Arsenic abrogates the estrogen-signaling pathway in the rat uterus

Natural antioxidants mitigate heavy metal induced reproductive toxicity: prospective mechanisms and biomarkers

Heavy metals are harmful environmental pollutants that have attracted widespread attention, attributed to their health hazards to humans and animals. Due to the non-degradable property of heavy metals, organisms are inevitably exposed to heavy metals such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). Several studies revealed that heavy metals can cause reproductive damage by the excessive production of reactive oxygen species (ROS), which exacerbates oxidative stress, inflammation, and endocrine disruption. Natural antioxidants, mainly polyphenols, carotenoids, and vitamins, have been shown to mitigate heavy metal-induced reproductive toxicity potentially. In this review, accumulated evidences on the influences of four non-essential heavy metals As, Cd, Pb, and Hg on both males and females reproductive system were established. The purpose of this review is to explore the potential mechanisms of the effects of heavy metals on reproductive function and point out the potential biomarkers of natural antioxidants interventions toward heavy metal-induced reproductive toxicity. Notably, increasing evidence proven that the regulations of hypothalamic-pituitary-gonadal axis, Nrf2, MAPK, or NF-κB pathways are the important mechanisms for the amelioration of heavy metal induced reproductive toxicity by natural antioxidants. It also provided a promising guidance for prevention and management of heavy metal-induced reproductive toxicity.

Prevalence of perturbed gut microbiota in pathophysiology of arsenic-induced anxiety- and depression-like behaviour in mice

Severe toxic effects of arsenic on human physiology have been of immense concern worldwide. Arsenic causes irrevocable structural and functional disruption of tissues, leading to major diseases in chronically exposed individuals. However, it is yet to be resolved whether the effects result from direct deposition and persistence of arsenic in tissues, or via activation of indirect signaling components. Emerging evidences suggest that gut inhabitants play an active role in orchestrating various aspects of brain physiology, as the gut-brain axis maintains cognitive health, emotions, learning and memory skills. Arsenic-induced dysbiosis may consequentially evoke neurotoxicity, eventually leading to anxiety and depression. To delineate the mechanism of action, mice were exposed to different concentrations of arsenic. Enrichment of Gram-negative bacteria and compromised barrier integrity of the gut enhanced lipopolysaccharide (LPS) level in the bloodstream, which in turn elicited systemic inflammation. Subsequent alterations in neurotransmitter levels, microglial activation and histoarchitectural disruption in brain triggered onset of anxiety- and depression-like behaviour in a dose-dependent manner. Finally, to confirm whether the neurotoxic effects are specifically a consequence of modulation of gut microbiota (GM) by arsenic and not arsenic accumulation in the brain, fecal microbiota transplantations (FMT) were performed from arsenic-exposed mice to healthy recipients. 16S rRNA gene sequencing indicated major alterations in GM population in FMT mice, leading to severe structural, functional and behavioural alterations. Moreover, suppression of Toll-like receptor 4 (TLR4) using vivo-morpholino oligomers (VMO) indicated restoration of the altered parameters towards normalcy in FMT mice, confirming direct involvement of the GM in inducing neurotoxicity through the arsenic-gut-brain axis. This study accentuates the potential role of the gut microbiota in promoting neurotoxicity in arsenic-exposed mice, and has immense relevance in predicting neurotoxicity under altered conditions of the gut for designing therapeutic interventions that will target gut dysbiosis to attenuate arsenic-mediated neurotoxicity.

Prenatal exposure to multiple environmental chemicals and birth size

BACKGROUND

Epidemiological studies addressing the combined effects of exposure to chemical mixtures at different stages of pregnancy on birth size are scarce.

OBJECTIVE

To evaluate the association between prenatal exposure to chemical mixtures and birth size.

METHODS

Our previous study repeatedly measured the urinary concentrations of 34 chemical substances among 743 pregnant women and identified three distinct clusters of exposed population and six dominant principal components of exposed chemicals in each trimester. In this study, we assessed the associations of these exposure profiles with birth weight, birth length, and ponderal index using multivariable linear regression.

RESULTS

We found that compared with women in cluster 1 (lower urinary chemical concentrations), women in cluster 2 (higher urinary concentrations of metals, benzothiazole, benzotriazole, and some phenols), and women in cluster 3 (higher urinary concentrations of phthalates) were more likely to give birth to children with higher birth length [0.23 cm (95% CI: -0.03, 0.49); 0.29 cm (95%CI: 0.03, 0.54), respectively]. This association was observed only in 1st trimester. In addition, prenatal exposure to PC3 (higher benzophenones loading) was associated with reduced birth length across pregnancy [-0.07 cm (95% CI: -0.18, 0.03) in 1st and 2nd trimester; -0.13 cm (95% CI: -0.24, -0.03) in 3rd trimester]. Exposure to PC6 (higher thallium and BPA loading in 2nd trimester) was associated with increased birth length [0.15 cm (95% CI: 0.05, 0.26)]. Compared with other outcomes, associations of both clusters and PCs with birth length were stronger, and these associations were more pronounced in boys.

IMPACT STATEMENT

Exposure to multiple chemicals simultaneously, the actual exposure situation of pregnant women, was associated with birth size, indicating that chemical mixtures should be taken more seriously when studying the health effects of pollutants.

Analysis of arsenic-modulated expression of hypothalamic estrogen receptor, thyroid receptor, and peroxisome proliferator-activated receptor gamma mRNA and simultaneous mitochondrial morphology and respiration rates in the mouse

Arsenic has been identified as an environmental toxicant acting through various mechanisms, including the disruption of endocrine pathways. The present study assessed the ability of a single intraperitoneal injection of arsenic, to modify the mRNA expression levels of estrogen- and thyroid hormone receptors (ERα,β; TRα,β) and peroxisome proliferator-activated receptor gamma (PPARγ) in hypothalamic tissue homogenates of prepubertal mice in vivo. Mitochondrial respiration (MRR) was also measured, and the corresponding mitochondrial ultrastructure was analyzed. Results show that ERα,β, and TRα expression was significantly increased by arsenic, in all concentrations examined. In contrast, TRβ and PPARγ remained unaffected after arsenic injection. Arsenic-induced dose-dependent changes in state 4 mitochondrial respiration (St4). Mitochondrial morphology was affected by arsenic in that the 5 mg dose increased the size but decreased the number of mitochondria in agouti-related protein- (AgRP), while increasing the size without affecting the number of mitochondria in pro-opiomelanocortin (POMC) neurons. Arsenic also increased the size of the mitochondrial matrix per host mitochondrion. Complex analysis of dose-dependent response patterns between receptor mRNA, mitochondrial morphology, and mitochondrial respiration in the neuroendocrine hypothalamus suggests that instant arsenic effects on receptor mRNAs may not be directly reflected in St3-4 values, however, mitochondrial dynamics is affected, which predicts more pronounced effects in hypothalamus-regulated homeostatic processes after long-term arsenic exposure.

Reproductive and Developmental Effects of Sex-Specific Chronic Exposure to Dietary Arsenic in Zebrafish (Danio rerio)

The present study investigated the reproductive and developmental effects of sex-specific chronic exposure to dietary arsenic in zebrafish. Adult zebrafish (Danio rerio) were exposed to environmentally realistic doses of arsenic via diet [0 (control; no added arsenic), 30 (low), 60 (medium), and 100 (high) μg/g dry weight, as arsenite] for 90 days. Following exposure, arsenic-exposed females from each dietary treatment were mated with control males, and similarly, arsenic-exposed males from each dietary treatment were mated with control females. In females, arsenic exposure resulted in a dose-dependent decrease in reproductive performance (fecundity, fertilization success, and hatching success). Moreover, a dose-dependent increase in developmental toxicity (larval deformities and larval mortality) was observed with maternal exposure to arsenic. In contrast, in males, arsenic exposure also induced similar reproductive and developmental toxicity; however, the adverse effects were mainly evident only in the medium and high dietary arsenic treatment groups. We also examined the sex-specific effects of dietary arsenic exposure on the expression of genes that regulate the hypothalamus-pituitary-gonadal-liver (HPG-L) axis in fish. The gene expression results indicated the downregulation of HPG-L axis genes in females irrespective of the arsenic treatment dose; however, the reduced expression of HPG-L axis genes in males was recorded only in the medium and high arsenic treatment groups. These observations suggest that chronic arsenic exposure in either females or males causes reproductive and developmental toxicity in zebrafish. However, these toxic effects are markedly higher in females than in males. Our results also suggest that arsenic can act as an endocrine disruptor and mediate reproductive and developmental toxicity by disrupting the HPG-L axis in zebrafish.

Neurotensin agonist PD149163 modulates lipopolysaccharide induced inflammation and oxidative stress in the female reproductive system of mice

Inflammation-mediated reproductive health problems in females have become an emerging concern. The present investigation was aimed to elucidate the efficacy of the PD149163, agonist of the type I neurotensin receptor, in preventing/ameliorating the lipopolysaccharide (LPS) induced inflammation of the female reproductive system of the mice. Female Swiss Albino Mice (8 weeks old) were maintained in three groups (6/group): Group I as Control, Group II and Group III were exposed to intraperitoneal (i.p) LPS (1 mg/kg bw) for 5 days followed by treatment with PD149163 (100 μg/kg BW i.p.) to Group III (LPS + PD) for 28 days. After termination of the experiment on 29th day, plasma levels of inflammatory cytokines, LH, FSH, estradiol, corticosterone, oxidative stress effects in the ovary and histopathological study of the ovary and uterine horn were done. LPS-induced inflammation of the ovary and uterine horn was ameliorated/prevented by PD149163 as reflected in the reduced histopathological scores, significant elevation of the plasma anti-inflammatory cytokine IL-10 and decrease of the pro inflammatory cytokines TNF-α and IL-6. Significant decrease of lipid peroxide, increase of antioxidant defense enzymes, Superoxide dismutase and Catalase in the ovary indicated reduction of oxidative stress. The plasma levels of the reproduction related hormones and corticosterone were restored. PD149163 acts as an anti-inflammatory and anti-oxidative agent in modulation of inflammation in the female reproductive system (ovary & uterine horn). These findings suggest that the therapeutic potential of the analogs of neurotensin including PD149163 should be explored for the treatment of the female reproductive health issues.

