Cadmium-mediated lung injury is exacerbated by the persistence of classically activated macrophages

Adverse effects of cadmium on lymphoid organs, immune cells, and immunological responses

Humans and animals possess robust immune systems to safeguard against foreign pathogens. However, recent reports suggest a greater incidence of immunity breakdown due to exposure to environmental pollutants, with heavy metals emerging as potential candidates in such immuno-toxicological studies. While we have extensive data on the general toxicity resulting from exposure to heavy metals, comprehensive documentation of their role as immune disruptors remains scarce. Cd (Cadmium) exerts immunomodulation by interfering with immune organs and cells, leading to altered structure, physiology, and function, thereby inducing symptoms of immune deregulation, inflammation and/or autoimmunity. This review aims to summarize the link between Cd exposure and immune dysfunction, drawing from case studies on exposed human subjects, as well as research conducted on various model organisms and in-vitro culture systems.

The Protective Effects of Ganoderma lucidum Active Peptide GLP4 on Lung Injury Induced by Cadmium Poisoning in Mice

Ganoderma triterpenes and spore powder have shown promising results in mitigating cadmium-induced renal and hepatic injuries. Ganoderma lucidum active peptide GLP4 is a natural protein with dual antioxidant activities derived from the mycelium of Ganoderma lucidum. However, its efficacy in alleviating cadmium-induced lung injury remains unexplored. This study aims to investigate the protective effects of GLP4 against cadmium-induced lung injury in mice. Mice were exposed to cadmium chloride via nebulization to induce lung injury. The protective effect of GLP4 was assessed by measuring the total cell count in BALF, levels of inflammatory cytokines, and the expression of NLRP3 in lung tissues a through histopathological examination of lung tissue changes. The results showed that GLP4 significantly mitigated histopathological damage in lung tissues, decreased the secretion of inflammatory cytokines, and reduced the expression of NLRP3, which was elevated in cadmium-exposed mice. In vitro studies further revealed that GLP4 inhibited the cadmium-induced activation of the NLRP3 inflammasome. Notably, acute cadmium exposure by the respiratory tract did not affect the liver and kidneys of the mice. The findings suggest that GLP4 reduces cadmium-induced lung injury in mice by inhibiting the activation of the NLRP3 inflammasome, which provides a theoretical foundation for using Ganoderma lucidum as a preventive and therapeutic agent against cadmium poisoning.

Associations between plasma metabolites and heavy metal exposure in residents of environmentally polluted areas

Heavy metals are commonly released into the environment through industrial processes such as mining and refining. The rapid industrialization that occurred in South Korea during the 1960s and 1970s contributed significantly to the economy of the country; however, the associated mining and refining led to considerable environmental pollution, and although mining is now in decline in South Korea, the detrimental effects on residents inhabiting the surrounding areas remain. The bioaccumulation of toxic heavy metals leads to metabolic alterations in human homeostasis, with disruptions in this balance leading to various health issues. This study used metabolomics to explore metabolomic alterations in the plasma samples of residents living in mining and refining areas. The results showed significant increases in metabolites involved in glycolysis and the surrounding metabolic pathways, such as glucose-6-phosphate, phosphoenolpyruvate, lactate, and inosine monophosphate, in those inhabiting polluted areas. An investigation of the associations between metabolites and blood clinical parameters through meet-in-the-middle analysis indicated that female residents were more affected by heavy metal exposure, resulting in more metabolomic alterations. For women, inhabiting the abandoned mine area, metabolites in the glycolysis and pentose phosphate pathways, such as ribose-5-phosphate and 3-phosphoglycerate, have shown a negative correlation with albumin and calcium. Finally, Mendelian randomization(MR) was used to determine the causal effects of these heavy metal exposure-related metabolites on heavy metal exposure-related clinical parameters. Metabolite biomarkers could provide insights into altered metabolic pathways related to exposure to toxic heavy metals and improve our understanding of the molecular mechanisms underlying the health effects of toxic heavy metal exposure.

