Associations between and risks of trace elements related to skin and liver damage induced by arsenic from coal burning

Transcriptional and biochemical changes in mouse liver following exposure to a metal/drug cocktail. Attenuating effect of a selenium-enriched diet

Real-life pollution usually involves simultaneous co-exposure to different chemicals. Metals and drugs are frequently and abundantly released into the environment, where they interact and bioaccumulate. Few studies analyze potential interactions between metals and pharmaceuticals in these mixtures, although their joint effects cannot be inferred from their individual properties. We have previously demonstrated that the mixture (PC) of the metals Cd and Hg, the metalloid As and the pharmaceuticals diclofenac (DCF) and flumequine (FLQ) impairs hepatic proteostasis. To gain a deeper vision of how PC affects mouse liver homeostasis, we evaluated here the effects of PC exposure upon some biochemical and morphometric parameters, and on the transcriptional profiles of selected group of genes. We found that exposure to PC caused oxidative damage that exceeded the antioxidant capacity of cells. The excessive oxidative stress response resulted in an overabundance of reducing equivalents, which hindered the metabolism and transport of metabolites, including cholesterol and bile acids, between organs. These processes have been linked to metabolic and inflammatory disorders, cancer, and neurodegenerative diseases. Therefore, our findings suggest that unintended exposure to mixtures of environmental pollutants may underlie the etiology of many human diseases. Fortunately, we also found that a diet enriched with selenium mitigated the harmful effects of this combination of toxicants.

The mitochondria-targeted antioxidant MitoQ ameliorates inorganic arsenic-induced DCs/Th1/Th2/Th17/Treg differentiation partially by activating PINK1-mediated mitophagy in murine liver

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.

Simultaneous removal of Cd(II) and As(V) by ferrihydrite-biochar composite: Enhanced effects of As(V) on Cd(II) adsorption

The coexistence of cadmium (Cd(II)) and arsenate (As(V)) pollution has long been an environmental problem. Biochar, a porous carbonaceous material with tunable functionality, has been used for the remediation of contaminated soils. However, it is still challenging for the dynamic quantification and mechanistic understanding of the simultaneous sequestration of multi-metals in biochar-engineered environment, especially in the presence of anions. In this study, ferrihydrite was coprecipitated with biochar to investigate how ferrihydrite-biochar composite affects the fate of heavy metals, especially in the coexistence of Cd(II) and As(V). In the solution system containing both Cd(II) and As(V), the maximum adsorption capacities of ferrihydrite-biochar composite for Cd(II) and As(V) reached 82.03 µmol/g and 531.53 µmol/g, respectively, much higher than those of the pure biochar (26.90 µmol/g for Cd(II), and 40.24 µmol/g for As(V)) and ferrihydrite (42.26 µmol/g for Cd(II), and 248.25 µmol/g for As(V)). Cd(II) adsorption increased in the presence of As(V), possibly due to the changes in composite surface charge in the presence of As(V), and the increased dispersion of ferrihydrite by biochar. Further microscopic and mechanistic results showed that Cd(II) complexed with both biochar and ferrihydrite, while As(V) was mainly complexed by ferrihydrite in the Cd(II) and As(V) coexistence system. Ferrihydrite posed vital importance for the co-adsorption of Cd(II) and As(V). The different distribution patterns revealed by this study help to a deeper understanding of the behaviors of cations and anions in the natural environment.

The Role of miR-150-5p/SOCS1 Pathway in Arsenic-Induced Pyroptosis of LX-2 Cells

This study aims to explore the mechanism of pyroptosis of human hepatocyte LX-2 cells induced by NaAsO2 through the miR-150-5p/SOCS1 pathway. LX-2 cells were transfected with different concentrations of NaAsO2, miR-150-5p inhibitor, and SOCS1 agonist. Cell activity, cell pyroptosis, and the expression of related genes and proteins were detected by scanning electron microscopy, CCK-8, qRT-PCR, western blot, and immunofluorescence. Compared with the control group, 10 µmol/L and 20 µmol/L NaAsO2 significantly elevated the protein expression levels of the pyroptosis-related proteins NLRP3, GSDMD, GSDMD-N, caspase1, and cleaved caspase1 as well as the mRNA levels of NLRP3, GSDMD, caspase1, IL-18, and IL-1β. The typical pyroptosis with swelling and rupture of the plasma membrane was observed through scanning electron microscopy. The expression of miR-150-5p of the NaAsO2 intervention group increased, while the expression of SOCS1 decreased; then the level of NF-κB p65 elevated. With co-treatment of miR-150-5p inhibitor, SOCS1 agonist, and NaAsO2, the cell pyroptosis was attenuated, and the expressions of NLRP3, caspase1, GSDMD, GSDMD-N, IL-18, IL-1β, p65 of the group of miR-150-5p inhibitor and NaAsO2 group, and of the group of SOCS1 agonist and NaAsO2 reduced compared with the NaAsO2 group. Arsenic exposure promotes miR-150-5p, inhibits the expression of SOCS1, and activates the NF-κB/NLRP3 pathway in LX-2 cell pyroptosis.

