Long-term dietary cadmium intake and postmenopausal endometrial cancer incidence: a population-based prospective cohort study

Plastic-related endocrine disrupting chemicals significantly related to the increased risk of estrogen-dependent diseases in women

OBJECTIVE

To evaluate the association between exposure to plastic-related endocrine-disrupting chemicals (EDCs), specifically Bisphenol A (BPA), Phthalates, Cadmium, and Lead, and the risk of estrogen-dependent diseases (EDDs) such as polycystic ovary syndrome (PCOS), endometriosis, or endometrial cancer by conducting a meta-analysis of relevant studies.

METHODS

PubMed, Web of Science, and Cochrane Library databases were used for literature retrieval of articles published until the 21st of April 2023. Literature that evaluated the association between BPA, phthalates, cadmium, and/or lead exposure and the risk of PCOS, endometriosis, or endometrial cancer development or exacerbation were included in our analysis. STATA/MP 17.0 was used for all statistical analyses.

RESULTS

Overall, 22 articles were included in our meta-analysis with a total of 83,641 subjects all of whom were females aged between 18 and 83 years old. The overall effect size of each study was as follows: endometriosis risk in relation to BPA exposure ES 1.82 (95% CI; 1.50, 2.20). BPA and PCOS risk ES 1.61 (95% CI; 1.39, 1.85). Phthalate metabolites and endometriosis risk; MBP ES 1.07 (95% CI; 0.86, 1.33), MEP ES 1.05 (95% CI; 0.87, 1.28), MEHP ES 1.15 (95% CI; 0.67, 1.98), MBzP ES 0.97 (95% CI; 0.63, 1.49), MEOHP ES 1.87 (95% CI; 1.21, 2.87), and MEHHP ES 1.98 (95% CI; 1.32, 2.98). Cadmium exposure and endometrial cancer risk ES 1.14 (95% CI; 0.92, 1.41). Cadmium exposure and the risk of endometriosis ES 2.54 (95% CI; 1.71, 3.77). Lead exposure and the risk of endometriosis ES 1.74 (95% CI; 1.13, 2.69).

CONCLUSION

Increased serum, urinary, or dietary concentration of MBzP and MEHP in women is significantly associated with endometriosis risk. Increased cadmium concentration is associated with endometrial cancer risk.

Ameliorative potential of eriocitrin against cadmium instigated hepatotoxicity in rats via regulating Nrf2/keap1 pathway

BACKGROUND

Cadmium (Cd) is a hazardous heavy metal that adversely affects the vital body organs particularly liver. Eriocitrin (ERCN) is a plant-based flavonoid that is well-known for its wide range of pharmacological potential. This research trial was aimed to determine the ameliorative potential of ERCN against Cd provoked hepatotoxicity in rats.

METHODOLOGY

Twenty-four rats (Rattus norvegicus) were apportioned into control, Cd treated (5 mg/kg), Cd (5 mg/kg) + ERCN (25 mg/kg) and only ERCN (25 mg/kg) administrated group. Expressions of Nrf2/Keap1 pathway and apoptotic markers were assessed through qRT-PCR. The levels of inflammatory and liver function markers were evaluated by using standard ELISA kits.

KEY FINDINGS

Cd exposure reduced the expression of Nrf2 and anti-oxidant genes as well as the activity of catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione (GSH) contents while escalating the expression of Keap1. Furthermore, Cd intoxication augmented malondialdehyde (MDA) and reactive oxygen species (ROS) levels in hepatic tissues. Exposure to Cd resulted in a notable elevation in the levels of alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST). Cd administration upregulated nuclear factor-kappa B (NF-κB), interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels as well as cyclooxygenase-2 (COX-2) activity. Furthermore, Cd administration upsurged Bax and Caspase-3 expression while reducing the expression of Bcl-2. Moreover, Cd intoxication disrupted the normal architecture of hepatic tissues. However, supplementation of ERCN significantly (p < 0.05) ameliorated the aforementioned disruptions induced by Cd intoxication.

CONCLUSION

ERCN treatment remarkably ameliorated the hepatic tissues owing to its antioxidant, anti-inflammatory, and anti-apoptotic potentials. These findings underscore the therapeutic potential of ERCN to counteract the adverse effects of environmental pollutants on hepatic tissues.

Rapid aggregation of amyloid-like protein enhanced by mTGase to prepare functional wool fabrics for efficient and sustainable remove heavy metals from wastewater

To counteract the increasing severity of water pollution and purify water sources, wastewater treatment materials are essential. In particular, it is necessary to improve the bonding strength between the adsorption material and the substrate in a long-term humid environment, and resist the invasion of microorganisms to prolong the service life. In this study, an amyloid-like aggregation method of lysozyme catalyzed by microbial transglutaminase (mTGase). Lysozyme self-assembles into an amyloid-like phase-transited lysozyme (PTL) in the presence of a reducing agent. Simultaneously, mTGase catalyzes acyl transfer reactions within lysozyme molecules or between lysozyme and keratin molecules, and driving PTL assembly on the wool fiber (TG-PTL@wool). This process enhances the grafting amount and fastness of PTL on the wool. Moreover, the tensile strength of wool fabric increased to 523 N. TG-PTL@wool achieves a 97.32 % removal rate of heavy metals, maintaining a removal rate of over 95 % after 5 cycles. TG-PTL@wool has excellent antibacterial property (99 %), and it remains above 90 % after 50 times of circulating washing. This study proved that mTGase can enhance the amyloid aggregation of lysozyme and enhance the bonding strength between PTL coating and substrate. Moreover, TG-PTL@wool provides a sustainable, efficient and cleaner solution for removing heavy metals from water.

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.

Highly Selective Turn-on Fluorescence Sensor for Cd2+ Ions by Tripodal Organic Ligand

Organic fluorescence sensor for selectively detecting and quantifying toxic heavy metal ions has received significant interest due to their environmental hazards. Herein, we have designed and synthesized a simple tripodal Schiff base ligand (1) based on hydroxy-naphthaldehyde and tris(2-aminoethyl)amine (TREN) and demonstrated highly selective turn-on fluorescence sensing of Cd2+ ions. The free ligand did not show any fluorescence in DMF. In contrast, Cd2+ (10- 4 M) addition exhibited a strong enhancement of fluorescence at 450 nm. Interestingly, other metal ions including Zn2+, which exhibit similar chemistry, did not show any turn-on fluorescence. The concentration-dependent studies of 1 with Cd2+ showed the detection limit of 6.78 × 10- 8 M. NMR spectra of 1 with Cd2+ and computational studies were performed to understand the mechanism of sense.

The dynamic face of cadmium-induced Carcinogenesis: Mechanisms, emerging trends, and future directions

Cadmium (Cd) is a malleable element with odorless, tasteless characteristics that occurs naturally in the earth's crust, underground water, and soil. The most common reasons for the anthropological release of Cd to the environment include industrial metal mining, smelting, battery manufacturing, fertilizer production, and cigarette smoking. Cadmium-containing products may enter the environment as soluble salts, vapor, or particle forms that accumulate in food, soil, water, and air. Several epidemiological studies have highlighted the association between Cd exposure and adverse health outcomes, especially renal toxicity, and the impact of Cd exposure on the development and progression of carcinogenesis. Also highlighted is the evidence for early-life and even maternal exposure to Cd leading to devastating health outcomes, especially the risk of cancer development in adulthood. Several mechanisms have been proposed to explain how Cd mediates carcinogenic transformation, including epigenetic alteration, DNA methylation, histone posttranslational modification, dysregulated non-coding RNA, DNA damage in the form of DNA mutation, strand breaks, and chromosomal abnormalities with double-strand break representing the most common DNA form of damage. Cd induces an indirect genotoxic effect by reducing p53's DNA binding activity, eventually impairing DNA repair, inducing downregulation in the expression of DNA repair genes, which might result in carcinogenic transformation, enhancing lipid peroxidation or evasion of antioxidant interference such as catalase, superoxide dismutase, and glutathione. Moreover, Cd mediates apoptosis evasion, autophagy activation, and survival mechanisms. In this review, we decipher the role of Cd mediating carcinogenic transformation in different models and highlight the interaction between various mechanisms. We also discuss diagnostic markers, therapeutic interventions, and future perspectives.