Cadmium-induced lung injury is associated with oxidative stress, apoptosis, and altered SIRT1 and Nrf2/HO-1 signaling; protective role of the melatonin agonist agomelatine

Cadmium (Cd) is a hazardous heavy metal extensively employed in manufacturing polyvinyl chloride, batteries, and other industries. Acute lung injury has been directly connected to Cd exposure. Agomelatine (AGM), a melatonin analog, is a drug licensed for treating severe depression. This study evaluated the effect of AGM against Cd-induced lung injury in rats. AGM was administered in a dose of 25 mg/kg/day orally, while cadmium chloride (CdCl2) was injected intraperitoneally in a dose of 1.2 mg/kg to induce lung injury. Pre-treatment with AGM remarkably ameliorated Cd-induced lung histopathological abrasions. AGM decreased reactive oxygen species (ROS) production, lipid peroxidation, suppressed NDAPH oxidase, and boosted the antioxidants. AGM increased Nrf2, GCLC, HO-1, and TNXRD1 mRNA, as well as HO-1 activity and downregulated Keap1. AGM downregulated Bax and caspase-3 and upregulated Bcl-2, SIRT1, and FOXO3 expression levels in the lung. In conclusion, AGM has a protective effect against Cd-induced lung injury via its antioxidant and anti-apoptotic effects mediated via regulating Nrf2/HO-1 and SIRT1/FOXO3 signaling.

Myeloid Heterogeneity Mediates Acute Exacerbations of Pulmonary Fibrosis

Epidemiological evidence indicates that exposure to particulate matter is linked to the development of idiopathic pulmonary fibrosis (IPF) and increases the incidence of acute exacerbations of IPF. In addition to accelerating the rate of lung function decline, exposure to fine particulate matter (particulate matter smaller than 2.5 μm [PM2.5]) is a risk factor for increased mortality in subjects with IPF. In this article, we show that exposure to PM2.5 mediates monocyte recruitment and fibrotic progression in mice with established fibrosis. In mice with established fibrosis, bronchoalveolar lavage cells showed monocyte/macrophage heterogeneity after exposure to PM2.5. These cells had a significant inflammatory and anti-inflammatory signature. The mixed heterogeneity of cells contributed to the proinflammatory and anti-inflammatory response. Although monocyte-derived macrophages were recruited to the lung in bleomycin-injured mice treated with PM2.5, recruitment of monocytes expressing Ly6Chi to the lung promoted progression of fibrosis, reduced lung aeration on computed tomography, and impacted lung compliance. Ly6Chi monocytes isolated from PM2.5-exposed fibrotic mice showed enhanced expression of proinflammatory markers compared with fibrotic mice exposed to vehicle. Moreover, IPF bronchoalveolar lavage cells treated ex vivo with PM2.5 showed an exaggerated inflammatory response. Targeting Ly6Chi monocyte recruitment inhibited fibrotic progression in mice. Moreover, the adoptive transfer of Ly6Chi monocytes exacerbated established fibrosis. These observations suggest that enhanced recruitment of Ly6Chi monocytes with a proinflammatory phenotype mediates acute exacerbations of pulmonary fibrosis, and targeting these cells may provide a potential novel therapeutic target to protect against acute exacerbations of IPF.

Immunostimulatory and anti-inflammatory impact of Fragaria ananassa methanol extract in a rat model of cadmium chloride-induced pulmonary toxicity