Arsenic Impairs Wound Healing Processes in Dermal Fibroblasts and Mice

Inorganic arsenic (NaAsO2) is a naturally occurring metalloid found in water resources globally and in the United States at concentrations exceeding the U.S. Environmental Protection Agency Maximum Contamination Level of 10 ppb. While exposure to arsenic has been linked to cancer, cardiovascular disease, and skin lesions, the impact of arsenic exposure on wound healing is not fully understood. Cultured dermal fibroblasts exposed to NaAsO2 displayed reduced migration (scratch closure), proliferation, and viability with a lowest observable effect level (LOEL) of 10 µM NaAsO2 following 24 h exposure. An enrichment of Matrix Metalloproteinase 1 (MMP1) transcripts was observed at a LOEL of 1 µM NaAsO2 and 24 h exposure. In vivo, C57BL/6 mice were exposed to 10 µM NaAsO2 in their drinking water for eight weeks, then subjected to two full thickness dorsal wounds. Wounds were evaluated for closure after 6 days. Female mice displayed a significant reduction in wound closure and higher erythema levels, while males showed no effects. Gene expression analysis from skin excised from the wound site revealed significant enrichment in Arsenic 3-Methyltransferase (As3mt) and Estrogen Receptor 2 (Esr2) mRNA in the skin of female mice. These results indicate that arsenic at environmentally relevant concentrations may negatively impact wound healing processes in a sex-specific manner.

Prenatal arsenite exposure alters maternal cardiac remodeling during late pregnancy

Exposure to inorganic arsenic through drinking water is widespread and has been linked to many chronic diseases, including cardiovascular disease. Arsenic exposure has been shown to alter hypertrophic signaling in the adult heart, as well as in utero offspring development. However, the effect of arsenic on maternal cardiac remodeling during pregnancy has not been studied. As such, there is a need to understand how environmental exposure contributes to adverse pregnancy-related cardiovascular events. This study seeks to understand the impact of trivalent inorganic arsenic exposure during gestation on maternal cardiac remodeling in late pregnancy, as well as offspring outcomes. C57BL/6 J mice were exposed to 0 (control), 100 or 1000 μg/L sodium arsenite (NaAsO2) beginning at embryonic day (E) 2.5 and continuing through E17.5. Maternal heart function and size were assessed via transthoracic echocardiography, gravimetric measurement, and histology. Transcript levels of hypertrophic markers were probed via qRT-PCR and confirmed by western blot. Offspring outcomes were assessed through echocardiography and gravimetric measurement. We found that maternal heart size was smaller and transcript levels of Esr1 (estrogen receptor alpha), Pgrmc1 (progesterone receptor membrane component 1) and Pgrmc2 (progesterone receptor membrane component 2) reduced during late pregnancy with exposure to 1000 μg/L iAs vs. non-exposed pregnant controls. Both 100 and 1000 μg/L iAs also reduced transcription of Nppa (atrial natriuretic peptide). Akt protein expression was also significantly reduced after 1000 μg/L iAs exposure in the maternal heart with no change in activating phosphorylation. This significant abrogation of maternal cardiac hypertrophy suggests that arsenic exposure during pregnancy can potentially contribute to cardiovascular disease. Taken together, our findings further underscore the importance of reducing arsenic exposure during pregnancy and indicate that more research is needed to assess the impact of arsenic and other environmental exposures on the maternal heart and adverse pregnancy events.

Attenuation of sodium arsenite mediated ovarian DNA damage, follicular atresia, and oxidative injury by combined application of vitamin E and C in post pubertal Wistar rats

Arsenic being a toxic metalloid ubiquitously persists in environment and causes several health complications including female reproductive anomalies. Epidemiological studies documented birth anomalies due to arsenic exposure. Augmented reactive oxygen species (ROS) generation and quenched antioxidant pool are foremost consequences of arsenic threat. On the contrary, Vitamin E (VE) and C (VC) are persuasive antioxidants and conventionally used in toxicity management. Present study was designed to explore the extent of efficacy of combined VE and VC (VEC) against Sodium arsenite (NaAsO2) mediated ovarian damage. Thirty-six female Wistar rats were randomly divided into three groups (Grs) and treated for consecutive 30 days; Gr I (control) was vehicle fed, Gr II (treated) was gavaged with NaAsO2 (3 mg/kg/day), Gr III (supplement) was provided with VE (400 mg/kg/day) & VC (200 mg/kg/day) along with NaAsO2. Marked histological alterations were evidenced by disorganization in oocyte, granulosa cells and zona pellucida layers in treated group. Considerable reduction of different growing follicles along with increased atretic follicles was noted in treated group. Altered activities ofΔ5 3β-Hydroxysteroid dehydrogenase and 17β-Hydroxysteroid dehydrogenase accompanied by reduced luteinizing hormone, follicle-stimulating hormone and estradiol levels were observed in treated animals. Irregular estrous cyclicity pattern was also observed due to NaAsO2 threat. Surplus ROS production affected ovarian antioxidant strata as evidenced by altered oxidative stress markers. Provoked oxidative strain further affects DNA status of ovary. However, supplementation with VEC caused notable restoration from such disparaging effects of NaAsO2 toxicities. Antioxidant and antiapoptotic attributes of those vitamins might be liable for such restoration.

Bioaccumulation of Non-Essential Trace Elements Detected in Women's Follicular Fluid, Urine, and Plasma Is Associated with Poor Reproductive Outcomes following Single Euploid Embryo Transfer: A Pilot Study

This study aims to determine the association of non-essential trace elements present in follicular fluid, plasma, and urine with reproductive outcomes of women undergoing intracytoplasmic sperm injection (ICSI), preimplantation genetic testing for aneuploidies (PGT-A) and single frozen euploid embryo transfer (SET/FET). This single-center, prospective cohort study included sixty women undergoing ICSI with PGT-A and SET/FET between 2018 and 2019. Urine, plasma and follicular fluid samples were collected on the vaginal oocyte retrieval day to simultaneously quantify ten non-essential trace elements (i.e., Ba, Sr, Rb, Sn, Ti, Pb, Cd, Hg, Sb, and As). We found several associations between the levels of these non-essential trace elements and clinical IVF parameters. Specifically, the increased levels of barium in follicular fluid were negatively associated with ovarian function, pre-implantation development and embryo euploidy, while elevated strontium concentrations in this biofluid were negatively associated with impaired blastulation and embryo euploidy. Elevated plasma strontium levels were negatively associated with ovarian function, fertilization and blastulation. Enhanced presence of other trace elements in plasma (i.e., rubidium and arsenic) were associated with a diminished ovarian function and limited the number of recovered oocytes, mature oocytes and zygotes, respectively. Fully adjusted models suggested significantly lower odds of achieving a live birth when increased concentrations of barium and tin were found in urine.

Synergistic toxicity of 2,4-dichlorophenoxyacetic acid and arsenic alters biomarkers in rats

2,4-dichlorophenoxyacetic acid (2,4-D) and arsenic cause severe and extensive biological toxicity in organisms. However, their interactions and toxic mechanisms in co-exposure remain to be fully elucidated. In this study, 28 four-week-old female rats were divided into four groups and exposed to 100 mg/L arsenic or/and 600 mg/L 2,4-D through drinking water for a period of 28 days. As a result, it was revealed that biochemical indicators (ALT, AST, ALP, blood urea nitrogen, and creatinine) were increased and decreased hormonal parameters (FSH, LH, PG, and E2) in arsenic and 2,4-D and arsenic combination-treated groups. Moreover, increased lipid peroxidation (malondialdehyde level) and decreased antioxidant status (superoxide dismutase and catalase activities) were found in the co-exposure groups compared with the individual-exposure groups. Meanwhile, severe DNA damage was observed in co-exposure groups. Additionally, the levels of apoptotic (Bax, Caspase-3, Caspase-8, Caspase-9, p53, and PARP) and inflammation (NFκB, Cox-2, TNF-α, and TGFβI) indexes in the co-exposure groups were markedly increased, whereas the levels of anti-apoptosis index (Bcl-2) were decreased. It was also observed that co-exposure with 2,4-D and arsenic caused more histopathological changes in tissues. Generally, these results show that co-exposure to 2,4-D and arsenic can seriously cause oxidative stress, DNA damage, apoptosis and inflammation while having toxicological risk for organisms.

Prenatal arsenic exposure, arsenic metabolism and neurocognitive development of 2-year-old children in low-arsenic areas

BACKGROUND

There is limited evidence on the effects of arsenic species and metabolic capacity on child neurodevelopment, particularly at low levels. Further, little is known about the critical window of exposure.

OBJECTIVE

To estimate the associations of arsenic exposure and arsenic metabolism in different pregnancy periods with neurodevelopment of two-year-old children.

METHODS

Concentrations of arsenobetaine (AsB), arsenite, arsenate, monomethyl arsenic acid (MMA), and dimethyl arsenic acid (DMA) in urine samples collected in three trimesters from 1006 mothers were measured using HPLC - ICPMS. Inorganic arsenic (iAs) was calculated as the sum of arsenite and arsenate. Total arsenic (tAs) was calculated as the sum of iAs, MMA and DMA. Child neurodevelopment was assessed with the Bayley Scales of Infant Development.

