Global burden of late-stage chronic kidney disease resulting from dietary exposure to cadmium, 2015

Association between blood metals mixture and chronic kidney disease in adults: NHANES 2013-2016

BACKGROUND

The association between single metal exposure and chronic kidney disease (CKD) has been established. However, there is limited research on the effects of multi-metal mixtures and their potential age-specific associations with kidney injury. This study aimed to examine the relationship between metal mixtures and kidney function in adults, while also exploring the modifying effects of age.

METHODS

We included a subset (n = 4250) of a nationally representative adult population in the National Health and Nutrition Examination Survey (NHANES) 2013-2016. Kidney function was assessed using the glomerular filtration rate (eGFR) and creatinine albumin ratio (ACR). The individual and combined effects of lead (Pb), cadmium (Cd), mercury, and manganese on kidney injury and the risk of CKD were evaluated.

RESULTS

Pb and Cd were found to be positively associated with decreased kidney function. For a one Ln-unit increase in lead and cadmium, the adjusted ORs of CKD were 1.60 (95% CI: 1.35, 1.90) and 1.41 (95% CI:1.12, 1.77), respectively. We also observed an interaction between lead and cadmium for ACR. We also observed the joint effect between Pb and Cd on eGFR, ACR and CKD. Stratified analysis found a higher risk of decreased kidney function among older individuals. The quantile-g calculation model further showed that metal mixture was associated with decreased kidney function and the risk of CKD (OR = 1.53, 95% CI: 1.22, 1.90). And lead and cadmium were the main contributors. And Pb and Cd were the major components that increased the risk of CKD.

CONCLUSION

Co-exposure to metal mixture were associated with reduced kidney function in adults, especially in older. Our findings support co-exposure to lead and cadmium as risk factors of CKD in adults.

Evaluating the health impact of increased linseed consumption in the Danish population

Consumption of linseeds has been suggested to have beneficial effects on human health. However, toxic constituents of linseed may compromise these benefits. We conducted a quantitative risk-benefit assessment to evaluate the overall health impact of increasing linseed intake up to 45 g/day in the Danish population (15-74 years). We quantified the risks associated with increased cadmium exposure and the benefits associated with increased intake of dietary fibre. Increased intakes of alpha-linoleic acid (ALA) were included in a sensitivity analysis. The overall health impact of different linseed intake scenarios was estimated in terms of Disability-Adjusted Life Years (DALYs). We found that the beneficial effects of linseed due to increased intake of dietary fibre outweighed the adverse health effects due to increased cadmium exposure in all scenarios. Up to 670 DALYs/100,000 individuals could be averted per year by increasing linseed consumption in the Danish population. The estimated beneficial health impact increased further when including ALA in the assessment. Different sources of uncertainty might affect the results, and more research is needed on both the health effects associated with intake of linseed and its constituents, and the bioavailability of ALA and cadmium from linseed to further improve the risk-benefit assessment.

The burden of chronic kidney disease associated with dietary exposure to cadmium in China, 2020

Cadmium (Cd) exposure increases the risk of chronic kidney disease (CKD). But the contribution of dietary Cd intake, the primary exposure route of Cd in humans, to the CKD burden remains to be evaluated in China. Concentrations of Cd in foods and population glomerular filtration rate (GFR) were retrieved from studies published between January 2000 and February 2023 in China. Daily food consumption in adults aged ≥35 years old was obtained from two nationwide Chinese surveys. Dietary Cd intake and its contribution rate among total Cd exposure from diet, inhalation, smoking and water were evaluated. Urinary Cd (UCd) was estimated using the toxicokinetic (TK) model based on dietary Cd intake. The effect of Cd on kidney function has been quantified with the previously published dose-response relationship between UCd and GFR. The incidence and disability-adjusted life years (DALYs) of CKD attributable to dietary Cd intake were derived considering the contribution rate of dietary Cd intake at the national and provincial levels. The national average dietary Cd intake was 0.6891 μg/kg bw/day, contributing 63.69% of total Cd exposure. The Cd exposure through foods resulted in 2.34 (95% uncertainty interval, UI: 1.54-3.40) stage 4 CKD and 0.37 (95% UI: 0.20-0.59) stage 5 CKD cases per 100,000 persons/year in mainland China, 2020. The corresponding DALYs loss associated with stage 4 and stage 5 CKD due to dietary Cd intake were 5.14 (95% UI: 3.24-7.67) and 4.78 (95% UI: 2.32-8.30) per 100,000 persons/year, together accounting for 2% of total DALYs of CKD. Greater dietary Cd intake and corresponding burden of late-stage CKD were observed in Southern areas than in Northern areas. Diet remains the primary exposure to Cd in Chinese adults. Efforts to reduce dietary Cd exposure would positively impact public health, especially in Southern provinces with high Cd exposure.