Cadmium is an extremely dangerous heavy metal that can lead to disastrous consequences in all organisms. Several natural remedies reduce the toxicities of experimentally generated metals in animals. Strawberry Fragaria ananassa contains several bioactive compounds that may mitigate heavy-metal toxicity. The study aim was to evaluate the ability of a strawberry fruit methanol extract (SE) to reduce Cd toxicity and to identify and quantify the active constituents of SE. Forty Wistar rats were classified into four groups: the control group- 1 ml saline IP; SE group- 100 mg of SE/kg rats orally; cadmium (Cd) group-2 mg CdCl2/kg body weight/IP daily; and treated group- SE given 1 hour before Cd administration. Administration of Cd induced several histopathological and immunohistochemical alterations in lung sections. Biochemical analysis of lung homogenates and mRNA levels of antioxidants and inflammatory cytokines indicated significant changes to the risk profile. SE administration significantly decreased the oxidative stress, inflammation, tissue damage, the mean area percentage of collagen fibers, and positive immuno-expressions of TNF-α and NF-κB induced by CdCl2. Moreover, the MDA, TNF-α, GM-CSF, and IL-1β levels in Cd-exposed rat lung tissue were significantly lower in the SE-treated group than in the Cd-group. SE significantly augmented lung GSH, SOD, HO-1, GPx-2, and Nrf2 levels in Cd-exposed rats. SE mitigated Cd-caused oxidative stress and lung inflammation. Therefore, regularly consuming a strawberry-rich diet could benefit general health and help prevent and treat diseases.

Saturated fatty acids synergizes cadmium to induce macrophages M1 polarization and hepatic inflammation

Exposure to the toxic metal cadmium (Cd) is a well-established risk factor for hepatic inflammation, but it remains unclear how metabolic components, such as different fatty acids (FAs), interact with Cd to influence this process. Understanding these interactions is essential for identifying potential preventative and therapeutic targets for this disorder. To address this question, we conducted in vitro and in vivo studies to investigate the combinatorial effect of Cd and saturated FAs on hepatic inflammation. Specifically, we assessed the cytotoxicity of Cd on macrophages and their polarization and inflammatory activation upon co-exposure to Cd and saturated FAs. Our results showed that while saturated FAs had minimal impact on the cytotoxicity of Cd on macrophages, they significantly collaborated with Cd in predisposing macrophages towards a pro-inflammatory M1 polarization, thereby promoting inflammatory activation. This joint effect of Cd and saturated FAs resulted in persistent inflammation and hepatic steatohepatitis in vivo. In summary, our study identified macrophage polarization as a novel mechanism by which co-exposure to Cd and saturated lipids induces hepatic inflammation. Our findings suggest that intervening in macrophage polarization may be a potential approach for mitigating the adverse hepatic effects of Cd.

Impaired PPARγ activation by cadmium exacerbates infection-induced lung injury

Emerging data indicate an association between environmental heavy metal exposure and lung disease, including lower respiratory tract infections (LRTIs). Here, we show by single-cell RNA sequencing an increase in Pparg gene expression in lung macrophages from mice exposed to cadmium and/or infected with Streptococcus pneumoniae. However, the heavy metal cadmium or infection mediated an inhibitory posttranslational modification of peroxisome proliferator-activated receptor γ (PPARγ) to exacerbate LRTIs. Cadmium and infection increased ERK activation to regulate PPARγ degradation in monocyte-derived macrophages. Mice harboring a conditional deletion of Pparg in monocyte-derived macrophages had more severe S. pneumoniae infection after cadmium exposure, showed greater lung injury, and had increased mortality. Inhibition of ERK activation with BVD-523 protected mice from lung injury after cadmium exposure or infection. Moreover, individuals residing in areas of high air cadmium levels had increased cadmium concentration in their bronchoalveolar lavage (BAL) fluid, increased barrier dysfunction, and showed PPARγ inhibition that was mediated, at least in part, by ERK activation in isolated BAL cells. These observations suggest that impaired activation of PPARγ in monocyte-derived macrophages exacerbates lung injury and the severity of LRTIs.