High-contrast multicolour photoswitching based on dithienylethene Schiff base with a hydrazinylquinoline moiety

A new asymmetrical photochromic diarylethene DTE-HQo composed of a 2-hydrazinoquinoline moiety as the binding unit for ions and dithenylethene as a photoswitching trigger was reported. DTE-HQo displayed favourable photochromism upon irradiation with UV/vis light. Its fluorescent behaviour could be efficiently modulated by light, Zn2+, Cd2+ and HSO4-. The binding of Zn2+ induced a strong fluorescence peak at 510 nm in DTE-HQo due to the formation of a 1:2 complex [Zn2+ + 2DTE-HQo], resulting in a notable colour change from dark to intense white emission. Triggered by Cd2+, DTE-HQo formed a 1:1 complex [Cd2+ + DTE-HQo], leading to an enhanced emission intensity by 21-fold with an emission peak red-shifted from 461 nm to 514 nm. Unexpectedly, [Zn2+ + 2DTE-HQo] underwent hydrolysis when stimulated with water, generating a yellow-emitting complex [Zn2+ + DTE-HQo]. This color change easily distinguishes it from Cd2+ complex. Additionally, DTE-HQo showed high selectivity towards HSO4- and exhibited distinct "turn-on" fluorescence with a colour change from dark to bright blue upon stimulation. Moreover, the strong emission complexes of DTE-HQo with Zn2+, Cd2+ and HSO4- could be effectively quenched during the photocyclization process. Therefore, DTE-HQo can serve as an unimolecular multicolour photoswitching chemosensor, offering potential applications as a multifunctional probe for detecting Zn2+, Cd2+ and HSO4-.

Total Effective Xenoestrogen Burden in Serum Samples and Risk of Endometrial Cancer in the Spanish Screenwide Case-Control Study

BACKGROUND

Endometrial cancer is a hormone-dependent cancer, and estrogens play a relevant role in its etiology. However, little is known about the effects of environmental pollutants that act as xenoestrogens or that influence estrogenic activity through different pathways.

OBJECTIVE

We aimed to assess the relationship between the combined estrogenic activity of mixtures of xenoestrogens present in serum samples and the risk of endometrial cancer in the Screenwide case-control study.

METHODS

The total effective xenoestrogen burden (TEXB) attributable to organohalogenated compounds (TEXB- α ) and to endogenous hormones and more polar xenoestrogens (TEXB- β ) was assessed in serum from 156 patients with endometrial cancer (cases) and 150 controls by combining chemical extraction and separation by high-performance liquid chromatography with the E-SCREEN bioassay for estrogenicity.

RESULTS

Median TEXB- α and TEXB- β levels for cases (0.30 and 1.25  Eeq pM / mL , respectively) and controls (0.42 and 1.28  Eeq pM / mL , respectively) did not significantly differ (p = 0.653 and 0.933, respectively). An inverted-U risk trend across serum TEXB- α and TEXB- β levels was observed in multivariate adjusted models: Positive associations were observed for the second category of exposure in comparison to the lowest category of exposure [odds ratio  ( OR ) = 2.11 (95% CI: 1.13, 3.94) for TEXB- α , and OR = 3.32 (95% CI: 1.62, 6.81) for TEXB- β ], whereas no significant associations were observed between the third category of exposure and the first [OR = 1.22 (95% CI: 0.64, 2.31) for TEXB- α , and OR = 1.58 (95% CI: 0.75, 3.33) for TEXB- β ]. In mutually adjusted models for TEXB- α and TEXB- β levels, the association of TEXB- α with endometrial cancer risk was attenuated [OR = 1.45 (95% CI: 0.61, 3.47) for the second category of exposure], as well as estimates for TEXB- β (OR = 2.68 ; 95% CI: 1.03, 6.99). Most of the individual halogenated contaminants showed no associations with both TEXB and endometrial cancer.

CONCLUSIONS

We evaluated serum total xenoestrogen burden in relation to endometrial cancer risk and found an inverted-U risk trend across increasing categories of exposure. The use of in vitro bioassays with human samples may lead to a paradigm shift in the way we understand the negative impact of chemical mixtures on human health effects. These results are relevant from a public health perspective and for decision-makers in charge of controlling the production and distribution of chemicals with xenoestrogenic activity. https://doi.org/10.1289/EHP13202.

Correlates of whole blood metal concentrations among reproductive-aged Black women

BACKGROUND

Metals may influence reproductive health, but few studies have investigated correlates of metal body burden among reproductive-aged women outside of pregnancy. Furthermore, while there is evidence of racial disparities in exposure to metals among U.S. women, there is limited research about correlates of metal body burden among Black women.

OBJECTIVE

To identify correlates of whole blood metal concentrations among reproductive-aged Black women.

METHODS

We analyzed cross-sectional data from a cohort of 1664 Black women aged 23-35 years in Detroit, Michigan, 2010-2012. We collected blood samples and questionnaire data. We measured concentrations of 17 metals in whole blood using inductively-coupled plasma-mass spectrometer-triple quadrupole and total mercury using Direct Mercury Analyzer-80. We used multivariable linear regression models to identify sociodemographic, environmental, reproductive, and dietary correlates of individual metal concentrations.

RESULTS

In adjusted models, age was positively associated with multiple metals, including arsenic, cadmium, and mercury. Education and income were inversely associated with cadmium and lead. Current smoking was strongly, positively associated with cadmium and lead. Alcohol intake in the past year was positively associated with arsenic, barium, copper, lead, mercury, vanadium, and zinc. Having pumped gasoline in the past 24 h was positively associated with cadmium, chromium, and molybdenum. Having lived in an urban area for the majority of residence in Michigan was positively associated with arsenic, lead, and nickel. Higher water intake in the past year was positively associated with several metals, including lead. Fish intake in the past year was positively associated with arsenic, cesium, and mercury. We also observed associations with body mass index, season, and other environmental, reproductive, and dietary factors.

SIGNIFICANCE

We identified potential sources of exposure to metals among reproductive-aged Black women. Our findings improve understanding of exposures to metals among non-pregnant reproductive-aged women, and can inform policies in support of reducing disparities in exposures.

IMPACT STATEMENT

There are racial disparities in exposures to metals. We analyzed correlates of blood metal concentrations among reproductive-aged Black women in the Detroit, Michigan metropolitan area. We identified sociodemographic, anthropometric, lifestyle, environmental, reproductive, and dietary correlates of metal body burden. Age was positively associated with several metals. Education and income were inversely associated with cadmium and lead, indicating socioeconomic disparities. We identified potential exposure sources of metals among reproductive-aged Black women, including smoking, environmental tobacco smoke, pumping gasoline, living in an urban area, and intake of alcohol, water, fish, and rice.

Effect of the Combination of Phosphate-Solubilizing Bacteria with Orange Residue-Based Activator on the Phytoremediation of Cadmium by Ryegrass

Amendments with activators or microorganisms to enhance phytoremediation in toxic-metal-polluted soils have been widely studied. In this research, the production of indoleacetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase by phosphate-solubilizing bacteria was investigated during a pure culture experiment. Pot experiments were performed using Cd-polluted soil with the following treatments: control (CK, only ultrapure water), orange-peel-based activator (OG), and a combination of phosphate-solubilizing bacteria (Acinetobacter pitti) and OG (APOG). Ryegrass plant height and fresh weight, Cd content in ryegrass, total and available Cd soil content, soil enzyme activity, and soil bacterial diversity were determined in this work. The findings showed that the height of ryegrass in OG and APOG increased by 14.78% and 21.23%. In the APOG group, a decreased ratio of Cd was 3.37 times that of CK, and the bioconcentration factor was 1.28 times that of CK. The neutral phosphatase activity of APOG was 1.33 times that of CK and catalase activity was 1.95 times that of CK. The activity of urease was increased by 35.48%. APOG increased the abundance of beneficial bacteria and Proteobacteria was the dominant bacterium, accounting for 57.38% in APOG. Redundancy analysis (RDA) showed that nutrient elements were conducive to the propagation of the dominant bacteria, the secretion of enzymes, and the extraction rate of Cd in the soil. The possible enhancement mechanism of phytoremediation of cadmium by A. pitti combined with OG was that, on the one hand, APOG increased soil nutrient elements and enzyme activities promoted the growth of ryegrass. On the other hand, APOG activated Cd and boosted the movement of Cd from soil to ryegrass. This research offers insight for the combination of phosphate-solubilizing bacteria with an orange-peel-based activator to improve phytoremediation of Cd-contaminated soils and also provides a new way for the resource utilization of fruit residue.