Effects of cadmium exposure on metabolism, antioxidant defense, immune function, and the hepatopancreas transcriptome of Cipangopaludina cathayensis

Cadmium (Cd) is a common contaminant in aquatic environments. However, little is known about the mechanisms underlying Cd toxicity in the freshwater snail Cipangopaludina cathayensis (Heude, 1890). This study to investigate the toxic effects of Cd on the standard metabolism, antioxidant activities, immune function, and hepatopancreas transcriptome profiles of C. cathayensis. C. cathayensis was exposed to 0.25, 0.5, 1.0, or 1.5 mg/L Cd for 3 h, with results showing that Cd significantly inhibited oxygen consumption and ammonia excretion and disrupted the respiratory metabolism of C. cathayensis. In addition, the O:N ratio dropped below 7, indicating that C. cathayensis may rely exclusively on proteins as an energy source under Cd stress. To understand how Cd impacts the antioxidant activities, immune function, and transcriptional profiles, C. cathayensis were exposed to 0.5 (low exposure, L14) or 1.5 (high exposure, H14) mg/L Cd for 14 days. Our results indicate that Cd exposure leads to oxidative stress and immunosuppression, with the latter effect being larger for exposure to higher Cd concentrations. A total of 2172 differentially expressed genes (DEGs) were identified by transcriptome analysis of the hepatopancreas, of which 885 were upregulated and 1287 were downregulated. Gene ontology and KEGG analyses revealed that the DEGs in the H14 group are enriched for energy generation terms and the "oxidative phosphorylation" pathway, respectively. Therefore, up-regulation of energy metabolism may be an adaptive strategy under Cd stress. Moreover, several genes involved in antioxidant activity were downregulated, whereas genes related to reactive oxygen species generation were upregulated. In addition, many immunity-related genes were identified within the DEGs, indicating that Cd toxicity may affect immune defense. Further, DEGs in the H14 group were enriched for disease-associated pathways. Taken together, our results indicate that Cd exposure leads to metabolic disorders, oxidative stress, and immunosuppression and thus may potentially contribute to disease outbreaks.

Cadmium exposure induces necroptosis of porcine spleen via ROS-mediated activation of STAT1/RIPK3 signaling pathway

Cadmium (Cd), a heavy metal, is used in a wide range of applications, such as plastics, electroplating process, electronics, and so forth. Due to its bioaccumulation ability, Cd can contaminate soil, water, air and food. To determine the effect of Cd exposure on the necroptosis in pig spleen and its mechanistic investigation, we constructed a model in pigs by feeding them food containing 20 mg/kg Cd. In this study, we analyzed the effects of Cd exposure on pig spleen through HE staining, Quantitative real-time PCR (qRT-PCR), Western blot (WB), and principal component analysis (PCA). Results show that Cd exposure can destroy the structure and function of pig spleen, which is closely related to necroptosis. Further results show that Cd exposure can induce necroptosis through ROS-mediated activation of Signal transducer and activator of transcription 1/Receptor-Interacting Serine/Threonine-Protein Kinase 3 (STAT1/RIPK3) signaling pathway in pig spleen. Additionally, Cd exposure also can affect the stability of mitochondrial-associated endoplasmic reticulum membrane (MAMs) structure, which also contributes to the process of necroptosis. Our study provides insights into the physiological toxicity caused by Cd exposure.

Establishment of LC-MS/MS Method for Determination of GMDTC in Rat Plasma and Its Application in Preclinical Pharmacokinetics

Sodium (S)-2-(dithiocarboxylato((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)-4(methylthio)butanoate (GMDTC) is the first compound to use cadmium repellent as an indication. In this paper, we established and validated a bioanalytical method for the determination of GMDTC in rat plasma, and used it to determine the drug concentrations in the plasma of rats after intravenous dosing in different genders and dosages. After pretreating the plasma samples with an acetonitrile-water-ammonia solution (70:30:1.25, v/v/v), liquid chromatographic separations were efficiently achieved with a XBridge C18 column using a 5 min gradient system of aqueous ammonium bicarbonate and 95% acetonitrile-water solution (95:5, v/v) as the eluent. The GMDTC and metolazone (internal standard, IS) detection were carried out using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS), monitored at m/z 390.06-324.1 (for the GMDTC, tR: 2.03 min) and m/z 366.0-259.2 (for IS, tR: 3.88 min). The GMDTC was stable under various testing conditions, and this analytical method conforms to the verification standard of biological analysis methods. The half-life (t_1/2) was determined to be 0.54-0.65 h for the intravenous, mean distribution volume and clearances were 1.08-2.08 L/kg and 1-3 L/h/kg, respectively. The AUC_0-t and AUC_0-∞ found after increasing the dosage exhibited a linear relationship with the administered dose. There were no statistically significant differences in the values obtained for the different genders at dosages of 50, 100 and 250 mg/kg, respectively (p > 0.05). This is the first report of a bioanalytical method to quantify GMDTC in rat plasma using LC-MS/MS, which provides useful information for the study of its pharmacological effects and clinical applications.

Associations of long-term cadmium exposure with peripheral white blood cell subtype counts and indices in residents of cadmium-polluted areas

BACKGROUND

Experimental evidence suggests that exposure to cadmium (Cd) could affect immune cells in vivo and in vitro. However, the associations of long-term Cd exposure with white blood cell (WBC) subtype counts and hemogram-derived indices have been rarely investigated. Therefore, we evaluated these relationships in residents of cadmium-polluted areas.

METHODS

This cross-sectional study included 431 participants aged 45-75 years without occupational exposure histories from Cd-contaminated areas of southern China. We detected WBC, neutrophil, lymphocyte, and monocyte counts using routine blood tests and calculated neutrophil-lymphocyte ratio (NLR), systemic inflammation response index (SIRI), and lymphocyte-monocyte ratio (LMR). Urinary Cd (U-Cd) was measured with inductively coupled plasma mass spectrometry and adjusted for creatinine. To evaluate the associations of U-Cd with peripheral WBC subtype counts and indices, we performed multivariate linear regression, logistic regression and subgroup analyses using U-Cd categorized into quartiles.

