Molecular and cellular mechanisms of cadmium carcinogenesis

Adsorptive Removal of Cd(II) Ions from Water by a Cheap Lignocellulosic Adsorbent and Its Reuse as a Catalyst for the Decontamination of Sulfamethoxazole

The work reports the removal of cadmium from water by applying an efficient low-cost lignocellulosic adsorbent, rooibos tea waste. The cadmium-loaded rooibos tea waste was used for the photocatalytic abatement of sulfamethoxazole to cater to the setback of secondary pollution mostly associated with the adsorption technique. The rooibos tea waste adsorbent displayed a high removal efficiency of about 90.63% for 10 mg/L Cd(II) ions at 45 °C, 180 min agitation time, pH 7, and a dosage of 500 mg. The process of Cd(II) adsorption was endothermic and spontaneous. Also, the spent adsorbent was found to be efficient toward the photocatalytic breakdown of 10 mg/L sulfamethoxazole with a degradation efficiency of 69% after 150 min. In addition, the extent of mineralization of the sulfamethoxazole by the spent adsorbent as obtained from the total organic carbon data was found to be 53%. Therefore, based on the results obtained from this work, rooibos tea waste lends itself as a cheap, eco-friendly, easily sourced, and viable adsorbent for the removal of toxic ions like Cd(II). Also, the successful reuse of the spent adsorbent is a promising approach to cater to the major setback of secondary pollution associated with adsorption technology.

Removal and assessment of cadmium contamination based on the toxic responds of a soil ciliate Colpoda sp

Bioremediation of cadmium (Cd) pollution, a recognized low-carbon green environmental protection technology, is significantly enhanced by the discovery of Cd-tolerant microorganisms and their underlying tolerance mechanisms. This study presents Colpoda sp., a soil ciliate with widespread distribution, as a novel bioindicator and bioremediator for Cd contamination. With a 24 h-LC50 of 5.39 mg l-1 and an IC50 of 24.85 μg l-1 in Cd-contaminated water, Colpoda sp. achieves a maximum bioaccumulation factor (BAF) of 3.58 and a Cd removal rate of 32.98 ± 0.74 % within 96 h. The toxic responses of Colpoda sp. to Cd stress were assessed through cytological observation with transmission electron microscopy (TEM), oxidative stress kinase activity, and analysis of Cd-metallothionein (Cd-MTs) and the cd-mt gene via qRT-PCR. The integrated biomarker response index version 2 (IBRv2) and structural equation models (SEM) were utilized to analyze key factors and mechanisms, revealing that the up-regulation of Cd-MTs and cd-mt expression, rather than the oxidative stress system, is the primary determinant of Cd accumulation and tolerance in Colpoda sp. The ciliate's ability to maintain growth under 24.85 μg l-1 Cd stress and its capacity to absorb and accumulate Cd particles from water into cells are pivotal for bioremediation. A new mathematical formula and regression equations based on Colpoda sp.'s response parameters have been established to evaluate environmental Cd removal levels and design remediation schemes for contaminated sites. These findings provide a novel bioremediation and monitoring pathway for Cd remobilization and accumulation in soil and water, potentially revolutionizing the governance of Cd pollution.

Is Cadmium Genotoxicity Due to the Induction of Redox Stress and Inflammation? A Systematic Review

The transition metal cadmium (Cd) is toxic to humans and can induce cellular redox stress and inflammation. Cd is a recognized carcinogen, but the molecular mechanisms associated with its genotoxicity and carcinogenicity are not defined. Therefore, a systematic review was undertaken to examine the scientific literature that has covered the molecular mechanism of Cd genotoxicity and its relationship to cellular redox stress and inflammation. An electronic database search of PubMed, Scopus, and the Web of Science Core Collection was conducted to retrieve the studies that had investigated if Cd genotoxicity was directly linked to the induction of redox stress and inflammation. Studies included exposure to Cd via in vitro and in vivo routes of administration. Of 214 publications retrieved, 10 met the inclusion criteria for this review. Preclinical studies indicate that Cd exposure causes the induction of reactive oxygen species (ROS) and, via concomitant activity of the transcription factor NF-κβ, induces the production of pro-inflammatory cytokines and a cytokine profile consistent with the induction of an allergic response. There is limited information regarding the impact of Cd on cellular signal transduction pathways, and the relationship of this to genotoxicity is still inconclusive. Nevertheless, pre-incubation with the antioxidants, N-acetylcysteine or sulforaphane, or the necroptosis inhibitor, necrostatin-1, reduces Cd toxicity; indicative that these agents may be a beneficial treatment adjunct in cases of Cd poisoning. Collectively, this review highlights that Cd-induced toxicity and associated tissue pathology, and ultimately the carcinogenic potential of Cd, may be driven by redox stress and inflammatory mechanisms.

Transcriptomic analysis provides insights into the molecular mechanism of melatonin-mediated cadmium tolerance in Medicago sativa L

Cadmium (Cd), a toxic element, often makes a serious threat to plant growth and development. Previous studies found that melatonin (Mel) reduced Cd accumulation and reestablished the redox balance to alleviate Cd stress in Medicago sativa L., however, the complex molecular mechanisms are still elusive. Here, comparative transcriptome analysis and biochemical experiments were conducted to explore the molecular mechanisms of Mel in enhancing Cd tolerance. Results showed that 7237 differentially expressed genes (DEGs) were regulated by Mel pretreatment to Cd stress compared to the control condition in roots of Medicago sativa L. Besides, in comparison with Cd stress alone, Mel upregulated 1081 DEGs, and downregulated 1085 DEGs. These DEGs were mainly involved in the transcription and translation of genes and folding, sorting and degradation of proteins, carbohydrate metabolism, and hormone signal network. Application of Mel regulated the expression of several genes encoding ribosomal protein and E3 ubiquitin-protein ligase involved in folding, sorting and degradation of proteins. Moreover, transcriptomic analyse suggested that Mel might regulate the expression of genes encoding pectin lyase, UDP-glucose dehydrogenase, sucrose-phosphate synthase, hexokinase-1, and protein phosphorylation in the sugar metabolism. Therefore, these could promote sucrose accumulation and subsequently alleviate the Cd damage. In conclusion, above findings provided the mining of important genes and molecular basis of Mel in mitigating Cd tolerance and genetic cultivation of Medicago sativa L.

Cadmium transport by mammalian ATP-binding cassette transporters

Cellular responses to toxic metals depend on metal accessibility to intracellular targets, reaching interaction sites, and the intracellular metal concentration, which is mainly determined by uptake pathways, binding/sequestration and efflux pathways. ATP-binding cassette (ABC) transporters are ubiquitous in the human body-usually in epithelia-and are responsible for the transfer of indispensable physiological substrates (e.g. lipids and heme), protection against potentially toxic substances, maintenance of fluid composition, and excretion of metabolic waste products. Derailed regulation and gene variants of ABC transporters culminate in a wide array of pathophysiological disease states, such as oncogenic multidrug resistance or cystic fibrosis. Cadmium (Cd) has no known physiological role in mammalians and poses a health risk due to its release into the environment as a result of industrial activities, and eventually passes into the food chain. Epithelial cells, especially within the liver, lungs, gastrointestinal tract and kidneys, are particularly susceptible to the multifaceted effects of Cd because of the plethora of uptake pathways available. Pertinent to their broad substrate spectra, ABC transporters represent a major cellular efflux pathway for Cd and Cd complexes. In this review, we summarize current knowledge concerning transport of Cd and its complexes (mainly Cd bound to glutathione) by the ABC transporters ABCB1 (P-glycoprotein, MDR1), ABCB6, ABCC1 (multidrug resistance related protein 1, MRP1), ABCC7 (cystic fibrosis transmembrane regulator, CFTR), and ABCG2 (breast cancer related protein, BCRP). Potential detoxification strategies underlying ABC transporter-mediated efflux of Cd and Cd complexes are discussed.

Metal(loid) contamination in Bangladesh: a comprehensive synthesis in different landscapes with ecological and health implications

Elevated metal(loid) concentrations in soil and foodstuffs is a significant global issue for many densely populated countries like Bangladesh, necessitating reliable estimation for sustainable management. Therefore, a comprehensive data synthesis from the published literature might help to provide a wholistic view of metal(loid) contamination in different areas in Bangladesh. This study provided a clearer view of metal(loid) contamination status and their associated ecological and health risks in different land use and ecosystems in Bangladesh. Comprehensive analyses were performed on data gathered from 143 published articles using multiple statistical techniques including meta-analysis. Considering the potential loading of metal(loid), the data were summarized under various groups, including coastal, rural, urban and industrial regions. Also, the concentrations of seven metal(loid)s, e.g., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), and arsenic (As) in soil, sediment, cereal, vegetable, fruit, surface water and groundwater were included. Results showed that the relative concentrations of metal(loid)s in comparison to the maximum permissible limit (MPL) were mostly less than one, although they varied significantly for locations and individual metal(loid). However, the normalized cumulative relative concentrations over the MPL for all seven metal(loid)s across different environmental samples were 4.75, 2.97, 1.51 and 2.79 for coastal, industrial, rural and urban areas, respectively, which was due to the higher concentration of Cd, Cr and Cu. Similar to the metal(loid) concentrations, the average of cumulative median non-cancer risks for all metal(loid)s was in the order of industrial (6.46) > urban (4.05) > rural (3.83) > coastal (2.41). This research outcome will provide a foundation for future research on metal(loid)s and will help in pertinent policy-making by the relevant authorities in Bangladesh.