Disease-associated metabolic pathways affected by heavy metals and metalloid

Increased exposure to environmental heavy metals and metalloids and their associated toxicities has become a major threat to human health. Hence, the association of these metals and metalloids with chronic, age-related metabolic disorders has gained much interest. The underlying molecular mechanisms that mediate these effects are often complex and incompletely understood. In this review, we summarize the currently known disease-associated metabolic and signaling pathways that are altered following different heavy metals and metalloids exposure, alongside a brief summary of the mechanisms of their impacts. The main focus of this study is to explore how these affected pathways are associated with chronic multifactorial diseases including diabetes, cardiovascular diseases, cancer, neurodegeneration, inflammation, and allergic responses upon exposure to arsenic (As), cadmium (Cd), chromium (Cr), iron (Fe), mercury (Hg), nickel (Ni), and vanadium (V). Although there is considerable overlap among the different heavy metals and metalloids-affected cellular pathways, these affect distinct metabolic pathways as well. The common pathways may be explored further to find common targets for treatment of the associated pathologic conditions.

Targeting immunometabolism against acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions triggered by multiple intra- and extra-pulmonary injury factors, characterized by complicated molecular mechanisms and high mortality. Great strides have been made in the field of immunometabolism to clarify the interplay between intracellular metabolism and immune function in the past few years. Emerging evidence unveils the crucial roles of immunometabolism in inflammatory response and ALI. During ALI, both macrophages and lymphocytes undergo robust metabolic reprogramming and discrete epigenetic changes after activated. Apart from providing ATP and biosynthetic precursors, these metabolic cellular reactions and processes in lung also regulate inflammation and immunity.In fact, metabolic reprogramming involving glucose metabolism and fatty acidoxidation (FAO) acts as a double-edged sword in inflammatory response, which not only drives inflammasome activation but also elicits anti-inflammatory response. Additionally, the features and roles of metabolic reprogramming in different immune cells are not exactly the same. Here, we outline the evidence implicating how adverse factors shape immunometabolism in differentiation types of immune cells during ALI and summarize key proteins associated with energy expenditure and metabolic reprogramming. Finally, novel therapeutic targets in metabolic intermediates and enzymes together with current challenges in immunometabolism against ALI were discussed.

Association between cadmium exposure and pulmonary function reduction: Potential mediating role of telomere attrition in chronic obstructive pulmonary disease patients

BACKGROUND

Environmental cadmium (Cd) exposure is linked to pulmonary function injury in the general population. But, the association between blood Cd concentration and pulmonary function has not been investigated thoroughly in chronic obstructive pulmonary disease (COPD) patients, and the potential mechanisms are unclear.

METHODS

All eligible 789 COPD patients were enrolled from Anhui COPD cohort. Blood specimens and clinical information were collected. Pulmonary function test was conducted. The subunit of telomerase, telomerase reverse transcriptase (TERT), was determined through enzyme linked immunosorbent assay (ELISA). Blood Cd was measured via inductively coupled-mass spectrometer (ICP-MS).

RESULTS

Blood Cd was negatively and dose-dependently associated with pulmonary function. Each 1-unit increase of blood Cd was associated with 0.861 L decline in FVC, 0.648 L decline in FEV1, 5.938 % decline in FEV1/FVC %, and 22.098 % decline in FEV1 % among COPD patients, respectively. Age, current-smoking, self-cooking and higher smoking amount aggravated Cd-evoked pulmonary function decrease. Additionally, there was an inversely dose-response association between Cd concentration and TERT in COPD patients. Elevated TERT obviously mediated 29.53 %, 37.50 % and 19.48 % of Cd-evoked FVC, FEV1, and FEV1 % declines in COPD patients, respectively.

CONCLUSION

Blood Cd concentration is strongly associated with the decline of pulmonary function and telomerase activity among COPD patients. Telomere attrition partially mediates Cd-induced pulmonary function decline, suggesting an underlying mechanistic role of telomere attrition in pulmonary function decline from Cd exposure in COPD patients.

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.

