL Dose

Cadmium is a critical toxic agent in occupational and non-occupational settings and acute and chronic environmental exposure situations that have recently been associated with metabolic disease development. Until now, the no observed adverse effect level (NOAEL) of cadmium has not been studied regarding insulin resistance development. Therefore, we aimed to monitor whether chronic oral exposure to cadmium NOAEL dose induces insulin resistance in Wistar rats and investigate if oxidative stress and/or inflammation are related. Male Wistar rats were separated into control (standard normocalorie diet + water free of cadmium) and cadmium groups (standard normocalorie diet + drinking water with 15 ppm CdCl₂). At 15, 30, and 60 days, oral glucose tolerance, insulin response, and insulin resistance were analyzed using mathematical models. In the liver glycogen, triglyceride, pro- and anti-inflammatory cytokines, cadmium, zinc, metallothioneins, and redox balance were quantified. Immunoreactivity analysis of proteins involved in metabolic and mitogenic insulin signaling was performed. The results showed that a cadmium NOAEL dose after 15 days of exposure causes ROS and mitogenic arm of insulin signaling to increase while hepatic glycogen diminishes. At 30 days, Cd accumulation accentuated ROS production, hepatic triglyceride overaccumulation, and mitogenic signals that develop insulin resistance. Finally, inflammation and lipid peroxidation appear after 60 days of Cd exposure, while lipids and carbohydrate homeostasis deteriorate. In conclusion, environmental exposure to cadmium NAOEL dose causes hepatic Cd accumulation and ROS overproduction that chronically declines the antioxidant defense, deteriorates metabolic homeostasis associated with the mitogenic pathway of insulin signaling, and induces insulin resistance.

Antagonism of cadmium-induced liver injury in ducks by α-bisabolol

Cadmium (Cd) is an ecological pollutant which causes hazardous effects in animals and humans. The aim of this study was to investigate the role of α-bisabolol (BISA) in antagonizing the Cd-induced hepatotoxicity in ducks. Two-week old ducks were allocated into 8 groups (10 ducks/group): Group I received basal diet and was gavaged with sunflower oil (BISA vehicle, 1.1 mL/kg/day); group II was administered BISA orally (50 mg/kg/day; diluted with sunflower oil); groups III, IV, and V were fed the basal diet mixed with CdCl2 at 37.5, 75, and 150 mg/kg diet, respectively, and were gavaged with sunflower oil; group VI, VII, and VIII were given basal diet containing CdCl2 at the aforementioned consecutive doses plus BISA. All treatments were provided daily for 4 weeks. Exposure to CdCl2 induced mortality in ducks, increased hepatic Cd content and serum levels of hepatopathic biomarkers, and caused oxidative stress and morphological alterations in ducks' liver. Furthermore, exposure to Cd caused upregulation of the mRNA of proinflammatory cytokine tumor necrosis factor-α and apoptotic gene Bax, and that of cyclooxygenase-2 protein in the liver. All effects of Cd were dose-dependent. BISA antagonized all of the aforementioned CdCl2-induced changes. These findings suggested that BISA exert the hepatoprotective effect against Cd toxicity through reducing the hepatic content of Cd as well as antagonizing oxidative insults, inflammation, and apoptosis. Thus, BISA has a great potential to be used as an antidote in the control of Cd poisoning.

Oral Subacute Exposure to Cadmium LOAEL Dose Induces Insulin Resistance and Impairment of the Hormonal and Metabolic Liver-Adipose Axis in Wistar Rats