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.

Fiber optic cadmium ion sensors based on functionalization of a magnetic ion-imprinted polymer

Cadmium poisoning is a chronic accumulation process, and long-term drinking of even low cadmium content water will cause kidney damage, so an ultra-low detection limit is particularly important. However, at the present stage, the traditional detection method cannot reach a sufficiently low detection limit, the response time is too long, and the cost of detection is very high, so that real-time measurement cannot be realized. Therefore, the traditional cadmium ion detection method has a slow response and an insufficient detection limit. This paper presents a fiber optic cadmium ion sensor functionalized based on an Fe3O4@SiO2@CS magnetic ion imprinting polymer (M-IIP). The sensor is based on the coupling characteristics of the optical microfiber coupler (OMC) cone region to achieve a highly sensitive response to the change in the cadmium ion concentration. M-IIP materials were prepared by surface imprinting polymerization to achieve low cross-sensitivity and thus improve the detection limit of the sensor. The results show that the developed fiber sensor has high specificity and a rapid response to cadmium ions. The experimental limit of detection (LOD) reached 0.051 nM within 0-1 μM with a response time of less than 50 s. Moreover, the proposed fiber cadmium ion sensor exhibits excellent performance in terms of sensitivity, stability, repeatability and biocompatibility.

Distinct concentration-dependent oxidative stress profiles by cadmium in a rat kidney proximal tubule cell line

Levels and chemical species of reactive oxygen/nitrogen species (ROS/RNS) determine oxidative eustress and distress. Abundance of uptake pathways and high oxygen consumption for ATP-dependent transport makes the renal proximal tubule particularly susceptible to cadmium (Cd2+)-induced oxidative stress by targeting ROS/RNS generation or antioxidant defence mechanisms, such as superoxide dismutase (SOD) or H2O2-metabolizing catalase (CAT). Though ROS/RNS are well-evidenced, the role of distinct ROS profiles in Cd2+ concentration-dependent toxicity is not clear. In renal cells, Cd2+ (10-50 µM) oxidized dihydrorhodamine 123, reaching a maximum at 2-3 h. Increases (up to fourfold) in lipid peroxidation by TBARS assay and H2O2 by Amplex Red were evident within 30 min. ROS and loss in cell viability by MTT assay with 50 µM Cd2+ could not be fully reversed by SOD mimetics Tempol and MnTBAP nor by SOD1 overexpression, whereas CAT expression and α-tocopherol were effective. SOD and CAT activities were attenuated below controls only with >6 h 50 µM Cd2+, yet augmented by up to 1.5- and 1.2-fold, respectively, by 10 µM Cd2+. Moreover, 10 µM, but not 25-50 µM Cd2+, caused 1.7-fold increase in superoxide anion (O2•-), detected by dihydroethidium, paralled by loss in cell viability, that was abolished by Tempol, MnTBAP, α-tocopherol and SOD1 or CAT overexpression. H2O2-generating NADPH oxidase 4 (NOX4) was attenuated by ~50% with 10 µM Cd2+ at 3 h compared to upregulation by 50 µM Cd2+ (~1.4-fold, 30 min), which was sustained for 24 h. In summary, O2•- predominates with low-moderate Cd2+, driving an adaptive response, whereas oxidative stress by elevated H2O2 at high Cd2+ triggers cell death signaling pathways.Highlights Different levels of reactive oxygen species are generated, depending on cadmium concentration. Superoxide anion predominates and H2O2 is suppressed with low cadmium representing oxidative eustress. High cadmium fosters H2O2 by inhibiting catalase and increasing NOX4 leading to oxidative distress. Superoxide dismutase mimetics and overexpression were less effective with high versus low cadmium. Oxidative stress profile could dictate downstream signalling pathways.

Tetramethylpyrazine Antagonizes the Subchronic Cadmium Exposure-Induced Oxidative Damage in Mouse Livers via the Nrf2/HO-1 Pathway

Hepatic oxidative stress is an important mechanism of Cd-induced hepatotoxicity, and it is ameliorated by TMP. However, this underlying mechanism remains to be elucidated. To investigate the mechanism of the protective effect of TMP on liver injuries in mice induced by subchronic cadmium exposure, 60 healthy male ICR mice were randomly divided into five groups of 12 mice each, namely, control (CON), Cd (2 mg/kg of CdCl2), Cd + 100 mg/kg of TMP, Cd + 150 mg/kg of TMP, and Cd + 200 mg/kg of TMP, and were acclimatized and fed for 7 d. The five groups of mice were gavaged for 28 consecutive days with a maximum dose of 0.2 mL/10 g/day. Except for the control group, all groups were given fluoride (35 mg/kg) by an intraperitoneal injection on the last day of the experiment. The results of this study show that compared with the Cd group, TMP attenuated CdCl2-induced pathological changes in the liver and improved the ultrastructure of liver cells, and TMP significantly decreased the MDA level (p < 0.05) and increased the levels of T-AOC, T-SOD, and GSH (p < 0.05). The results of mRNA detection show that TMP significantly increased the levels of Nrf2 in the liver compared with the Cd group as well as the HO-1 and mRNA expression levels in the liver (p < 0.05). In conclusion, TMP could inhibit oxidative stress and attenuate Cd group-induced liver injuries by activating the Nrf2 pathway.

An umbrella review of the evidence associating occupational carcinogens and cancer risk at 19 anatomical sites

Occupational exposure to carcinogens of increasing cancer risk have been extensively suggested. A robust assessment of these evidence is needed to guide public policy and health care. We aimed to classify the strength of evidence for associations of 13 occupational carcinogens (OCs) and risk of cancers. We searched PubMed and Web of Science up to November 2022 to identify potentially relevant studies. We graded the evidence into convincing, highly suggestive, suggestive, weak, or not significant according to a standardized classification based on: random-effects p value, number of cancer cases, 95% confidence interval of largest study, heterogeneity between studies, 95% prediction interval, small study effect, excess significance bias and sensitivity analyses with credibility ceilings. The quality of meta-analysis was evaluated by AMSTAR 2. Forty-eight articles yielded 79 meta-analyses were included in current umbrella review. Evidence of associations were convincing (class I) or highly suggeastive (class II) for asbestos exposure and increasing risk of lung cancer among smokers (RR = 8.79, 95%CI: 5.81-13.25 for cohort studies and OR = 8.68, 95%CI: 5.68-13.24 for case-control studies), asbestos exposure and increasing risk of mesothelioma (RR = 4.61, 95%CI: 2.57-8.26), and formaldehyde exposure and increasing risk of sinonasal cancer (RR = 1.68, 95%CI: 1.38-2.05). Fifteen associations were supported by suggestive evidence (class III). In summary, the current umbrella review found strong associations between: asbestos exposure and increasing risk of lung cancer among smokers; asbestos exposure and increasing risk of mesothelioma; and formaldehyde exposure and higher risk of sinonasal cancer. Other associations might be genuine, but substantial uncertainty remains.

Risk assessment of pesticide compounds: IPT and TCZ cause hepatotoxicity, activate stress pathway and affect the composition of intestinal flora in red swamp crayfish (Procambarusclarkii)

Isoprothiolane (IPT) and tricyclazole (TCZ) are widely used in rice farming and recently in combined rice-fish farming. However, co-cultured animals are affected by these pesticides. To investigate the organismal effects and toxicity of pesticides, crayfish were exposed to 0, 1, 10, or 100 ppt TCZ or IPT for 7 days. Pesticide bioaccumulation, survival rate, metabolic parameters, structure of intestinal flora, and antioxidant-, apoptosis-, and HSP-related gene expression were determined. Pesticide exposure caused bioaccumulation of IPT or TCZ in the hepatopancreas and muscles of crayfish; however, IPT bioaccumulation was higher than that of TCZ. Both groups showed significant changes in hepatopancreatic serum biochemical parameters. Mitochondrial damage and chromosomal agglutination were observed in hepatopancreatic cells exposed to 100 ppt IPT or TCZ. IPT induced more significant changes in serum biochemical parameters than TCZ. The results of intestinal flora showed that Vibro, Flavobacterium, Anaerorhabdus and Shewanella may have potential for use as a bacterial marker of TCZ and IPT. Antioxidant-, apoptosis-, and HSP-related gene expression was disrupted by pesticide exposure, and was more seriously affected by IPT. The results suggest that IPT or TCZ induce hepatopancreatic cell toxicity; however, IPT or TCZ content in dietary crayfish exposed to 1 ppt was below the food safety residue standard. The data indicated that IPT exposure may be more toxic than TCZ exposure in hepatopancreas and intestines and toxicity of organism are alleviated by activating the pathway of stress-response, providing an understanding of pesticide compounds in rice-fish farming and food safety.