The function of omega-3 polyunsaturated fatty acids in response to cadmium exposure

Throughout history, pollution has become a part of our daily life with the improvement of life quality and the advancement of industry and heavy industry. In recent years, the adverse effects of heavy metals, such as cadmium (Cd), on human health have been widely discussed, particularly on the immune system. Here, this review summarizes the available evidence on how Cd exposure may affect health. By analyzing the general manifestations of inflammation caused by Cd exposure, we find that the role of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) in vivo can counteract Cd-induced harm. Additionally, we elucidate the effects of n-3 PUFAs on the immune system, and analyze their prophylactic and therapeutic effects on Cd exposure. Overall, this review highlights the role of n-3 PUFAs in the pathological changes induced by Cd exposure. Although n-3 PUFAs remain to be verified whether they can be used as therapeutic agents, as rehabilitation therapy, supplementation with n-3 PUFAs is reliable and effective.

Inflammation resolution in environmental pulmonary health and morbidity

Inflammation and resolution are dynamic processes comprised of inflammatory activation and neutrophil influx, followed by mediator catabolism and efferocytosis. These critical pathways ensure a return to homeostasis and promote repair. Over the past decade research has shown that diverse mediators play a role in the active process of resolution. Specialized pro-resolving mediators (SPMs), biosynthesized from fatty acids, are released during inflammation to facilitate resolution and are deficient in a variety of lung disorders. Failed resolution results in remodeling and cellular deposition through pro-fibrotic myofibroblast expansion that irreversibly narrows the airways and worsens lung function. Recent studies indicate environmental exposures may perturb and deregulate critical resolution pathways. Environmental xenobiotics induce lung inflammation and generate reactive metabolites that promote oxidative stress, injuring the respiratory mucosa and impairing gas-exchange. This warrants recognition of xenobiotic associated molecular patterns (XAMPs) as new signals in the field of inflammation biology, as many environmental chemicals generate free radicals capable of initiating the inflammatory response. Recent studies suggest that unresolved, persistent inflammation impacts both resolution pathways and endogenous regulatory mediators, compromising lung function, which over time can progress to chronic lung disease. Chronic ozone (O3) exposure overwhelms successful resolution, and in susceptible individuals promotes asthma onset. The industrial contaminant cadmium (Cd) bioaccumulates in the lung to impair resolution, and recurrent inflammation can result in chronic obstructive pulmonary disease (COPD). Persistent particulate matter (PM) exposure increases systemic cardiopulmonary inflammation, which reduces lung function and can exacerbate asthma, COPD, and idiopathic pulmonary fibrosis (IPF). While recurrent inflammation underlies environmentally induced pulmonary morbidity and may drive the disease process, our understanding of inflammation resolution in this context is limited. This review aims to explore inflammation resolution biology and its role in chronic environmental lung disease(s).

Can PPAR γ Keep Cadmium in Check?

Cd, a naturally occurring endocrine toxin found in tobacco leaves, originates in the environment and enters the body through inhalation, targeting the lungs and kidneys. A study published by Larsen-Carey et al. revealed that cadmium mediates the persistence of classically activated lung macrophages to exacerbate lung injury. The research discovered a novel role for PPAR γ as an effective regulator for the alternative activation of macrophages in response to Cd and Cd-induced lung injury.

Use of Generalized Weighted Quantile Sum Regressions of Tumor Necrosis Factor Alpha and Kidney Function to Explore Joint Effects of Multiple Metals in Blood

Exposure to heavy metals could lead to adverse health effects by oxidative reactions or inflammation. Some essential elements are known as reactors of anti-inflammatory enzymes or coenzymes. The relationship between tumor necrosis factor alpha (TNF-α) and heavy metal exposures was reported. However, the interaction between toxic metals and essential elements in the inflammatory response remains unclear. This study aimed to explore the association between arsenic (As), cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn) in blood and TNF-α as well as kidney function. We enrolled 421 workers and measured the levels of these seven metals/metalloids and TNF-α in blood; kidney function was calculated by CKD-EPI equation. We applied weighted quantile sum (WQS) regression and group WQS regression to assess the effects of metal/metalloid mixtures to TNF-α and kidney function. We also approached the relationship between metals/metalloids and TNF-α by generalized additive models (GAM). The relationship of the exposure−response curve between Pb level and TNF-α in serum was found significantly non-linear after adjusting covariates (p < 0.001). Within the multiple-metal model, Pb, As, and Zn were associated with increased TNF-α levels with effects dedicated to the mixture of 50%, 31%, and 15%, respectively. Grouped WQS revealed that the essential metal group showed a significantly negative association with TNF-α and kidney function. The toxic metal group found significantly positive associations with TNF-α, serum creatinine, and WBC but not for eGFR. These results suggested Pb, As, Zn, Se, and mixtures may act on TNF-α even through interactive mechanisms. Our findings offer insights into what primary components of metal mixtures affect inflammation and kidney function during co-exposure to metals; however, the mechanisms still need further research.