RESULTS

In models adjusted for all potential confounders, U-Cd was negatively associated with WBC, neutrophil, and monocyte counts in Q2, compared with Q1 of U-Cd (p < 0.05). A similar relationship was observed between U-Cd and NLR and SIRI, whereas the corresponding association for LMR was positive (p < 0.05). In subgroup analyses, U-Cd was negatively associated with neutrophil count, except for never smokers, after full adjustment.

CONCLUSIONS

U-Cd was negatively associated with WBC count, neutrophil count, monocyte count, NLR, and SIRI, and positively associated with LMR. Therefore, neutrophil count could be a potential indicator of long-term Cd exposure-associated immunosuppressive effect.

Microcystin-LR Combined with Cadmium Exposures and the Risk of Chronic Kidney Disease: A Case-Control Study in Central China

Increasing evidence indicates that exposure to microcystin-LR (MC-LR) can cause kidney damage. However, the association between MC-LR exposure and chronic kidney disease (CKD) risk in humans has not been studied. Therefore, we conducted a population-based case-control study involving 135 CKD cases and 135 matched controls in central China and analyzed the effects of MC-LR alone as well as combined with the known risk factor cadmium (Cd). Compared to the lowest quartile of MC-LR exposure, the highest quartile had a 6.56-fold (95% confidence interval [CI]: 2.46, 17.51) significantly increased risk for CKD, displaying a dose-response relationship (p_trend < 0.001). Our animal study also showed that MC-LR exposure induced kidney injury via the PI3K/AKT/mTOR signaling pathway. Comparing the highest Cd quartile to the lowest, the adjusted odds ratio for CKD was 3.88 (95% CI: 1.47, 10.28), exhibiting a dose-response relationship (p_trend < 0.006). Furthermore, a positive additive interaction was observed between MC-LR and Cd (relative excess risk due to interaction = 1.81, 95% CI: 0.42, 3.20; attributable proportion of interaction = 0.70, 95% CI: 0.35, 1.05). Our study firstly revealed that MC-LR exposure is an independent risk factor for CKD and has a synergistic relationship with Cd. MC-LR and Cd exposures are associated with CKD risk in a dose-response manner.

Modeling the risk of low bone mass and osteoporosis as a function of urinary cadmium in U.S adults aged 50-79 years

We developed an association model to estimate the risk of femoral neck low bone mass and osteoporosis from exposure to cadmium for women and men aged 50-79 in the U.S, as a function of the urinary cadmium (U-Cd) levels. We analyzed data from the NHANES 2005-2014 surveys and evaluated the relationship between U-Cd and femoral neck bone mineral density (BMD) using univariate and multivariate regression models with a combination of NHANES cycle, gender, age, smoking, race/ethnicity, height, body weight, body mass index, lean body mass, diabetes, kidney disease, physical activity, menopausal status, hormone replacement therapy, urinary lead, and prednisone intake as confounding variables. The regression coefficient between U-Cd and femoral neck BMD obtained with the best multivariate regression was used to develop an association model that can estimate the additional risk of low bone mass or osteoporosis in the population given a certain level of U-Cd. Results showed a linear relationship between U-Cd and BMD, conditional to body weight, where individuals with higher U-Cd had decreased BMD values. Our results do not support the hypothesis of a threshold for the effect of Cd on bone. Our model estimates that exposure to Cd results in an increase of 0.51 percentage points (CI95% 0.00, 0.92) of the population diagnosed with osteoporosis, compared to a theoretical absence of exposure. We estimate that 16% (CI95%: 0.00, 40%) of osteoporosis cases in the U.S. 50-79 aged population are a result of Cd exposure. This study presents the first continuous model estimating low bone mass and osteoporosis risk in the U.S. population given actual or potential changes in U-Cd levels. Our model will provide information to inform FDA's Closer to Zero initiative goal to reduce exposure to toxic elements.

Speciation, transportation, and pathways of cadmium in soil-rice systems: A review on the environmental implications and remediation approaches for food safety

Cadmium (Cd) contamination in paddy fields is a serious health concern because of its high toxicity and widespread pollution. Recently, much progress has been made in elucidating the mechanisms involved in Cd uptake, transport, and transformation from paddy soils to rice grains, aiming to mitigate the associated health risk; however, these topics have not been critically reviewed to date. Here, we summarized and reviewed the (1) geochemical distribution and speciation of Cd in soil-rice systems, (2) mobilization, uptake, and transport of Cd from soil to rice grains and the associated health risks, (3) pathways and transformation mechanisms of Cd from soil to rice grains, (4) transporters involved in reducing Cd uptake, transport, and accumulation in rice plants, (5) factors governing Cd bioavailability in paddy, and (6) comparison of remediation approaches for mitigating the environmental and health risks of Cd contamination in paddy fields. Briefly, this review presents the state of the art about the fate of Cd in paddy fields and its transport from soil to grains, contributing to a better understanding of the environmental hazards of Cd in rice ecosystems. Challenges and perspectives for controlling Cd risks in rice are thus raised. The summarized findings in this review may help to develop innovative and applicable methods for controlling Cd accumulation in rice grains and sustainably manage Cd-contaminated paddy fields.