Biotic Ligand Modeling for the Effect of Major Cations on the Uptake of Cadmium in Folsomia candida Exposed in a Sand-Solution Medium

Biotic ligand modeling (BLM) approaches are already applied to predict the bioavailability and possible risk of metals in surface water, but need further development for soils. The present study investigated the effect of major cations (Ca2+ , Mg2+ , Na+ , K+ , and H+ ) on cadmium bioaccumulation in the springtail Folsomia candida. To avoid the complexity of real soils and enable control of elemental speciation in the exposure medium, the animals were exposed to different cadmium concentrations in an inert quartz sand-solution medium. Accumulation of cadmium in the animals was measured after 7 days exposure at different cation concentrations. Among the cations, only Ca2+ significantly affected the uptake of cadmium in the springtails. Mg2+ also had higher effects compared with other selected cations. Using a BLM approach, the uptake of cadmium in the animals predicted by taking into account both Ca2+ and Mg2+ activities correlated well with the measured values (R2  = 0.68). The final estimated conditional binding constants for cadmium (log KCd-BL ), Ca (log KCa-BL ), and Mg (log KMg-BL ) of 1.06, 2.14, and 1.23 L/mol, respectively, were in agreement with previously reported values. The match between predicted and measured uptake data confirms the applicability and usefulness of the BLM for predicting the bioavailability of cadmium to springtails and opens the way for its application in soil. Environ Toxicol Chem 2024;00:1-7. © 2024 SETAC.

Toxicological Aspects Associated with Consumption from Electronic Nicotine Delivery System (ENDS): Focus on Heavy Metals Exposure and Cancer Risk

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as "liquid e-cigarettes" (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the "heated tobacco products" (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk.

Multi-endpoint analysis of cadmium chloride-induced genotoxicity shows role for reactive oxygen species and p53 activation in DNA damage induction, cell cycle irregularities, and cell size aberrations

Cadmium chloride (CdCl2) is a known genotoxic carcinogen, with a mechanism of action thought to partly involve the generation of reactive oxygen species (ROS). We applied here a multi-endpoint approach in vitro to explore the impact of CdCl2 on both the genome and on wider cell biology pathways relevant to cancer. Multi-endpoint approaches are believed to offer greater promise in terms of understanding the holistic effects of carcinogens in vitro. This richer understanding may help better classification of carcinogens as well as allowing detailed mechanisms of action to be identified. We found that CdCl2 caused DNA damage [micronuclei (MN)] in both TK6 and NH32 cells in a dose-dependent manner after 4 h exposure (plus 23 h recovery), with lowest observable effect levels (LOELs) for MN induction of 1 μM (TK6) and 1.6 μM (NH32). This DNA damage induction in TK6 cells was ROS dependent as pretreatment with the antioxidant N-Acetyl Cysteine (1 mM), abrogated this effect. However, 2',7'-dichlorofluorescin diacetate was not capable of detecting the ROS induced by CdCl2. The use of NH32 cells allowed an investigation of the role of p53 as they are a p53 null cell line derived from TK6. NH32 showed a 10-fold increase in MN in untreated cells and a similar dose-dependent effect after CdCl2 treatment. In TK6 cells, CdCl2 also caused activation of p53 (accumulation of total and phosphorylated p53), imposition of cell cycle checkpoints (G2/M) and intriguingly the production of smaller and more eccentric (elongated) cells. Overall, this multi-endpoint study suggests a carcinogenic mechanism of CdCl2 involving ROS generation, oxidative DNA damage and p53 activation, leading to cell cycle abnormalities and impacts of cell size and shape. This study shows how the integration of multiple cell biology endpoints studied in parallel in vitro can help mechanistic understanding of how carcinogens disrupt normal cell biology.

Melatonin as an Ameliorative Agent Against Cadmium- and Lead-Induced Toxicity in Fish: an Overview

Diverse anthropogenic activities and lack of knowledge on its consequences have promoted serious heavy metal contaminations in different aquatic systems throughout the globe. The non-biodegradable nature of most of these toxic heavy metals has increased the concern on their possible bioaccumulation in aquatic organisms as well as in other vertebrates. Among these aquatic species, fish are most sensitive to such contaminated water that not only decreases their chance of survivability in the nature but also increases the probability of biomagnifications of these heavy metals in higher order food chain. After entering the fish body, heavy metals induce detrimental changes in different vital organs by impairing multiple physiological and biochemical pathways that are essential for the species. Such alterations may include tissue damage, induction of oxidative stress, immune-suppression, endocrine disorders, uncontrolled cell proliferation, DNA damage, and even apoptosis. Although uncountable reports have explored the toxic effects of different heavy metals in diverse fish species, but surprisingly, only a few attempts have been made to ameliorate such toxic effects. Since, oxidative stress seems to be the underlying common factor in such heavy metal-induced toxicity, therefore, a potent and endogenous antioxidant with no side effect may be an appropriate therapeutic solution. Apart from summarizing the toxic effects of two important toxicants, i.e., cadmium and lead in fish, the novelty of the present treatise lies in its arguments in favor of using melatonin, an endogenous free radical scavenger and indirect antioxidant, in ameliorating the toxic effects of heavy metals in any fish species.

Cadmium as an ovarian toxicant: A review

Cadmium (Cd) is a ubiquitous heavy metal toxicant with no biological function in the human body. Considerably, because of its long biological half-life and very low excretion rate, Cd is inclined to accumulate and cause deleterious effects on various body organs (e.g., liver, kidney, and ovary) in humans and animals. Ovaries are the most vulnerable targets of Cd toxicity. Cd has been shown to induce oxidative stress, follicular atresia, hormonal imbalance, and impairment of oocyte growth and development. Moreover, Cd toxicity has been associated with increasing incidences of menstrual disorders, pregnancy loss, preterm births, delayed puberty, and female infertility. Therefore, it is crucial to understand how Cd poisoning impacts specific ovarian processes for the development of preventive interventions to enhance female fertility. The current review attempts to collate the recent findings on Cd-induced oxidative stress, follicular apoptosis, steroid synthesis inhibition, and teratogenic toxicity, along with their possible mechanisms in the ovarian tissue of different animal species. Additionally, the review also summarizes the studies related to the use of many antioxidants, medicinal herbs, and other compounds as remedial approaches for managing Cd-induced ovarian toxicity.

Effect of cadmium on the regulatory mechanism of steroidogenic pathway of Leydig cells during spermatogenesis

Cadmium is a male reproductive toxicant that interacts with a variety of pathogenetic mechanisms. However, the effect of cadmium on the regulatory mechanism of the steroidogenic pathway of Leydig cells during spermatogenesis is still ambiguous. Light microscopy, Western blot, immunohistochemistry, immunofluorescence, and quantitative polymerase chain reaction were performed to study the regulatory mechanism of the steroidogenic pathway of Leydig cells during spermatogenesis. The results indicated that in the control group, Leydig cells showed dynamic immunoreactivity and immunosignaling action with a strong positive significant secretion of 3β-hydroxysteroid hydrogenase (3β-HSD) in the interstitial compartment of the testis. Leydig cells showed a high active regulator mechanism of the steroidogenic pathway with increased the proteins and genes expression level of steroidogenic acute regulatory protein (STAR), cytochrome P450 cholesterol (CYP11A1), cytochrome P450 cholesterol (CYP17A1), 3β-hydroxysteroid hydrogenase (3β-HSD) 17β-hydroxysteroid hydrogenase (17β-HSD), and androgen receptor (AR) that maintained the healthy and vigorous progressive motile spermatozoa. However, on treatment with cadmium, Leydig cells were irregularly dispersed in the interstitial compartment of the testis. Leydig cells showed reduced immunoreactivity and immunosignaling of 3β-HSD protein. Meanwhile, cadmium impaired the regulatory mechanism of the steroidogenic process of the Leydig cells with reduced protein and gene expression levels of STAR, CYP11A1, CYP17A1, 3β-HSD, 17β-HSD, and AR in the testis. Additionally, treatment with cadmium impaired the serum LH, FSH, and testosterone levels in blood as compared to control. This study explores the hazardous effect of cadmium on the regulatory mechanism of the steroidogenic pathway of Leydig cells during spermatogenesis.