Associations of arsenic exposure and arsenic metabolism with the risk of non-alcoholic fatty liver disease

Growing evidences supported that arsenic exposure contributes to non-alcoholic fatty liver disease (NAFLD) risk, but findings were still inconsistent. Additionally, once absorbed, arsenic is methylated into monomethyl and dimethyl arsenicals. However, no studies investigated the association of arsenic metabolism with NAFLD. Our objectives were to evaluate the associations of arsenic exposure and arsenic metabolism with NAFLD prevalence. We conducted a case-control study with 1790 participants derived from Dongfeng-Tongji cohort and measured arsenic species (arsenite, arsenate, monomethylarsonate [MMA], dimethylarsinate [DMA], and arsenobetaine) in urine. Arsenic exposure (∑As) was defined as the sum of inorganic arsenic (iAs), MMA, and DMA. Arsenic metabolism was evaluated as the proportions of inorganic-related species (iAs%, MMA%, and DMA%) and methylation efficiency ratios (primary methylation index [PMI], secondary methylation index [SMI]). NAFLD was diagnosed by liver ultrasound. Logistic regression was used to evaluate the associations. The median of ∑As was 13.24 μg/g creatinine. The ∑As showed positive and nonlinear association with moderate/severe NAFLD (OR: per log-SD = 1.33, 95% CI: [1.03,1.71]; Pfor nonlinearity = 0.021). The iAs% (OR: per SD = 1.16, 95% CI: [1.03,1.30]) and SMI (OR: per log-SD = 1.16, 95% CI: [1.03,1.31]) showed positive while MMA% (OR: per SD = 0.80, 95% CI: [0.70,0.91]) and PMI (OR: per log-SD = 0.86, 95% CI: [0.77,0.96]) showed inverse associations with NAFLD. Moreover, the ORs (95% CI) of NAFLD for each 5% increase in iAs% was 1.36 (1.17,1.58) when MMA% decreased and 1.07 (1.01,1.13) when DMA% decreased; and for each 5% increase in MMA%, it was 0.74 (0.63,0.86) and 0.79 (0.69,0.91) when iAs% and DMA% decreased, respectively. The results suggest that inorganic arsenic exposure is positively associated with NAFLD risk and arsenic methylation efficiency plays a role in the NAFLD. The findings provide clues to explore potential interventions for the prevention of NAFLD. Prospective studies are needed to validate our findings.

Assessing the mechanisms and adjunctive therapy for arsenic-induced liver injury in rats

Environmental arsenic exposure is a significant global public health concern. Previous studies have demonstrated the association between arsenic-induced liver injury and oxidative stress as well as ferroptosis. However, the knowledge of the interactions among these mechanisms remains limited. Moreover, there is a lack of research on potential therapeutic interventions for liver injury resulting from arsenic exposure. To address these limitations, we established a rat model with liver injury caused by arsenic exposure and investigated the impact of the nuclear factor E2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4) signaling pathway and ferroptosis on arsenic-induced liver injury. Our findings revealed that arsenic increased Nrf2 expression and decreased GPx4 expression in the rat liver. This was accompanied by a substantial generation of reactive oxygen species and disruption of the antioxidant defense system, ultimately promoting liver injury through ferroptosis. Subsequently, we conducted intervention experiments using Rosa roxburghii Tratt (RRT) in rats exposed to arsenic. The results showed that the detrimental effects mentioned earlier were partially alleviated following RRT intervention. This study offers preliminary evidence that persistent activation of Nrf2 by arsenic triggers an adaptive antioxidant response, leading to liver injury through the promotion of ferroptosis. Additionally, we discovered that RRT inhibits Nrf2-mediated adaptive antioxidant responses by reducing hepatic ferroptosis, thereby mitigating liver injury caused by arsenic exposure in rats. Our study contributes to a deeper understanding of the molecular mechanisms underlying liver injury resulting from arsenic exposure. Furthermore, our findings may facilitate the identification of a potential edible and medicinal plant extracts that could be utilized to develop a more effective adjunctive treatment approach.

The ROS/NF-κB/HK2 axis is involved in the arsenic-induced Warburg effect in human L-02 hepatocytes

Arsenic has been identified as a carcinogen, although the molecular mechanism underlying itscarcinogenesis has not been fully elucidated. To date, only a few studies have attempted to confirm a direct link between oxidative stress and the Warburg effect . This study demonstrated that 0.2 μmol/L As3+ induced the Warburg effect to contribute to abnormal proliferation of L-02 cells, that was mediated by upregulation of hexokinase 2 (HK2), a key enzyme in glycolysis. Further study indicated that arsenic-induced accumulation of reactive oxygen species (ROS) activated the nuclear factor kappa B (NF-κB) signaling pathway by phosphorylation of p65 at the Ser536 and Ser276 sites, leading to upregulated expression of HK2. We therefore concluded that the ROS/NF-κB/HK2 axis contributes to the Warburg effect and cell proliferation induced by low doses of arsenic.AbbreviationsROS, Reactive oxygen species; NAC, N-acetyl-L-cysteine; 2-DG, 2-deoxy-D-glucose; 2-NBDG, 2-Deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose.

