Subchronic Arsenic Exposure Through Drinking Water Alters Lipid Profile and Electrolyte Status in Rats

Application of Human Plasma Targeted Lipidomics and Analysis of Toxic Elements to Capture the Metabolic Complexities of Hypothyroidism

BACKGROUND

Hypothyroidism (HT) affects millions worldwide and can lead to various lipid disorders. The metabolic complexity and the influence of toxic elements in autoimmune and non-autoimmune HT subtypes are not fully understood. This study aimed to investigate the relationships between plasma lipidome, toxic elements, and clinical classifications of HT in unexposed individuals.

METHODS

Samples were collected from 120 adults assigned to a study group with Hashimoto's disease and non-autoimmune HT, and a healthy control group. Quantification of 145 pre-defined lipids was performed by using triple quadrupole tandem mass spectrometry (TQ MS/MS) in multiple reactions monitoring (MRM) mode via positive electrospray ionization (ESI). Levels of toxic elements were determined using inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Significant associations between altered levels of several components of the plasma lipidome and Al, Cd, Ni, As, and Pb with HT were found. We show metabolic differences in lysophosphatidylcholines (LPC) and phosphatidylcholines (PC) between HT and controls, with distinct predicted activation patterns for lysolecithin acyltransferase and phospholipase A2.

CONCLUSIONS

There are significant changes in the lipidome profiles of healthy subjects compared to euthyroid HT patients treated with L-thyroxine, which are related to the type of hypothyroidism and non-occupational exposure to toxic elements.

ASC/Caspase-1-activated endothelial cells pyroptosis is involved in vascular injury induced by arsenic combined with high-fat diet

Environmental arsenic (As) or high-fat diet (HFD) exposure alone are risk factors for the development of cardiovascular disease (CVDs). However, the effects and mechanisms of co-exposure to As and HFD on the cardiovascular system remain unclear. The current study aimed to investigate the combined effects of As and HFD on vascular injury and shed some light on the underlying mechanisms. The results showed that co-exposure to As and HFD resulted in a significant increase in serum lipid levels and significant lipid accumulation in the aorta of rats compared with exposure to As or HFD alone. Meanwhile, the combined exposure altered blood pressure and disrupted the morphological structure of the abdominal aorta in rats. Furthermore, As combined with HFD exposure upregulated the expression of vascular endothelial cells pyroptosis-related proteins (ASC, Pro-caspase-1, Caspase-1, IL-18, IL-1β), as well as the expression of vascular endothelial adhesion factors (VCAM-1 and ICAM-1). More importantly, we found that with increasing exposure time, vascular injury-related indicators were significantly higher in the combined exposure group compared with exposure to As or HFD alone, and the vascular injury was more severe in female rats compared with male rats. Taken together, these results suggested that the combination of As and HFD induced vascular endothelial cells pyroptosis through activation of the ASC/Caspase-1 pathway. Therefore, vascular endothelial cells pyroptosis may be a potential molecular mechanism for vascular injury induced by As combined with HFD exposure.

Subchronic Arsenite Exposure Induced Atrophy and Erythropoietin Sensitivity Reduction in Skeletal Muscle Were Relevant to Declined Serum Melatonin Levels in Middle-Aged Rats

Arsenic is a kind of widespread environmental toxicant with multiorgan-toxic effects, and arsenic exposure is associated with the occurrence and development of many chronic diseases. The influence of environmental arsenic exposure on skeletal muscle, which is a vital organ of energy and glucose metabolism, has received increasing attention. This study aimed to investigate the types of inorganic arsenic-induced skeletal muscle injury, and the potential regulatory effects of melatonin (MT) and erythropoietin (EPO) in young (3-month-old) and middle-aged (12-month-old) rats. Our results showed that 1 mg/L sodium arsenite exposure for 3 months could accelerate gastrocnemius muscle atrophy and promote the switch of type II fibers to type I fibers in middle-aged rats; however, it did not cause significant pathological changes of gastrocnemius muscle in young rats. In addition, arsenite could inhibit serum MT levels, and promote serum EPO levels but inhibit EPO receptor (EPOR) expression in gastrocnemius muscle in middle-aged rats, while serum MT levels and EPOR expression in gastrocnemius muscle showed an opposite effect in young rats. Importantly, exogenous MT antagonized the arsenite-induced skeletal muscle toxic effect and restored serum EPO and gastrocnemius muscle EPOR expression levels in middle-aged rats. There was a positive correlation among gastrocnemius muscle index, serum MT level, and gastrocnemius muscle EPOR protein level in arsenite-exposed rats. This study demonstrated that inorganic arsenic could accelerate skeletal muscle mass loss and type II fiber reduction in middle-aged rats, which may be related to decreased MT secretion and declined EPO sensitivity in skeletal muscle.