RESULTS

The geometric mean (GM) of SG-adjusted tAs in the first, second, third trimester was 16.37, 12.94, 13.04 μg/L, respectively. The mental development index (MDI) score was inversely associated with iAs and tAs. Compared to the 1st quartile, the MDI score decreased 0.43 (95%CI: -4.22, 3.36) for the 2nd, 6.50 (95%CI: -11.73, -1.27) for the 3rd, 5.42 (95%CI: -10.74, -0.10) for the 4th quartiles of iAs, and decreased 4.03 (95%CI: -7.90, -0.15) in the 4th quartile of tAs. In trimester-specific models, negative associations of DMA [-1.94 (95%CI: -3.18, -0.71)] and tAs [-1.61 (95%CI: -3.02, -0.20)] with the psychomotor development index (PDI) were only observed in 1st trimester.

CONCLUSIONS

Our study found inverse associations between prenatal arsenic exposure, especially in early pregnancy, and neurodevelopment of children at two years old, even at low exposure levels.

Association between heavy metals exposure and infertility among American women aged 20-44 years: A cross-sectional analysis from 2013 to 2018 NHANES data

Background

Infertility has been confirmed as a significant medical and social problem. Heavy metal exposure refers to a risk factor for infertility, which is capable of damaging the reproductive system of males and females. However, heavy metal exposure and female infertility have rarely been investigated. The aim of this study was to analyze the association between heavy metal exposure and female infertility.

Methods

A cross-sectional study using data from three cycles of the National Health and Nutrition Examination Survey (NHANES, 2013-2018) was performed. Female infertility was evaluated by positive responses to question rhq074 in the questionnaire. Cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) levels in blood or urine were examined by inductively coupled plasma mass spectrometry. The correlation between heavy metal and female infertility was analyzed through weighted logistic regression.

Results

A total of 838 American women aged 20-44 years were covered in the study. Among all participants, 112 (13.37%) women were subjected to infertility. Urinary Cd and urinary As levels were significantly higher in infertile women than in control women (P < 0.05, P < 0.05). Urinary As showed a positive correlation with the prevalence of female infertility, and the risk of infertility rose with the increase of urinary As levels (P for trend = 0.045). Urinary Cd was associated with female infertility in some weighted logistic regression (Crude, Q2: OR = 3.99, 95% CI 1.82, 8.74, Q3: OR = 2.90, 95% CI 1.42, 5.92. Model 1, Q2: OR = 3.68, 95% CI 1.64, 8.27, Q3: OR = 2.33, 95% CI 1.13, 4.48. Model 2, Q2: OR = 4.11, 95% CI 1.63, 10.07, Q3: OR = 2.44, 95% CI 1.07, 5.53. Model 3, Q2: OR = 3.77, 95% CI 1.52, 9.35). Moreover, blood Pb (OR = 1.52, 95% CI 1.07, 2.16), urinary Pb (OR = 1.68, 95% CI 1.11, 2.55), and urinary As (OR = 1.02, 95% CI 1.00, 1.03) were positively correlated with the risk of infertility in women aged 35-44 years. The blood Pb (OR = 1.67, 95% CI 1.16, 2.40, 2.49) and urinary Pb (OR = 1.54, 95% CI 1.00, 2.38) in women with BMI ≥25 were positively correlated with the risk of infertility.

Conclusions

Urinary As was significantly associated with female infertility, and the risk of infertility increased with higher urinary As levels. To some extent, urinary Cd was correlated with infertility. Blood/urine Pb was related to infertility in advanced age and overweight/obese women. The results of this study need to be further validated in future prospective studies.

Ameliorative effect of Brassica oleracea var. Italica extract on oxidative damage of arsenic in the rat's brain: biochemical, pathological, and behavioral aspects

Brain damage caused by the metal accumulation may result in the permanent injuries including severe neurological disorders. Thus, the aim of this study was to determine the medicinal efficacy of broccoli extract in arsenic-induced brain poisoning. Twenty-eight female rats were classified into 4 groups; control, receiving sodium arsenate (As), As + broccoli extract (As + Bc), and (Bc). Then, the Elevated Plus-Maze and pathological-biochemical assessment of the brain tissue were performed. Moreover, the GC-MS was used to explore the quantity and quality of broccoli extract. The catalase had a significant decrease in the As group compared to that of the control group; As + Bc and Bc groups also showed a significant increase compared to that of the As group. Glutathione peroxidase was the lowest in the As group (1.84 ± 0.97) and the highest in the Bc group (5.51 ± 2.31). The Treatment significantly reduced pro-inflammatory cytokines in the As + Bc group. In addition, in terms of behavioral changes, the duration of presence in the open arm was reduced in the As group compared to that of the control group. Besides, the open arm duration increased significantly in the Bc group. Interestingly, there was a significant increase in estrogen and gonadotropin hormones in the Bc group compared to the other groups. Pathological findings showed that the condition of cortical neurons was improved and the surrounding space was reduced in As + Bc compared to that of the As group. In addition, more than 30% of the extract's compounds are made up Phytol,1-isothiocyanate-4-[methylsulfinyl] butane, and γ-Sitosterol. Thereby, the broccoli extract with active substances was highly effective in enhancing the behavioral and pathological parameters switch in rats with arsenic-induced poisoned brains.

Exposure to heavy metals and hormone levels in midlife women: The Study of Women's Health Across the Nation (SWAN)

Exposure to heavy metals may alter the circulating levels of sex hormones. However, epidemiologic studies on heavy metals and sex hormones have been limited, and results have been inconsistent. We assessed the associations of heavy metals assayed in urine, including arsenic, cadmium, lead, and mercury, with repeated measures of serum estradiol (E2), follicle-stimulating hormone (FSH), testosterone, and sex hormone-binding globulin (SHBG) levels in the Study of Women's Health Across the Nation Multi-Pollutant Study. The sample included 1355 White, Black, Chinese, and Japanese women, aged 45-56 years at baseline (1999-2000), whose serum hormone levels were repeatedly measured through 2017. Urinary metal concentrations were measured at baseline. Linear mixed effect models were used to calculate percent changes in serum hormone levels per doubling of urinary metal concentrations, adjusting for demographics, socioeconomic status, lifestyle, health-related factors, and urinary creatinine. After multivariable adjustment, a doubling of urinary metal concentration was associated with lower E2 levels by 2.2% (95% CI: 4.0%, -0.3%) for mercury and 3.6% (95% CI: 5.7%, -1.6%) for lead; higher FSH levels by 3.4% (95% CI: 0.9%, 5.9%) for lead; and higher SHBG levels by 3.6% (95% CI: 1.3%, 5.9%) for cadmium. The overall joint effect using the Bayesian kernel machine regression showed that metal mixtures were inversely associated with E2 and positively associated with FSH levels. No association was found between metals and testosterone levels. Results from this prospective cohort study demonstrate that environmental heavy metal exposures, including cadmium, mercury, and lead, may disturb circulating levels of E2, FSH, and SHBG in midlife women.

Assessment of nano-iron particles impact on the reproductive health of female Wistar rats

Background

Iron oxide nanoparticles, especially nano-magnetite, are promising candidates for use in a variety of applications. The present study aimed to investigate the effect of nano-magnetite on the reproductive health of female Wistar rats. Twenty-one adult female rats were divided into three groups: Group 1 served as the control group, Group 2 received a low dose of 5 mg/kg of nano-magnetite, and Group 3 received a high dose of 10 mg/kg of nano-magnetite. For 30 days, rats were intraperitoneally injected three times per week.

The main findings

Revealed that nano-magnetite did not induce a change in body weight or absolute as well as relative reproductive organs weight. Nano-magnetite nanoparticles influenced the reproductive serum hormone levels as well as imbalanced the ovarian and uterine malondialdehyde and total antioxidant activity. After nano-magnetite nanoparticle injection, the histopathological examination revealed apoptosis of granulosa cells of various types of follicles, degenerated corpora lutea, congested blood vessels, and uterine epithelial cells of uterine tissue showed a high level of apoptosis and inflammation. Immunohistochemistry studies demonstrated a significant increase in activated caspase-3 following nano-magnetite injection, indicating an increase in cell apoptosis.

Conclusion

This study demonstrated the negative effect of magnetite nanoparticle on reproductive health and increased the likelihood of infertility.

Epigenetic Dysregulations in Arsenic-Induced Carcinogenesis

Arsenic is a crucial environmental metalloid whose high toxicity levels negatively impact human health. It poses significant health concerns to millions of people in developed and developing countries such as the USA, Canada, Bangladesh, India, China, and Mexico by enhancing sensitivity to various types of diseases, including cancers. However, how arsenic causes changes in gene expression that results in heinous conditions remains elusive. One of the proposed essential mechanisms that still has seen limited research with regard to causing disease upon arsenic exposure is the dysregulation of epigenetic components. In this review, we have extensively summarized current discoveries in arsenic-induced epigenetic modifications in carcinogenesis and angiogenesis. Importantly, we highlight the possible mechanisms underlying epigenetic reprogramming through arsenic exposure that cause changes in cell signaling and dysfunctions of different epigenetic elements.