Arsenic induces ferroptosis and acute lung injury through mtROS-mediated mitochondria-associated endoplasmic reticulum membrane dysfunction

The goal of this study was to analyze whether mitochondria-associated endoplasmic reticulum membrane (MAMs) dysfunction mediated arsenic (As)-evoked pulmonary ferroptosis and acute lung injury (ALI). As exposure led to alveolar structure damage, inflammatory cell infiltration and pulmonary function decline in mice. Ferritin, the marker of iron overload, was increased, GPX4, the index of lipid peroxidation, was decreased in As-exposed lungs and pulmonary epithelial cells (MLE-12). Pretreatment with ferrostatin-1 (Fer-1), the inhibitor of ferroptosis, alleviated As-evoked ALI. In addition, As-induced non-heme iron deposition was inhibited in Fer-1 pretreated-mice. Moreover, As-triggered mitochondria damage and ferroptosis were mitigated in Fer-1 pretreated-MLE-12 cells. Mechanistically, PERK phosphorylation and mitofusin-2 (Mfn-2) reduction was observed in As-exposed MLE-12 cells and mice lungs. Additionally, the interaction between PERK and Mfn-2 was downregulated and MAMs dysfunction was observed in As-exposed MLE-12 cells. Intriguingly, PERK inhibitor and Mfn-2-overexpression all mitigated As-induced ferroptosis in MLE-12 cells. Additionally, CLPP and mtHSP70, the markers of mitochondrial stress, were upregulated, mitochondrial ROS (mtROS) was elevated, mitochondrial membrane potential (MMP) and ATP were decreased in As-exposed MLE-12 cells. Mitoquinone mesylate (MitoQ), a novel mitochondrial-targeted antioxidant, alleviated As-induced excess mtROS, mitochondrial stress, MAMs dysfunction in pulmonary epithelial cells. Similarly, in vivo experiments indicated that MitoQ pretreatment countered As-induced pulmonary ferroptosis and ALI. These data indicated that mtROS-initiated MAMs dysfunction is, at least partially, implicated in As-evoked ferroptosis and ALI.

Korean red ginseng water extract inhibits cadmium-induced lung injury via suppressing MAPK/ERK1/2/AP-1 pathway

Background

Few studies reported the therapeutic effect of Korean Red Ginseng (KRG) in lung inflammatory diseases. However, the anti-inflammatory role and underlying molecular in cadmium-induced lung injury have been poorly understood, directly linked to chronic lung diseases (CLDs): chronic obstructive pulmonary disease (COPD), cancer etc. Therefore, in this study we aim to investigate the therapeutic activities of water extract of KRG (KRG-WE) in mouse cadmium-induced lung injury model.

Method

The anti-inflammatory roles and underlying mechanisms of KRG-WE were evaluated in vitro under cadmium-stimulated lung epithelial cells (A549) and HEK293T cell line and in vivo in cadmium-induced lung injury mouse model using semi-quantitative polymerase chain reaction (RT-PCR), quantitative real-time PCR (qPCR), luciferase assay, immunoblotting, and FACS.