A single 8-hydroxyquinoline-appended bile acid fluorescent probe obtained by click chemistry for solvent-dependent and distinguishable sensing of zinc(II) and cadmium(II)

Construction of fluorescent probes for zinc ion (Zn2+ ) and cadmium ion (Cd2+ ) is significant for the safety of humans. However, the discriminating recognition of Zn2+ and Cd2+ by a single probe remains challenging owing to their similar properties. Herein, a novel deoxycholic acid derivative containing 8-hydroxyquinoline fluorophore has been facilely synthesized through click chemistry to form a clamp-like probe. Using its perfect bonding cavity from 1,2,3-triazole and quinoline, this molecule showed favorable solvent-dependent fluorescent responses and distinguished Zn2+ and Cd2+ in different solvents. In ethanol aqueous solution, it displayed good selectivity and ratiometric fluorescence to Zn2+ with 30 nm spectroscopic red-shifts. In acetonitrile aqueous solution, it exhibited good selectivity and ratiometric fluorescence to Cd2+ with 18 nm spectroscopic red-shifts. Moreover, the unique microstructural features of the probe in assembly were used to reflect its recognition processes. Due to its merits of low detection limit and instant response time, the probe was utilized for sensing Zn2+ and Cd2+ in water, beer and urine with high accuracy. Meanwhile, this probe served as a handy tool and was employed to obtain inexpensive test strips for the prompt and semiqualitative analysis of Zn2+ and Cd2+ with the naked eye.

Assessment of salivary cadmium levels and breast density in the Marin Women's Study

BACKGROUND

We aimed to determine if salivary cadmium (Cd) levels had any association with breast density, hoping to establish a less invasive cost-effective method of stratifying Cd burden as an environmental breast cancer risk factor.

METHODS

Salivary Cd levels were quantified from the Marin Women's Study, a Marin County, California population composite. Volumetric compositional breast density (BDsxa ) data were measured by single x-ray absorptiometry techniques. Digital screening mammography was performed by the San Francisco Mammography Registry. Radiologists reviewed mammograms and assigned a Breast Imaging-Reporting and Data System score. Early morning salivary Cd samples were assayed. Association analyses were then performed.

RESULTS

Cd was quantifiable in over 90% of saliva samples (mean = 55.7 pg/L, SD = 29). Women with higher saliva Cd levels had a non-significant odds ratio of 1.34 with BI-RAD scores (3 or 4) (95% CI 0.75-2.39, p = 0.329). Cd levels were higher in current smokers (mean = 61.4 pg/L, SD = 34.8) than former smokers or non-smokers. These results were non-significant. Pilot data revealed that higher age and higher BMI were associated with higher BI-RAD scores (p < 0.001).

CONCLUSION

Salivary Cd is a viable quantification source in large epidemiologic studies. Association analyses between Cd levels and breast density may provide additional information for breast cancer risk assessment, risk reduction plans, and future research directions. Further work is needed to demonstrate a more robust testing protocol before the extent of its usefulness can be established.

Exposure to particulate matter may affect semen quality via trace metals: Evidence from a retrospective cohort study on fertile males

Particulate matter (PM) exposure may be associated with male semen quality. Besides, PM exposure induces up and down levels of trace metals in tissues or organs. The levels of trace metals in semen are critical for adverse male semen quality. This study aims to evaluate the concentrations of seminal-level trace metals in fertile men and assess its associations with PM exposure and to explore the mediation role of trace metals in seminal plasma plays in the relationship between PM exposure and semen quality. Total 1225 fertile men who participated in a cohort study from 2014 to 2016 were finally recruited. Multivariate linear regression was applied to explore associations between each two of PM exposure, trace metals and semen parameters. 1-year PM2.5 and PM10 exposure levels were positively associated with arsenic (As), mercury (Hg), lanthanum (La), praseodymium (Pr), neodymium (Nd) but negatively associated with vanadium (V), magnesium (Mg), strontium (Sr), barium (Ba) in semen. It was also found that most of the elements were associated with total sperm number, followed by sperm concentration. Redundancy analysis (RDA) also determined several strong positive correlations or negative correlations between 1-year PM exposure and trace metals. Mediation analysis found that trace metals had a potentially compensatory or synergetic indirect effect on the total effect of the association between 1-year PM exposure and semen quality. The retrospective cohort study provides long-term PM exposure that may cause abnormal semen quality by affecting seminal plasma element levels.

An ultrasensitive Cd2+ detection biosensor based on DNAzyme and CRISPR/Cas12a coupled with hybridization chain reaction

The detection of cadmium is essential because it poses a significant threat to human health and the environment. Recent advancements in biosensors that detect nonnucleic-acid targets using CRISPR/Cas12a in combination with aptamers or DNAzymes show promising performance. Herein, we integrated DNAzyme, hybridization chain reaction (HCR) and CRISPR/Cas12a into a single biosensor for the first time and realized the ultrasensitive detection of Cd2+. A single phosphorothioate ribonucleobase (rA)-containing oligonucleotide (PS substrate) and a Cd2+-specific DNAzyme (Cdzyme) are used for Cd2+ recognition, releasing short single-stranded DNA. Then, the HCR is triggered by the cleavage products for signal transduction and amplification. Next, the trans-cleavage activity of Cas12a is activated due to the presence of crRNA complementary strands and PAM sites in the HCR products. As a result, FQ-reporters are cleaved, and the fluorescence values can be easily read using a fluorometer, allowing Cd2+ quantification by measuring the fluorescent signal. The Cd2+ detection biosensor is ultrasensitive with a detection limit of 1.25 pM. Moreover, the biosensor shows great stability under different pH and various anion conditions. The proposed sensor was utilized for environmental water sample detection, demonstrating the dependability of the detection system. Considering the high sensitivity and reliable performance of the assay, it could be further used in environmental monitoring. In addition, the design strategy reported in this study could extend the application of CRISPR/Cas12a in heavy metal detection.

Saccharomyces cerevisiae additions normalized hemocyte differential genes expression and regulated crayfish (Procambarus clarkii) oxidative damage under cadmium stress

Because China produces the most crayfish in the world, safe solutions must be improved to mitigate the risks of ongoing heavy metal stressors accumulation. This study aimed to use Saccharomyces cerevisiae as a bioremediation agent to counteract the harmful effect of cadmium (Cd) on crayfish (Procambarus clarkia). Our study used three concentrations of S. cerevisiae on crayfish feed to assess their Cd toxicity remediation effect by measuring total antioxidant capacity (TAC) and the biomarkers related to oxidative stress like malondialdehyde (MDA), protein carbonyl derivates (PCO), and DNA-protein crosslink (DPC). A graphite furnace atomic absorption spectroscopy device was used to determine Cd contents in crayfish. Furthermore, the mRNA expression levels of lysozyme (LSZ), metallothionein (MT), and prophenoloxidase (proPO) were evaluated before and following the addition of S. cerevisiae. The results indicated that S. cerevisae at 5% supplemented in fundamental feed exhibited the best removal effect, and Cd removal rates at days 4th, 8th, 12th, and 21st were 12, 19, 29.7, and 66.45%, respectively, which were significantly higher than the basal diet of crayfish. The addition of S. cerevisiae increased TAC levels. On the other hand, it decreased MDA, PCO, and DPC, which had risen due to Cd exposure. Furthermore, it increased the expression of proPO, which was reduced by Cd exposure, and decreased the expression of LSZ and MT, acting in the opposite direction of Cd exposure alone. These findings demonstrated that feeding S. cerevisiae effectively reduces the Cd from crayfish and could be used to develop Cd-free crayfish-based foods.

Simultaneous detection of mercury and cadmium ions: A colorimetric method in aqueous media

Hg and Cd are the two most toxic heavy metal ions that could be found in aqueous solutions. In this study, a chemosensor based on 5-(4-((4-nitrophenyl) diazenyl) phenyl)-1,3,4-oxadiazole-2-thiol (DOT) was reported to detect these ions simultaneously. DOT showed high selectivity towards Hg ion by changing the color of the solution from beige to gold-yellow at different concentrations of Hg ion. In comparison, other relevant metals, such as Li+, Na+, K+, Cs+, Mg2+, Ca2+, Al3+, Fe2+, Ag+, Cu2+, Pb2+, Ni2+, Zn2+, Cr3+, Fe3+, Pb4+, Mn2+, and Cd2+ did not affect the color of the DOT solution as the interfering ions. Despite no changes in the color of DOT solution in the presence of Cd ion, a solution containing DOT-Hg complex was changed from gold-yellow to orange by adding Cd ion, providing an approach for detecting Hg and Cd ion simultaneously with UV-Vis and Fluorescent spectroscopy. DOT exhibited a high association constant with a detection limit of 0.05 μM for Hg and Cd ions in an aqueous solution. The results of quantum mechanics (QM) calculations were also consistent with the experimental observations, which indicated that changes in the band gap could explain the various colors of DOT complex with metal ions.

Transcriptome Changes Reveal the Toxic Mechanism of Cadmium and Lead Combined Exposure on Silk Production and Web-Weaving Behavior of Spider A. ventricosus

The combined exposure of multiple metals imposes a substantial burden on the ecophysiological functions in organisms; however, the precise mechanism(s) remains largely unknown. Here, adult female A. ventricosus were exposed to single and combined exposure to cadmium (Cd) and lead (Pb) through the food chain. The aim was to explore the combined toxicity of these metals on silk production and web-weaving behavior at physiological, cellular morphological, and transcriptomic levels. The Cd and Pb combined exposure significantly inhibited the ability of silk production and web-weaving, including reduced silk fiber weight and diameter of single strands, lowered weaving position, induced nocturnal weaving, and increased instances of no-web, and showed a dose-response relationship on the Cd and Pb bioaccumulation. Concurrently, severe oxidative stress and degenerative changes in cells were observed. In addition, the combined pollution of Cd and Pb demonstrated synergistic effects, influenced by variations in concentration, on the enrichment of metals, inhibition of silk weight, oxidative damage, and cellular degeneration. At the transcriptome level, the upregulated ampullate spidroin genes and downregulated amino acid anabolic genes, upregulated Far genes and downregulated cytoskeleton-related TUBA genes, and overexpressed AChE and Glu genes may tend to present promising potential as biomarkers for silk protein synthesis, cellular degeneration, and neurotransmitter induction. This study offers an enormous capability for a comprehensive understanding of the eco-toxicological effects and mechanisms of multiheavy metals pollution.