Arsenic exposure diminishes ovarian follicular reserve and induces abnormal steroidogenesis by DNA methylation

Arsenic contamination is a worldwide public health problem, and the effect of arsenic on male reproduction has been extensively studied; however, data on the biotoxicity of arsenic in terms of female reproduction are more scarce. In this study, a human-cell-animal translational strategy was applied to explore the effect of arsenic exposure on ovarian steroidogenesis and its potential mechanism. We conducted a 1:1 propensity score matched case-control study involving 127 diminished ovarian reserve (DOR) cases and 127 healthy controls. The ovarian follicular fluid levels of 21 metal elements, including arsenic, were measured. The results showed that there were significant differences in follicular fluid metal profiles between DOR patients and controls and that arsenic, molybdenum, and strontium played important roles in DOR progression [OR (95 % CI): 2.203 (1.385, 3.503), 2.308 (1.490, 3.575) and 2.922 (1.864, 4.580), respectively]. In the primary ovarian granulosa cell culture model, we found that treatment with 8 μM arsenic for 24 and 48 h induced a decrease in human granulosa cell viability. The estradiol (E₂) level was significantly decreased after arsenic exposure (P < 0.05), which was dependent on significant alterations (P < 0.05) in key enzymes in steroidogenesis. In addition, a model for sodium arsenite exposure through water in rats from weaning to sexual maturity was established. We evaluated ovarian development by monitoring the estrous cycle, observing ovarian pathology, and calculating the follicular proportion. RT-qPCR, Western blotting, and bisulfite-sequencing PCR were used to investigate the effect of arsenic exposure on ovarian steroidogenesis and its possible mechanism. The results indicated that steroidogenic factor-1 (SF-1) was an important target of the steroidogenesis disorder induced by arsenic exposure. Arsenic significantly increased the DNA methylation level (P < 0.05) in the promoter region of SF-1 to reduce its expression, subsequently decreasing the levels of steroidogenic acute regulatory protein (StAR), P450 cholesterol side-chain cleavage enzyme (CYP11A1), and aromatase (CYP19A1) (P < 0.05), leading to premature depletion of ovarian follicles.

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

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

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Epigenetic modifications from arsenic exposure: A comprehensive review

Arsenic is a notorious element with the potential to harm exposed individuals in ways that include cancerous and non-cancerous health complications. Millions of people across the globe (especially in South and Southeast Asian countries including China, Vietnam, India and Bangladesh) are currently being unknowingly exposed to precarious levels of arsenic. Among the diverse effects associated with such arsenic levels of exposure is the propensity to alter the epigenome. Although a large volume of literature exists on arsenic-induced genotoxicity, cytotoxicity, and inter-individual susceptibility due to active research on these subject areas from the last millennial, it is only recently that attention has turned on the ramifications and mechanisms of arsenic-induced epigenetic changes. The present review summarizes the possible mechanisms involved in arsenic induced epigenetic alterations. It focuses on the mechanisms underlying epigenome reprogramming from arsenic exposure that result in improper cell signaling and dysfunction of various epigenetic components. The mechanistic information articulated from the review is used to propose a number of novel therapeutic strategies with a potential for ameliorating the burden of worldwide arsenic poisoning.

Engineered Whole-Cell-Based Biosensors: Sensing Environmental Heavy Metal Pollutants in Water-a Review

The frequent exposure and accumulation of heavy metals in organisms cause serious health issues affecting a range of organs such as the brain, liver, and reproductive organs in adults, infants, and children. Several parts of the world have high levels of heavy metals affecting millions of people, costing millions of dollars for improving the potability of water and medical treatment of the affected. Hence, water quality assessment is required to monitor the degree of heavy metal contamination in potable water. In nature, organisms respond to various environmental pollutants such as heavy metals, allowing their survival in a diverse environmental niche. With the advent of recombinant DNA technology, it is now possible to manipulate these natural bioreporters into controlled systems which either turn on or off gene expression or activity of enzymes in the presence of specific heavy metals (compound-specific biosensors) otherwise termed as whole-cell biosensors (WCBs). WCBs provide an upper hand compared to other immunosensors, enzyme-based sensors, and DNA-based sensors since microbes can be relatively easily manipulated, scaled up with relative ease, and can detect only the bioavailable heavy metals. In this review, we summarize the current knowledge of the various mechanisms of toxicity elicited by various heavy metals, thence emphasizing the need to develop heavy metal sensing platforms. Following this, the biosensor-based platforms including WCBs for detecting heavy metals developed thus far have been briefly elaborated upon, emphasizing the challenges and solutions associated with WCBs.

Arsenic-protein interactions as a mechanism of arsenic toxicity

Millions of people worldwide are exposed to arsenic, a metalloid listed as one of the top chemical pollutants of concern to human health. Epidemiological and experimental studies link arsenic exposure to the development of cancer and other diseases. Several mechanisms have been proposed to explain the effects induced by arsenic. Notably, arsenic and its metabolites interact with proteins by direct binding to individual cysteine residues, cysteine clusters, zinc finger motifs, and RING finger domains. Consequently, arsenic interactions with proteins disrupt the functions of proteins and may lead to the development and progression of diseases. In this review, we focus on current evidence in the literature that implicates the interaction of arsenic with proteins as a mechanism of arsenic toxicity. Data show that arsenic-protein interactions affect multiple cellular processes and alter epigenetic regulation, cause endocrine disruption, inhibit DNA damage repair mechanisms, and deregulate gene expression, among other adverse effects.

Resveratrol attenuates arsenic-induced cognitive deficits via modulation of Estrogen-NMDAR-BDNF signalling pathway in female mouse hippocampus

BACKGROUND

Chronic inorganic arsenic (iAs) exposure induces deleterious effects on CNS including oxidative stress, cognitive deficits and altered brain neurochemistry. Little is known about the association between iAs and estrogen receptor expression in brain regions.

AIMS AND OBJECTIVES

Owing to the neuroprotective and estrogenic activities of resveratrol (RES), we examined the combined effects of arsenic trioxide (As₂O₃) and RES on neurobehavioural functions, estrogen signalling and associated neurochemical changes in mouse hippocampus.

MATERIALS AND METHODS

As₂O₃ alone (2 and 4 mg/kg bw) or along with RES (40 mg/kg bw) was administered orally for 45 days to adult female mice. From days 33 to 45, open field, elevated plus maze and Morris water maze tests were conducted to evaluate locomotion, anxiety and learning and memory. On day 46, animals were euthanized and brain tissue and hippocampi obtained therefrom were processed for atomic absorption spectrophotometry and western blotting respectively.

RESULTS

As₂O₃ alone exposure resulted in enhanced anxiety levels, reduced locomotion and impaired learning and memory. As₂O₃-induced behavioural deficits were accompanied by downregulation of estrogen receptor (ERα) expression with a concomitant reduction of BDNF and NMDAR 2B levels in the hippocampus. However, the behavioural alterations and expression of these markers were restored in RES-supplemented mice. Moreover, a dose-dependent iAs accumulation was observed in serum and brain tissues of mice receiving As₂O₃ alone whereas simultaneous administration of As₂O₃ with RES facilitated iAs efflux.

CONCLUSIONS

These results suggest that reduced ERα expression with associated downregulation of BDNF and NMDAR 2B levels could be a mechanism by which iAs induces cognitive impairment; hence, the modulation of estrogen-NMDAR-BDNF pathway by RES represents a potential avenue to recover behavioural deficits induced by this neurotoxin.

Low Blood-As Levels and Selected Genotypes Appears to Be Promising Biomarkers for Occurrence of Colorectal Cancer in Women

In following study we examined whether blood arsenic (As) levels combined with specific polymorphisms in MT1B, GSTP1, ABCB1, NQO1, CRTC3, GPX1, SOD2, CAT, XRCC1, ERCC2 can be used as a marker for the detection of colorectal cancer (CRC) among Polish women. A retrospective case-control study of CRC included 83 CRC cases and 78 healthy controls. From each study participant pre-treatment peripheral blood was collected for As level measurement by inductively coupled–plasma mass spectrometry (ICP-MS). We estimated the odds ratio (OR) of the association between blood-As levels and CRC using multivariable unconditional logistic regression models. A low blood-As level (0.27–0.67 µg/L) was associated with an increased frequency of CRC (OR: 3.69; p = 0.005). This correlation was significantly greater when participants carried particular gene variants: CAT, rs1001179-nonCC (OR: 19.4; p = 0.001); ABCB1 rs2032582–CC (OR: 14.8; p = 0.024); GPX1 rs1050450-CC (OR: 11.6; p = 0.002) and CRTC3 rs12915189-nonGG (OR: 10.3; p = 0.003). Our study provides strong evidence that low blood-As levels are significantly associated with increased CRC occurrence and that particular gene variants significantly enhanced this correlation however, due to the novelty of these findings, we suggest further validation before a definitive statement that the combined effect of low blood-As levels with specific gene polymorphisms is a suitable CRC biomarker.

Self Nano-Emulsifying Curcumin (SNEC30) attenuates arsenic-induced cell death in mice

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Sodium arsenite disrupts the histoarchitecture and cell morphology causing cell death in thymus and spleen of Swiss albino mice.

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Activation of apoptotic cell death occurred due to high level of ROS generation and increased promotion of autophagy upon arsenic insult.

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SNEC30 restored cellular architecture, reduced ROS generation and ameliorated autophagy-mediated cell death in the immune organs.

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This study clearly demonstrated anti-oxidative and anti-apoptotic properties of SNEC30 against NaAsO₂-induced in vivo immunotoxicity.