Association between Heavy Metals, Metalloids and Metabolic Syndrome: New Insights and Approaches

Metabolic syndrome (MetS) is an important public health issue that affects millions of people around the world and is growing to pandemic-like proportions. This syndrome is defined by the World Health Organization (WHO) as a pathologic condition characterized by abdominal obesity, insulin resistance, hypertension, and hyperlipidemia. Moreover, the etiology of MetS is multifactorial, involving many environmental factors, including toxicant exposures. Several studies have associated MetS with heavy metals exposure, which is the focus of this review. Environmental and/or occupational exposure to heavy metals are a major risk, contributing to the development of chronic diseases. Of particular note, toxic metals such as mercury, lead, and cadmium may contribute to the development of MetS by altering oxidative stress, IL-6 signaling, apoptosis, altered lipoprotein metabolism, fluid shear stress and atherosclerosis, and other mechanisms. In this review, we discuss the known and potential roles of heavy metals in MetS etiology as well as potential targeted pathways that are associated with MetS. Furthermore, we describe how new approaches involving proteomic and transcriptome analysis, as well as bioinformatic tools, may help bring about an understanding of the involvement of heavy metals and metalloids in MetS.

Association between combined exposure to plasma heavy metals and dyslipidemia in a chinese population

BACKGROUND

Exposure to heavy metals in the environment is widespread, while the relationship between combined exposure to heavy metals and dyslipidemia is unclear.

METHODS

A cross-sectional study was performed, and 3544 participants aged 30 years or older were included in the analyses. Heavy metal concentrations in plasma were based on inductively coupled plasma‒mass spectrometry. The relationship between heavy metals and dyslipidemia was estimated by logistic regression. BKMR was used to evaluate metal mixtures and their potential interactions.

RESULTS

In logistic regression analysis, participants in the fourth quartile of Fe and Zn (Fe > 1352.38 µg/L; Zn > 4401.42 µg/L) had a relatively higher risk of dyslipidemia (Fe, OR = 1.13, 95% CI: 0.92,1.38; Zn, OR = 1.30, 95% CI: 1.03,1.64). After sex stratification, females in the third quartile of plasma Zn (1062.05-4401.42 µg/L) had a higher relative risk of dyslipidemia (OR = 1.75, 95% CI: 1.28, 2.38). In BKMR analysis, metal mixtures were negatively associated with dyslipidemia in females when all metal concentrations were above the 50th percentile. In the total population (estimated from 0.030 to 0.031), As was positively associated with dyslipidemia when other metals were controlled at the 25th, 50th, or 75th percentile, respectively, and As was below the 75th percentile. In females (estimated from - 0.037 to -0.031), Zn was negatively associated with dyslipidemia when it was above the 50th percentile.

CONCLUSION

This study indicated that As was positively associated with dyslipidemia and that Zn may be negatively associated with dyslipidemia in females. Combined metal exposure was negatively associated with dyslipidemia in females. Females with low plasma Zn levels are more likely to develop dyslipidemia and should receive more clinical attention in this population.

