Metals and female reproductive toxicity

Associations between follicular fluid trace elements and ovarian response during in vitro fertilization

INTRODUCTION

Exposure to trace elements has been associated with ovarian response in experimental studies. We conducted a hypothesis-generating study of associations between ovarian follicular fluid (FF) trace elements and measures of ovarian response among women using in vitro fertilization (IVF).

METHODS

We collected ovarian FF specimens from 56 women. We determined concentrations (μg/L) of 11 trace elements using inductively coupled plasma-tandem mass spectrometry. We estimated associations between women's FF trace elements per interquartile range difference, and measures of ovarian response using linear (peak estradiol (E2), baseline anti-mullerian hormone (AMH), and follicle stimulating hormone (FSH)) and negative binomial (baseline antral follicle count (AFC) and oocyte count) regression, adjusting for confounding factors. We used principal component analysis (PCA) to estimate the associations of the FF trace elements mixture. We also explored FF oxidative stress enzymes as causal mediators of the associations.

RESULTS

Higher FF cobalt was associated with greater peak E2 (mean difference = 351.48 pg/mL; 95%CI: 21.76, 724.71) and AFC (rate ratio = 1.14; 95%CI: 1.01, 1.28), and higher FF copper was associated with greater peak E2 (mean difference = 335.66 pg/mL; 95%CI: 81.77, 753.08) and oocyte count (rate ratio = 1.19; 95%CI: 1.02, 1.43). Higher FF mercury was also associated with greater peak E2 (mean difference = 410.70 pg/mL; 95%CI: 61.90, 883.39). Higher FF lead was associated with lesser AFC (rate ratio = 0.85; 95%CI: 0.73, 0.98). Using PCA, the mixture of Sr, Hg, and As was associated with higher peak estradiol, AFC, and oocyte count. FF glutathione peroxidase, paraoxonase, and arylesterase activities were inconsistent mediators of the associations, but the effect estimates were imprecise.

CONCLUSION

Our results suggest that essential and non-essential trace elements in FF were associated with ovarian response during IVF.

Towards prolonging ovarian reproductive life: Insights into trace elements homeostasis

Ovarian aging is marked by a reduction in the quantity and quality of ovarian follicles, leading to a decline in female fertility and ovarian endocrine function. While the biological characteristics of ovarian aging are well-established, the exact mechanisms underlying this process remain elusive. Recent studies underscore the vital role of trace elements (TEs) in maintaining ovarian function. Imbalances in TEs can lead to ovarian aging, characterized by reduced enzyme activity, hormonal imbalances, ovulatory disorders, and decreased fertility. A comprehensive understanding of the relationship between systemic and cellular TEs balance and ovarian aging is critical for developing treatments to delay aging and manage age-related conditions. This review consolidates current insights into TEs homeostasis and its impact on ovarian aging, assesses how altered TEs metabolism affects ovarian aging, and suggests future research directions to prolong ovarian reproductive life. These studies are expected to offer novel approaches for mitigating ovarian aging.

Associations between multiple metal exposure and fertility in women: A nested case-control study

Metal pollution can cause a decline in female fertility, however, previous studies have focused more on the effect of a single metal on fertility. In this study, we evaluated the effect of metal mixtures on female fertility based on nested case-control samples. The plasma levels of 22 metal elements from 180 women were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Minimum absolute contraction and selection operator (LASSO) penalty regression selected metals with the greatest influence on clinical outcome. Logistic regression was used to analyze the correlation between single metals and fertility while a Bayesian kernel function regression (BKMR) model was used to analyze the effect of mixed metals. Eight metals (Calcium (Ca), Chromium (Cr), Cobalt (Co), Copper (Cu), Zinc (Zn), Rubidium (Rb), Strontium (Sr) and Zirconium (Zr)) were selected by LASSO regression for subsequent analysis. After adjusting for covariates, the logistic model showed that Cu (Odds Ratio(OR):0.33, 95% CI: 0.13 - 0.84) and Co (OR:0.38, 95% CI: 0.15 -0.94) caused a significant reduction in fertility, and identified the protective effect of Zn (OR: 2.96, 95% CI:1.21 -7.50) on fertility. Trend tests showed that increased Cr, Cu, and Rb levels were associated with reduced fertility. The BKMR model showed that Cr, Co, Cu, and Rb had a nonlinear relationship with fertility decline when controlling for the concentrations of other metals and suggested that Cu and Cr might exert an influence on fertility. Analysis showed a negative correlation between Cu, Cr, Co, Rb, and fertility, and a positive correlation between Zn and fertility. Furthermore, we found evidence for the interaction between Cu and Cr. Our findings require further validation and may identify new mechanisms in the future.