Several precedents have confirmed numerous infirmities caused by arsenic poisoning, including immune suppression and cancer. Exposure to arsenic leads to alterations of the cellular machinery and eventually cell death, depending on the dose and duration of exposure. Oxidative stress induced by arsenic is the major mechanism by which it inflicts cellular toxicity, challenging the survival-support - autophagy and culminating in apoptosis in the thymus and spleen of mice. Curcumin, a potent dietary anti-oxidant with known anti-apoptotic and anti-inflammatory properties, was assessed for therapeutic benefits. However, the major caveat of this polyphenol is its low water solubility and limited bioavailability. Therefore, Self Nano-Emulsifying Curcumin (SNEC30) was used to treat mice exposed to arsenic. When administered, SNEC30 effectively ameliorated the adverse effects of arsenic in mice, by restoring structural alterations and reducing ROS-mediated cell death, thereby endorsing the importance of nutraceuticals in counteracting heavy metal-induced cellular toxicity.

Low‑Level Environmental Heavy Metals are Associated with Obesity Among Postmenopausal Women in a Southern State

Both arsenic and cadmium are reported to be toxic to humans. The use of saliva as a biomarker of low-level exposures to these elements has not been adequately explored, and the putative relationship between exposure and obesity is unclear. This cross-sectional study aims to investigate the relationship between salivary arsenic and cadmium concentrations and their association with obesity. Arsenic and cadmium concentrations were analyzed in human saliva samples by Inductively Coupled Plasma-Mass Spectrometry on 270 randomly selected women who participated in the Arkansas Rural Community Health Study. Multivariable logistic regression was performed to evaluate the association between heavy metal concentrations and obesity. Stratified logistic regression was performed based on menopausal status. Generalized linear models were used to evaluate weight gain velocity. Significant positive associations were observed in postmenopausal women for both arsenic (OR = 4.43, 95% CI 1.91-10.28) and cadmium (OR = 2.72, 95% CI 1.23-5.99) concentrations, as well as significant trends among tertiles (p < 0.01 and p = 0.01, respectively). No relationship with obesity was evident among premenopausal women for either metal. A dose-response relationship was observed between increasing weight gain velocity and increasing metal concentrations. At concentrations well below governmental and industrial standards for acute toxicity, significant associations between obesity and concentration of these heavy metals are evident. The rate at which individuals gain weight is affected by metal concentrations and may play a role in the rapid increase in weight in postmenopausal women. These results might explain, in part, the missing variability in the increasing obesity pandemic in certain population exposed to these environmental toxicants.

Hybrid Dietary-Blood Inflammatory Profiles and Postmenopausal Breast Cancer: A Case-Control Study

The carcinogenesis process is associated with inflammation, which can be modified by diet. There is limited evidence regarding the inflammatory status and diet in association with breast cancer (BC). The aim of this study was to investigate the association of hybrid dietary-blood inflammatory profiles (HD-BIPs) with postmenopausal breast cancer occurrence. The case-control study was conducted among 420 women (230 controls, 190 primary BC cases) aged 40–79 years from north-eastern Poland. Blood levels of C-reactive protein (CRP), interleukin-6 (IL-6) and leukocyte count were marked in 129 postmenopausal women (82 controls, 47 cases). The 62-item food frequency questionnaire (FFQ-6) was used to the dietary data collection. Two HD-BIPs were found using the Principal Component Analysis (PCA). The “Pro-healthy/Neutral-inflammatory” profile was characterized by the frequent consumption of wholemeal cereals/coarse groats, legumes, vegetables, fruits, nuts/seeds and fish. The “Unhealthy/Pro-inflammatory” profile was characterized by the frequent consumption of red/processed meats, animal fats, sugar/honey/sweets, refined cereals/fine groats, and an increased concentration of CRP, IL-6 and granulocyte-to-lymphocyte ratio. The lower odds ratio (OR) of breast cancer was associated with the higher adherence to the “Pro-healthy/Neutral-inflammatory” profile (OR = 0.38; 95% Cl: 0.18–0.80; p < 0.01 for the higher level vs. lower level, crude model; OR for one-point score increment: 0.61; 95% Cl: 0.42–0.87; p < 0.01, adjusted model). The higher OR of breast cancer was associated with the higher adherence to the “Unhealthy/Pro-inflammatory” profile (OR = 3.07; 95%Cl: 1.27–7.44; p < 0.05 for the higher level v.s. lower level, adjusted model; OR for one-point score increment: 1.18; 95%Cl: 1.02–1.36; p < 0.05, adjusted model). This study revealed that the consumption of highly processed, high in sugar and animal fat foods should be avoided because this unhealthy diet was positively associated with postmenopausal breast cancer occurrence through its pro-inflammatory potential. Instead, the frequent consumption of low-processed plant foods and fish should be recommended since this pro-healthy diet was inversely associated with the cancer occurrence even though its anti-inflammatory potential has not been confirmed in this study sample.

A case-control study of arsenic exposure with the risk of primary ovarian insufficiency in women

Arsenic, a well-known toxic metalloid, is ubiquitously existed in environment. Arsenic exposure has been associated with female reproductive health. However, a potential association between arsenic exposure and primary ovarian insufficiency (POI) in women has not been recognized yet. In this case-control study, a total of 169 POI cases and 209 healthy controls were recruited to determine urinary concentrations of arsenic and serum levels of reproductive hormones (follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Mullerian hormone (AMH) and estradiol). The median concentration of urinary arsenic in cases (21.5 μg/L, 28.0 μg/g for creatinine adjustment) was significantly higher than that of controls (13.8 μg/L, 19.3 μg/g for creatinine adjustment). Urinary arsenic concentrations were significantly positively associated with the risk of POI (adjusted odds ratio (OR) = 2.66, 95% CI: 1.43-4.95 for the highest vs lowest tertile of arsenic, p = 0.002; p for trend = 0.004). We also assessed the associations between arsenic exposure and reproductive hormones that are important for ovarian functions. FSH and LH levels were positively associated with urinary arsenic, whereas AMH and estradiol levels were negatively correlated with this element. This study provided evidence that arsenic exposure could be the potential risk factor for POI in women.

Casein- and pea-enriched high-protein diet can take care of the reprotoxic effects of arsenic in male rats

Arsenic toxicity is a significant health problem featured with several incidents of male reproductive dysfunctions. We studied the protective effects of a casein- and pea-enriched formulated high-protein diet (FHPD) on arsenic-mediated testicular dysfunctions in rats. Adult male rats sustained on either a benchmark diet (n = 8) or an isocaloric FHPD (n = 8) were gavaged with arsenic trioxide (3mg/kg body wt/rat/day) for 30 consecutive days. A vehicle-fed group (n = 8) maintained on the standard diet served as control. The arsenic-treated group continued on the standard diet had a significantly reduced testicular and accessory sex organs weights. They exhibited decreased count, motility, viability and disrupted plasma membrane integrity of caudal spermatozoa with a higher incidence of gross morphological anomalies and DNA damage. Attenuated steroidogenic enzyme activities and low serum testosterone level vouched for a compromised state of testicular steroidogenesis. An increased testicular malondialdehyde and protein carbonyl contents coupled with impaired activities of antioxidant enzymes and free radical scavengers mirrored a situation of exacerbated testicular oxidative imbalance and disrupted redox homeostasis. FHPD, by and large, countermanded testicular steroidogenesis and antioxidant defence system and revoked the ill effects of arsenic. We conclude that specific protein-enriched diet may serve as prospective weaponry in encountering the arsenic-threatened testicular functions.

In utero exposure to arsenite contributes to metabolic and reproductive dysfunction in male offspring of CD-1 mice

In utero exposure to arsenite (iAs) is known to increase disease risks later in life. We investigated the effect of in utero exposure to iAs in the drinking water on metabolic and reproductive parameters in male mouse offspring at postnatal and adult stages. Pregnant CD-1 mice were exposed to iAs (as sodium arsenite) in the drinking water at 0 (control), 10 ppb (EPA standard for drinking water), and 42.5 ppm (tumor-inducing dose in mice) from embryonic day (E) 10-18. At birth, pups were fostered to unexposed females. Male offspring exposed to 10 ppb in utero exhibited increase in body weight at birth when compared to controls. Male offspring exposed to 42.5 ppm in utero showed a tendency for increased body weight and a smaller anogenital distance. The body weight in iAs-exposed pups continued to increase significantly compared to control at 3 weeks and 11 weeks of age. At 5 months of age, iAs-exposed males exhibited greater body fat content and glucose intolerance. Male offspring exposed to 10 ppb in utero had higher circulating levels of leptin compared to control. In addition, males exposed to 42.5 ppm in utero exhibited decreased total number of pups born compared to controls and lower average number of litters sired over a six-month period. These results indicate that in utero exposure to iAs at either human relevant concentration or tumor-inducing concentration is a potential cause of developmental origin of metabolic and reproductive dysfunction in adult male mice.

Evaluating the effects between metal mixtures and serum vaccine antibody concentrations in children: a prospective birth cohort study

BACKGROUND

Many populations are exposed to arsenic, lead, and manganese. These metals influence immune function. We evaluated the association between exposure to single and multiple metals, including arsenic, lead, and manganese, to humoral immunity as measured by antibody concentrations to diphtheria and tetanus toxoid among vaccinated Bangladeshi children. Additionally, we examined if this association was potentially mediated by nutritional status.

METHODS

Antibody concentrations to diphtheria and tetanus were measured in children's serum at age 5 (n = 502). Household drinking water was sampled to quantify arsenic (W-As) and manganese (W-Mn), whereas lead was measured in blood (B-Pb). Exposure samples were taken during pregnancy, toddlerhood, and early childhood. Multiple linear regression models (MLRs) with single or combined metal predictors were used to determine the association with antibody outcomes. MLR results were transformed to units of percent change in outcome per doubling of exposure to improve interpretability. Structural equation models (SEMs) were used to further assess exposure to metal mixtures. SEMs regressed a latent exposure variable (Metals), informed by all measured metal variables (W-As, W-Mn, and B-Pb), on a latent outcome variable (Antibody), informed by measured antibody variables (diphtheria and tetanus). Weight-for-age z-score (WFA) at age 5 was evaluated as a mediator.