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.

Assessment of Cadmium (Cd) and Lead (Pb) Blood Concentration on the Risk of Endometrial Cancer

BACKGROUND

Cadmium (Cd) and lead (Pb) are heavy metals with carcinogenic potential. Their increased concentration has been correlated with a risk of malignancies, including breast, lung, kidney, gastrointestinal, and gynecological cancers. Most of the studies have evaluated tissue heavy metal concentration. To the best of our knowledge, this is the first study to evaluate blood Cd and lead levels in different uterine pathologies and the risk of endometrial cancer.

METHODS

This study included 110 patients with a histopathological diagnosis of endometrial cancer, endometrial polyps, endometrial hyperplasia, uterine myoma, and normal endometrium. The patients included in the study were assessed in terms of their endometrial cancer risk factors and blood heavy metal levels. The analysis was conducted using inductively coupled plasma optical emission spectrometry.

RESULTS

There was a significant difference in the Cd and Cd/Pb ratio among the different groups of patients (p = 0.002), with higher a median Cd concentration among the endometrial cancer patients. The differences in Pb concentration were not significant (p = 0.717). There were also no differences in the Cd and Pb concentrations based on the patients' menopausal status nor BMI index. The univariate logistic regression showed a blood cadmium concentration above the median to be associated with an increased risk of endometrial cancer (OR = 5.25; 95% CI 1.56, 17.72). No significant associations were observed between the Pb concentration or Cd/Pb ratio and endometrial cancer risk.

CONCLUSION

The concentration of Cd varies in patients diagnosed with different uterine pathologies. Increased blood cadmium concentration seems to be a risk factor for endometrial studies. Further research on greater populations, accounting for environmental and lifestyle heavy metal exposure, is required to validate our findings.

Cadmium, Lead, Chronic Physiological Stress and Endometrial Cancer: How Environmental Policy Can Alter the Exposure of At-Risk Women in the United States

The health and life outcomes of individuals are intertwined with the context in which they grow and live. The totality of exposures one experiences affects health in the short term and throughout the life course. Environmental exposure to multiple contaminants can increase stress levels in individuals and neighborhoods with psychosocial stressors such as crime, drug and alcohol misuse, and violence also taking a toll on individual and neighborhood wellbeing. In addition, the availability, organization, and quality of local institutions and infrastructure all affect health in the short and long term. The role of these factors in endometrial cancer will be explored in this paper. In addition, policy implications regarding lead, chronic physiological stress, and endometrial cancer will be explored to ascertain the impact of these factors on at-risk women.

Exposure to environmental chemicals and cancer risk: epidemiological evidence from Japanese studies

Exposure to certain chemicals in the environment may contribute to the risk of developing cancer. Although cancer risk from environmental chemical exposure among general populations is considered low compared to that in occupational settings, many people may nevertheless be chronically exposed to relatively low levels of environmental chemicals which vary by such various factors as residential area, lifestyle, and dietary habits. It is therefore necessary to assess population-specific exposure levels and examine their association with cancer risk. Here, we reviewed epidemiological evidence on cancer risk and exposure to dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFASs), cadmium, arsenic, and acrylamide. Japanese are widely exposed to these chemicals, mainly through the diet, and an association with increased cancer risk is suspected. Epidemiological evidence from Japanese studies to date does not support a positive association between blood concentrations of DDT, HCH, PCBs, and PFASs and risk of breast or prostate cancer. We established assessment methods for dietary intake of cadmium, arsenic, and acrylamide using a food frequency questionnaire. Overall, dietary intakes of cadmium, arsenic, and acrylamide were not significantly associated with increased risk of total cancer and major cancer sites in the Japan Public Health Center-based Prospective Study. However, statistically significant positive associations were observed between dietary cadmium intake and risk of estrogen receptor-positive breast cancer among postmenopausal women, and dietary arsenic intake and risk of lung cancer among male smokers. In addition, studies using biomarkers as exposure assessment revealed statistically significant positive associations between urinary cadmium concentration and risk of breast cancer, and between ratio of hemoglobin adducts of acrylamide and glycidamide and risk of breast cancer. Epidemiological studies of general populations in Japan are limited and further evidence is required. In particular, studies of the association of organochlorine and organofluorine compounds with risk of cancer sites other than breast and prostate cancer are warranted, as are large prospective studies of the association between biomarkers of exposure and risk of cancer.

Dietary omega-3 fatty acids and endometrial cancer risk in the Epidemiology of Endometrial Cancer Consortium: An individual-participant meta-analysis

BACKGROUND

Limited data from prospective studies suggest that higher dietary intake of long-chain omega-3 polyunsaturated fatty acids (LCn3PUFA), which hold anti-inflammatory properties, may reduce endometrial cancer risk; particularly among certain subgroups characterized by body mass and tumor pathology.

MATERIALS AND METHODS

Data from 12 prospective cohort studies participating in the Epidemiology of Endometrial Cancer Consortium were harmonized as nested case-control studies, including 7268 endometrial cancer cases and 26,133 controls. Habitual diet was assessed by food frequency questionnaire, from which fatty acid intakes were estimated. Two-stage individual-participant data mixed effects meta-analysis estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) through logistic regression for associations between study-specific energy-adjusted quartiles of LCn3PUFA and endometrial cancer risk.

RESULTS

Women with the highest versus lowest estimated dietary intakes of docosahexaenoic acid, the most abundant LCn3PUFA in diet, had a 9% increased endometrial cancer risk (Quartile 4 vs. Quartile 1: OR 1.09, 95% CI: 1.01-1.19; P trend = 0.04). Similar elevated risks were observed for the summary measure of total LCn3PUFA (OR 1.07, 95% CI: 0.99-1.16; P trend = 0.06). Stratified by body mass index, higher intakes of LCn3PUFA were associated with 12-19% increased endometrial cancer risk among overweight/obese women and no increased risk among normal-weight women. Higher associations appeared restricted to White women. The results did not differ by cancer grade.

CONCLUSION

Higher dietary intakes of LCn3PUFA are unlikely to reduce endometrial cancer incidence; rather, they may be associated with small to moderate increases in risk in some subgroups of women, particularly overweight/obese women.

Electrochemical detection mechanism of estrogen effect induced by cadmium: The regulation of purine metabolism by the estrogen effect of cadmium

Some heavy metals in the environment may have estrogen-like activity, which probably lead to major diseases such as breast cancer. It is of great importance to establish new methods to evaluate the estrogen effect of heavy metals from multiple angles due to the complex mechanism of estrogen effect. In this paper, using MCF-7 cells as model, the electrochemical detection mechanism of the estrogen effect of heavy metal cadmium (Cd) was studied. The two electrochemical signals of MCF-7 cells derived from uric acid (0.30 V) and the mixture of guanine and xanthine (0.68 V) increased in a time and dose-dependent manner when MCF-7 cells induced by Cd, reaching the maximum at 96 h and 10-9 mol L-1. Further studies found that three purine metabolism pathways about de novo synthesis, salvage synthesis and decomposition metabolism were activated by the estrogen effect of Cd. The expression of PRPP amidotransferase in purine de novo synthesis pathway and HPRT in purine salvage synthesis pathway up-regulated, especially HPRT, which promoted cell proliferation together. Nevertheless, the expression of GDA and ADA, the key enzymes in purine decomposition metabolism pathway, up-regulated in a time and dose-dependent manner, which had same tendency with that of ERα, thereby increased the content of intracellular hypoxanthine, guanine, xanthine and uric acid, and enhanced electrochemical signals.