Cadmium alters whole animal ionome and promotes the re-distribution of iron in intestinal cells of Caenorhabditis elegans

The chronic exposure of humans to the toxic metal cadmium (Cd), either occupational or from food and air, causes various diseases, including neurodegenerative conditions, dysfunction of vital organs, and cancer. While the toxicology of Cd and its effect on the homeostasis of biologically relevant elements is increasingly recognized, the spatial distribution of Cd and other elements in Cd toxicity-caused diseases is still poorly understood. Here, we use Caenorhabditis elegans as a non-mammalian multicellular model system to determine the distribution of Cd at the tissue and cellular resolution and its effect on the internal levels and the distribution of biologically relevant elements. Using inductively coupled plasma-mass spectrophotometry (ICP-MS), we show that exposure of worms to Cd not only led to its internal accumulation but also significantly altered the C. elegans ionome. Specifically, Cd treatment was associated with increased levels of toxic elements such as arsenic (As) and rubidium (Rb) and a decreased accumulation of essential elements such as zinc (Zn), copper (Cu), manganese (Mn), calcium (Ca), cobalt (Co) and, depending on the Cd-concentration used in the assay, iron (Fe). We regarded these changes as an ionomic signature of Cd toxicity in C. elegans. We also show that supplementing nematode growth medium with Zn but not Cu, rescues Cd toxicity and that mutant worms lacking Zn transporters CDF-1 or SUR-7, or both are more sensitive to Cd toxicity. Finally, using synchrotron X-Ray fluorescence Microscopy (XRF), we showed that Cd significantly alters the spatial distribution of mineral elements. The effect of Cd on the distribution of Fe was particularly striking: while Fe was evenly distributed in intestinal cells of worms grown without Cd, in the presence of Cd, Fe, and Cd co-localized in punctum-like structures in the intestinal cells. Together, this study advances our understanding of the effect of Cd on the accumulation and distribution of biologically relevant elements. Considering that C. elegans possesses the principal tissues and cell types as humans, our data may have important implications for future therapeutic developments aiming to alleviate Cd-related pathologies in humans.

Vaping, Environmental Toxicants Exposure, and Lung Cancer Risk

Lung cancer (LC) is the second-most prevalent tumor worldwide. According to the most recent GLOBOCAN data, over 2.2 million LC cases were reported in 2020, with an estimated new death incident of 1,796,144 lung cancer cases. Genetic, lifestyle, and environmental exposure play an important role as risk factors for LC. E-cigarette, or vaping, products (EVPs) use has been dramatically increasing world-wide. There is growing concern that EVPs consumption may increase the risk of LC because EVPs contain several proven carcinogenic compounds. However, the relationship between EVPs and LC is not well established. E-cigarette contains nicotine derivatives (e.g., nitrosnornicotine, nitrosamine ketone), heavy metals (including organometal compounds), polycyclic aromatic hydrocarbons, and flavorings (aldehydes and complex organics). Several environmental toxicants have been proven to contribute to LC. Proven and plausible environmental carcinogens could be physical (ionizing and non-ionizing radiation), chemicals (such as asbestos, formaldehyde, and dioxins), and heavy metals (such as cobalt, arsenic, cadmium, chromium, and nickel). Air pollution, especially particulate matter (PM) emitted from vehicles and industrial exhausts, is linked with LC. Although extensive environmental exposure prevention policies and smoking reduction strategies have been adopted globally, the dangers remain. Combined, both EVPs and toxic environmental exposures may demonstrate significant synergistic oncogenicity. This review aims to analyze the current publications on the importance of the relationship between EVPs consumption and environmental toxicants in the pathogenesis of LC.

Toxic Effects of Two Redox States of Thallium on Immortalised Hypothalamic GT1-7 Neuronal Cells

Thallium (Tl), is a highly toxic heavy metal that exists in monovalent (Tl(I)) and trivalent (Tl(III)) ionic states. This study aimed to compare the toxicities of Tl(I) and Tl(III) in a mouse hypothalamic GT1-7 neuronal cell line. Decreased viability and increased cytotoxicity were observed in the GT1-7 cells 16 h after Tl(I) or Tl(III) treatment. Tl(III) was more cytotoxic, than Tl(I), as indicated by extracellular lactate dehydrogenase levels. Both treatments induced caspase 3 activity, DNA fragmentation, malondialdehyde (MDA) production, and superoxide dismutase activity in the cells. MDA production was higher after Tl(III) than after Tl(I) treatment. Moreover, co-treatment with antioxidants, such as mannitol, ascorbic acid, or tocopherol, significantly attenuated the Tl-induced decrease in GT1-7 cell numbers. Therefore, both treatments induced oxidative stress-related apoptosis. Furthermore, Tl(III) reduced the cell viability more subtly than Tl(I) after 1 and 3 h of treatment. This effect was enhanced by co-treatment with maltol or citric acid, which promoted the influx of metallic elements into the cells. Thus, Tl(III) entered GT1-7 cells later than Tl(I) and had a delayed onset of toxicity. However, Tl(III) likely produces more extracellular lipid peroxides, which may explain its stronger cytotoxicity.

Biogenic Elements and Heavy Metals in Hermann's Tortoises-Testudo hermanni: Effect on Serum Biochemistry and Oxidative Status Parameters

BACKGROUND

Conservation of species diversity is the need of the hour for preserving life forms on Earth. Extinction of any part of the ecosystem has negative impacts on many processes and systems. The objective of this work was to analyze some biochemical and molecular indicators and their correlations to biogenic elements and heavy metals in Testudo hermanni (n = 16).

METHODS

Biochemical parameters were analyzed using the commercial kit DiaSys and biochemical analyzer Randox RX Monza. Sodium, potassium, and chlorides were measured using the EasyLite analyzer. Oxidative stress was evaluated using colorimetric and luminometric methods. Quantification of chemical elements in the blood was carried out using inductively coupled plasma mass spectrometry (ICPS).

RESULTS

Biochemical values of analyzed samples from Hermann's tortoises were almost the same as referential values described by multiple authors, with minor aberrations in the total protein parameter. Values of arsenic (As) and nickel (Ni) showed correlation with biochemical parameters and the parameters of oxidative stress. Cadmium (Cd) exhibited correlation with aspartate aminotransferase (AST).

CONCLUSIONS

This study reports correlations among four heavy metals, and their levels were again correlated with biochemical and molecular parameters in Hermann's tortoises.

Selenium alleviates biological toxicity of thiamethoxam (TMX): Bioaccumulation of TMX, organ damage, and antioxidant response of red swamp crayfish (Procambarus clarkii)

Pesticides are important for agricultural development; however, animals involved in rice-fish farming absorb the pesticides used during the farming process. Thiamethoxam (TMX) is extensively used in agriculture and is gradually occupying the market for traditional pesticides. Therefore, this study aimed to investigate whether selenomethionine (SeMet) could affect the survival rate, bioaccumulation of TMX, serum biochemical parameters, lipid peroxidation, antioxidants in the hepatopancreas, and expression of stress genes after exposure of red swamp crayfish to 10 ppt TMX for 7 days. The results showed that the survival rate significantly increased and the bioaccumulation of TMX significantly decreased with SeMet administration (P < 0.05). Furthermore, severe histological damage to the hepatopancreas of red crayfish was observed after exposure to TMX; however, this damage was alleviated after SeMet administration. SeMet also significantly reduced the TMX-induced changes in serum biochemical parameters, malondialdehyde content, and antioxidant enzyme activity in crayfish hepatopancreas (P < 0.05). Notably, analysis of the expression of 10 stress response genes showed that 0.5 mg/kg SeMet might decrease cell damage in the hepatopancreas. Consequently, our findings suggest that higher levels of TMX in crayfish may cause hepatopancreatic cell toxicity, which can be harmful to human health; however, SeMet could mitigate these effects, providing an understanding of pesticide compounds and food safety.