RESULTS

Diphtheria antibody was negatively associated with W-As during pregnancy in MLR, but associations were attenuated after adjusting for W-Mn and B-Pb (- 2.9% change in diphtheria antibody per doubling in W-As, 95% confidence interval [CI]: - 7%, 1.5%). Conversely, pregnancy levels of B-Pb were positively associated with tetanus antibody, even after adjusting for W-As and W-Mn (13.3%, 95% CI: 1.7%, 26.3%). Overall, null associations were observed between W-Mn and antibody outcomes. Analysis by SEMs showed that the latent Metals mixture was significantly associated with the latent Antibody outcome (β = - 0.16, 95% CI: - 0.26, - 0.05), but the Metals variable was characterized by positive and negative loadings of W-As and B-Pb, respectively. Sex-stratified MLR and SEM analyses showed W-As and B-Pb associations were exclusive to females. Mediation by WFA was null, indicating Metals only had direct effects on Antibody.

CONCLUSIONS

We observed significant modulation of vaccine antibody concentrations among children with pregnancy and early life exposures to drinking water arsenic and blood lead. We found distinct differences by child sex, as only females were susceptible to metal-related modulations in antibody levels. Weight-for-age, a nutritional status proxy, did not mediate the association between the metal mixture and vaccine antibody.

Domain- and sex-specific effects of prenatal exposure to low levels of arsenic on children's development at 6 months of age: Findings from the Ma'anshan birth cohort study in China

The relationship between prenatal arsenic exposure at low levels and poor development in children, especially in regard to neurodevelopment, has aroused several concerns, but the conclusions have been inconsistent. It still remains unclear whether such adverse effect is associated with a specific profile of the developing brain in early life. To investigate the association between arsenic exposure in utero and children's development and behaviour, we performed a large prospective birth cohort study including 2315 mother-infant pairs in Anhui Province, China. The Ages and Stages Questionnaire of China (ASQ-C) was used to assess the status of children's development and behaviour at 6 months postpartum, and the levels of arsenic were determined in umbilical cord serum samples. Odds ratios for suspected developmental delay (SDD) in each domain of the ASQ-C clusters were estimated using logistic regression models. Compared with low arsenic levels group, medium and high arsenic levels were significantly associated with the increased risks of SDD in the personal-social domain among infants aged 6 months after adjustment for all potential confounders (OR = 1.33, 95% CI (1.01, 1.75) and OR = 1.47, 95% CI (1.08, 2.00), respectively). Sex stratification analysis demonstrated that this association was stronger in females. The sensitivity analyses also showed that high cord serum arsenic levels were associated with a 1.80-fold (95% CIs (1.12, 2.90)) higher risk of a more severe developmental delay in the personal-social domain among six-month-old females. Our results suggest that low-level arsenic exposure in utero could have an adverse domain-specific effect on children's development at 6 months of age, particularly among females. Further studies are warranted to support the findings and explore the mechanism of these domain-and sex-specific associations.

Arsenic and smokeless tobacco exposure induces DNA damage and oxidative stress in reproductive organs of female Swiss albino mice

Arsenic contamination in the groundwater of Southern Assam, India is well-documented. A specific type of smokeless tobacco (sadagura, SG) is highly prevalent among the local population. Thus, the present study is aimed to evaluate the toxicological implications of arsenic and smokeless tobacco co-exposure on the reproductive health of female mice. The estrous cycle of experimental animals was monitored for 30 days. Histopathological studies and comet assay of ovarian and uterine tissues were performed after 30 days of exposure to SG and arsenic (sodium arsenite, SA). Oxidative stress was estimated biochemically by taking tissue glutathione, lipid peroxidation (LPO), and superoxide dismutase activity as endpoints. Our findings indicated a prolonged diestrus phase in the SG + L + SA group (p < 0.001). Histopathological study revealed abnormal tissue architecture in treated groups. Comet assay study showed that SG + SA exposure significantly induced DNA damage in test animals. The elevated LPO level in the SG + SA group indicated oxidative stress generation in the reproductive tissues. The present study suggests that female reproductive organs are vulnerable to SA and SG and oxidative stress generation may be the possible mechanism behind DNA damage, impaired follicular growth, atresia, and altered estrous cycle in the mice test system.

Arsenic-induced immunomodulatory effects disorient the survival-death interface by stabilizing the Hsp90/Beclin1 interaction

Ground water arsenic contamination is a global menace. Since arsenic may affect the immune system, leading to immunesuppression, we investigated the effects of acute arsenic exposure on the thymus and spleen using Swiss albino mice, exposed to 5 ppm, 15 ppm and 300 ppm of sodium arsenite for 7 d. Effects on cytokine balance and cell survivability were subsequently analyzed. Our data showed that arsenic treatment induced debilitating alterations in the tissue architecture of thymus and spleen. A dose-dependent decrease in the ratio of CD4⁺-CD8⁺ T-cells was observed along with a pro-inflammatory response and redox imbalance. In addition, pioneering evidences established the ability of arsenic to induce an up regulation of Hsp90, eventually resulting in stabilization of its client protein Beclin-1, an important autophagy-initiating factor. This association initiated the autophagic process, confirmed by co-immunoprecipitation assay, acridine orange staining and Western blot, indicating the effort of cells trying to survive at lower doses. However, increased arsenic assault led to apoptotic cell death in the lymphoid organs, possibly by increased ROS generation. There are several instances of autophagy and apoptosis taking place either simultaneously or sequentially due to oxidative stress. Since arsenic is a potent environmental stress factor, exposure to arsenic led to a dose-dependent increase in both autophagy and apoptosis in the thymus and spleen, and cell death could therefore possibly be induced by autophagy. Therefore, exposure to arsenic leads to serious effects on the immune physiology in mice, which may further have dire consequences on the health of exposed animals.

Patterns of ovarian cancer and uterine cancer mortality and incidence in the contiguous USA

The main objective is to investigate the geographical variation in ovarian cancer and uterine cancer mortality, and to test associations between some risk factors and these cancer types in the contiguous US for mortality and for incidence. The modern disease surveillance software SaTScan™ was used for a spatial cluster analysis to assess any observable geographical variation in ovarian and uterine cancer mortality rates and to identify and test for spatial clusters with elevated relative risk. The analyses were first completed using age adjusted cancer rates for ovarian cancer and for uterine cancer. The cancer data was then adjusted for the risk factors (or covariates) obesity rate, smoking rate, urban, poverty rate, college education rate, race, opioids mortality rate, and for arsenic intake from well water rate. All used data for cancer mortality were for 2000-2014 while incidence data were for 2011-2015. There exist seven significant mortality clusters of ovarian cancer, with large clusters in NW, NE and SE of the US, and there exist two large mortality clusters of uterine cancer in NE and Central US. Most risk factors studied for mortality and for incidence were significant at significance levels much lower than 0.05 for either of the two cancer types, except race for ovarian cancer mortality and arsenic for ovarian incidence. This study has identified several important factors, and these findings could be used for a more effective search for cancer prevention for uterine and ovarian cancer. LIMITATIONS OF THE STUDY: The accuracy of the data could not be controlled as data were downloaded from websites. While the mortality data was complete, the incidence data had counties with missing data. The data were obtained at the county resolution. No data were available on women who had one type of cancer and then had the second type of cancer later in life. Only purely spatial clusters were studied and no temporal analysis was done.

High-Protein Diet Ameliorates Arsenic-Induced Oxidative Stress and Antagonizes Uterine Apoptosis in Rats

Arsenic toxicity purportedly threats a broad spectrum of female reproductive functions. We investigated the remedial role of a casein- and pea protein-enriched high-protein diet (HPD) in combating the arsenic insult. Cyclic female rats maintained on standard diet (n = 6) or an isocaloric HPD (n = 6) were gavaged with As₂O₃ at 3 mg/kg BW/rat/day (n = 12) for 28 days. Vehicle-fed rats (n = 6) maintained on the standard diet served as the control. We monitored the estrus cycles and performed the histomorphometric analyses of the uterus and ovary. Uterine luminal epithelial (ULE) ultrastructure was appraised by scanning electron microscopy. Uterine oxidative stress was evaluated in the forms of ROS generation and activities of the ROS scavengers. The uterine apoptotic manifestation was blueprinted by Western blot analysis of caspase-3 and Bax expression. Arsenic treatment arrested the follicular maturation and disrupted the estrus cycles with a typical increase in the diestrus index. Shrunken endometrial glands and thinned microvilli density of the ULE reflected loss of cell polarity and mislaid uterine homeostasis. Increased ROS generation and attenuated activities of the ROS scavengers marked a state of uterine oxidative imbalance and loss of redox regulation. Superfluous expression of procaspase-3, cleaved caspase-3, and Bax mirrored an inflated state of uterine apoptosis. HPD supplementation, by and large, counteracted these arsenic impacts and maintained the frameworks close to the control levels. In conclusion, arsenic mediates its reproductive toxicity, at least in part, by upsetting the uterine ROS homeostasis and redox regulation. Pea proteins and casein-supplemented HPD can counteract the arsenic effects and maintain the reproductive functions.