The Role of Lead and Cadmium in Gynecological Malignancies

Lead and cadmium are non-essential and toxic heavy metals. Their presence and elevated levels can lead to many pathologies. They disrupt the antioxidant properties of many enzymes, consume the resources of antioxidant cells, and thus participate in the generation of oxidative stress, which may result in DNA damage. In addition, they have been found to be carcinogenic through their genotoxic properties. They have been shown to be present in various types of cancer, including cancer of the female reproductive system. Both metals have been recognized as metalloestrogens, which are important in hormone-related cancers. Participation in the oncogenesis of ovarian, endometrial and cervical cancer was analysed in detail, using the available research in this field. We emphasize their role as potential biomarkers in cancer risk and diagnosis as well as advancement of gynaecological malignancies.

An Assessment of Metallothionein-Cadmium Binding in Rat Uterus after Subchronic Exposure Using a Long-Term Observation Model

Cadmium (Cd) is an environmental pollutant known to pose a public health issue. The mechanism of Cd toxicity on the uterus, including the protective role of metallothionein (MT), is still not fully understood. The aim of the study was to evaluate the degree of MT-Cd binding in the uterus of rats exposed per os to Cd at daily doses of 0.09, 0.9, 1.8 and 4.5 mg Cd/kg b.w. for 90 days. To assess the permanence of the bond, the rats were observed over long observation periods: 90 and 180 days after termination of exposure. Additionally, uterine concentration of Zn, Cu, Ca, Mg was determined. Cd leads immediately after exposure to a max. 30-fold increase in the concentration of Cd in the uterus, with only small amounts being bound to MT. After 90 days following termination of exposure, and especially after 180 days, an increase in MT-Cd concentration was noted for the three highest doses; even so, the degree of Cd binding by MT was still small. Additionally, the accumulation of Cd in the uterus disturbs the homeostasis of determined essential elements, manifested by a significant increase in Cu concentration and a decrease in Zn, Mg and Ca, especially 180 days after termination of exposure. The obtained results indicate that MT has only a slight protective role in the uterus and that Cd ions may have harmful effects not related to MT: directly on the uterine tissue, and indirectly by disturbing the homeostasis of its essential elements.

Mechanism of macroalgae Gracilaria bailiniae responding to cadmium and lanthanum

Macroalgae can accumulate a wide array of metals, leading to their appliance as biomonitors of aquatic environments. With the rapid development of industrial and agricultural-based activities, Cd pollution in aquatic environments is considered an increasingly severe problem worldwide. Although La could alleviate the Cd stress in higher terrestrial plants, the response mechanisms of macroalgae to Cd and La are unknown. Along these lines, in this work, Cd significantly affected the growth, internal cellular structure, photosynthesis, pigment content, antioxidant enzyme activity, and lipid peroxidation level of G. bailiniae. However, the presence of La alleviated these adverse effects from Cd. Furthermore, the response mechanism of G. bailiniae to Cd was attributed to the self-antioxidant ability enhancement, membrane defense, and programmed-cellular regulation. However, the presence of La mediated the biosynthesis of both flavonoids and lipids, which inhibited the Cd accumulation, modulated algal stress signalling networks, renewed the impaired chlorophyll molecule, maintained the activity of the crucial enzyme, enhanced antioxidant ability, and maintained the stabilization of redox homeostasis, alleviating the adverse impact from Cd and improve the growth of G. bailiniae. The experimental results successfully demonstrate a new detoxicant to alleviate Cd stress, promoting a more comprehensive array of macroalgal applications.

Porphyrin COF and its mechanical pressing-prepared carbon fiber hybrid membrane for ratiometric detection, removal and enrichment of Cd2

A nitrogen (N), oxygen (O)-rich porphyrin-based covalent organic framework (COF), in which interlayer porphyrin molecules are vertically stacked, is prepared and characterized. As-prepared N,O-rich TpTph COF shows a high adsorption capacity for Cd²⁺ due to the abundant coordination sites. More interesting, it is found that the formation of COF enlarges the porphyrin ring center space, thus facilitating the Cd²⁺coordination, and the resulting optical signal changes make the ratiometric detection of Cd²⁺ possible. Furthermore, using carbon fiber (CF) filaments, which are obtained from low cost and easy-to-obtain actived carbon mask, as support, porphyrin COF-based CF@TpTph membrane is prepared through in-situ growth of COF on the support followed by simple mechanical pressing. The CF@TpTph membrane is demonstrated to work well for both Cd²⁺ removal and enrichment from soil and water samples, and shows the advantages of ease of handling, robust stability, reduced secondary pollution risk to samples, and good reusability. This work provides a powerful tool for Cd²⁺ removal and enrichment, exhibits that preparing porphyrin-based COFs is a feasible way to promote the interactions between porphyrin ring and Cd²⁺, and demonstrates that mechanical pressing is a promising strategy for the design of COF-based monolithic materials to promote the practical applications of COFs.

A systematic review of adverse health effects associated with oral cadmium exposure

Scientific data characterizing the adverse health effects associated with dietary cadmium (Cd) exposure were identified in order to make informed decisions about the most appropriate toxicological reference value (TRV) for use in assessing dietary Cd exposure. Several TRVs are available for Cd and regulatory organizations have used epidemiologic studies to derive these reference values; however, risk of bias (RoB) evaluations were not included in the assessments. We performed a systematic review by conducting a thorough literature search (through January 4, 2020). There were 1714 references identified by the search strings and 328 studies identified in regulatory assessments. After applying the specific inclusion and exclusion criteria, 208 studies (Human: 105, Animal: 103) were considered eligible for further review and data extraction. For the epidemiologic and animal studies, the critical effects identified for oral Cd exposure from the eligible studies were a decrease in bone mineral density (BMD) and renal tubular degeneration. A RoB analysis was completed for 49 studies (30 epidemiological and 19 animal) investigating these endpoints. The studies identified through the SR that were considered high quality and low RoB (2 human and 5 animal) can be used to characterize dose-response relationships and inform the derivation of a Cd TRV.

Chain modeling for the biogeochemical nexus of cadmium in soil-rice-human health system

This paper presents a novel chain model named soil-food-human (SFH) for clarifying the biogeochemical cascades among the triple challenges of cadmium contamination, food safety, and related public health effect. The model was developed based on the integration of spatial distribution pattern of soil environment and the biogeochemical process of cadmium in soil-rice-human health, and it was validated through a case study. In soil environment terms, SFH predicted the spatial distribution of soil properties with an average prediction accuracy of 82.28%. In food production terms, the SFH can identify the safe production zones for planting rice and unsafe area for adjusting croppingsystems with a relative error of 39.41%. In food consumption terms, SFH mapped the high-resolution map of cadmium exposure dose, which gives a new solution to assess the food safety risks for self-sufficient populations. For the health effect of rice cadmium exposure, SFH simulated the spatiotemporal pattern of urinary cadmium based on toxicokinetic which revealed the health effect of rice cadmium exposure. The chain model provides a new insight in understanding the biogeochemical cascades between food production, food safety, and public health, making it possible to develop a comprehensive strategy to tackle cadmium pollution in soil-rice-human health system.

Paternal cadmium exposure affects testosterone synthesis by reducing the testicular cholesterol pool in offspring mice

Cadmium（Cd） is a heavy metal that is harmful to human health. Early studies have shown that cadmium can damage testicular structure, affecting testosterone synthesis and spermatogenesis. However, the effect of paternal Cd exposure on the reproductive system of offspring remains unclear. In this study, male 8-week C57BL/6 J mice were used as research objects, and Cd was injected intraperitoneally every other day at a dose of 1 mg/kg for 5 weeks, after which the effect on the reproductive system of offspring male mice was studied. Our results showed that the body weight of the offspring male mice increased faster, with increases of the testicular and epididymis indices under Cd exposure. At the same time, the serum testosterone and free cholesterol decreased, total cholesterol increased, and the sperm concentration decreased. Further qRT-PCR and western blot analyses showed that the expressions of StAR, P450scc, 3β-HSD and 17β-HSD, which are related to testosterone synthesis, was significantly downregulated. Additionally, ATGL, LDLR and SR-BI, which are related to the intracellular cholesterol pool were downregulated, leading to the reduction of the cholesterol pool and the accumulation of lipid droplets. Oil red O and BODIPY staining revealed an increase in the abundance of lipid droplets in testicular tissue of newborn and adult mice. Prediction of tsRNA target genes in the sperm of parents and testicular transcriptome of newborn mice showed that the differentially expressed genes were associated with catabolism of fatty acids, cholesterol and ion channels, while the mitochondrial and lysosome functions of testicular tissue of adult offspring mice were decreased. Overall, our results suggest that paternal Cd exposure reduced the intracellular cholesterol pool of testicular of offspring, affected testosterone synthesis and reproductive system development.