The Role of BNIP3 and Blocked Autophagy Flux in Arsenic-Induced Oxidative Stress-Induced Liver Injury in Rats

Arsenic is a widely distributed environmental toxic substance in nature. Chronic arsenic exposure can cause permanent damage to the liver, resulting in the death of poisoned patients. However, the mechanism of liver damage caused by arsenic poisoning is yet unclear. Here, four different concentrations of sodium arsenite (NaAsO2) (0 mg/L (control group), 25 mg/L, 50 mg/L, and 100 mg/L group)were established to induce liver injury in rats. Taking this into account, the relationship and potential mechanisms of oxidative stress, Bcl-2/adenovirus E1B-19-kDa-interacting protein 3 (BNIP3), and inhibition of autophagy flux in liver injury caused by arsenic poisoning were studied. The results indicated that long-term exposure to NaAsO2 could induce oxidative stress, leading to high expression of BNIP3, thereby impaired autophagy flux, and ultimately resulting in liver damage. This research provides an important basis for future research on liver damage caused by chronic arsenic exposure and prevention and treatment with BNIP3 as the target.

Reduced Peripheral Blood Mitochondrial DNA Copy Number as Identification Biomarker of Suspected Arsenic-Induced Liver Damage

Arsenic (As) can cause liver damage and liver cancer and is capable of seriously affecting human health. Therefore, it is important to identify biomarkers of arsenic-induced liver damage. Mitochondria are key targets of hepatotoxicity caused by arsenic. The mitochondrial DNA copy number (mtDNAcn) is the number of mitochondrial DNA (mtDNA) copies in the genome. mtDNA is vulnerable to exogenous chemical attacks, thus causing mtDNAcn to change after exposure to environmental pollutants. Therefore, mtDNAcn can serve as a potential marker to identify and assess the risk of diseases caused by exposure to environmental pollutants. In this study, we selected 272 arsenicosis patients (155 cases without liver damage and 117 cases with liver damage) and 218 participants not exposed to arsenic (155 cases without liver damage and 63 cases with liver damage) as subjects to investigate the correlation between peripheral blood mtDNAcn and arsenic-induced liver damage, as well as the ability of peripheral blood mtDNAcn to identify and assess the risk of arsenic-induced liver damage. Peripheral blood mtDNAcn in patients with arsenic-induced liver damage is significantly decreased and negatively correlated with serum ALT, AST, and GGT levels. The decrease of peripheral blood mtDNAcn was associated with an increased risk of arsenic-induced liver damage. The receiver operating characteristic (ROC) curve analysis indicated that peripheral blood mtDNAcn could specifically identify patients with liver damage in the arsenicosis group. The decision tree C5.0 model was established to identify arsenicosis in all patients with liver damage. Peripheral blood mtDNAcn was included in the model and played the most important role in the identification of arsenic-induced liver damage. This study provided a basis for the identification and evaluation of arsenic-induced liver damage by peripheral blood mtDNAcn, indicating that peripheral blood mtDNAcn is expected to be a potential biomarker of arsenic-induced liver damage, and provides clues for exploring the mechanism of arsenic-induced liver damage from mitochondria damage.

Mechanisms Associated with Cognitive and Behavioral Impairment Induced by Arsenic Exposure

Arsenic (As) is a metalloid naturally present in the environment, in food, water, soil, and air; however, its chronic exposure, even with low doses, represents a public health concern. For a long time, As was used as a pigment, pesticide, wood preservative, and for medical applications; its industrial use has recently decreased or has been discontinued due to its toxicity. Due to its versatile applications and distribution, there is a wide spectrum of human As exposure sources, mainly contaminated drinking water. The fact that As is present in drinking water implies chronic human exposure to this metalloid; it has become a worldwide health problem, since over 200 million people live where As levels exceed safe ranges. Many health problems have been associated with As chronic exposure including cancer, cardiovascular diseases, gastrointestinal disturbances, and brain dysfunctions. Because As can cross the blood-brain barrier (BBB), the brain represents a target organ where this metalloid can exert its long-term toxic effects. Many mechanisms of As neurotoxicity have been described: oxidative stress, inflammation, DNA damage, and mitochondrial dysfunction; all of them can converge, thus leading to impaired cellular functions, cell death, and in consequence, long-term detrimental effects. Here, we provide a current overview of As toxicity and integrated the global mechanisms involved in cognitive and behavioral impairment induced by As exposure show experimental strategies against its neurotoxicity.