Biological and molecular modifications induced by cadmium and arsenic during breast and prostate cancer development

Breast and prostate cancer are two of the most common malignancies worldwide. Both cancers can develop into hormone -dependent or -independent subtypes and are associated to environmental exposure in the context of an inherited predisposition. As and Cd have been linked to the onset of both cancers, with the exception of As, which lacks a definitive association with breast carcinogenesis. The two elements exert an opposite effect dependent on acute versus chronic exposure. High doses of As or Cd were shown to induce cell death in acute experimental exposure, while chronic exposure triggers cell proliferation and viability, which is no longer limited by telomere shortening and apoptosis. The chronically exposed cells also increase their invasion capacity and tumorigenic potential. At molecular level, malignant transformation is evidenced mainly by up-regulation of BCL-2, MMP-2, MMP-9, VIM, Snail, Twist, MT, MLH and down-regulation of Casp-3, PTEN, E-CAD, and BAX. The signaling pathways most commonly activated are KRAS, p53, TGF-β, TNF-α, WNT, NRF2 and AKT. This knowledge could potentially raise public awareness over the health risks faced by the human population living or working in a polluted environment and smokers. Human exposure to As and Cd should be minimize as much as possible. Healthcare policies targeting people belonging to these risk categories should include analysis of: DNA damage, oxidative stress, molecular alterations, and systemic level of heavy metals and of essential minerals. In this review, we present the literature regarding cellular and molecular alterations caused by exposure to As or Cd, focusing on the malignant transformation of normal epithelial cells after long-term intoxication with these two carcinogens.

Dietary CCPS from bitter gourd attenuates sodium arsenite induced female reproductive ailments cum infertility in wistar rats: anti-inflammatory and anti-apoptotic role

This investigation explored a dietary therapy of pectic polysaccharide (CCPS) (2 mg/ Kg BW) against female repro-toxicity and infertility triggered by sodium arsenite (As3+) (10 mg/ Kg BW) in Wistar rats. The isolated CCPS consists of D-galactose and D-methyl galacturonate with a molar ratio of 1: 4. FTIR spectral analysis of CCPS and CCPS- sodium arsenite (As3+) complex indicated a possible chelating property of CCPS in presence of binding sites (OH-/COOH) for As3+. Series of negatively charged galacturonate residues in CCPS provide better potential for cation chelation. CCPS significantly mitigated As3+ induced ovarian, uterine lipid peroxidation, and reactive oxygen species (ROS) generation by the restoration of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities. CCPS post-treatment enhanced ovarian steroidogenesis along with a restoration of normal tissue histoarchitecture in As3+ fed rats by regulating the estradiol receptor alpha (ER-α). CCPS suppressed anti-inflammatory properties effectively found since a down-regulation of NF-kappa B (NF-қB), pro-inflammatory tumor necrosis-α (TNF-α) and interleukin-6 (IL-6) were observed in arsenicated rats with CCPS. This study confirmed the up-regulation of uterine pro-apoptotic/ apoptotic proteins caspase-3, poly ADP ribose polymerase (PARP), proliferating cell nuclear antigen (PCNA), phospho p53 and Bax, followed by down-regulation of Bcl-2 and protein Kinase B (AKT) signaling pathway along with uterine tissue regeneration in As3+ exposed rats. Oral CCPS attenuated the above apoptotic expressional changes significantly and dietary CCPS ensured successful fertility with the birth of healthy pups in lieu of infertile condition in As3+ fed rats. Moreover, this study also supports that CCPS treatment attenuated the As3+ toxicity by modulating the S-adenosine methionine (SAM) pool components, B12, folate and homocysteine.

Blood arsenic levels and the risk of familial breast cancer in Poland

Arsenic is recognized as a potent carcinogen at high concentrations, but the relationship between environmental arsenic and breast cancer risk has not well been studied. Most research has focused on the effect of arsenic in populations with high endemic exposure, and not in populations with arsenic levels within normal limits. We sought to determine if blood arsenic levels predict the risk of breast and other cancers risk among women in northern Poland. The cohort consisted of 1,702 healthy women, aged 40 and above, identified between 2010 and 2017. Blood arsenic level was determined by inductively coupled plasma mass spectrometry. After an average of 4.5 years of follow‐up (range 0.7–7.3 years), there were 110 incident cases of cancer diagnosed in the cohort, including 68 cases of breast cancer. Women in the highest quartile of arsenic had a highly significant 13‐fold increased risk of developing breast cancer, compared to women in the lowest quartile (hazard ratio [HR] = 13.2; 95% confidence interval [CI] 4.02–43.0). Results were similar for arsenic and all incident cancers (HR quartile 4 vs. quartile 1 = 13.3; 95% CI 4.78–37.0). If confirmed, our study suggests that the blood arsenic level may be a useful predictive marker of cancer risk in women.

What's new?

Arsenic has long been recognized as a potent carcinogen at high concentrations. But can it affect cancer risk at “normal,” environmental concentrations? In this Polish study, the authors found that women whose blood levels of arsenic were in the highest quartile had a 13‐fold increased risk of developing breast cancer, compared to women in the lowest quartile. If confirmed in further studies, these results suggests that blood arsenic level may be a useful predictive marker of cancer risk in women.

Association of Vitamin B12, Lactate Dehydrogenase, and Regulation of NF-κB in the Mitigation of Sodium Arsenite-Induced ROS Generation in Uterine Tissue by Commercially Available Probiotics

Managing arsenic intoxication with conventional metal chelators is a global challenge. The present study demonstrated the therapeutic role of probiotics against arsenic-induced oxidative stress and female reproductive dysfunction. Sodium arsenite-treated (1.0 mg/100 g body weight) Wistar female rats were followed up by a post-treatment of commercially available probiotic mixture in powder form (0.25 mg/100 g body weight) orally. Rats that experienced arsenic ingestion showed a significant lessening in the activities of uterine superoxide dismutase (SOD), catalase activities, and the level of non-protein soluble thiol (NPSH) with a concomitant increase in malondialdehyde (MDA) and conjugated dienes (CD). Exposure to arsenic significantly lowered the levels of vitamin B₁₂ and estradiol. Exposure to arsenic highly expressed the inflammatory marker and transcription factor NF-κB. Arsenic-mediated instability of these above parameters was controlled by the probiotics with a rebuilding of better function of anti-oxidant components. Besides its function in regulating endogenous anti-oxidant system, probiotics were able to augment the protection against mutagenic uterine DNA-breakage, necrosis, and ovarian-uterine tissue damages in arsenicated rats.

Involvement of proinflammatory cytokines and metallothionein in the repairing of arsenic-mediated uterine tissue damage by curcumin

Background Curcumin is extensively used as a therapeutic intervention for treating several ailments. The antioxidant curcumin has an anti-inflammatory and chelating property with arsenic to exhibit a strong therapeutic effect on reproductive organs. This study was undertaken to describe the protective effect of noninvasive administration of curcumin against sodium-arsenite-mediated uterine hazards in female Wistar rats. Methods Twenty-four female Wistar rats were randomly divided into four groups. The treatment was continued for 8 days and given orally sodium arsenite (10 mg/kg body weight) in combination with curcumin (20 mg/kg body weight). Results Our evaluation revealed that 8 days of sodium arsenite (10 mg/kg body weight) treatment reduced the activities of the uterine enzymatic antioxidants superoxide dismutase, catalase, and peroxidase. Blood levels of vitamin B12 and folic acid decreased followed by an increased serum lactate dehydrogenase, homocysteine level, and hepatic metallothionein-1 in arsenic-treated rats. Necrosis of uterine tissue along with the disruption of ovarian steroidogenesis was marked in arsenic-treated rats with an upregulation of uterine NF-κB and IL-6 along with a raised level of serum TNF-α. Oral administration of curcumin (20 mg/kg body weight/day) in arsenic-treated rats significantly reinstated these alterations of the antioxidant system followed by an improvement of ovarian steroidogenesis and the circulating level of B12 and folate along with the downregulation of serum homocysteine, metallothionein-1, and cytokines. Conclusions The findings of this study clearly and strongly elucidated that arsenic-induced oxidative stress in uterus is linked to an alteration of inflammation-signaling biomarkers and these have been protected through the co-administration of curcumin due to its anti-inflammatory, free radical scavenging, and antioxidant activity by the possible regulation of an S-adenosine methionine pool.

Mercury leads to features of polycystic ovary syndrome in rats

Mercury (Hg) is a heavy metal and Hg exposure is associated with various neural, immune, and cardiovascular abnormalities. However, few studies have evaluated Hg's toxicologic effect on reproductive and metabolic functions. In this study, we assessed whether Hg exposure results in reproductive and metabolic abnormalities. Hg was administered to adult female Wistar rats, mimicking the Hg levels found in exposed human blood, and their reproductive and metabolic function was assessed. Rats exposed to Hg displayed abnormal estrous cyclicity and ovarian follicular development, with a reduction in ovarian antral follicles and an increase in atretic and cystic ovarian follicles. Uterine atrophy with the presence of inflammatory cells was observed in Hg-exposed rats. The presence of abnormal ovarian fat accumulation, as well as increased ovarian lipid drops accumulation, was observed in Hg-exposed rats. Ovarian oxidative stress was also present in the Hg-exposed rats. High fasting glucose levels, glucose, and insulin intolerance were observed in Hg-exposed rats. Thus, these data suggest that Hg exposure led to abnormal reproductive and metabolic features similar to those found in the polycystic ovary syndrome (PCOS) rat models.