Effects of biochar underwent different aging processes on soil properties and Cd passivation

This study aims to determine the efficacy of biochar underwent different aging process including freeze-thaw cycling aging (FB), acidified aging (AB), and microbial aging (MB) on soil physicochemical properties and Cd passivation. The Cd-contaminated soil (3 mg·kg^-1) amended with the three kinds of aging biochar (at 4% w:w) were subjected to 56-day incubation. The application of FB and MB in soil increased the soil pH (0.82-1.04, 0.27-9.36), CEC (1.06-2.53 cmol·kg^-1, 1.66-2.59 cmol·kg^-1), and organic matter content (2.28-4.67 g·kg^-1, 3.70-5.48 g·kg^-1). FB performed best in stabilizing Cd (17.06-23.65%). On the contrary, AB decreased the soil pH and CEC by 0.82-1.04 and 1.32-2.40 cmol·kg^-1 and activated Cd by 11.6-19.24%. In conclusion, the efficacy of biochar on soil remediation and Cd passivation varied with aging method and cycle, and freeze-thaw treatment is an effective approach to improve the performance of biochar.

Endocrine Disruptors and Endometrial Cancer: Molecular Mechanisms of Action and Clinical Implications, a Systematic Review

It has been widely demonstrated that endocrine disruptors play a central role in various physiopathological processes of human health. In the literature, various carcinogenic processes have been associated with endocrine disruptors. A review of the molecular mechanisms underlying the interaction between endocrine disruptors and the endometrial cancer has been poorly developed. A systematic review was performed using PubMed^®/MEDLINE. A total of 25 in vivo and in vitro works were selected. Numerous endocrine disruptors were analyzed. The most relevant results showed how Bisphenol A (BPA) interacts with the carcinogenesis process on several levels. It has been demonstrated how BPA can interact with hormonal receptors and with different transcription proliferative and antiproliferative factors. Furthermore, the effect of Polycyclic aromatic hydrocarbons on Aryl hydrocarbon receptors was investigated, and the role of flame retardants in promoting proliferation and metastasis was confirmed. The results obtained demonstrate how the mechanisms of action of endocrine disruptors are manifold in the pathophysiology of endometrial cancer, acting on different levels of the cancerogenesis process.

Cancer Mortality and Long-Term Environmental Exposure of Cadmium in Contaminated Community Based on a Third Retrospective Cause of Death Investigation of Residents Living in the Guangdong Province from 2004 to 2005

This study compared the temporal and geographic trends of cancer in China with a specific focus on the long-term exposure to soil cadmium (Cd) pollution. The geographic information system (GIS; kriging interpolation method) was used to detect the Cd contained in the soil from the Dabaoshan area, Guangdong Province. The standard rate ratio (SRR) was calculated to describe the relationship between Cd exposure and cancer mortality risk using the low-exposure group as a reference. Eight hundred six cancer deaths (533 male and 273 female) in the total population of 972,970 were identified, and the age-standardized rate (world) was 145.64 per 100,000. Significant dose-response relationships were found using the low-exposure group as the reference group. The Cd soil levels were positively associated with the cancer mortality risk in the community population, particularly for all cancers (SRR = 3.27; 95% CI = 2.42-4.55), esophageal cancer (SRR = 5.42; 95% CI = 1.07-30.56), stomach cancer (SRR = 5.99; 95% CI = 2.00-18.66), liver cancer (SRR = 4.45; 95% CI = 2.16-10.34), and lung cancer (SRR = 2.86; 95% CI = 1.62-5.31) for the total population. Additionally, similar results were obtained when using the 2000 China standard population. Cd exposure significantly affected the standardized mortality rates (China) by age group for all cancers, esophageal cancer, stomach cancer, liver cancer, and lung cancer in the total population, particularly in the age groups of 35-54, 55-74, and ≥ 75 years, respectively. Cd soil level is likely positively associated with increased cancer mortality of all cancer types and esophageal, stomach, liver, and lung cancers but not for other specific categories of cancer.

Cadmium Intake as a Prognostic Factor in Endometrial Cancer: A Swedish Cohort-Based Study

Metalloendocrinology is a new interdisciplinary field, which was established due to the importance of connections between inorganic chemicals and hormonal mechanisms. The role of cadmium in hormone-related tumors is an excellent example of this connection, as cadmium mimics estrogen in the human body. Since endometrial cancer (EC) is hormone-related, it is well-suited for assessing the estrogenic effects of cadmium. Therefore, the present study aims to explore the role of dietary cadmium intake in the progression-free survival (PFS) and overall survival (OS) in women with EC. Dietary cadmium intake was estimated based on a large cohort of Swedish women (n = 416) with EC. Median dietary cadmium intake was then analyzed in relation to different tumor characteristics and clinical outcomes. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Median daily dietary cadmium intake in the cohort was 13.1 μg (interquartile range 25%-75%=6.4). High dietary cadmium intake (μg/day) was associated with significantly decreased OS in the study cohort (HR = 0.956, 95% CI = 0.914-1.001, p = 0.05). Dietary cadmium intake was not associated with PFS (HR = 0.975, 95% CI = 0.924-1.028, p = 0.348). Therefore, our results indicate that high dietary cadmium intake could be associated with poor outcome in women with EC.

Cadmium stress in paddy fields: Effects of soil conditions and remediation strategies

Cadmium (Cd) toxicity in paddy soil and accumulation in rice plants and grains have got global concern due to its health effects. This review highlights the effects of soil factors including soil organic matter, soil pH, redox potential, and soil microbes which influencing Cd uptake by rice plant. Therefore, a comprehensive review of innovative and environmentally friendly management practices for managing Cd stress in rice is lacking. Thus, this review discusses the effect of Cd toxicity in rice and describes management strategies to offset its effects. Moreover, future research thrusts to reduce its uptake by rice has also been highlighted. Through phytoremediation, Cd may be extracted and stabilized in the soil while through microbes Cd can be sequestrated inside the microbial bodies. Increased Cd uptake in hyperaccumulator plants to remediate and convert the toxic form of Cd into non-toxic forms. While in chemical remediation, Cd can be washed out, immobilized and stabilized in the soil through chemical amendments. The organic amendments may help through an increase in soil pH, adsorption in its functional groups, the formation of complexations, and the conversion of exchangeable to residual forms. Developing rice genotypes with restricted Cd uptake and reduced accumulation in grain through conventional and marker-assisted breeding are fundamental keys for safe rice production. In this regard, the use of molecular techniques including identification of QTLs, CRISPR/Cas9, and functional genomics may be quite helpful.

Chronic Exposure to Cadmium Induces Differential Methylation in Mice Spermatozoa

Cadmium exposure is ubiquitous and has been linked to diseases including cancers and reproductive defects. Since cadmium is nonmutagenic, it is thought to exert its gene dysregulatory effects through epigenetic reprogramming. Several studies have implicated germline exposure to cadmium in developmental reprogramming. However, most of these studies have focused on maternal exposure, while the impact on sperm fertility and disease susceptibility has received less attention. In this study, we used reduced representation bisulfite sequencing to comprehensively investigate the impact of chronic cadmium exposure on mouse spermatozoa DNA methylation. Adult male C57BL/J6 mice were provided water with or without cadmium chloride for 9 weeks. Sperm, testes, liver, and kidney tissues were collected at the end of the treatment period. Cadmium exposure was confirmed through gene expression analysis of metallothionein-1 and 2, 2 well-known cadmium-induced genes. Analysis of sperm DNA methylation changes revealed 1788 differentially methylated sites present at regulatory regions in sperm of mice exposed to cadmium compared with vehicle (control) mice. Furthermore, most of these differential methylation changes positively correlated with changes in gene expression at both the transcription initiation stage as well as the splicing levels. Interestingly, the genes targeted by cadmium exposure are involved in several critical developmental processes. Our results present a comprehensive analysis of the sperm methylome in response to chronic cadmium exposure. These data, therefore, highlight a foundational framework to study gene expression patterns that may affect fertility in the exposed individual as well as their offspring, through paternal inheritance.