Misuse of Cardiac Lipid upon Exposure to Toxic Trace Elements-A Focused Review

Heavy metals and metalloids like cadmium, arsenic, mercury, and lead are frequently found in the soil, water, food, and atmosphere; trace amounts can cause serious health issues to the human organism. These toxic trace elements (TTE) affect almost all the organs, mainly the heart, kidney, liver, lungs, and the nervous system, through increased free radical formation, DNA damage, lipid peroxidation, and protein sulfhydryl depletion. This work aims to advance our understanding of the mechanisms behind lipid accumulation via increased free fatty acid levels in circulation due to TTEs. The increased lipid level in the myocardium worsens the heart function. This dysregulation of the lipid metabolism leads to damage in the structure of the myocardium, inclusive fibrosis in cardiac tissue, myocyte apoptosis, and decreased contractility due to mitochondrial dysfunction. Additionally, it is discussed herein how exposure to cadmium decreases the heart rate, contractile tension, the conductivity of the atrioventricular node, and coronary flow rate. Arsenic may induce atherosclerosis by increasing platelet aggregation and reducing fibrinolysis, as exposure interferes with apolipoprotein (Apo) levels, resulting in the rise of the Apo-B/Apo-A1 ratio and an elevated risk of acute cardiovascular events. Concerning mercury and lead, these toxicants can cause hypertension, myocardial infarction, and carotid atherosclerosis, in association with the generation of free radicals and oxidative stress. This review offers a complete overview of the critical factors and biomarkers of lipid and TTE-induced cardiotoxicity useful for developing future protective interventions.

Calcium carbide-induced derangement of hematopoiesis and organ toxicity ameliorated by cyanocobalamin in a mouse model

Background

Calcium carbide (CaC₂) is a chemical primarily used in the production of acetylene gas. The misuse of CaC₂ to induce fruit ripening is a global challenge with a potential adverse effects to human health. Additionally, CaC₂ is known to contain some reasonable amount of arsenic and phosphorous compounds that are toxic and pose a danger to human health when ingested. The current study sought to characterize CaC₂ toxicity and elucidate any protective effects by cyanocobalamin (vitamin B₁₂), a well-established antioxidant and anti-inflammatory bio-molecule. Female Swiss white mice were randomly assigned into three groups; the first group was the control, while the second group was administered with CaC₂. The third group received CaC₂ followed by administration of vitamin B12. The mice were sacrificed at 60 days post treatment, hematological, biochemical, glutathione assay, cytokine ELISA and standard histopathology was performed.

Results

CaC₂ administration did not significantly alter the mice body weight. CaC₂ administration resulted in a significant decrease in packed cell volume (PCV), hemoglobin (Hb), red blood cells (RBCs) and RBC indices; indicative of CaC₂-driven normochromic microcytic anaemia. Further analysis showed CaC₂-driven leukopenia. Evidently, vitamin B₁₂ blocked CaC₂-driven suppression of PCV, Hb, RBCs and WBCs. Monocytes and neutrophils were significantly up-regulated by CaC₂. CaC₂-induced elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and bilirubin signaled significant liver damage. Notably, vitamin B₁₂ stabilized AST, ALT and bilirubin in the presence of CaC_2, an indication of a protective effect. Histopathological analysis depicted that vitamin B₁₂ ameliorated CaC₂-driven liver and kidney injury. CaC₂ resulted in the depletion of glutathione (GSH) levels in the liver; while in the brain, kidney and lungs, the GSH levels were elevated. CaC₂ administration resulted in elevation of pro-inflammatory cytokines TNF-α and IFN-γ. Vitamin B₁₂ assuaged the CaC₂-induced elevation of these pro-inflammatory cytokines.

Conclusions

These findings demonstrate for the first time that oral supplementation with vitamin B₁₂ can protect mice against CaC₂-mediated toxicity, inflammation and oxidative stress. The findings provide vital tools for forensic and diagnostic indicators for harmful CaC₂ exposure; while providing useful insights into how vitamin B₁₂ can be explored further as an adjunct therapy for CaC₂ toxicity.

A longitudinal study of rural Bangladeshi children with long-term arsenic and cadmium exposures and biomarkers of cardiometabolic diseases