A biphenyl thiosemicarbazide based fluorogenic chemosensor for selective recognition of Cd2+: application in cell bioimaging

A diversified biphenyl thiosemicarbazide based chemosensor (HBMC) has been fabricated and reported for the specific detection of Cd2+ in a MeOH : H2O (4 : 1) solution. We observed a chromogenic change from colorless to light yellow colour, and it showed a "turn-on" fluorogenic change from non fluorescent to blooming cyan colour. In fluorometric titration a sharp "turn-on" emission for Cd2+ was observed with a ∼16 fold increase in fluorescence intensity value at 496 nm by incremental addition of Cd2+ ions in the MeOH : H2O (4 : 1) solution. The reversibility of the chemosensor (HBMC) was confirmed by a sequential addition of the EDTA solution. Again the binding stoichiometry of HBMC with Cd2+ was found to be 2 : 1, as confirmed by Job's plot analysis and HRMS spectra of the HBMC-Cd2+ complex. The mechanism for Cd2+ sensing in MeOH : H2O (4 : 1) is based upon the inhibition of CN isomerization and ESIPT process and simultaneously turning on the CHEF (chelation enhanced fluorescence) process. The limit of detection for Cd2+ was found to be in the order of 10-8 (M), which implies that HBMC is an efficient probe to detect Cd2+ at the microscopic level. A reusability study was performed and on-sight detection of cadmium ions by the chemosensor (HBMC) was established by dip-stick experiment. In vitro detection of Cd2+ in human breast cancer cells (MDA-MB-231) by HBMC discloses its cell permeability and biocompatible nature. Computational studies (DFT and TDDFT) with the probe HBMC and HBMC-Cd2+ complex were also performed.

Cadmium, von Willebrand factor and vascular aging

Vascular aging is a major contributing factor to cardiovascular disease. The aged blood vessels, characterized by vascular wall thickening and stiffening, are instigated by endothelial cell dysfunction induced by oxidative stress and inflammation. von Willebrand Factor (vWF) is a glycoprotein known for its role in coagulation, and plasma levels of vWF are increased with age. Elevated vWF promotes thrombosis, atherosclerotic plaque formation, inflammation and proliferation of vascular smooth muscle cells. Cadmium (Cd) is an environmental pollutant associated with increased morbidity and mortality of cardiovascular disease. At low concentrations, Cd activates pro-survival signaling in endothelial cells, however enhances intima-media thickness and atherogenesis. A non-cytotoxic dose of Cd also increases endothelial vWF expression and secretion in vivo and in vitro. In this review, we summarize the molecular mechanisms underlying vWF-promoted vascular aging-associated pathologies and Cd-induced vWF expression. In addition, we propose that exposure to low-dose Cd is a risk factor for vascular aging, through elevation of plasma vWF.

Cadmium induced bioaccumulation, histopathology, gene regulation in fish and its amelioration - A review

Different anthropogenic activities as well as natural sources contribute enormously towards various heavy metal contaminations in aquatic habitats. Cadmium (Cd) is one of most prevalent and toxic heavy metals with a long half life. Unlike terrestrial animals, exposure of Cd in fishes may happen not only through feeds but also from its habitat water. Bioaccumulation of Cd in fishes occurs in many tissues, but mainly in gill, liver, kidney, skin, and muscle. The concentrations of Cd in fish tissues depend upon the extent and duration of Cd exposure, species and age of fishes, dietary minerals and antioxidant concentrations, and habitat water quality. Specific histopathological observations in liver, kidney, and gill are useful to understand the effects of Cd, which could help to determine the ameliorating methods to be adopted. Exposure of Cd exerts several adverse effects on general growth and development, reproductive processes, osmoregulation, morphological and histological structures, stress tolerance, and endocrine system, mainly due to changes in biological functions induced by differential expressions of several genes related to oxidative stress, apoptosis, inflammation, immunosuppressions, genotoxicity, Cd chelation and carbohydrate metabolism. Chronic biomagnifications of Cd exceeding the permitted level may be harmful not only to the fishes itself but also to humans through food chains. Amelioration of such toxic heavy metal that has been categorized as a potent carcinogenic in humans is of utmost importance. Main modes of amelioration encompas reducing oxidative damages by promoting the antioxidative defenses, decreasing Cd absorption, increasing excretion through excretory system and improving the tolerance of fishes to Cd toxicity. Many amelioration measures such as use of minerals (for example, zinc, calcium, and iron), vitamins (vitamin C, A, and E), different herbs, probiotics and other agents (taurine, bentonite, chitosan, zeolite, and metallothionein) have been explored for their effective roles to reduce Cd bioaccumulation and toxicity symptoms in fishes. The present review discusses bioaccumulation of Cd, histopathological alterations, oxidative stress, synergism-antagonism, and gene regulation in different tissues, and its amelioration measures in fishes.

Effects of cadmium and copper mixtures on antibiotic resistance genes in rhizosphere soil

The evolvement and development of antibiotic resistance in microorganisms may be influenced by metals; however, it is still unclear how cadmium (Cd) and copper (Cu) combined affect the distribution and presence of antibiotic-resistance genes (ARGs) in rhizosphere soil. The aims of this research were to (1) compare the distribution patterns of bacterial communities and ARGs in response to the effects of Cd and Cu both separately and combined; (2) explore the possible mechanisms underlying the variation in soil bacterial communities and ARGs in addition to the combined effects of Cd, Cu, and various environmental variables (nutrients, pH, etc.); and (3) provide a reference for assessing the risks of metals (Cd and Cu) and ARGs. The findings showed that the multidrug resistance genes acrA and acrB and the transposon gene intI-1 were present in high relative abundance in bacterial communities. Cadmium and Cu had a substantial interaction effect on the abundance of acrA, whereas Cu had a notable main effect on the abundance of intI-1. According to the network analysis, the strong links between bacterial taxa and specific ARGs revealed that most ARGs were hosted by Proteobacteria, Actinobacteria, and Bacteroidetes. According to structural equation modeling, Cd had a larger effect on ARGs than Cu. Compared to previous analyses of ARGs, bacterial community diversity had little effect on ARGs in this study. Overall, the results may have important consequences for determining the possible hazard of soil metals and extend the understanding of how Cd and Cu co-select ARGs in rhizosphere soils.

Current Levels of Environmental Exposure to Cadmium in Industrialized Countries as a Risk Factor for Kidney Damage in the General Population: A Comprehensive Review of Available Data

The growing number of reports indicating unfavorable outcomes for human health upon environmental exposure to cadmium (Cd) have focused attention on the threat to the general population posed by this heavy metal. The kidney is a target organ during chronic Cd intoxication. The aim of this article was to critically review the available literature on the impact of the current levels of environmental exposure to this xenobiotic in industrialized countries on the kidney, and to evaluate the associated risk of organ damage, including chronic kidney disease (CKD). Based on a comprehensive review of the available data, we recognized that the observed adverse effect levels (NOAELs) of Cd concentration in the blood and urine for clinically relevant kidney damage (glomerular dysfunction) are 0.18 μg/L and 0.27 μg/g creatinine, respectively, whereas the lowest observed adverse effect levels (LOAELs) are >0.18 μg/L and >0.27 μg/g creatinine, respectively, which are within the lower range of concentrations noted in inhabitants of industrialized countries. In conclusion, the current levels of environmental exposure to Cd may increase the risk of clinically relevant kidney damage, resulting in, or at least contributing to, the development of CKD.

Trace elements in Foodstuffs from the Mediterranean Basin-Occurrence, Risk Assessment, Regulations, and Prevention strategies: A review

Trace elements (TEs) are chemical compounds that naturally occur in the earth's crust and in living organisms at low concentrations. Anthropogenic activities can significantly increase the level of TEs in the environment and finally enter the food chain. Toxic TEs like cadmium, lead, arsenic, and mercury have no positive role in a biological system and can cause harmful effects on human health. Ingestion of contaminated food is a typical route of TEs intake by humans. Recent data about the occurrence of TEs in food available in the Mediterranean countries are considered in this review. Analytical methods are also discussed. Furthermore, a discussion of existing international agency regulations will be given. The risk associated with the dietary intake of TEs was estimated by considering consumer exposure and threshold values such as Benchmark dose lower confidence limit and provisional tolerable weekly intake established by the European Food Safety Authority and the Joint FAO/WHO Expert Committee on Food Additives, respectively. Finally, several remediation approaches to minimize TE contamination in foodstuffs were discussed including chemical, biological, biotechnological, and nanotechnological methods. The results of this study proved the occurrence of TEs contamination at high levels in vegetables and fish from some Mediterranean countries. Lead and cadmium are more abundant in foodstuffs than other toxic trace elements. Geographical variations in TE contamination of food crops clearly appear, with a greater risk in developing countries. There is still a need for the regular monitoring of these toxic element levels in food items to ensure consumer protection.

Thallium-induced DNA damage, genetic, and epigenetic alterations

Thallium (Tl) is a toxic heavy metal responsible for noxious effects in living organisms. As a pollutant, Tl can be found in the environment at high concentrations, especially in industrial areas. Systemic toxicity induced by this toxic metal can affect cell metabolism, including redox alterations, mitochondrial dysfunction, and activation of apoptotic signaling pathways. Recent focus on Tl toxicity has been devoted to the characterization of its effects at the nuclear level, with emphasis on DNA, which, in turn, may be responsible for cytogenetic damage, mutations, and epigenetic changes. In this work, we review and discuss past and recent evidence on the toxic effects of Tl at the systemic level and its effects on DNA. We also address Tl's role in cancer and its control.