Inorganic arsenic exposure induces sex-disparate effects and exacerbates ischemia-reperfusion injury in the female heart

Arsenic is a common contaminant in drinking water throughout the world, and recent studies support a link between inorganic arsenic (iAS) exposure and ischemic heart disease in men and women. Female hearts exhibit an estrogen-dependent reduction in susceptibility to myocardial ischemic injury compared with males, and as such, female hearts may be more susceptible to the endocrine-disrupting effects of iAS exposure. However, iAS exposure and susceptibility to ischemic heart injury have not been examined in mechanistic studies. Male and female mice (8 wk) were exposed to environmentally relevant concentrations of sodium arsenite (0, 10, 100, and 1,000 parts/billion) via drinking water for 4 wk. Pre- and postexposure echocardiography was performed, and postexposure plasma was collected for 17β-estradiol measurement. Hearts were excised and subjected to ischemia-reperfusion (I/R) injury via Langendorff perfusion. Exposure to 1,000 parts/billion iAS led to sex-disparate effects, such that I/R injury was exacerbated in female hearts but unexpectedly attenuated in males. Assessment of echocardiographic parameters revealed statistically significant structural remodeling in iAS-treated female hearts with no change in function; males showed no change. Plasma 17β-estradiol levels were not significantly altered by iAS in male or female mice versus nontreated controls. Although total eNOS protein levels did not change in whole heart homogenates from iAS-treated male or female mice, eNOS phosphorylation (Ser¹¹⁷⁷) was significantly elevated in iAS-treated male hearts. These results suggest that iAS exposure can induce sex-disparate effects and modulate susceptibility to ischemic heart injury by targeting distinct sex-dependent pathways. NEW & NOTEWORTHY This is the first mechanistic study examining iAS exposure on myocardial ischemia-reperfusion injury in male and female mice. Following iAS exposure, ischemia-reperfusion injury was exacerbated in female hearts but attenuated in males. iAS treatment induced statistically significant cardiac remodeling in females, with no change in males. iAS treatment also enhanced phosphorylated eNOS levels at Ser¹¹⁷⁷, but only in male hearts. These results suggest that iAS alters susceptibility to myocardial I/R injury through distinct sex-dependent pathways.

Involvement of metallothionein, homocysteine and B-vitamins in the attenuation of arsenic-induced uterine disorders in response to the oral application of hydro-ethanolic extract of Moringa oleifera seed: a preliminary study

The painful invasive chelation therapy makes it challenging to continue the prolonged treatment against arsenic toxicity. Hence, the significance of the present preliminary investigation was to explore a noninvasive treatment strategy against sodium arsenite (As³⁺) by the use of a hydroethanolic extract of Moringa oleifera (MO) seed. Arsenic treatment (10 mg/kg body-weight) in animals showed significant level of oxidative stress as evidenced by increased serum levels of malondialdehyde (MDA), conjugated dienes (CD) and reduced level of non-protein thiol (NPSH). A significant diminution in the activities of enzymatic antioxidants was noted in As³⁺-treated rats. As³⁺ treatment showed a lengthy phase of metestrous in animals followed by significantly diminished ovarian steroidogenesis, increased ovarian follicular degeneration and distortion of uterine tissue histomorphology. In addition, there was a significant depletion of Vitamin-B₉ (folate) and B₁₂ following As³⁺ ingestion. The levels of circulating TNF-α, homocysteine (Hcy), uterine-IL-6, and liver metallothionein (MT-1) were significantly elevated in arsenic treated rats. MO at a dose of 100 mg/kg body-weight could successfully mitigate the uterine ROS generation by maintaining the uterine antioxidant status in As³⁺- treated rats. This seed extract prevented the deterioration of As³⁺-mediated ovarian-steroidogenesis and ovarian and uterine histoarchitecture significantly. B₉ and B₁₂ levels were also improved following the ingestion of the MO extract in arsenicated animals. Elevation of Hcy, TNF-α and IL-6 was also prevented by this MO seed extract in As³⁺-treated rats. A further increase of MT-1 level was achieved after MO ingestion in As³⁺-treated rats. Here, the alleviation of arsenic toxicity might involve via the regulation of the components of S-adenosine methionine (SAM) pool and MT-1.

Impact of styrene maleic anhydride (SMA) based hydrogel on rat fallopian tube as contraceptive implant with selective antimicrobial property

Development of non-hormonal female contraception is a need to combat against increasing population growth. The presently available short term or long term female contraceptives and sterilization methods have their own restrictions and side effects. With this objective, herein, we describe an innovative insight about the use of hydrogel formulation consisting of Styrene Maleic Anhydride (SMA) dissolved in Dimethyl Sulfoxide (DMSO) as non-hormonal fallopian tube contraceptive implant. Firstly, in vitro behavior of SMA hydrogel was evaluated by in vitro swelling and rheological properties to comprehend the polymeric hydrogel property post implantation inside the fallopian tube. Simulated Uterine Fluid (SUF) was used to simulate female reproductive tract environment in this study. Mechanical strength of the hydrogel when subjected to dynamic environment post implantation in the fallopian tube was estimated by the G' values demonstrated. SMA hydrogel expressed selective antimicrobial activity against opportunistic pathogens (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) while having limited consequence over the growth of Lactobacillus spp. After confirmation of cytocompatibility against primary rat endometrial cell lines, the polymeric hydrogel was implanted inside the uterine horns of Sprague-Dawley rats. In vivo biocompatibility of the hydrogel was confirmed by histological and immunohistochemical evaluation of uterine tissue sections. Hematology, blood biochemistry and organ toxicity (kidney, liver, spleen, lungs and heart) also revealed biocompatibility of SMA hydrogel. The results of the current study indicated that the SMA copolymer dissolved in DMSO to form hydrogel has excellent biocompatibility for application as female contraceptive gel which can be implanted in the fallopian tube.

Arjunolic Acid Improves the Serum Level of Vitamin B12 and Folate in the Process of the Attenuation of Arsenic Induced Uterine Oxidative Stress

Continuation of prolonged treatment against arsenicosis with conventional chelating therapy is a global challenge. The present study was intended to evaluate the defensive effect of arjunolic acid against arsenic-induced oxidative stress and female reproductive dysfunction. Wistar strain adult female rats were given sodium arsenite (10 mg/kg body weight) in combination with arjunolic acid (10 mg/kg body weight) orally for two estrous cycles. Electrozymographic analysis explored that arjunolic acid co-treatment counteracted As³⁺-induced ROS production in uterine tissue by stimulating the activities of endogenous enzymatic antioxidants. Arjunolic acid was able to enhance the protection against mutagenic uterine DNA breakage, necrosis, and ovarian-uterine tissue damages in arsenicated rats by improving the ovarian steroidogenesis. The mechanisms might be coupled with the augmentation of antioxidant defense system, partly through the elimination of arsenic with the involvement of S-adenosyl methionine pool where circulating levels of vitamin B₁₂, folic acid, and homocysteine play critical roles as evidenced from our present investigation.

The consequence of NAC on sodium arsenite-induced uterine oxidative stress

Arsenic consumption through drinking water is a worldwide major health problem. Management of arsenic intoxication with invasive, painful therapy using metal chelators is usually used as a conventional treatment strategy in human. In this present study, we examined the efficacy of oral administration of N-acetyl l-cysteine (NAC) in limiting arsenic-mediated female reproductive disorders and oxidative stress in female Wistar rats. The treatment was continued for 8 days (2 estrus cycles) on rats with sodium arsenite (10 mg/Kg body weight) orally. We examined the electrozymographic imprint of three different enzymatic antioxidants in uterine tissue. Rats fed with sodium arsenite exhibited a significant lessening in the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx). Uterine DNA breakage, necrosis, ovarian and uterine tissue damage, disruption in steroidogenesis were also found in arsenic treated rats. Co-administration of NAC at different doses (50 mg/kg body weight, 100 mg/kg body weight, respectively) significantly reversed the action of uterine oxidative stress markers like malondialdehyde (MDA), conjugated dienes (CD) and non protein soluble thiol (NPSH); and noticeably improved antioxidant status of the arsenic fed rats. This ultimately resulted in the uterine tissue repairing followed by improvement of ovarian steroidogenesis. However, this effective function of NAC might be crucial for the restoration of arsenic-induced female reproductive organ damage in rats.

Toxic elements as biomarkers for breast cancer: a meta-analysis study

AIMS AND BACKGROUND

Breast cancer (BC) is responsible for a large proportion of incidence of cancer in the world. Identifying the risk factors contributing to the incidence of BC is crucial to find efficient preventive and management strategies for this disease. Several studies have examined Arsenic (As), Cadmium (Cd), and Nickel (Ni) as risk factors for BC. The present study aimed at studying the link between As, Cd, and Ni concentrations and BC by using a meta-analysis.

MATERIALS AND METHODS

All case-control studies addressing the relationship between As, Cd, and Ni concentrations with BC were identified through electronic search databases (Scopus, ISI Web of Science, PubMed, EmBase, and Cochrane Library). The relevant data obtained from these papers were analyzed by a random-effects model. The heterogeneity of studies was secured by using I2 index. Funnel plots and Egger's test were used to examine publication bias.

RESULTS

In the present study, due to different measurement methods used for measuring As, Cd, and Ni, the concentration of these elements was measured in various subgroups (1: plasma, 2: breast tissue, and 3: scalp hair and nail) of individuals with BC and healthy subjects. The overall integration of data from the 3 groups led to the conclusion that there was a significant difference in Cd and Ni statuses between healthy and BC patients; the standard mean difference was 2.65 (95% CI: 1.57-3.73; P=0.000) and 2.06 (95% CI: 1.20-3.32; P=0.000), respectively. Whereas, there was no significant statistical difference in As status between healthy subjects and BC patients; the standard mean difference between them being 0.52 (95% CI: -0.12-1.16; P=0.114).

CONCLUSION

The present study indicates that there is a direct and positive association between Cd and Ni concentrations and BC risk. It is a warning to health care providers and policy makers to find viable solutions and take requisite measures to reduce BC risk in the society.