There is growing interest in understanding the contribution of environmental toxicant exposure in early life to development of cardiometabolic diseases (CMD) in adulthood. We aimed to assess associations of early life exposure to arsenic and cadmium with biomarkers of CMD in children in rural Bangladesh. From a longitudinal mother-child cohort in Matlab, Bangladesh, we followed up 540 pairs. Exposure to arsenic (U-As) and cadmium (U-Cd) was assessed by concentrations in urine from mothers at gestational week 8 (GW8) and children at ages 4.5 and 9 years. Blood pressure and anthropometric indices were measured at 4.5 and 9 years. Metabolic markers (lipids, glucose, hemoglobin A1c, adipokines, estimated glomerular filtration rate (eGFR) were determined in plasma/blood of 9 years old children. In linear regression models, adjusted for child sex, age, height-for-age z score (HAZ), BMI-for-age z score (BAZ), socioeconomic status (SES) and maternal education, each doubling of maternal and early childhood U-Cd was associated with 0.73 and 0.82 mmHg increase in systolic blood pressure (SBP) respectively. Both early and concurrent childhood U-Cd was associated with diastolic (D)BP (β = 0.80 at 4.5 years; β = 0.75 at 9 years). Each doubling of U-Cd at 9 years was associated with decrements of 4.98 mg/dL of total cholesterol (TC), 1.75 mg/dL high-density lipoprotein (HDL), 3.85 mg/dL low-density lipoprotein (LDL), 0.43 mg/dL glucose and 4.29 units eGFR. Each doubling of maternal U-Cd was associated with a decrement of 1.23 mg/dL HDL. Both maternal and childhood U-As were associated with decrement in TC and HDL. Multiple comparisons were checked with family-wise error rate Bonferroni-type-approach. The negative associations of arsenic and cadmium with biomarkers of CMD in preadolescent children indicated influence of both metal(loid)s on fat and carbohydrate metabolism, while cadmium additionally influenced kidney function and BP. Thus, fewer outcomes were associated with U-As compared to U-Cd at preadolescence.

Effects of arsenic exposure on lipid metabolism: a systematic review and meta-analysis

Lipid metabolism dysfunction is a risk factor for cardiovascular diseases. Reportedly, arsenic exposure could affect lipid metabolism, but this finding remains controversial. Herein, we updated and reevaluated evidence regarding the relationship between arsenic exposure and lipid metabolism. Electronic and manual searches were performed to determine the effect of arsenic exposure on lipid metabolism from inception up to 30 November 2019. Overall, five studies were included in our meta-analysis. Two reviewers independently extracted information. Standardized mean difference (SMD) and 95% confidence intervals (CI) were used to analyze the combined effects of four indicators related to lipid metabolism (total cholesterol [TC], triglyceride [TG], high-density lipoprotein [HDL], low-density lipoprotein [LDL]). Afterwards, subgroup and sensitivity analyses were performed to explore the source of heterogeneity. Publication bias was tested using funnel plots and Begg's test. In this study, we observed that arsenic exposure can affect lipid metabolism by reducing serum HDL levels and increasing serum LDL levels. Following subgroup analysis, the arsenic concentration appeared to affect lipid metabolism. Funnel plot and Begg's test suggested no asymmetry. In conclusion, we recommend that potential influencing factors, including age, exposure time, and multiple concentration gradients, should be considered to further explore the relationship between arsenic exposure and lipid metabolism.

Associations between metabolic syndrome and four heavy metals: A systematic review and meta-analysis

Four most concerned heavy metal pollutants, arsenic, cadmium, lead, and mercury may share common mechanisms to induce metabolic syndrome (MetS). However, recent studies exploring the relationships between MetS and metal exposure presented inconsistent findings. We aimed to clarify the relationship between heavy metal exposure biomarkers and MetS using a meta-analysis and systematic review approach. Literature search was conducted in international and the Chinese national databases up to June 2020. Of selected studies, we extracted the relevant data and evaluated the quality of each study's methodology. We then calculated the pooled effect sizes (ESs), standardized mean differences (SMDs), and their 95% confidence intervals (CIs) using a random-effect meta-analysis approach followed by stratification analyses for control of potential confounders. Involving 55,536 participants, the included 22 articles covered 52 observational studies reporting ESs and/or metal concentrations on specific metal and gender. Our results show that participants with MetS had significantly higher levels of heavy metal exposure [pooled ES = 1.16, 95% CI: 1.09, 1.23; n = 42, heterogeneity I2 = 75.6%; and SMD = 0.22, 95% CI: 0.15, 0.29; n = 32, I2 = 94.2%] than those without MetS. Pooled ESs in the subgroups stratified by arsenic, cadmium, lead, and mercury were 1.04 (95% CI: 0.97, 1.10; n = 8, I2 = 61.0%), 1.10 (0.95, 1.27; 11, 45.0%), 1.21 (1.00, 1.48; 12, 82.9%), and 1.26 (1.06, 1.48; 11, 67.7%), respectively. Pooled ESs in the subgroups stratified by blood, urine, and the other specimen were 1.22 (95% CI: 1.08, 1.38; n = 26, I2 = 75.8%), 1.06 (1.00, 1.13; 14, 58.1%), and 2.41 (1.30, 4.43; 2, 0.0%), respectively. In conclusion, heavy metal exposure was positively associated with MetS. Further studies are warranted to examine the effects of individual metals and their interaction on the relationship between MetS and heavy metals.