Cessation Restores Blood Pressure Levels and Endothelial Function Affected by Cadmium Exposure on Rats

Chronic cadmium exposure produces high blood pressure and endothelial damage; however, it is not known whether these effects could be reversed by interrupting the exposure to the metal. Therefore, we evaluate the systolic blood pressure (SBP) and vascular reactivity during and following chronic cadmium-exposure discontinuance. Rats received 100 mg.L^-1 cadmium chloride (CdCl₂) in the drinking water or tap water (Ct) for 30 days and/or tap water for 30 days more. The cadmium plasma content, blood pressure and vascular reactivity of isolated aorta were evaluated. Cadmium exposure increased cadmium plasma content, SBP and aorta contractile responses to phenylephrine, all reversed after suspending exposure. Endothelial removal and nitric oxide synthase (NOS) inhibition increased phenylephrine response both on control and Cd-discontinuation models. Cd-discontinuation group presented increased CAMKII and PKA protein expression, as peNOS^Ser1177. Superoxide dismutase (SOD) incubation reduced contractile response on control group, and catalase incubation enhanced the response to phenylephrine in this group. Meanwhile, both SOD2 and catalase protein expression were increased in Cd-cessation rats. Our findings provide evidence that increased SBP and endothelial dysfunction induced by Cd chronic exposure are reversed by suspending the metal exposure probably due to an improvement of antioxidant enzymes and eNOS function.

An Assessment of MT1A (rs11076161), MT2A (rs28366003) and MT1L (rs10636) Gene Polymorphisms and MT2 Concentration in Women with Endometrial Pathologies

Several studies have indicated a relationship between metallothionein (MT) polymorphisms and the development of different pathologies, including neoplastic diseases. However, no studies thus far have been conducted on the influence of MT polymorphisms and the development of endometrial lesions, including endometrial cancer. This study included 140 patients with normal endometrial tissue, endometrial polyps, uterine myomas and endometrial cancer. The tissue MT2 concentration was determined using the ELISA method. MT1A, MT2A and MT1L polymorphisms were analyzed using TaqMan real-time PCR genotyping assays. We found no statistical difference between the tissue MT2 concentration in patients with EC vs. benign endometrium (p = 0.579). However, tissue MT2 concentration was significantly different between uterine fibromas and normal endometrial tissue samples (p = 0.019). Menopause status did not influence the tissue MT2 concentration (p = 0.282). There were no significant associations between the prevalence of MT1A, MT2A and MT1L polymorphisms and MT2 concentration. The age, menopausal status, and diabetes status of patients were identified as EC risk factors.

Modeling DNA Methylation Profiles and Epigenetic Analysis of Safflower (Carthamus tinctorius L.) Seedlings Exposed to Copper Heavy Metal

Heavy metals are chemical elements with high density that can be toxic or poisonous even at low concentrations. They are widely distributed in the environment due to industrial activities, mining, pesticide use, automotive emissions and domestic wastes. This study aimed to investigate the toxic effects of copper (Cu) heavy metal on safflower plants in terms of genetic and epigenetic parameters. Safflower seeds were exposed to different concentrations of Cu heavy metal solution (20, 40, 80, 160, 320, 640, 1280 mg L^-1) for three weeks, and changes in the genomic template stability (GTS) and methylation pattern in the root tissues were analyzed using PCR and coupled restriction enzyme digestion-random amplification (CRED-RA) techniques. The results indicated that high doses of Cu have genotoxic effects on the genome of safflower plants. Epigenetic analysis revealed four different methylation patterns, with the highest total methylation rate of 95.40% observed at a 20 mg L^-1 concentration, and the lowest rate of 92.30% observed at 160 mg L^-1. Additionally, the maximum percentage of non-methylation was detected at 80 mg L^-1. These results suggest that changes in the methylation patterns can serve as an important mechanism of protection against Cu toxicity. Furthermore, safflower can be used as a biomarker to determine the pollution in soils contaminated with Cu heavy metal.

Potential Carcinogens in Makeup Cosmetics

Facial makeup cosmetics are commonly used products that are applied to the skin, and their ingredients come into contact with it for many years. Consequently, they should only contain substances that are considered safe or used within an allowable range of established concentrations. According to current European laws, all cosmetics approved for use should be entirely safe for their users, and the responsibility for this lies with manufacturers, distributors, and importers. However, the use of cosmetics can be associated with undesirable effects due to the presence of certain chemical substances. An analysis of 50 random facial makeup cosmetics commercially available on the European Union market and manufactured in six European countries was carried out, concerning the presence of substances with potential carcinogenic properties, as described in recent years in the literature. Nine types of facial makeup cosmetics were selected, and their compositions, as declared on the labels, were analyzed. The carcinogens were identified with information present in the European CosIng database and according to the Insecticide Resistance Action Committee's (IRAC) classification. As a result, the following potential carcinogens were identified: parabens (methylparaben, propylparaben, butylparaben, and ethylparaben), ethoxylated compounds (laureth-4, lautreth-7, or ethylene glycol polymers known as PEG), formaldehyde donors (imidazolidinyl urea, quaternium 15, and DMDM hydantoin), and ethanolamine and their derivatives (triethanolamine and diazolidinyl urea), as well as carbon and silica. In conclusion, all of the analyzed face makeup cosmetics contain potential carcinogenic substances. The literature review confirmed the suppositions regarding the potential carcinogenic effects of selected cosmetic ingredients. Therefore, it seems necessary to carry out studies on the long-term exposure of compounds present in cosmetics and perhaps introduce stricter standards and laws regulating the potential presence of carcinogens and their activity in cosmetics.

Cadmium exposure and DNA damage (genotoxicity): a systematic review and meta-analysis

Existing literature suggests an association between chronic cadmium (Cd) exposure and the induction of DNA damage and genotoxicity. However, observations from individual studies are inconsistent and conflicting. Therefore current systematic review aimed to pool evidence from existing literature to synthesize quantitative and qualitative corroboration on the association between markers of genotoxicity and occupational Cd exposed population. Studies that evaluated markers of DNA damage among occupationally Cd-exposed and unexposed workers were selected after a systematic literature search. The DNA damage markers included were chromosomal aberrations (chromosomal, chromatid, sister chromatid exchange), Micronucleus (MN) frequency in mono and binucleated cells (MN with condensed chromatin, lobed nucleus, nuclear buds, mitotic index, nucleoplasmatic bridges, pyknosis, and karyorrhexis), comet assay (tail intensity, tail length, tail moment, and olive tail moment), and oxidative DNA damage (8-hydroxy-deoxyguanosine). Mean differences or standardized mean differences were pooled using a random-effects model. The Cochran-Q test and I² statistic were used to monitor heterogeneity among included studies. Twenty-nine studies with 3080 occupationally Cd-exposed and 1807 unexposed workers were included in the review. Cd among the exposed group was higher in blood [4.77 μg/L (-4.94-14.48)] and urine samples [standardized mean difference 0.47 (0.10-0.85)] than in the exposed group. The Cd exposure is positively associated with higher levels of DNA damage characterized by increased frequency of MN [7.35 (-0.32-15.02)], sister chromatid exchange [20.30 (4.34-36.26)], chromosomal aberrations, and oxidative DNA damage (comet assay and 8OHdG [0.41 (0.20-0.63)]) compared to the unexposed. However, with considerable between-study heterogeneity. Chronic Cd exposure is associated with augmented DNA damage. However, more extensive longitudinal studies with adequate sample sizes are necessary to assist the current observations and promote comprehension of the Cd's role in inducing DNA damage.Prospero Registration ID: CRD42022348874.

Effect of Cadmium on Oxidative Stress Indices and Vitamin D Concentrations in Children

Heavy metal poisoning can have serious health consequences, including damage to the brain, kidneys, and other organs. Cadmium is a toxic heavy metal that can accumulate in the body over time and the exposure to this element has been linked to a variety of adverse health effects. Cadmium toxicity can lead to an imbalance in the cellular redox state and be a source of oxidative stress. On the molecular level, cadmium ions negatively affect cellular metabolism, including the disruption of energy production, protein synthesis, and DNA damage. The study has been carried out on a group of 140 school-age children (8 to 14 years old) inhabiting the industrialized areas of Upper Silesia. The study population was divided into two sub-groups based on the median concentration of cadmium in blood (0.27 µg/L): Low-CdB and High-CdB. Measured traits comprised blood cadmium levels (CdB) as well as a blood count and selected oxidative stress markers. This research study aimed to demonstrate a correlation between the impact of exposure to elevated cadmium concentrations in a population of children and certain markers of oxidative stress, and 25-OH vitamin D3 concentration. A negative correlation has been found between cadmium concentration and 25-OH vitamin D3 level, protein sulfhydryl groups content in blood serum, glutathione reductase activity, and lipofuscin and malondialdehyde levels in erythrocytes. The concentration of 25-OH vitamin D₃ in the High-CdB group was decreased by 23%. The oxidative stress indices can be considered a valuable indicator of early Cd-toxicity effects to be included in the routinely-applied cadmium exposure monitoring parameters, allowing the evaluation of stress intensity to the cell metabolism.