Adipose tissue cadmium concentrations as a potential risk factor for insulin resistance and future type 2 diabetes mellitus in GraMo adult cohort

Adipose tissue has been recently highlighted as a promising matrix for evaluation of cadmium's (Cd) long-term exposure although not frequently considered in epidemiological studies. The association between Cd exposure and type 2 Diabetes Mellitus (T2DM) remains unclear. This work aimed to explore the association between adipose tissue Cd levels and T2DM incidence over a 16-year follow-up in an adult cohort from Southern Spain considering smoking status. We also performed complementary cross-sectional analyses focused on subclinical markers of glucose homeostasis at recruitment. Clinical information was obtained from hospital databases. Socio-demographic characteristics, lifestyle and diet were collected by face-to-face interviews. Homeostatic model assessment (HOMA) values of insulin sensitivity/resistance and β-cell function were calculated using fasting serum glucose, insulin, and C-peptide levels at recruitment. Adipose tissue Cd concentrations were quantified by inductively coupled plasma mass spectrometry. Statistical analyses were performed by means of Cox-regression and multivariable linear regression models. Participants in the 4th quartile (Q4) of Cd concentrations showed a non statistically-significant increased T2DM risk (Hazard Ratio (HR) Q4 vs Q1: 1.97; 95% Confidence Interval (CI): 0.69, 5.66). This association was particularly strong and suggestive in current smokers (HR: 2.19; 95% CI: 0.98, 4.98). Interestingly, smokers in the 2nd tertile (T2) of adipose tissue Cd levels showed increased log-transformed insulin resistance (beta T2 vs T1: 0.52; 95% CI: 0.07, 0.97), as well as higher log-transformed insulin levels (beta T2 vs T1: 0.52; 95% CI: 0.08, 0.95). We found evidences supporting that Cd exposure, particularly from tobacco smoking, could be a risk factor for T2DM. In addition, our results support the potential relevance of adipose tissue as a matrix for Cd exposure assessment.

Risk-Benefit Assessment of Consumption of Rice for Adult Men in China

Objective: To evaluate the health impact of current and alternative patterns of rice consumption in Chinese adult men (40-79 years of age). Methods: We applied a risk-benefit assessment (RBA) model that took into account the health effects of selenium (Se), cadmium (Cd), and inorganic arsenic (i-As). The health effects included the prevention of prostate cancer associated with exposure to Se, and an increased risk of lung, bladder, and skin cancer for i-As and chronic kidney disease (CKD) for Cd. We defined the baseline scenario (BS) as the current individual mean daily consumption of rice in the population of interest and two alternative scenarios (AS): AS1 = 50 g/day and AS2 = 200 g/day. We estimated the health impact for different age groups in terms of change in Disability-Adjusted Life Years (ΔDALY). Results: The BS of rice consumption was 71.5-105.4 g/day in different age groups of adult men in China. We estimated that for AS1, the mean ΔDALY was -2.76 to 46.2/100,000 adult men of 40-79 years old. For AS2, the mean ΔDALY was 41.3 to 130.8/100,000 individuals in this population group. Conclusion: Our results showed that, based on associated exposure to selenium, cadmium, and i-As in rice, the current consumption of rice does not pose a risk to adult men in China. Also, a lower (50 g/day) or higher (200 g/day) rice consumption will not bring larger beneficial effects.

Bayesian toxicokinetic modeling of cadmium exposure in Chinese population

Cadmium (Cd) is a toxic heavy metal widely present in the environment. Estimating its internal levels for a given external exposure using toxicokinetic (TK) models is key to the human health risk assessment of Cd. In this study, existing Cd TK models were adapted to develop a one-compartment TK model and a multi-compartment physiologically based toxicokinetic (PBTK) model by estimating the characteristics of Cd kinetics based on Cd exposure data from 814 Chinese residents. Both models not only considered the effect of gender difference on Cd kinetics, but also described the model parameters in terms of distributions to reflect individual variability. For both models, the posterior distributions of sensitive parameters were estimated using the Markov chain-Monte Carlo method (MCMC) and the approximate Bayesian computation-MCMC algorithm (ABC-MCMC). Validation with the test dataset showed 1.4-22.5% improvement in the root mean square error (RMSE) over the original models. After a systematic literature search, the optimized models showed acceptable prediction on other Chinese datasets. The study provides a method for parameter optimization of TK models under different exposure environment, and the validated models can serve as new quantitative assessment tools for the risk assessment of Cd in the Chinese population.

Effects of co-pyrolysis of rice husk and sewage sludge on the bioavailability and environmental risks of Pb and Cd

In this study, biochars were produced by co-pyrolysis of rice husk and sewage sludge, the environmental risk of heavy metal (Pd and Cd) in the biochars was assessed. Co-pyrolysis resulted in a lower yield but a higher C content compared with sewage sludge pyrolysis alone, the relative contents of Pb and Cd in biochars were declined. Co-pyrolysis process transformed the bioavailable heavy metals into stable speciation. The environmental risk assessment codes of Pb and Cd were reduced by 1-2 grades. The co-pyrolysis technology provides a feasible method for the safe disposal of heavy metal-contaminated sewage sludge.