Evaluation of different types of arsenic methylation and its relationship with metabolic syndrome in an area chronically exposed to arsenic

Evidence suggests that the relationship between arsenic metabolism and diseases, including metabolic syndrome, is complex. The aim of this study was to evaluate the different types of arsenic methylation and its association with metabolic syndrome in an arsenic endemic area. A cross-sectional study was conducted on 132 subjects from Shahid-Abad Village, Qazvin province, Iran (arsenic endemic area). Demographic characteristics, metabolic syndrome, and urinary arsenic species, including iAs (inorganic arsenic), MMA (monomethylarsonic acid), and DMA (dimethylarsinic acid) were measured for all patients and their relationship was analyzed by appropriate statistical methods. In this study, 34.5% of the participants had metabolic syndrome. The decrease in %MMA, increase in %DMA and increase in secondary methylation index (DMA/MMA) were associated with increased risk of metabolic syndrome (p<0.05). We did not find any association between the incidence of metabolic syndrome with primary methylation index (MMA/iAs) and %iAs (p>0.05). This study showed that the prevalence of metabolic syndrome was significantly higher in people with metabolic syndrome than in the general population. A closer examination revealed that the secondary methylation index is related to the metabolic syndrome and its components. Given the higher prevalence of cardiovascular disease and diabetes in patients with metabolic syndrome, it is necessary to change the pathogenesis of the disease using comprehensive management methods for decreasing patient complications.

Heavy metals interfere with plasma metabolites, including lipids and amino acids, in patients with breast cancer

The aim of the present study was to examine the association between plasma heavy metals and the metabolome in patients with breast cancer (BC), and the association with cancer development. Nuclear magnetic resonance was used to determine the metabolites involved and an inductively coupled plasma mass spectrometry system was used to quantify the heavy metals in the plasma samples. It was indicated that cadmium was significantly higher in the plasma of patients with BC compared with that in the control population (~15-fold increase). Chromium, arsenic and lead were also elevated in the plasma of patients with BC by ~3.24, 2.14 and 1.52 fold, respectively. A number of small molecules, including amino acids and salts, were altered in the plasma of patients with BC compared with the control population. Another notable finding in this investigation was that plasma lipid levels were elevated in patients with BC compared with those in the control population. The findings of the present study suggest that exposure to heavy metals, including cadmium, arsenic, chromium and lead, may influence blood lipid levels and other small molecule metabolites, which in turn may be involved in BC development. Further studies surrounding urinary heavy metals and the metabolome are required to further determine the impact of metals on metabolism and on BC development.

Early-life arsenic exposure promotes atherogenic lipid metabolism in adolescence: A 15-year birth cohort follow-up study in central Taiwan

BACKGROUND

Inorganic arsenic (iAs) exposure potentially causes diabetes and cardiovascular diseases in adults. However, its effect on glucose and lipid metabolism in early life remains unknown.

OBJECTIVE

We evaluated the associations between early-life arsenic exposure and profiles of glucose and lipids in a 15-year birth cohort in central Taiwan.

METHODS

We studied 237 adolescents through 5 waves of follow-up interviews and examinations at ages of approximately 2, 5, 8, 11, and 14 y. We obtained at least one follow-up urine measurement for arsenic species and blood sample collection up to 14 y of age and identified group-based trajectories of serial iAs by semiparametric mixture modeling. Multiple linear and logistic regressions were performed to assess the effect of the arsenic exposure trajectory on serum fasting glucose, total cholesterol (TCHO), triglycerides (TGs), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL).