A Novel Quinazoline Derivative Prevents and Treats Arsenic-Induced Liver Injury by Regulating the Expression of RecQ Family Helicase

Arsenic is a carcinogenic metalloid toxicant widely found in the natural environment. Acute or prolonged exposure to arsenic causes a series of damages to the organs, mainly the liver, such as hepatomegaly, liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Therefore, it is imperative to seek drugs to prevent arsenic-induced liver injury. Quinazolines are a class of nitrogen heterocyclic compounds with biological and pharmacological effects in vivo and in vitro. This study was designed to investigate the ameliorating effects of quinazoline derivatives on arsenic-induced liver injury and its molecular mechanism. We investigated the mechanism of the quinazoline derivative KZL-047 in preventing and ameliorating arsenic-induced liver injury in vitro by cell cycle and apoptosis. We performed real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blotting combined with molecular docking. In vivo, the experiments were performed to investigate the mechanism of KZL-047 in preventing and ameliorating arsenic-induced liver injury using arsenic-infected mice. Physiological and biochemical indices of liver function in mouse serum were measured, histopathological changes in liver tissue were observed, and immunohistochemical staining was used to detect changes in the expression of RecQ-family helicases in mouse liver tissue. The results of in vitro experiments showed that sodium arsenite (SA) inhibited the proliferation of L-02 cells, induced apoptosis, blocked the cell cycle at the G1 phase, and decreased the expression of RecQ family helicase; after KZL-047 treatment in arsenic-induced L-02 cells, the expression of RecQ family helicase was upregulated, and the apoptosis rate was slowed, leading to the restoration of the cell viability level. KZL-047 inhibited arsenic-induced oxidative stress, alleviated oxidative damage and lipid peroxidation in vivo, and ameliorated arsenic toxicity-induced liver injury. KZL-047 restored the expression of RecQ family helicase proteins, which is consistent with the results of in vitro studies. In summary, KZL-047 can be considered a potential candidate for the treatment of arsenic-induced liver injury.

Depletion of S-adenosylmethionine induced by arsenic exposure is involved in liver injury of rat through perturbing histone H3K36 trimethylation dependent bile acid metabolism

Long-term exposure to arsenic, a common environmental pollutant, can induce various types of liver injury, but the mechanism and treatment measures remain unclear. This study constructed a rat model of arsenic-induced liver injury, with methyl group donor S-adenosylmethionine (SAM) supplementation and Rosa roxburghii Tratt juice intervention, to explore the epigenetic mechanism and intervention method of arsenic-induced liver injury from the perspective of hepatic bile acid metabolism. The results showed that arsenic exposure induced the accumulation of total bile acids (TBA) in the liver and serum of rats, and the abnormalities in liver function and liver histopathology. Arsenic reduced histone H3K36 trimethylation (H3K36me3) in the liver via consuming methyl group donor SAM. The reduction of H3K36me3 was involved in arsenic-induced bile acid accumulation by inhibiting the transcription of negative feedback regulators Fxr and Fgfr4 for hepatic bile acid synthesis. SAM supplementation reversed arsenic-induced bile acid accumulation and liver injury by reactivating H3k36me3-dependent transcription of Fxr and Fgfr4. Moreover, this study found that Rosa roxburghii Tratt juice could rescue arsenic-induced SAM consumption, recover H3K36me3-dependent negative feedback regulation of hepatic bile acid synthesis, and alleviate arsenic-induced bile acid accumulation and liver injury. In conclusion, arsenic exposure perturbed H3K36me3-dependent hepatic bile acid metabolism via depleting SAM, thereby inducing hepatic bile acid accumulation and liver injury, which was ameliorated by the supporting effect of Rosa roxburghii Tratt juice on SAM. This study contributes to understanding the mechanism of arsenic-induced liver injury from the perspective of SAM-dependent epigenetics, providing new insight into its prevention and treatment.

PTEN Overexpression Alters Autophagy Levels and Slows Sodium Arsenite-Induced Hepatic Stellate Cell Fibrosis