Multi-walled carbon nanotube-based nanobiosensor for the detection of cadmium in water

Industrial and agricultural processes have led to the prevalence of cadmium in the ecosystem. A successive build-up of cadmium in food and drinking water can result in inadvertent consumption of hazardous concentrations. Such environmental contamination of cadmium can pose a substantial threat to human and animal life. In humans, it is known to cause hypertension, cardiovascular diseases, DNA lesions, inhibition of DNA repair protein or disturb the functioning of lung, liver, prostate and kidney. The development of a reliable method for Cd (II) ions detection would reduce the exposure and complement existing conventional methods. In this study, a DNA based electrochemical method is employed for the detection of Cd (II) ions using ethyl green (EG) and multi-walled carbon nanotube (MWCNT). Glassy carbon electrode (GCE)/MWCNT forms the working electrode for differential pulse voltammetry (DPV) analysis for the detection of Cd (II) ions. The dsDNA is immobilized onto the working electrode. The indicator dye EG, preferably binds to ssDNA and its reduction peak current is noticeably less in the presence of dsDNA. The Cd (II) ions after interacting with dsDNA, unwinds the dsDNA to ssDNA, upon which the EG molecules bind to ssDNAs, giving a higher reduction peak current. The difference in the reduction peak currents in the presence and absence of Cd (II) ions is proportional to its concentration. The linear detection range achieved in this method is 2 nM-10.0 nM with a sensitivity of around 5 nA nM^-1 and the limit of detection is 2 nM, which is less than the permissible limit of WHO for human exposure. This study considerably broadens the possible application of multi-walled carbon nanotube modified electrodes as biosensors and holds prospects for the detection of other heavy metals in environmental samples.

Study on toxicological effect and the mechanism of cadmium in rice and inorganic cadmium on ICR mice

Cadmium (Cd) exposure may induce chronic intoxication, but the harm of cadmium in rice to human at chronic low-level Cd exposure remains unclear. This study employed a mouse model to investigate the toxicity and mechanism of cadmium in rice and CdCl2. After 8-week exposure to Cd (CdCl2 and Cd-contaminated rice), the biochemical indicators and oxidation indicators in the serum and liver of mice were determined, and used mRNA sequencing to investigate the mechanism of different forms of Cd. Results showed that the cadmium concentration of the liver in the CdCl2 + Rice-N group (CdCl2 mixed with feed and normal rice, 0.4mg/kg.bw) was higher than that in the Rice-H group (0.4mg/kg.bw). However, the cadmium concentration of the kidneys in the Rice-H group was higher than that in the CdCl2 + Rice-N group. Our study demonstrated that Cd-treated (Cd in rice and CdCl2) ICR mice generated obviously tissues injury, such as the increased biochemical studies, the activity of antioxidant enzymes debasement. Simultaneously, our data also indicated that there existed difference of the hepatic toxicity between Cd in rice and CdCl2. By means of transcriptomics, we discovered that CdCl2 and Cd in rice may affect different gene expression at the molecular level. We hope to provide some theoretical basis for the revision of food security standards.

MicroRNA-363-3p promotes apoptosis in response to cadmium-induced renal injury by down-regulating phosphoinositide 3-kinase expression

We previously determined that specific microRNAs (miRNAs) are involved in renal pathophysiological occurrences induced by cadmium (Cd) in rats. This study expands our studies on miRNAs, determining their role in Cd-induced nephrotoxicity in occupational workers. We performed miRNA microarray analyses of blood and urine samples from patients diagnosed as occupational chronic Cd poisoning (OCCP) with abnormally elevated concentrations of urinary beta-2-microglobulin (U-β₂-MG), an indicator of tubular proteinuria. We also performed in vitro bioinformatics-based investigations of apoptosis-related genes targeted by miRNAs involved in the biological response to Cd exposure. We tested five differentially expressed miRNAs and determined a significant increase of sera miR-363-3p. Also, we determined that miR-363-3p increase is associated with phosphoinositide 3-kinase (PI3K) down-regulation and the suppressed proliferation and enhanced apoptosis of renal tubule epithelial cells. The obtained results suggest miR-363-3p involvement in the pathophysiology of Cd-induced renal injury in humans and maybe considered for possible interventional therapeutic strategies for Cd-associated kidney damage.

Burden of osteoporosis and costs associated with human biomonitored cadmium exposure in three European countries: France, Spain and Belgium

Cadmium (Cd) is a toxic heavy metal widespread in the environment leading to human exposure in particular through diet (when smoking is excluded), as documented by recent human biomonitoring (HBM) surveys. Exposure to Cd at environmental low-exposure levels has been associated with adverse effects such as renal toxicity and more recently bone effects. The implication, even if limited, of Cd in the etiology of osteoporosis can be of high importance at the population level given the significant prevalence of osteoporosis and the ubiquitous and life-long exposure to Cd. Therefore, the osteoporosis cases attributable to Cd exposure was estimated in three European countries (Belgium, France and Spain), based on measured urinary Cd levels from HBM studies conducted in these countries. The targeted population was women over 55 years old, for which risk levels associated with environmental Cd exposure were available. Around 23% of the cases were attributed to Cd exposure. Moreover, in a prospective simulation approach of lifelong urinary Cd concentrations assuming different intakes scenarios, future osteoporosis attributable cases were calculated, based on urinary Cd levels measured in women aged under 55. Between 6 and 34% of the considered populations under 55 years were at risk for osteoporosis. Finally, the costs associated to the burden of osteoporosis-related fractures attributable to Cd for each country targeted in this paper were assessed, standing for a major contributing role of Cd exposure in the overall social costs related to osteoporosis. Absolute costs ranged between 0.12 (low estimate in Belgium) and 2.6 billion Euros (high estimate in France) in women currently over 55 years old and at risk for fractures. Our results support the importance of reducing exposure of the general population to Cd.