Results

KRG-WE strongly ameliorated the symptoms of CdSO₄-induced lung injury in mice according to total cell number in bronchoalveolar lavage fluid (BALF) and severity scores as well as cytokine levels. KRG-WE significantly suppressed the upregulation of inflammatory signaling comprising mitogen-activated protein kinases (MAPK) and their upstream enzymes. In in vitro study, KRG-WE suppressed expression of interleukin (IL)-6, matrix metalloproteinase (MMP)-2, and IL-8 while promoting recovery in CdSO₄-treated A549 cells. Similarly, KRG-WE reduced phosphorylation of MAPK and c-Jun/c-Fos in cadmium-exposed A549 cells.

Conclusion

KRG-WE was found to attenuate symptoms of cadmium-induced lung injury and reduce the expression of inflammatory genes by suppression of MAPK/AP-1-mediated pathway.

Chronic exposure to low-dose cadmium facilitated nonalcoholic steatohepatitis in mice by suppressing fatty acid desaturation

Exposure to cadmium (Cd), a toxic metal, is epidemiologically linked to nonalcoholic steatohepatitis (NASH) in humans. However, the role of Cd in NASH remains to be fully elucidated. This study employed a novel murine NASH model to investigate the effects of chronic low-dose Cd on hepatic pathology and its underlying mechanisms. NASH is characterized by lipid accumulation, extensive cell death, and persistent inflammation in the liver. We found that treatment with Cd in drinking water (10 mg/L) for 6 or 12 weeks significantly boosted hepatic fat deposition, increased hepatocyte destruction, and amplified inflammatory responses in mice, confirming that low-dose Cd can facilitate NASH development in vivo. Mechanistically, chronic Cd exposure reshaped the hepatic transcriptional landscape, with PPAR-mediated fatty acid metabolic pathways being the most significantly altered. In particular, Cd repressed fatty acid desaturation, leading to the accumulation of saturated fatty acids whose lipotoxicity exacerbated cell death and, consequently, inflammatory activation. In summary, we validated the causal effects of chronic low-dose Cd on NASH in vivo and identified the fatty acid desaturation program as a novel target for Cd to instigate hepatopathological alterations.

Cadmium Body Burden and Inflammatory Arthritis: A Pilot Study in Patients from Lower Silesia, Poland

The purpose of this study was to determine the relationship between cadmium exposure and the likelihood of developing or exacerbating symptoms of inflammatory arthritis (IA). The study included 51 IA patients and 46 control subjects. Demographic and lifestyle data were collected. Haematological and biochemical parameters and blood cadmium levels (Cd-B) were determined. Cd-B correlated positively with age, smoking, living in a high-traffic area, and serum levels of inflammatory markers and negatively with mean corpuscular haemoglobin concentration (MCHC). The binary logistic regression model implied that high Cd-B (≥0.65 μg/L) is linked with an increased risk of IA in the studied population (odds ratio: 4.4). High levels of DNA oxidative damage marker (8-hydroxy-2’-deoxyguanosine) (≥7.66 ng/mL) and cyclooxygenase-2 (≥22.9 ng/mL) and frequent consumption of offal was also associated with increased risk of IA. High Cd-B was related to increased risk of disease symptoms onset in the group of IA patients, decreased the level of interleukin 10, and positively correlated with the disease activity. Increased Cd-B is associated with intensified inflammatory processes and decreased haemoglobin levels; in IA patients with decreased anti-inflammatory interleukin 10. These changes partly explain why cadmium exposure and a high cadmium body burden may raise the risk of IA and of disease symptoms exacerbation.

Cadmium and wild boar: environmental exposure and immunological impact on macrophages

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Wild boar represents useful bioindicator for Cadmium environmental exposure.

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Cadmium can be absorbed by wild boar moMФ with subsequent cell viability decrease.

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Moderate cadmium concentration down-regulated IL-12p40, TNF-α expression in moMФ.

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Moderate cadmium concentration decreased antimicrobial molecules expression in moMФ.

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Moderate cadmium concentration down-regulated expression of several TLRs in moMФ.