Melatonin protects against cadmium-induced oxidative stress via mitochondrial STAT3 signaling in human prostate stromal cells

Melatonin protects against Cadmium (Cd)-induced toxicity, a ubiquitous environmental toxicant that causes adverse health effects by increasing reactive oxygen species (ROS) production and mitochondrial dysfunction. However, the underlying mechanism remains unclear. Here, we demonstrate that Cd exposure reduces the levels of mitochondrially-localized signal transducer and activator of transcription 3 (mitoSTAT3) using human prostate stromal cells and mouse embryonic fibroblasts. Melatonin enhances mitoSTAT3 abundance following Cd exposure, which is required to attenuate ROS damage, mitochondrial dysfunction, and cell death caused by Cd exposure. Moreover, melatonin increases mitochondrial levels of GRIM-19, an electron transport chain component that mediates STAT3 import into mitochondria, which are downregulated by Cd. In vivo, melatonin reverses the reduced size of mouse prostate tissue and levels of mitoSTAT3 and GRIM-19 induced by Cd exposure. Together, these data suggest that melatonin regulates mitoSTAT3 function to prevent Cd-induced cytotoxicity and could preserve mitochondrial function during Cd-induced stress.

Polypropylene microplastics affect the distribution and bioavailability of cadmium by changing soil components during soil aging

Compared with the widespread and serious heavy metal contamination in soils, microplastic pollution has gained attention only recently. Little is known about how microplastics affect the distribution of heavy metals in soils, especially across soil components level. In this study, a 180-day soil aging experiment and soil density fractionation were performed to investigate the effect of polypropylene (PP) microplastics on the binding behavior of cadmium (Cd) to solid components, i.e. particulate organic matter, organo-mineral complexes (OMC), and mineral. Results showed addition of 2-10% microplastics in soils induced the decomposition of OMC fraction by 10.88-23.10%. Compared to the control, the content of dissolved organic carbon increased, and pH, humic substances, and soil organic matter decreased with microplastics. After 180d of aging, the content of Cd in OMC fraction increased by 17.92%, while microplastics made Cd contents decline by 10.01-19.75%. The impacts strongly depended on the dose and surface characteristic of microplastics. Overall, PP microplastics increased the concentration of bioavailable Cd in soils via decreasing soil retention of Cd by the OMC fraction. These findings based on the solid components level will provide a new perspective for understanding microplastics effects on soil systems and pollutants.

Synthesized nanoliposome-encapsulated kaempferol attenuates liver health parameters and gene expression in mice challenged by cadmium-induced toxicity

In the present research, we encapsulated a flavonoid called kaempferol into nanoliposomal structures and the health-promoting effects of synthesized nanoliposome-loaded kaempferol (NLK) were evaluated in mice challenged by cadmium-induced . The NLK characteristics, such as size, zeta potential, and polydispersity index, were 218.4 nm, -28.55 mV, and 0.29, respectively. The in vivo experiment revealed that the mice receiving water containing cadmium (2 mg/kg body weight/day) showed significant (p < 0.05) weight loss, an increase in liver enzyme activities, and hepatic oxidative stress. Dietary supplementation with NLK at concentrations of 2.5 and 5 mg/kg mice body weight notably (p < 0.05) improved the body weight, liver enzyme activities, hepatic oxidative stress, and antioxidant potential of the liver. Our findings elucidated that NLK could alleviate the toxicity of cadmium in mice challenged by cadmium-induced toxicity.

Endoplasmic reticulum stress mediated by ROS participates in cadmium exposure-induced MC3T3-E1 cell apoptosis

Cadmium (Cd), as one of the seventh most toxic heavy metal pollutants, widely persisted in the environment, leading to osteoblast dysfunction and ultimately Cd-related skeletal disease. However, the damaging effects of Cd on cellular functions and the potential pathogenic mechanisms are still unclear. In our study, Cd is believed to induce mitochondrial dysfunction and endoplasmic reticulum stress (ERS) in a dose-dependent manner, thereby leading to apoptosis, as evident by elevated Drp1, Fis1, GRP78, CHOP, ATF4, P-EIF2α, P-PERK, BAX, cleaved caspase 3 proteins expression and ROS levels, and decreased the levels of Mfn2, OPA1, Bcl2, and intracellular Collagen I, B-ALP, RUNX2, and BGP genes. Additionally, when the exogenous addition of NAC and 4-PBA was added, it was found that NAC and 4-PBA had a positive moderating effect on Cd-induced cell dysfunction. Mechanistically, Cd-induced oxidative stress and apoptosis by upregulating the PERK-EIF2α-ATF4-CHOP signaling pathway and inhibiting the Nrf2/NQO1 pathway. In conclusion, we found that Cd was involved in mitochondrial dysfunction, ERS, and apoptosis in MC3T3-E1 cells, While NAC and 4-PBA relieved ERS and attenuated cell apoptosis.

A soybean based-diet prevents Cadmium access to rat cerebellum, maintaining trace elements homeostasis and avoiding morphological alterations

Cadmium (Cd) is one of the most dangerous heavy metals that exists. A prolonged exposure to Cd causes toxic effects in a variety of tissues, including Central Nervous System (CNS), where it can penetrate the Blood Brain Barrier (BBB). Cd exposure has been linked to neurotoxicity and neurodegenerative diseases. Soy isoflavones have a strong antioxidant capacity, and they have been shown to have positive effects on cognitive function in females. However, the mechanisms underlying Cd neurotoxicity remain completely unresolved. The purpose of this study was to characterize the potential protective effect of a soy-based diet vs. a casein-based diet against Cd toxicity in rat cerebellum. Female Wistar rats were fed with casein (Cas) or soybean (So) as protein sources for 60 days. Simultaneously, half of the animals were administered either 15 ppm of Cadmium (CasCd and SoCd groups) in water or regular tap water as control (Cas and So groups). We analyzed Cd exposure effects on trace elements, oxidative stress, cell death markers, GFAP expression and the histoarchitecture of rat cerebellum. We found that Cd tissue content only augmented in the Cas intoxicated group. Zn, Cu, Mn and Se levels showed modifications among the different diets. Expression of Nrf-2 and the activities of CAT and GPx decreased in Cas and So intoxicated groups,while 3-NT expression increased only in the CasCd group. Morphometry analyses revealed alterations in the purkinje and granular cells morphology, decreased number of granular cells and reduced thickness of the granular layer in Cd-intoxicated rats, whereas no alterations were observed in animals under a So diet. In addition, mRNA expression of apoptotic markers BAX/Bcl-2 ratio and p53 expression increased only in the CasCd group, a finding confirmed by positive TUNEL staining in the cerebellum granule cell layer in the same group. Also, Cd intoxication elicited overexpression of GFAP by astrocytes, which was prevented by soy. White matter alterations were only subtle and characterized by intramyelinic edema in the CasCd group. Overall, these results unmask an irreversible toxic effect of a subchronic Cd intoxication on the cerebellum, and identify a protective role by a soy-based diet with potential as a therapeutic strategy for those individuals exposed to this dangerous environmental contaminant.

Prognostic biomarker prediction for glioma induced by heavy metals and their mixtures: An in-silico study

Although there is an association between heavy metals and glioma, the molecular mechanisms involved in glioma development remain unclear. Therefore, this study aimed to assess the molecular mechanisms implicated in glioma development induced by heavy metals and their mixtures using various methodologies and databases (CTD, Google Scholar, PubMed, ScienceDirect, SpringerLink, miRNAsong, GeneMANIA, Metascape, MIENTURNET, UALCAN). I found that heavy metals, particularly arsenic, mercury, lead, and cadmium, as well as their mixtures, have substantial influences on the etiology of gliomas. "glioblastoma signaling pathways," "integrated cancer pathway," "central carbon metabolism in cancer," "microRNAs in cancer," "p53 signaling pathway," "chemical carcinogenesis-DNA adducts," "glioma," "TP53 network," and "MAPK signaling pathway" were the predominant molecular pathways implicated in the glioma development induced by the studied heavy metals and their mixtures. Five genes (SOD1, CAT, GSTP1, PTGS2, TNF), two miRNAs (hsa-miR-26b-5p and hsa-miR-143-3p), and transcription factors (DR1 and HNF4) were identified as key components related to combined heavy metal and glioma development. Physical interactions were found to be the most common among the heavy metals and their mixtures studied (ranging from 45.2% to 77.6%). The expression level of SOD1 was significantly lower in glioblastoma multiforma samples compared to normal samples, whereas GSTP1 and TP53 expression levels were significantly higher. Brain lower and grade glioma patients who had higher levels of TP53, hsa-miR-25, hsa-miR-34, hsa-miR-222, and hsa-miR-143 had a reduced likelihood of survival. Our findings suggest that further priority should be given to investigating the impact of specific heavy metals or their mixtures on these molecular processes.