Cadmium-induced Oxidative Stress and Immunosuppression Mediated Mitochondrial Apoptosis via JNK-FoxO3a-PUMA pathway in Common Carp (Cyprinus carpio L.) Gills

Cadmium (Cd)-caused water environment pollution has become a matter of concern. Gill is an organ with respiratory and mucosal immune functions, and is also one of the organs directly attacked by pollutants. It was found that excess Cd could cause Cd accumulation and gill injury in carp. However, the mechanism of Cd-caused damage in common carp gills is still unclear. Oxidative stress, immunosuppression, and apoptosis took part in the mechanism of poisoning caused by some harmful substances. The aim of the study was to investigate complex molecular mechanism of apoptotic injury caused by Cd in common carp gills. Hence, in this study, we established a Cd poisoning model to explore whether excess Cd can induce apoptosis through observing histomorphology and apoptotic cells; and determining mineral elements, oxidative stress-related factors, immune-related, and apoptosis-related genes in common carp gills. Fifty-four fish were randomly separated into the control group and the Cd group and were cultured for 45 days. The water of the control group was drinking water and the water of the Cd group was CdCl₂-added drinking water (0.26 mg/L Cd). In our results, we found that excess Cd increased Cd level, decreased the levels of essential mineral elements (Cu, Fe, Zn, and Mn), damaged mitochondria, and increased apoptotic cells in common carp gills, meaning that excess Cd caused Cd accumulation and apoptotic injury via mitochondrion in common carp gills. Furthermore, we found that Cd inhibited anti-apoptosis-related gene Bcl-2 and stimulated pro-apoptosis-related genes (JNK, FoxO3a, PUMA, Bax, Apaf-1, Caspase-9, and Caspase-3) on 15th, 30th, and 45th days. Above data meant that Cd exposure caused apoptosis via mitochondrion and JNK-FoxO3a-PUMA pathway in common carp gills. In addition, in our experiment, Cd treatment increased oxidants (H₂O₂ and MDA) and decreased antioxidants (CAT, GPx, GST, SOD, T-AOC, and GSH), indicating that Cd caused oxidative stress via oxidation/antioxidation imbalance. Meanwhile, compared to the control group, T-help 17 (Th17) cell-related factors (IL-17, TNF-α, and RORγ) were up-regulated, regulatory T (Treg) cell-related factors (IL-10 and Foxp3) were down-regulated, and IL-17/IL-10, TNF-α/IL-10, and RORγ/Foxp3 were increased in Cd-exposed group; meaning that excess Cd induced immunosuppression via the imbalance of Th17/Treg cells. Taken together, our findings indicated that JNK-FoxO3a-PUMA pathway and mitochondrion participated in oxidative stress and immunosuppression-mediated apoptosis caused by Cd in common carp (Cyprinus carpio L.) gills. Our data provided new perspectives on the negative effects of heavy metal pollutants on fish.

The burden of disease of three food-associated heavy metals in clusters in the Danish population - Towards targeted public health strategies

Lifestyle and sociodemographics are likely to influence dietary patterns, and, as a result, human exposure to chemical contaminants in foods and their associated health impact. We aimed to characterize subgroups of the Danish population based on diet and sociodemographic indicators, and identify those bearing a higher disease burden due to exposure to methylmercury (MeHg), cadmium (Cd) and inorganic arsenic (i-As). We collected dietary, lifestyle, and sociodemographic data on the occurrence of chemical contaminants in foods from Danish surveys. We grouped participants according to similarities in diet, lifestyle, and sociodemographics using Self-Organizing Maps (SOM), and estimated disease burden in disability-adjusted life years (DALY). SOM clustering resulted in 12 population groups with distinct characteristics. Exposure to contaminants varied between clusters and was largely driven by intake of fish, seafood and cereal products. Five clusters had an estimated annual burden >20 DALY/100,000. The cluster with the highest burden had a high proportion of women of childbearing age, with most of the burden attributed to MeHg. Individuals belonging to the top three clusters had higher education and physical activity, were mainly non-smokers and lived in urban areas. Our findings may facilitate the development of preventive strategies targeted to the most affected subgroups.

Food Safety Implications of Transitions Toward Sustainable Healthy Diets

Despite increased political attention, foodborne diseases still cause a substantial public health, economic, and social burden worldwide. Children younger than 5 years, people living in developing regions, and in the poorest areas of the world are disproportionally affected, bearing a large proportion of the global burden of foodborne disease. Yet, food safety is a prerequisite to ensuring food security globally: Foods that are responsible for important food safety problems are also crucial to ensure food security in some regions and are essential sources of nutrition. Moreover, together with calls for action to meeting international sustainable development goals, global efforts to promote food security and healthy diets have now highlighted the need to modify food systems globally. This article therefore explores the food safety dimensions of transitions toward food systems that promote sustainable healthy diets. The current body of evidence points to the combined health and environmental benefits of shifting toward a more plant-based diet, including vegetables and fruits, nuts, pulses, and whole grains. As a shift toward more plant-based diets may also lead to higher exposures to chemicals or pathogens present in these foods, an evaluation of food safety implications of such transitions is now imperative. We conclude that several synergies between public health, environmental, and food safety strategies can be identified to support dietary transitions.