Cadmium is a nonessential transition metal considered one of the more hazardous environmental contaminants. The population is chronically exposed to this metal at low concentrations, designated as the LOAEL (lowest observable adverse effect level) dose. We aimed to investigate whether oral subacute exposure to cadmium LOAEL disrupts hormonal and metabolic effects of the liver-adipose axis in Wistar rats. Fifty male Wistar rats were separated into two groups: control (standard normocalorie diet + water free of cadmium) and cadmium (standard normocalorie diet + drinking water with 32.5 ppm CdCl₂). After 1 month, zoometry, a serum lipid panel, adipokines, and proinflammatory cytokines were evaluated. Tests of glucose and insulin tolerance (ITT) and insulin resistance were performed. Histological studies on structure, triglyceride distribution, and protein expression of the insulin pathway were performed in the liver and retroperitoneal adipose tissue. In both tissues, the cadmium, triglyceride, glycogen, and proinflammatory cytokine contents were also quantified. The cadmium group developed dyslipidemia, glucose intolerance, hyperinsulinemia, hyperleptinemia, inflammation, and selective insulin resistance in the liver and adipose tissue. In the liver, glycogen synthesis was diminished, while de novo lipogenesis increased, which was associated with low GSK3β-pS9 and strong expression of SREBP-1c. Dysfunctional adipose tissue was observed with hypertrophy and lipolysis, without changes in SREBP-1c expression and low glycogen synthesis. Both tissues accumulated cadmium and developed inflammation. In conclusion, oral subacute cadmium LOAEL dose exposure induces inflammation, insulin signaling modifications, an early insulin resistance stage (insensibility), and impairment of the hormonal and metabolic liver-adipose axis in Wistar rats.

Association between lung function impairment with urinary heavy metals in a community in Klang Valley, Malaysia

Lung function status can be directly or indirectly affected by exposure to pollutants in the environment. Urinary heavy metals may be an indirect indicator of lung function impairment that leads to various diseases such as chronic obstructive pulmonary disease (COPD). This study aimed to explore the prevalence of lung function impairment as well as its association with urinary heavy metal levels and other influencing factors among the community in Klang Valley, Malaysia. Urinary sampling was done during various community events in the housing areas of Klang Valley between March and October 2019. Only respondents who consented would undergo a lung function test. Urine samples were obtained and sent for Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis for heavy metal cadmium (Cd) and lead (Pb) concentration. Of the 200 recruited respondents, 52% were male and their ages ranged from 18 years old to 74 years old with a mean age of 38.4 ± 14.05 years. Urinary samples show high urinary Cd level in 12% of the respondents (n = 24) whereas none recorded a high urinary Pb level. There was a positive correlation between the levels of urinary Cd and urinary Pb (r = 0.303; p = 0.001). Furthermore, a negative correlation was detected between urinary Cd level and forced vital capacity (FVC) (r =  - 0.202, p = 0.004), force expiratory volume at the first second (FEV1) (r =  - 0.225, p = 0.001), and also force expiratory flow between 25-75% of FVC (FEF 25-75%) (r =  - 0.187, p = 0.008). However, urinary Pb did not show any correlation with lung function parameters. Multiple linear regression analysis showed that urinary Cd had a significant negative effect on FVC (p = 0.025) and FEV1 (p = 0.004) based on the predicted value. Additionally, other factors such as education level (p = 0.013) also influenced lung function. However, no interaction was detected between heavy metals or other factors. In short, there was a significant negative linear relationship between urinary Cd and lung function, whereas urinary Pb was not associated with lung function. Beside acting as a biomarker for cadmium exposure level, urinary Cd may also be applied as indirect biomarker for asymptomatic chronic lung function deterioration among the healthy population.

Cadmium mediates pyroptosis of human dermal lymphatic endothelial cells in a NLRP3 inflammasome-dependent manner

Pyroptosis is a form of inflammasome-trigged programmed cell death in response to a variety of stimulators, including environmental cytotoxic pollutant Cadmium (Cd). Vascular endothelial cell is one of the first-line cell types of Cd cell toxicity. Studies report that Cd exposure causes pyroptosis in vascular endothelial cells. Vascular and lymphatic endothelial cells have many common properties, but these two cell types are distinguished in gene expression profile and the responsive behaviors to chemokine or physical stimulations. Whether Cd exposure also causes pyroptosis in lymphatic endothelial cells has not been investigated. Here, we found that Cd treatment significantly decreased the viability of human dermal lymphatic endothelial cells (HDLECs). Cd treatment induced inflammasome activation indicated by elevated cleavage of pro-caspase-1 into active form Casp1p20, elevated secretion of pro-inflammatory cytokines and production of reactive oxygen species (ROS). Flow cytometry showed that caspase-1 activity was significantly increased in Cd-treated cells. Moreover, knockdown of NLRP3 effectively rescued Cd-induced inflammasome activation and pyroptosis in HDLECs. Collectively, our results indicated that Cd induced pyroptosis in a NLRP3 inflammasome-dependent manner in lymphatic endothelial cells.