Immobilization of Cd Using Mixed Enterobacter and Comamonas Bacterial Reagents in Pot Experiments with Brassica rapa L

Enterobacter sp. A11 and Comamonas sp. A23 were isolated and identified. Coculturing these two strains with Cd(II) led to the production of biofilm, H₂S, and succinic acid (SA), and Cd(II) was adsorbed by cells and formed CdS precipitates. After centrifugation, 97% Cd(II) was removed from the coculture. Proteomic and metabolomic analyses of the cocultured bacteria revealed that H₂S and SA production pathways, metal transportation, and TCA cycle were active under Cd(II) stress. In vitro addition of SA enhanced the production of H₂S and biofilm formation and Cd(II) adsorption. Two-season greenhouse pot experiments with Brassica rapa L. were performed with and without the coculture bacteria. Compared with the control, the average Cd amounts of the two-season pot experiments of the aboveground plants were decreased by 71.3%, 62.8%, and 38.6%, and the nonbioavailable and immobilized Cd in the soils were increased by 211.8%, 213.4%, and 116.7%, for low-, medium-, and high- Cd-spiked soils, respectively. The two strains survived well in soil during plant growth using plate counting, quantitative real-time PCR, and metagenomics analysis. Our results indicate that the combination of Enterobacter and Comamonas strains with the production of H₂S and biofilm are important effectors for the highly efficient immobilization of Cd.

Effects of Cadmium, Lead, and Mercury on the Structure and Function of Reproductive Organs

Reproductive organs are essential not only for the life of an individual but also for the survival and development of the species. The response of reproductive organs to toxic substances differs from that of other target organs, and they may serve as an ideal “barometer” for the deleterious effects of environmental pollution on animal and human health. The incidence of infertility, cancers, and associated maladies has increased in the last fifty years or more, while various anthropogenic activities have released into the environment numerous toxic substances, including cadmium, lead, and mercury. Data from epidemiological studies suggested that environmental exposure to cadmium, lead, and mercury may have produced reproductive and developmental toxicity. The present review focused on experimental studies using rats, mice, avian, and rabbits to demonstrate unambiguously effects of cadmium, lead, or mercury on the structure and function of reproductive organs. In addition, relevant human studies are discussed. The experimental studies reviewed have indicated that the testis and ovary are particularly sensitive to cadmium, lead, and mercury because these organs are distinguished by an intense cellular activity, where vital processes of spermatogenesis, oogenesis, and folliculogenesis occur. In ovaries, manifestation of toxicity induced by cadmium, lead, or mercury included decreased follicular growth, occurrence of follicular atresia, degeneration of the corpus luteum, and alterations in cycle. In testes, toxic effects following exposure to cadmium, lead, or mercury included alterations of seminiferous tubules, testicular stroma, and decrease of spermatozoa count, motility and viability, and aberrant spermatozoa morphology.

A Systematic Review of Environmental Health Outcomes in Selected American Indian and Alaska Native Populations

BACKGROUND

Economic and social marginalization among American Indians and Alaska Natives (AI/ANs) results in higher chronic disease prevalence. Potential causal associations between toxic environmental exposures and adverse health outcomes within AI/AN communities are not well understood.

OBJECTIVES

This review examines epidemiological literature on exposure to toxicants and associated adverse health outcomes among AI/AN populations.

METHODS

PubMed, Embase, Cochrane, Environment Complete, Web of Science Plus, DART, and ToxLine were searched for English-language articles. The following data were extracted: lead author's last name, publication year, cohort name, study location, AI/AN tribe, study initiation and conclusion, sample size, primary characteristic, environmental exposure, health outcomes, risk estimates, and covariates.

RESULTS

About 31 articles on three types of environmental exposures met inclusion criteria: persistent organic pollutants (POPs), heavy metals, and open dumpsites. Of these, 17 addressed exposure to POPs, 10 heavy metal exposure, 2 exposure to both POPs and heavy metals, and 2 exposure to open dumpsites. Studies on the Mohawk Nation at Akwesasne; Yupik on St. Lawrence Island, Alaska; Navajo Nation; Gila River Indian Community; Cheyenne River Sioux; 197 Alaska Native villages; and 13 tribes in Arizona, Oklahoma, North Dakota, and South Dakota that participated in the Strong Heart Study support associations between toxicant exposure and various chronic conditions including cardiovascular conditions, reproductive abnormalities, cancer, autoimmune disorders, neurological deficits, and diabetes.

DISCUSSION

The complex interplay of environmental and social factors in disease etiology among AI/ANs is a product of externally imposed environmental exposures, systemic discrimination, and modifiable risk behaviors. The connection between environmental health disparities and adverse health outcomes indicates a need for further study.

Serum concentrations of heavy metals in women with endometrial polyps

Endometrial polyps are one of the common reasons of abnormal uterine bleeding in women. Industrialisation, urbanisation and increased air pollution cause increased heavy metal exposure. Heavy metals that have oestrogenic effects in human body are named as metalloestrogens. The aim of this study was to investigate the serum metalloestrogen levels such as copper (Cu), zinc (Zn), aluminium (Al), lead (Pb), nickel (Ni) and Cu/Zn ratio and their possible relationship with the occurrence of endometrial polyps. Eighty women with abnormal uterine bleeding were divided into two groups: 40 women diagnosed with endometrial polyp (study group) and 40 women without endometrial polyp (control group). Ages, body mass indices, smoking behaviours, drinking water choices, chronic diseases and intrauterine device histories were noted for all patients. Blood levels of Cu, Zn, Al, Pb, Ni and Cu/Zn ratio were analysed by inductively coupled plasma-mass spectrometry method for both groups. No statistically significant differences were observed in terms of serum median levels of Cu and Pb between the study and the control groups. The serum median levels of Zn, Ni and Al were found to be statistically lower in the study group when compared with the control group. The Cu/Zn ratio was statistically higher in the study group. High Cu/Zn ratio, as a biomarker of oxidative stress, suggests the role of oxidative stress in etiopathogenesis of endometrial polyps.IMPACT STATEMENTWhat is already known on this subject? Studies demonstrate that oestrogen and progesterone play an important role in pathogenesis of endometrial polyps. Inorganic heavy metal ions that bind and activate oestrogen receptors are referred to as 'metalloestrogens'. Apart from toxic effects, metalloestrogens have been linked to the aetiology of oestrogen-dependent diseases such as breast and endometrium cancer and endometriosis. However, serum levels of heavy metals were not investigated in a large group of endometrial polyp patients.What do the results of this study add? This is the first study investigating the serum levels of heavy metals in a large group of endometrial polyp patients. We did not observe any increased serum levels of heavy metals in endometrial polyp patients. Our results might suggest that oestrogenic heavy metal exposure has no role in the appearance of endometrial polyps. However, increased Cu/Zn ratio due to low serum levels zinc suggests oxidative stress might play a role in endometrial polyps.What are the implications of these findings for clinical practice and/or further research? Further research of heavy metals in endometrial polyps with simultaneous blood and tissue samples could show the precise effect of environmental exposure of metalloestrogens in aetiopathogenesis of endometrial polyps.