Cadmium causes hepatopathy by changing the status of DNA methylation in the metabolic pathway

Toxicity caused by the heavy metal Cadmium leads to liver diseases; this finding has generated interest among researchers. We detected DNA methylation using Whole Genome Bisulfite Sequencing (WGBS) to study the relationship between Cadmium exposure and liver damage. Forty-eight Sprague-Dawley rats were randomly divided into six groups, and given normal saline or 2.5, 5, 10, 20, and 40 mg/kg body weight per day CdCl₂ by gavage. Twelve weeks later, their liver tissues were collected for pathological examination and DNA extraction. Increased exposure to Cadmium led to a reduction in the amount of weight gain as well as pathological degeneration and necrosis of liver cells of the rats. Using WGBS, we found that DNA methylation changes in the high-dose exposure group were more remarkable, and most of the changes occurred in the gene promoter region. GO enrichment analysis showed that the genes were enriched in the biological process of "response to stimulus." KEGG analysis revealed that metabolic pathways, like MAPK, PI3K-Akt and cAMP, had the largest number of enriched genes. Using Integrative Genomics Viewer (IGV), the demethylation of F2rl3 after Cadmium poisoning was established. This finding may explain why there are changes in liver metabolism after Cadmium poisoning.

Forty Years of Food Safety Risk Assessment: A History and Analysis

Before the founding of the Society for Risk Analysis (SRA) in 1980, food safety in the United States had long been a concern, but there was a lack of systematic methods to assess food-related risks. In 1906, the U.S. Congress passed, and President Roosevelt signed, the Pure Food and Drug Act and the Meat Inspection Act to regulate food safety at the federal level. This Act followed the publication of multiple reports of food contamination, culminating in Upton Sinclair's novel The Jungle, which highlighted food and worker abuses in the meatpacking industry. Later in the 20th century, important developments in agricultural and food technology greatly increased food production. But chemical exposures from agricultural and other practices resulted in major amendments to federal food laws, including the Delaney Clause, aimed specifically at cancer-causing chemicals. Later in the 20th century, when quantitative risk assessment methods were given greater scientific status in a seminal National Research Council report, food safety risk assessment became more systematized. Additionally, in these last 40 years, food safety research has resulted in increased understanding of a range of health effects from foodborne chemicals, and technological developments have improved U.S. food safety from farm to fork by offering new ways to manage risks. We discuss the history of food safety and the role risk analysis has played in its evolution, starting from over a century ago, but focusing on the last 40 years. While we focus on chemical risk assessment in the U.S., we also discuss microbial risk assessment and international food safety.

Phospholipase D1 Ameliorates Apoptosis in Chronic Renal Toxicity Caused by Low-Dose Cadmium Exposure

Exposure to cadmium (Cd), a common heavy metal used in industry, can result in long-term chronic toxicity. It has been well characterized that kidneys are the main organs that are targeted by toxicity, which can cause apoptosis, necrosis, and atrophy of renal tubular epithelial cells. However, the molecular mechanisms associated with Cd toxicity remain unclear. In this study, the expression of renal proteins in Sprague-Dawley rats exposed to chronic Cd was analyzed with iTRAQ proteomics. Bioinformatics analysis indicated that phospholipase D1 (PLD1) was significantly underexpressed and may correlate strongly with Cd-induced chronic kidney impairment. Previous studies have shown that PLD1 promotes cell proliferation and inhibits apoptosis, indicating that PLD1 may be implicated in the pathogenesis of kidney injury induced by Cd. Studies in vivo and in vitro all demonstrate that the mRNA and protein levels of PLD1 decrease significantly both in kidney tissue and in proximal tubular cell lines exposed to Cd. Overexpression of PLD1 and its downstream product PA could ameliorate Cd-induced apoptosis. Moreover, we identified that miR-122-5p was a regulatory miRNA of PLD1. miR-122-5p was overexpressed after Cd exposure and promoted cell apoptosis by downregulating PLD1 through binding the 3'UTR of the locus at 1761-1784 nt. In conclusion, our results indicated that PLD1 and its downstream PA were strongly implicated in Cd-induced chronic kidney impairment and could be a novel player in the defense against Cd-induced nephrotoxicity.

Selenium Mitigates Cadmium-Induced Adverse Effects on Trace Elements and Amino Acids Profiles in Chicken Pectoral Muscles

Cadmium (Cd), as one of the most toxic heavy metals, has become a widespread environmental contaminant and threats the food quality and safety. The protective effect of selenium (Se) on Cd-induced tissue lesion and cytotoxicity in chicken has been extensively reported. The objective of this study was to investigate the antagonistic effect of Se on Cd-induced damage of chicken pectoral muscles via analyzing the trace elements and amino acids profiles. Firstly, 19 trace elements contents were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that under Cd exposure, the contents of Cd, lead (Pb), mercury (Hg), aluminum (Al), and lithium (Li) were significantly elevated, and the contents of Se, iron (Fe), and chromium (Cr) were significantly reduced. However, supplementing Se significantly reversed the effects induced by Cd. Secondly, the amino acids contents were detected by L-8900 automatic amino acid analyzer. The results showed that supplementing Se increased significantly Cd-induced decrease of valine (Val), leucine (Leu), arginine (Arg), and proline (Pro). Thirdly, the results of principal component analysis (PCA) showed that cobalt (Co), manganese (Mn), silicium (Si), and Pro may play special roles in response to the process of Se antagonizes Cd-induced damage of pectoral muscles in chickens. In summary, these results indicated that different trace elements and amino acids possessed and exhibited distinct responses to suffer from Se and/or Cd in chicken pectoral muscles. Notably, Se alleviated Cd-induced adverse effects by regulating trace elements and amino acids profiles in chicken pectoral muscles.