Exposure to inorganic arsenic remains a global public health problem. The liver is the main target organ, leading to arsenic-induced liver fibrosis. Phosphatase and tensin homology deleted on chromosome ten (PTEN) may participate in arsenic-induced liver fibrosis by regulating autophagy, but the exact mechanisms remain unclear. We established a mouse model of arsenic poisoning through their drinking water and a fibrosis model using the human hepatic stellate cell line LX-2 through NaAsO₂ exposure for 24 h. Masson staining measured liver fibrosis. The cells were transfected with a PTEN overexpression plasmid. Western blot and qRT-PCR determined the levels of protein/mRNA expression. Fibrosis was evident in both the mouse model and arsenic-exposed LX-2 cells. NaAsO₂ upregulated expression of autophagic markers microtubule-associated protein light chain A/B (LC3), recombinant human autophagy effector protein (Beclin-1), and hairy and enhancer of split homolog-1 (HES1), but downregulated PTEN. Alongside this, α-smooth muscle actin (α-SMA) expression was significantly upregulated by NaAsO₂. PTEN overexpression altered NaAsO₂-induced autophagy and downregulated LC3 and Beclin-1. While Notch1, HES1, α-SMA, and collagen I expression were all downregulated in the NaAsO₂ groups. Therefore, PTEN overexpression might decrease autophagy and inhibit fibrosis progression caused by arsenic, and the NOTCH1/HES1 pathway is likely involved.

Integrated metabolomics and network pharmacology revealing the mechanism of arsenic-induced hepatotoxicity in mice

Endemic arsenic (As) poisoning is a severe biogeochemical disease that endangers human health. Epidemiological investigations and animal experiments have confirmed the damaging effects of As on the liver, but there is an urgent need to investigate the underlying mechanisms. This study adopted a metabolomic approach using UHPLC-QE/MS to identify the different metabolites and metabolic mechanisms associated with As-induced hepatotoxicity in mice. A network pharmacology approach was applied to predict the potential target of As-induced hepatotoxicity. The predicted targets of differential metabolites were subjected to a deep matching for elucidating the integration mechanisms. The results demonstrate that the levels of ALT and AST in plasma significantly increased in mice after As exposure. In addition, the liver tissue showed disorganized liver lobules, lax cytoplasm and inflammatory cell infiltration. Metabolomic analysis revealed that As exposure caused disturbance to 40 and 75 potential differential metabolites in plasma and liver, respectively. Further investigation led to discovering five vital metabolic pathways, including phenylalanine, tyrosine, and tryptophan biosynthesis and nicotinate and nicotinamide metabolism pathways. These pathways may responded to As-induced hepatotoxicity primarily through lipid metabolism, apoptosis, and deoxyribonucleic acid damage. The network pharmacology suggested that As could induce hepatotoxicity in mice by acting on targets including Hsp90aa1, Akt2, Egfr, and Tnf, which regulate PI3K Akt, HIF-1, MAPK, and TNF signaling pathways. Finally, the integrated metabolomics and network pharmacology revealed eight key targets associated with As-induced hepatoxicity, namely DNMT1, MAOB, PARP1, MAOA, EPHX2, ANPEP, XDH, and ADA. The results also suggest that nicotinic acid and nicotinamide metabolisms may be involved in As-induced hepatotoxicity. This research identified the metabolites, targets, and mechanisms of As-induced hepatotoxicity, offering meaningful insights and establishing the groundwork for developing antidotes for widespread As poisoning.

Genome-wide DNA methylation pattern in whole blood of patients with coal-burning arsenic poisoning

Exposure to coal-burning arsenic leads to an increased risk of cancer, multi-systems damage and chronic diseases, with DNA methylation one potential mechanism of arsenic toxicity. There are few studies on genome-wide methylation in the coal-burning arsenic poisoning population. Illumina 850 K methylation beadchip is the most suitable technology for DNA methylation of epigenome-wide association analysis. This study used 850 K to detect changes in Genome-wide DNA methylation in whole blood samples of 12 patients with coal-burning arsenic poisoning ( Arsenic poisoning group) and four healthy control participants (Healthy control group). There is clearly abnormal genome-wide DNA methylation in coal-burning arsenic poisoning, with 647 significantly different methylation positions, 524 different methylation regions and 335 significantly different methylation genes in arsenic poisoning patients compared with healthy controls. Further functional analysis of Gene ontology (GO) and Kyoto encyclopedia of genes (KEGG) found 592 GO items and 131 KEGG pathways between patients of coal-burning arsenic poisoning and healthy control. Then, analysis of gene degree and combined-score identified NAPRT1, NT5C3B, NEDD4L, SLC22A3 and RAB11B as target genes. Further validation by qRT-PCR indicates that mRNA expression of five genes changes significantly in the arsenic poisoning group (n = 72) compared to the healthy control group (n = 72). These results showed the genome-wide methylation pattern and highlighted five critical genes within the coal-burning arsenic poisoning population that involve Nicotinate and nicotinamide metabolism, Choline metabolism in cancer, and Ubiquitin mediated proteolysis. Next, the methylation profile of coal burning arsenic poisoning will be further excavation and the mechanism of coal burning arsenic poisoning will be further explored from five genes related pathways and functions.