Chronic exposure to cadmium induces a malignant transformation of benign prostate epithelial cells

Epidemiological evidence suggests that cadmium (Cd) is one of the causative factors of prostate cancer, but the effect of Cd on benign prostatic hyperplasia (BPH) remains unclear. This study aimed to determine whether Cd exposure could malignantly transform BPH1 cells and, if so, to dissect the mechanism of action. We deciphered the molecular signaling responsible for BPH1 transformation via RNA-sequencing and determined that Cd induced the expression of zinc finger of the cerebellum 2 (ZIC2) in BPH1 cells. We noted Cd exposure increased ZIC2 expression in the Cd-transformed BPH1 cells that in turn promoted anchorage-independent spheroids and increased expression of stem cell drivers, indicating their role in stem cell renewal. Subsequent silencing of ZIC2 expression in transformed cells inhibited spheroid formation, stem cell marker expression, and tumor growth in nude mice. At the molecular level, ZIC2 interacts with the glioma-associated oncogene family (GLI) zinc finger 1 (GLI1), which activates prosurvival factors (nuclear factor NFκB, B-cell lymphoma-2 (Bcl2), as well as an X-linked inhibitor of apoptosis protein (XIAP)) signaling in Cd-exposed BPH1 cells. Conversely, overexpression of ZIC2 in BPH1 cells caused spheroid formation confirming the oncogenic function of ZIC2. ZIC2 activation and GLI1 signaling induction by Cd exposure in primary BPH cells confirmed the clinical significance of this oncogenic function. Finally, human BPH specimens had increased ZIC2 versus adjacent healthy tissues. Thus, we report direct evidence that Cd exposure induces malignant transformation of BPH via activation of ZIC2 and GLI1 signaling.

Subchronic Exposure to Cadmium Causes Persistent Changes in the Reproductive System in Female Wistar Rats

Cadmium (Cd) is an environmental toxicant and endocrine disruptor in humans and animals, and recent studies have illustrated that the uterus is exceedingly sensitive to Cd toxicity. The aim of the study was to investigate the influence of subchronic (90 days) oral Cd exposure in daily doses of 0.09-4.5 mg/kg b.w. on the balance of sex hormones by estimating estradiol (E₂) and progesterone (P) concentrations in the uterus and plasma in comparison with the effects of 17β-E₂. Additionally, the uterine weight, histopathological changes in the uterus and ovaries, the regularity of the estrous cycle, Cd bioaccumulation in uterine tissue, and selected biochemical parameters of oxidative stress were determined. A long period of observation (three and six months following the administration period) was used to assess whether the existing effects are reversible. The lowest dose of Cd caused effects similar to 17β-E₂: an increase of E₂ concentration in the uterus, endometrial epithelium thickness, and disturbed estrous cycle with estrus phase prolongation. The obtained results suggest that Cd causes nonlinear response. Higher doses of Cd caused a significant decrease in E₂ concentration in the uterus and plasma, estrous cycle disturbances, endometrium atrophy, and structural damage in the ovaries. This dose additionally induces lipid peroxidation in the uterine tissues. It is noteworthy that a prolonged time of observation after terminating the exposure showed persistent changes in the concentration of E₂ in uterine tissue, as well as alterations in estrous cycle phases, and an increase in lipid peroxidation in the uterus. Moreover, significant positive correlations between the plasma E₂ concentration and endometrial epithelium thickness in all studied groups were found. In summary, subchronic oral Cd exposure of female rats may result in impaired fertility processes.

Tobacco carcinogens and the methionine metabolism in human bladder cancer

Cigarette smoking is a strong risk factor for bladder cancer. It has been shown that the duration of smoking is associated with a poor prognosis and a higher risk of recurrence. This is due to tobacco carcinogens forming adducts with DNA and proteins that participate in the DNA repair mechanisms. Additionally, polymorphisms of genes responsible for methyl group transfer in the methionine cycle and dosages of vitamins (from diet and supplements) can cause an increased risk of bladder cancer. Upregulated DNA methyltransferase 1 expression and activity results in a high level of methylated products of metabolism, as well as hypermethylation of tumor suppressor genes. The development of a market that provides new inhibitors of DNA methyltransferase or alternatives for current smokers is essential not only for patients but also for people who are under the danger of secondhand smoking and can experience its long-term exposure consequences.

Blood Cadmium Level Is Associated with Short Progression-Free Survival in Nasopharyngeal Carcinoma

The prognosis of nasopharyngeal carcinoma (NPC) is poor with disease progression. Cadmium exposure is a risk factor for NPC. We aimed to investigate the effect of cadmium exposure, by measuring cadmium level, and clinicopathologic factors on NPC disease progression and prognosis. A total of 134 NPC cases were analyzed and venous blood samples were collected. Blood cadmium level was analyzed by graphite furnace atomic absorption spectrophotometry. Clinical data were collected at baseline for patients and tumor characteristics from medical records. Progression-free survival (PFS) was analyzed during follow-up. The effect of cadmium exposure and clinical factors on PFS was analyzed by the Kaplan-Meier method and Cox regression models. Blood cadmium level was associated with history of disease and smoking history and pack-years. On Kaplan-Meier analysis, a high blood cadmium level, male sex, smoking history and increasing pack-years, as well as advanced clinical stage were all associated with short PFS. On multivariate analysis, blood cadmium level was an independent risk factor and predictor of NPC prognosis and disease progression. Cadmium exposure and related clinical factors can affect the prognosis of NPC, which merits further study to clarify.

A novel cadmium-containing wastewater treatment method: Bio-immobilization by microalgae cell and their mechanism

Heavy metal cadmium (Cd) has drawn tremendous comcern due to its rigorous environmental and health hazards. Herein, we have presented an efficient and economical strategy for the removal and recycling of hazardous Cd ions using microalgae cells as the bioreactors. Remarkably, the green bio-platform for the bioproduction of CdSe nanoparticles (NPs) was developed depending on their orderly regulated and sustainable cellular environment. The biofabricated CdSe NPs manifested favorable photoluminescence properties, and presented well monodispersed spherical morphology and certain crystallinity structure with mean size of smaller than 7 nm. Especially, the fluorescence "turn off" sensing system based on the CdSe NPs was established to detect Hg²⁺. The nanosensor enables the quantitative analyses of Hg²⁺ with a linear range of 0-2.0 μM and a detection limit of 0.021 μM. Furthermore, it was preliminarily speculated that the reducing biomolecules in the algae cells could be involved in the formation of CdSe NPs. This work not only provides new insights into the removal and recycling of hazardous Cd ions, but also brings a promising route for biosynthesis of CdSe NPs.

A bifunctional sensor based on diarylethene for the colorimetric recognition of Cu2+ and fluorescence detection of Cd2+

A novel bifunctional sensor based on diarylethene with a benzyl carbazate unit was synthesized successfully. It not only served as a colorimetric sensor for the recognition of Cu²⁺ by showing changes in absorption spectra and solution color, but also acted as a fluorescent sensor for the detection of Cd²⁺ through obvious emission intensity enhancement and fluorescence color change. The sensor exhibited excellent selectivity and sensitivity towards Cu²⁺ and Cd²⁺, and the limits of detection for Cu²⁺ and Cd²⁺ were 8.36 × 10⁻⁸ mol L⁻¹ and 1.71 × 10⁻⁷ mol L⁻¹, respectively, which were much lower than those reported by the WHO and EPA in drinking water. Furthermore, its application in practical samples demonstrated that the sensor can be effectively applied for the detection of Cu²⁺ and Cd²⁺ in practical water samples.

A bifunctional sensor for colorimetric recognition of Cu²⁺ and fluorescent detection of Cd²⁺ was synthesized. It not only showed high selectivity and sensitivity to Cu²⁺ and Cd²⁺, but also could be used in practical water samples with high accuracy.

Chronic cadmium exposure aggravates malignant phenotypes of nasopharyngeal carcinoma by activating the Wnt/β-catenin signaling pathway via hypermethylation of the casein kinase 1α promoter

BACKGROUND

Our previous study has shown that cadmium (Cd) exposure is not only a risk factor for nasopharyngeal carcinoma (NPC), but also correlated with the clinical stage and lymph node metastasis. However, the underlying molecular events of Cd involved in NPC progression remain to be elucidated.

PURPOSE

The objective of this study was to decipher how Cd impacts the malignant phenotypes of NPC cells.