RESULTS

Three trajectories of postnatal arsenic exposure were identified, namely stable-low (31.4%), stable-high (48.2%), and rising-high (20.4%) groups. Compared with the stable-low trajectory group, the percent changes in TCHO and LDL was 14% (95% confidence interval 4-24%) and 23% (9-38%) for the group with "rising-high" trajectory and was 8% (-1-16%) and 16% (4-29%) for the group with "stable-high" trajectory. The rising-high group was also associated with an increase in the TCHO/HDL ratio by 14% (95% CI 3%-25%). The adjusted odds ratios of high developmental trajectories of TCHO, TG, LDL, and non-HDL levels were 4.0 (95% CI 1.2-13.7), 12.2 (2.2-67), 7.3 (1.8-30), and 3.6 (0.9-14.6), respectively, in the rising-high group (reference: stable-low group).

CONCLUSION

Our findings suggest that conversion to an atherogenic lipid profile in adolescents may be associated with early-life exposure to environmental arsenic, particularly during the pre-adolescent period. An environmental modification approach for preventing As-related cardiovascular disease is recommended to begin early in life.

The Association of Arsenic Exposure and Arsenic Metabolism With the Metabolic Syndrome and Its Individual Components: Prospective Evidence From the Strong Heart Family Study

Inorganic arsenic exposure is ubiquitous, and both exposure and interindividual differences in its metabolism have been associated with cardiometabolic risk. However, the associations of arsenic exposure and arsenic metabolism with the metabolic syndrome (MetS) and its individual components are relatively unknown. We used Poisson regression with robust variance to evaluate the associations of baseline arsenic exposure (urinary arsenic levels) and metabolism (relative percentage of arsenic species over their sum) with incident MetS and its individual components (elevated waist circumference, elevated triglycerides, reduced high-density lipoprotein cholesterol, hypertension, and elevated fasting plasma glucose) in 1,047 participants from the Strong Heart Family Study, a prospective family-based cohort study in American Indian communities (baseline visits were held in 1998-1999 and 2001-2003, follow-up visits in 2001-2003 and 2006-2009). Over the course of follow-up, 32% of participants developed MetS. An interquartile-range increase in arsenic exposure was associated with a 1.19-fold (95% confidence interval: 1.01, 1.41) greater risk of elevated fasting plasma glucose concentration but not with other individual components of the MetS or MetS overall. Arsenic metabolism, specifically lower percentage of monomethylarsonic acid and higher percentage of dimethylarsinic acid, was associated with higher risk of overall MetS and elevated waist circumference but not with any other MetS component. These findings support the hypothesis that there are contrasting and independent associations of arsenic exposure and arsenic metabolism with metabolic outcomes which may contribute to overall diabetes risk.

Morphological and morphometrical changes on adult Wistar rat testis caused by chronic sodium arsenite exposure

Arsenic is a contaminant that occurs naturally in the environment, and it is related to several diseases, such as cancer and severe metabolic diseases. Sodium arsenite effects on testes rats are not fully understood regarding morphology and stereology; thus, it becomes necessary to evaluate possible changes in these parameters under low concentrations and simulating occupational exposure. Therefore, the aim of this study was to analyze the morphometrical and stereological changes on rat testis treated with sodium arsenite. The treatment was accomplished using 5 mg/kg of sodium arsenite by gastric gavage in Wistar rats, which experiment lasted 8 weeks. Organs were weighed and gonadosomatic index (GSI) was calculated. Using the software Image Pro Plus, seminiferous tubule diameter was measured, and the volume densities of testicular parenchymal components were obtained. It was counted 200 hundred spermatozoa and classified as normal or abnormal. The parameters means of control (N = 5) and treated (N = 7) groups were compared by U Mann-Whitney's test, and the results were considered significant for P < 0.05. We observed a decrease in seminiferous tubule diameter, as well as testis weight. These finds may be related with disorders of testosterone metabolism due to activation of immunological responses of macrophage, which inhibit the steroidogenesis. Thus, we conclude that sodium arsenic does not impair the animal's general health, but its exposure induces biochemical and tissue changes.