LC/MS/MS-Based Liver Metabolomics to Identify Chronic Liver Injury Biomarkers Following Exposure to Arsenic in Rats

Arsenic is a widespread natural metalloid element. Long-term chronic exposure to arsenic can lead to different degrees of liver injury. Although the etiology of this disease is well known, to date, the underlying mechanism of arsenic-induced liver injury remains unclear, and no specific treatment exists because of the complexity of arsenic. In the present study, potential biomarkers and metabolic pathways in the livers of Wistar rats treated with arsenic for 24 weeks were investigated using an integrated metabolic approach with an LC-Orbitrap Q Exactive™ HF-X mass spectrometer. Markedly increased liver levels of arsenic, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bile acid (TBA) were detected in the arsenic treatment groups (P < 0.05). Furthermore, histopathological examination of liver tissues showed obviously swollen, loose cytoplasm and increased necrosis in the arsenic treatment groups compared with those in the control group (P < 0.05). Metabonomics results showed that 109 metabolites (variable importance in the projection (VIP) > 1; fold change > 2 or < 0.5; P adjusted < 0.05) changed significantly after exposure to arsenic and included 71 upregulated metabolites and 38 downregulated metabolites. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that 6 metabolic pathways with statistical significance-phenylalanine metabolism, pyruvate metabolism, glycolysis/gluconeogenesis, citrate cycle (TCA cycle), thiamine metabolism, and vitamin B6 metabolism-were selected, and 13 differential metabolites were detected to be involved in regulating these metabolic pathways. The present study could help identify potential biomarkers and their functions, as well as metabolic pathways, likely providing evidence for the early diagnosis, prevention, and mechanistic study of arsenism.

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 Exposure through Dietary Intake and Associated Health Hazards in the Middle East

Dietary arsenic (As) contamination is a major public health issue. In the Middle East, the food supply relies primarily on the import of food commodities. Among different age groups the main source of As exposure is grains and grain-based food products, particularly rice and rice-based dietary products. Rice and rice products are a rich source of core macronutrients and act as a chief energy source across the world. The rate of rice consumption ranges from 250 to 650 g per day per person in South East Asian countries. The source of carbohydrates through rice is one of the leading causes of human As exposure. The Gulf population consumes primarily rice and ready-to-eat cereals as a large proportion of their meals. Exposure to arsenic leads to an increased risk of non-communicable diseases such as dysbiosis, obesity, metabolic syndrome, diabetes, chronic kidney disease, chronic heart disease, cancer, and maternal and fetal complications. The impact of arsenic-containing food items and their exposure on health outcomes are different among different age groups. In the Middle East countries, neurological deficit disorder (NDD) and autism spectrum disorder (ASD) cases are alarming issues. Arsenic exposure might be a causative factor that should be assessed by screening the population and regulatory bodies rechecking the limits of As among all age groups. Our goals for this review are to outline the source and distribution of arsenic in various foods and water and summarize the health complications linked with arsenic toxicity along with identified modifiers that add heterogeneity in biological responses and suggest improvements for multi-disciplinary interventions to minimize the global influence of arsenic. The development and validation of diverse analytical techniques to evaluate the toxic levels of different As contaminants in our food products is the need of the hour. Furthermore, standard parameters and guidelines for As-containing foods should be developed and implemented.

Histone demethylase JHDM2A participates in the repair of arsenic-induced DNA damage in L-02 cells by regulating DDB2

Arsenic is widely present in nature and is a class I carcinogen confirmed by the World Health Organization and the International Agency for Research on Cancer. The liver is responsible for biotransformation in the body and is one of the major organs where arsenic accumulates in the body, but the mechanisms of arsenic-induced abnormal DNA damage repair pathways in the liver are still unclear. Recent studies have revealed that epigenetic mechanisms play an important role in arsenic-induced lesions. In this study, an in vitro model was established using human normal hepatocytes L-02 to investigate the mechanism of the specific demethylase JHDM2A of H3K9me2 in the repair of arsenic-induced DNA damage in L-02 cells. The results showed that with the increase of arsenic concentrations, the extent of DNA damage in L-02 cells showed an increasing trend and total intracellular H3K9me2 expression was downregulated. In addition, the enrichment level of H3K9me2 in the promoter region of DBB2, a key factor of nucleotide repair (NBR), increased, while protein and mRNA expression levels showed a decreasing trend. Thereafter, we overexpressed and repressed JHDM2A and found a close association between JHDM2A and arsenic-induced DNA damage. DDB2 protein and mRNA expression was downregulated with JHDM2A overexpression and upregulated with JHDM2A repression, while DBB2 promoter region H3K9me2 enrichment levels remained at a high level, although they were affected after JHDM2A overexpression or knockdown to some extent. These results suggest a potential mechanism by which JHDM2A may regulate DDB2 gene expression, participate in the NBR process, and play a role in arsenic-induced DNA damage in L-02 cells, which is not the result of JHDM2A exerting demethylation on H3K9me2 in the DDB2 promoter region. Our results provided an epigenetic mechanism for endemic arsenicosis, as well as a scientific basis for potential prevention and control measures.