METHODS

NPC cell lines CNE-1 and CNE-2 were continuously exposed with 1 μM Cd chloride for 10 weeks, designating as chronic Cd treated NPC cells (CCT-NPC). MTT assay, colony formation assay and xenograft tumor growth were used to assess cell viability in vitro and in vivo. Transwell assays were performed to detect cell invasion and migration. The protein levels of E-cadherin, N-cadherin, Vimentin as well as β-catenin and casein kinase 1α(CK1α) were measured by Western blot. Immunofluorescence staining was used to observe the distribution of filament actin (F-actin), β-catenin and CK1α. The mRNA levels of downstream target genes of β-catenin were detected by RT-PCR. Wnt/β-catenin signaling activity was assessed by TOPFlash/FOPFlash dual luciferase report system. MS-PCR was used to detect the methylation status of CK1α. Finally, the activation of Wnt/β-catenin pathway and cell biological properties were examined following treatment of CCT-NPC cells with 5-aza-2-deoxy-cytidine(5-aza-CdR).

RESULTS

CCT-NPC cells showed an increase in cell proliferation, colony formation, invasion and migration compared to the parental cells. Cd also induced cytoskeleton reorganization and epithelial-to-mesenchymal transition. Upregulation and nuclear translocation of β-catenin and increased luciferase activity accompanied with transcription of downstream target genes were found in CCT-NPC cells. Treatment of CCT-CNE1 cells with 5-aza-CdR could reverse the hypermethylation of CK1α and attenuate the cell malignancy.

CONCLUSION

These results support a role for chronic Cd exposure as a driving force for the malignant progression of NPC via epigenetic activation of the Wnt/β-catenin pathway.

A carcinogenic trigger to study the function of tumor suppressor genes in Schmidtea mediterranea

Planarians have been long known for their regenerative ability, which hinges on pluripotency. Recently, however, the planarian model has been successfully established for routine toxicological screens aimed to assess overproliferation, mutagenicity and tumorigenesis. In this study, we focused on planarian tumor suppressor genes (TSGs) and their role during chemically induced carcinogenic stress in Schmidtea mediterranea Combining in silico and proteomic screens with exposure to human carcinogen type 1A agent cadmium (Cd), we showed that many TSGs have a function in stem cells and that, in general, exposure to Cd accelerated the onset and increased the severity of the observed phenotype. This suggested that the interaction between environmental and genetic factors plays an important role in tumor development in S. mediterranea Therefore, we further focused on the synergistic effects of Cd exposure and p53 knockdown (KD) at the cellular and molecular levels. Cd also produced a specific proteomic landscape in homeostatic animals, with 172 proteins differentially expressed, 43 of which were downregulated. Several of these proteins have tumor suppressor function in human and other animals, namely Wilms Tumor 1 Associated Protein (WT1), Heat Shock Protein 90 (HSP90), Glioma Pathogenesis-Related Protein 1 (GLIPR1) and Matrix Metalloproteinase B (Smed-MMPB). Both Glipr1 and MmpB KD produced large outgrowths, epidermal lesions and epidermal blisters. The epidermal blisters that formed as a consequence of Smed-MmpB KD were populated by smedwi1+ cells, many of which were actively proliferating, while large outgrowths contained ectopically differentiated structures, such as photoreceptors, nervous tissue and a small pharynx. In conclusion, Smed-MmpB is a planarian TSG that prevents stem cell proliferation and differentiation outside the proper milieu.

Engineering low-cadmium rice through stress-inducible expression of OXS3-family member genes

Cadmium (Cd) as a carcinogen poses a great threat to food security and public health through plant-derived foods such as rice, the staple for nearly half of the world's population. We have previously reported that overexpression of truncated gene fragments derived from the rice genes OsO3L2 and OsO3L3 could reduce Cd accumulation in transgenic rice. However, we did not test the full length genes due to prior work in Arabidopsis where overexpression of these genes caused seedling lethality. Here, we report on limiting the overexpression of OsO3L2 and OsO3L3 through the use of the stress- inducible promoter RD29B. However, despite generating 625 putative transformants, only 7 lines survived as T1 seedlings and only 1 line of each overexpressed OsO3L2 or OsO3L3-produced T2 progeny. The T2 homozygotes from these 2 lines showed the same effect of reducing accumulation of Cd in root and shoot as well as in T3 grain. As importantly, the concentrations of essential metals copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) were unaffected. Analysis of the expression profile suggested that low Cd accumulation may be due to high expression of OsO3L2 and OsO3L3 in the root tip region. Cellular localization of OsO3L2 and OsO3L3 indicate that they are histone H2A interacting nuclear proteins in vascular cells and especially in the root tip region. It is possible that interaction with histone H2A modifies chromatin to regulate downstream gene expression.

Cancer Mortality in Residents of the Cadmium-Polluted Jinzu River Basin in Toyama, Japan

After 26 years, we followed up 7348 participants in a 1979-1984 health screening survey in the Jinzu River basin, the heaviest cadmium-polluted area in Japan. We assessed the associations of cadmium exposure levels and mortality from cancer and renal damage, indicated by records of proteinuria and glucosuria in the original survey. Mortality risks (hazard ratios) were analyzed using the Cox proportional hazards model, stratified by sex, after adjusting for age, smoking status, and hypertension, as indicated in the original survey records. In men, the adjusted hazard ratio for mortality from lung cancer was significantly lower in individuals residing in an area of historically high cadmium exposure and in subjects with a historical record of proteinuria, glucosuria, and glucoproteinuria. The risk of mortality from prostate cancer was borderline higher in cadmium-exposed men. In women, historical cadmium exposure was not associated with an increased risk of mortality from malignant neoplasms, but the adjusted hazard ratios for death from total malignant neoplasms or from renal and uterine cancers were significantly higher in exposed subjects with a historical record of proteinuria, glucosuria, and glucoproteinuria. These findings suggest that women residing in cadmium-polluted areas who exhibit markers of renal damage may be at risk of dying of cancer.

A Reversible Bis(Salamo)-Based Fluorescence Sensor for Selective Detection of Cd2+ in Water-Containing Systems and Food Samples

A novel, simple, highly selective, and sensitive fluorescence chemosensor for detecting Cd2+ that was constructed from a bis(salamo)-type compound (H₄L) with two N₂O₂ chelating moieties as ionophore was successfully developed. Sensor H₄L could show fluorescence turn-on response rapidly and significant selectivity to Cd2+ over many other metallic ions (Cu2+, Ba2+, Ca2+, K⁺, Cr3+, Mn2+, Sr2+, Co2+, Na⁺, Li⁺, Ni2+, Ag⁺, and Zn2+), and a clear change in color from colorless to yellow that can be very easily observed via the naked eyes in the existence of Cd2+, while other metallic ions do not induce such a change. Interestingly, its fluorescent intensity was increased sharply with the increased concentration of Cd2+. The detection limit of sensor H₄L towards Cd2+ was down to 8.61 × 10-7 M.

An Assessment of Dietary Exposure to Cadmium in Residents of Guangzhou, China

Cadmium and its compounds are human carcinogens with severe organ toxicity, and their contamination of agricultural soil in China has been frequently reported; however, the dietary exposure to cadmium in residents and the relevant health risk have seldom been reported. In this study, the concentration of cadmium in various types of food collected from 2013 to 2015 were analyzed using graphite furnace atomic absorption spectrometry, and the dietary exposure to cadmium assessed based on a dietary survey in 2976 Guangzhou residents. In total, 3074 out of 4039 food samples had cadmium levels above the limit of detection. The mean ± standard deviation (50th, 95th percentile) cadmium content in all samples was 159.0 ± 112.7 (8.6, 392.4) μg/kg, with levels ranging from 1.0 to 7830 μg/kg. Using the mean cadmium concentrations, the average monthly dietary exposure of Guangzhou residents to cadmium was 14.4 (μg/kg body weight (BW), accounting for 57.6% of the provisional tolerable monthly intake (PTMI). Rice, laver, vegetables, and live aquatic products were the main sources of cadmium intake, on average accounting for 89% of the total value. The dietary cadmium exposure in high consumers (95th percentile food consumption) was 41.0 μg/kg·BW/month, accounting for 163% of the PTMI. Additionally, dietary cadmium exposure at mean consumption but high cadmium food concentration (95th percentile) was 32.3 μg/kg·BW/month, corresponding to 129% of the PTMI. The level of dietary exposure to cadmium in most Guangzhou residents was within the safety limit, thus increased health risk from dietary cadmium exposure is low at present. However, continued efforts by local governments to monitor the levels of cadmium in the four main food categories contributing to exposure are necessary.