Cadmium (Cd²⁺) is regarded as one of the most toxic heavy metals, which can enter the food chain through environmental contamination and be bioaccumulated. Its exposure in Ligurian wild boars was monitored between 2016–2020 and revealed high level of this heavy metal in different provinces. In one of these polluted area, 21 wild boars were additionally sampled and the relationship between hepatic and renal Cd²⁺ concentration suggested that majority of these animals presented chronic intoxication. Cd²⁺ exposure of wild boar might lead to an immunosuppression status, thus in vitro experiments on wild boar monocyte-derived macrophages (moMФ) were carried out. Effects of Cd²⁺ scalar doses were evaluated through viability and adsorption assays, ELISA, qPCR. Moderate doses of this environmental pollutant (20 μM) were absorbed by moMФ, with subsequent reduction of their viability. This heavy metal did not trigger release of either IFN- β, anti-inflammatory or pro-inflammatory cytokines by moMФ, instead 24 h treatment with 20 μM of Cd²⁺ resulted in down-regulated expression of TNF-α, IL-12p40, several TLRs, CD14, MD2, BD2, MyD88, p65, and NOS2. The results of our monitoring activity suggested that wild boar can be useful to monitor environmental exposure of this heavy metal and can help in understanding the type of contamination. In addition, in vitro experiments on wild boar moMФ revealed that Cd²⁺ exposure negatively affected the immune function of these cells, likely leading to increased susceptibility to infection.

Vanillin Attenuates Cadmium-Induced Lung Injury Through Inhibition of Inflammation and Lung Barrier Dysfunction Through Activating AhR

Vanillin, the main constituents of vanillin beans, has been reported to exhibit anti-inflammatory effects. However, the effects of vanillin on the cadmium-induced lung injury are still unclear. Therefore, we assay whether vanillin has potential preventive activity on cadmium-induced lung injury in mice. Mice were given vanillin (5, 10, 20 mg/kg) and treated with cadmium for 7 days. The detection data of vanillin on lung tissue changes were analyzed after the cadmium treatment. The results displayed that vanillin obviously decreased the lung histological alterations and myeloperoxidase (MPO) activity. Vanillin also suppressed the levels of TNF-α, IL-1β, and IL-6 in BALF. Furthermore, vanillin prevented cadmium-induced NF-κB activation and upregulation the expression of tight junction protein ZO-1 and occludin. In addition, vanillin significantly increased the expression of aryl hydrocarbon receptor (AhR), and inhibition of AhR by its agonist could reverse the protective effects of vanillin on cadmium-induced lung injury. To sum up, vanillin could be a potential drug for the treatment of cadmium-induced lung injury.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

Zinc and Cadmium in the Aetiology and Pathogenesis of Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are inflammatory articular conditions with different aetiology, but both result in joint damage. The nutritionally essential metal zinc (Zn²⁺) and the non-essential metal cadmium (Cd²⁺) have roles in these arthritic diseases as effectors of the immune system, inflammation, and metabolism. Despite both metal ions being redox-inert in biology, they affect the redox balance. It has been known for decades that zinc decreases in the blood of RA patients. It is largely unknown, however, whether this change is only a manifestation of an acute phase response in inflammation or relates to altered availability of zinc in tissues and consequently requires changes of zinc in the diet. As a cofactor in over 3000 human proteins and as a signaling ion, zinc affects many pathways relevant for arthritic disease. How it affects the diseases is not just a question of zinc status, but also an issue of mutations in the many proteins that maintain cellular zinc homoeostasis, such as zinc transporters of the ZIP (Zrt-/Irt-like protein) and ZnT families and metallothioneins, and the multiple pathways that change the expression of these proteins. Cadmium interferes with zinc's functions and there is increased uptake under zinc deficiency. Remarkably, cadmium exposure through inhalation is now recognized in the activation of macrophages to a pro-inflammatory state and suggested as a trigger of a specific form of nodular RA. Here, we discuss how these metal ions participate in the genetic, metabolic, and environmental factors that lead to joint destruction. We conclude that both metal ions should be monitored routinely in arthritic disease and that there is untapped potential for prognosis and treatment.