Assessing the Association of Element Imbalances With Arsenism and the Potential Application Value of Rosa roxburghii Tratt Juice

Endemic arsenism caused by coal burning is a unique type of biogeochemical disease that only exists in China, and it is also a disease of element imbalances. Previous studies have shown that element imbalances are involved in the pathogenesis of arsenic; however, the interaction between the various elements and effective preventive measures have not been fully studied. This study first conducted a cross-sectional study of a total of 365 participants. The results showed that arsenic exposure can increase the content of elements (Al, As, Fe, Hg, K, and Na) in the hair (p < 0.05), but the content of other elements (Ca, Co, Cu, Mn, Mo, P, Se, Sr, V, and Zn) was significantly decreased (p < 0.05). Also, the high level of As, Fe, and Pb and the low level of Se can increase the risk of arsenism (p < 0.05). Further study found that the combined exposure of Fe–As and Pb–As can increase the risk of arsenism, but the combined exposure of Se–As can reduce the risk of arsenism (p < 0.05). In particular, a randomized, controlled, double-blind intervention study reveals that Rosa roxburghii Tratt juice (RRT) can reverse the abovementioned element imbalances (the high level of Al, As, and Fe and the low level of Cu, Mn, Se, Sr, and Zn) caused by arsenic (p < 0.05). Our study provides some limited evidence that the element imbalances (the high level of As, Fe, and Pb and the low level of Se) are the risk factors for the occurrences of arsenism. The second major finding was that RRT can regulate the element imbalances, which is expected to improve arsenism. This study provides a scientific basis for further understanding a possible traditional Chinese health food, RRT, as a more effective detoxication of arsenism.

The Molecular Mechanism of Hepatic Lipid Metabolism Disorder Caused by NaAsO2 through Regulating the ERK/PPAR Signaling Pathway

Chronic arsenic exposure is a risk factor for human fatty liver disease, and the ERK signaling pathway plays an important role in the regulation of liver lipid metabolism. However, whether ERK plays a role in the progression of arsenic-induced liver lipid metabolism disorder and the specific mechanism remain unclear. Here, by constructing a rat model of liver lipid metabolism disorder induced by chronic arsenic exposure, we demonstrated that ERK might regulate arsenic-induced liver lipid metabolism disorders through the PPAR signaling pathway. Arsenic could upregulate the expression of PPARγ and CD36 in the rat liver, decrease the expression of PPARα and CPT-1 in the rat liver, increase the organ coefficient of the rat liver, decrease the content of TG in rat serum, and promote fat deposition in the rat liver. In the arsenic-induced rat model of hepatic lipid metabolism disorder, we found that the expression of p-ERK was increased. In order to further explore whether the ERK signaling pathway was involved in arsenic-induced liver lipid metabolism disorder, we exposed L-02 cells to different arsenic concentrations, and the results showed that arsenic significantly increased the expression of P-ERK in L-02 cells in a dose-dependent manner. We further treated L-02 cells with ERK inhibitors and found that the expression of TG, PPARα, and CPT-1 in L-02 cells increased, while the expression of P-ERK, PPARγ, and CD36 decreased. In conclusion, ERK may be involved in arsenic-induced liver lipid metabolism disorder by regulating the PPAR signaling pathway. These findings are expected to provide a new targeting strategy for arsenic-induced liver lipid metabolism disorder.

Hydroxyapatite-based adsorbents: Applications in sequestering heavy metals and dyes

Hydroxyapatite (HAp) is a calcium phosphate material that was used primarily in bone regeneration and repair as a result of its chemical similarity with bone. However, HAp has emerged as a very promising adsorbent for sequestering contaminants like heavy metals, dyes, hydrocarbons as well as other emerging pollutants from wastewater as a result of its versatility and encouraging adsorptive properties. Contaminants like heavy metals and dyes have been a major source of environmental concern. Research studies involving the use of HAp as adsorbents for the adsorptive treatment of heavy metal- and dye-contaminated wastewater have become increasingly popular due to its eco-friendliness, easy synthesis, unique adsorption properties etc. Various methods are available for the synthesis of HAp and its composites with some of these methods used in combination with other methods to obtain more efficient HAp-based adsorbents. In this work, the adsorptive removal of heavy metals and dyes by HAp and its composites was extensively reviewed as well as the parametric effects of process factors like contact time, solution pH, temperature, solute concentration etc on the adsorption process. Kinetic, thermodynamic, and isotherm models for elucidating the adsorption process were also considered. Generally, from the works reviewed, HAp-based adsorbents were found to be very effective for sequestering heavy metals and dyes from solution and thus presents a low-cost option for adsorptive wastewater treatment.