Protective role of curcumin in cadmium-induced testicular injury in mice by attenuating oxidative stress via Nrf2/ARE pathway

The aim of the present study was to investigate whether curcumin (CUR) can ameliorate cadmium-induced reproductive toxicity and its mechanism. A total of 48 male mice were equally divided into 4 groups: control, CdCl₂ (2 mg/kg, intraperitoneally inject) curcumin (50 mg/kg, intraperitoneally inject), co-treatment with curcumin (50 mg/kg), and CdCl₂ (2 mg/kg) for 10 days. The results demonstrated that CdCl₂ reduces sperm motility, decreases the sperm density and serum testosterone content, and significantly improves the rate of sperm deformity. CdCl₂ increased the level of testicular total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) activity, and glutathione (GSH), and CdCl₂ declined the level of malondialdehyde (MDA). However, the semen quality of the mice in the curcumin intervention group was improved. Moreover, the testosterone content and antioxidant capacity were increased. In the Cd group mice, the expression of testicular Nrf2, as well as the mRNA and protein expressions of the downstream target molecules, glutathione peroxidase (GSH-Px), and γ-glutamylcysteine synthetase (γ-GCS) of Nrf2 declined, while the above genetic expressions elevated significantly in the curcumin intervention group. Our results suggested that curcumin could protect against Cd-induced testicular injury via activating the Nrf2/ARE signaling pathway.

Estimates of the 2015 global and regional disease burden from four foodborne metals - arsenic, cadmium, lead and methylmercury

The impact of foodborne metals on the burden of disease has been largely overlooked, in comparison to the attention on acute diseases associated with infectious foodborne agents. Four articles in this special section describe in detail the burden of disease from foodborne lead, methylmercury, arsenic, and cadmium. Ingested lead and methylmercury are causally associated with lifelong intellectual disability. Long term ingestion of arsenic is causally associated with an increased risk of cancer. Long term ingestion of cadmium is causally associated with an increased risk of late stage chronic kidney disease. This article presents an overview of the burden of disease from these four foodborne metals and discusses them in the context of the World Health Organization's initiative to estimate the global burden of foodborne disease. The results indicate that in 2015, ingestion of arsenic, methylmercury, lead, and cadmium resulted in more than 1 million illnesses, over 56,000 deaths, and more than 9 million disability-adjusted life years (DALYs) worldwide. The greatest impact on DALYs was in the Western Pacific B subregion. All of the metals were found to have high DALYs per case in comparison with other foodborne disease agents, including infectious and parasitic agents. In addition, lead, arsenic, and methylmercury were found to have high DALYs per 100,000 population in comparison to other foodborne disease agents.

Levels and determinants of adipose tissue cadmium concentrations in an adult cohort from Southern Spain

This study was conceived as a first step to evaluate the suitability of adipose tissue cadmium (Cd) concentrations as a biomarker for the assessment of long-term exposure. Specifically, the aim of this work was to explore the socio-demographic, dietary, and lifestyle determinants of adipose tissue Cd concentrations. The study population is a subsample of GraMo cohort. Adipose tissue samples were intraoperatively collected from 226 adult volunteers recruited in two public hospitals from Granada, Spain. Cd concentrations in adipose tissue were analyzed by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Data on socio-demographic characteristics, lifestyle, diet and health status were collected by face-to-face interviews. Predictors of Cd concentrations were assessed by multivariable linear regression with a stepwise variable selection. We found detectable levels of Cd in the adipose tissue of all the study participants, with a mean concentration (±standard deviation) of 12.66 ± 18.91 μg/kg. Smoking habit at recruitment was associated with increased adipose tissue Cd concentrations (β for smokers = 0.669 p < 0.001; β for former smokers = 0.502, p < 0.001; reference = non-smokers). Age was positively associated with Cd concentrations (β = 0.014, p < 0.001), and men showed lower concentrations than women (β = -0.424, p < 0.001). Obesity, measured as Body Mass Index (BMI), showed an inverse association with Cd concentrations (β = -0.038, p < 0.001). Egg consumption ≥2 portions/week (β = 0.241, p = 0.025) was positively associated with Cd concentrations. Perceived exposure to paints was also positively associated with Cd concentrations. The observed associations with age, smoking habit, BMI, and egg and meat consumption did not substantially change after sex/gender stratification. Our results are consistent with currently-known Cd sources and suggest other potential pathways, which might be population-specific. As a whole, our findings underline the potential relevance of adipose tissue as a biological matrix for exposure characterization to Cd, as well as for the assessment of long-term clinical implications of the exposure, particularly in obesity-related diseases.