The hypermethylation of FOXP3 gene as an epigenetic marker for the identification of arsenic poisoning risk

Background and Purpose: Arsenic exposure can lead to skin lesions and multiple organ damage, which are not easily reversible and for which there is no effective therapeutics. Identification of reliable epigenetic markers is essential for early recognition of arsenic poisoning risk. Anomalous DNA methylation of immune homeostasis regulator FOXP3 is a critical mechanism for triggering arsenic poisoning. This study aims to explore the value of FOXP3 methylation in the identification of arsenic poisoning risk.Methods: 88 arsenic poisoning subjects and 41 references were recruited. Urinary arsenic contents and FOXP3 methylation in PBLCs was measured by ICP-MS and pyrosequencing, respectively.Results: The results showed that the elevated FOXP3 methylation in PBLCs were associated with the increased levels of urinary arsenic and were positively associated with the increased risk of arsenic poisoning and its progression. The result of mediation analysis revealed that 24.3% of the effect of arsenic exposure on the risk of arsenic poisoning was mediated by increased FOXP3 methylation. Additionally, we constructed a nomogram model with FOXP3 methylation as an epigenetic predictor to assess the probability of individual arsenic poisoning. The model showed a robust ability in the discrimination of arsenic poisoning risk, with an area under receiver operating characteristics curve of 0.897(0.845-0.949) and more than 70% accuracy. The calibration curves and the Harrell concordance index showed that the consistency rate between the probability predicted by the nomogram model and the actual probability is 89.7%.Conclusions: Taken together, we found the great potential of FOXP3 methylation for the identification of arsenic poisoning risk and provided a new approach to the application of epigenetic markers in accurately quantifying the risk of adverse outcomes.

Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry for the Analysis of Complex Compounds in Serum and Its Application in Accurate Detection of Early Arsenic Exposure

With the acceleration of industrialization, environmental arsenic pollution is threatening human health. However, by the time clinical symptoms appear, arsenic toxicity has usually caused irreversible damage to the body, so it is important to establish a rapid and accurate screening method for early arsenic exposure. In this work, 32 female C57BL/6 mice were exposed to different concentrations of inorganic arsenic in drinking water for a week. By analyzing the changes in serum, more than 20 compounds were detected to increase or decrease with the increase of arsenic intake. The abnormal increase in inosine, xanthine, xanthosine, and hypoxanthine and the abnormal purine pathway were found at the same time. Dimethylarsenic acid, an important inorganic arsenic metabolite in the body, was also found in serum. Combined with statistical analysis, early arsenic exposure can be easily and quickly detected, and the potential health risks of short-term exposure can be revealed simultaneously.

Molecular Mechanism of Arsenic-Induced Neurotoxicity including Neuronal Dysfunctions

Arsenic is a key environmental toxicant having significant impacts on human health. Millions of people in developing countries such as Bangladesh, Mexico, Taiwan, and India are affected by arsenic contamination through groundwater. Environmental contamination of arsenic leads to leads to various types of cancers, coronary and neurological ailments in human. There are several sources of arsenic exposure such as drinking water, diet, wood preservatives, smoking, air and cosmetics, while, drinking water is the most explored route. Inorganic arsenic exhibits higher levels of toxicity compared its organic forms. Exposure to inorganic arsenic is known to cause major neurological effects such as cytotoxicity, chromosomal aberration, damage to cellular DNA and genotoxicity. On the other hand, long-term exposure to arsenic may cause neurobehavioral effects in the juvenile stage, which may have detrimental effects in the later stages of life. Thus, it is important to understand the toxicology and underlying molecular mechanism of arsenic which will help to mitigate its detrimental effects. The present review focuses on the epidemiology, and the toxic mechanisms responsible for arsenic induced neurobehavioral diseases, including strategies for its management from water, community and household premises. The review also provides a critical analysis of epigenetic and transgenerational modifications, mitochondrial oxidative stress, molecular mechanisms of arsenic-induced oxidative stress, and neuronal dysfunction.

Fate of arsenic in living systems: Implications for sustainable and safe food chains

Arsenic, a group 1 carcinogen for humans, is abundant as compared to other trace elements in the environment and is present mainly in the Earth's crust and soil. The arsenic distributions in different geographical regions are dependent on their geological histories. Anthropogenic activities also contribute significantly to arsenic release into the environment. Arsenic presents several complications to humans, animals, and plants. The physiology of plants and their growth and development are affected by arsenic. Arsenic is known to cause cancer and several types of organ toxicity, such as cardiotoxicity, nephrotoxicity, and hepatotoxicity. In the environment, arsenic exists in variable forms both as inorganic and organic species. From arsenic containing compartments, plants can absorb and accumulate arsenic. Crops grown on these contaminated soils pose several-fold higher toxicity to humans compared with drinking water if arsenic enters the food chain. Information regarding arsenic transfer at different trophic levels in food chains has not been summarized until now. The present review focuses on the food chain perspective of arsenic, which affects all components of the food chain during its course. The circumstances that facilitate arsenic accumulation in flora and fauna, as components of the food chain, are outlined in this review.