Association of blood metal exposure with age at menarche in Korean women: KNHANES (2008-2017)

Humans are exposed to metals in their daily lives and this metal exposure is responsible for various adverse health effects. Delayed pubertal development has been suggested as an adverse outcome of metal exposure; however, evidence in nationally representative populations, especially in Asia, is limited. We evaluated the association of blood cadmium (Cd), lead (Pb), and mercury (Hg) levels with the age at menarche in Korean females whose blood heavy metals were measured as part of the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2017. Among the females 16 years of age or older, all measured heavy metals in blood, i.e., Cd, Pb, and Hg, were positively associated with age at menarche. These associations remained significant in a model adjusted for age, survey year, income, education, body mass index, smoking history, and menopausal status as covariates (β: 0.10, 95% confidence interval (CI): 0.03-0.18 for Cd; β: 0.17, 95%CI: 0.06-0.27 for Pb; β: 0.12, 95%CI: 0.05-0.19 for Hg). When the population was separated by age group at the time of the survey, the significance between heavy metal levels and age at menarche became inconsistent, but the general trends were similar. Among those in their 20s and 40s, blood Cd showed a significant association, while Pb was significant among those in their 40s and 50s. A similar trend was observed in the sensitivity analysis in the girls aged 10-15 years at the time of the survey. Blood Cd levels were associated with decreased odds of precocious menarche (OR: 0.57, 95%CI: 0.31-1.03). Delayed menarche is a risk factor for cardiovascular and chronic kidney diseases in later life; hence, public health implication of heavy metal exposure warrants a public health attention.

Heavy Metals and Trajectories of Anti-Müllerian Hormone During the Menopausal Transition

BACKGROUND

Experimental and epidemiological studies have linked metals with women's reproductive aging, but the mechanisms are not well understood. Disrupted ovarian folliculogenesis and diminished ovarian reserve could be a pathway through which metals impact reproductive hormones and outcomes.

OBJECTIVE

The study aimed to evaluate the associations of heavy metals with anti-Müllerian hormone (AMH), a marker of ovarian reserve.

METHODS

The study included 549 women from the Study of Women's Health Across the Nation with 2252 repeated AMH measurements from 10 to 0 years before the final menstrual period (FMP). Serum AMH concentrations were measured using picoAMH ELISA. Urinary concentrations of arsenic, cadmium, mercury, and lead were measured using high-resolution inductively coupled plasma mass spectrometry. Multivariable linear mixed regressions modeled AMH as a function of time before the FMP interaction terms between metals and time to the FMP were also included.

RESULTS

Adjusting for confounders, compared with those in the lowest tertile, women in the highest tertile of urinary arsenic or mercury concentrations had lower AMH concentrations at the FMP (percent change: -32.1%; 95% CI, -52.9 to -2.2, P-trend = .03 for arsenic; percent change: -40.7%; 95% CI, -58.9 to -14.5, P-trend = .005 for mercury). Higher cadmium and mercury were also associated with accelerated rates of decline in AMH over time (percent change per year: -9.0%; 95% CI, -15.5 to -1.9, P-trend = .01 for cadmium; -7.3%; 95% CI, -14.0 to -0.1, P-trend = .04 for mercury).

CONCLUSION

Heavy metals including arsenic, cadmium, and mercury may act as ovarian toxicants by diminishing ovarian reserve in women approaching the FMP.

Effects of the real-life metal(oid)s mixture on female reproductive function: Less is different

The current study aimed to examine the effect of toxic metal(oid) mixtures (lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), and nickel (Ni)) on female reproductive function in Wistar rats after the 28- and 90-day exposure to dose levels calculated on the basis of the previously conducted human study. Experimental groups included: 2 controls (28- and 90-day), treated groups - doses based on: median- F2 (28) and F2(90) and 95th percentile concentrations in the general human population - F3(28) and F3(90); calculated lower Benchmark dose confidence limit (BMDL) for effects on hormone levels - F1(28) and F1(90) and a group given the doses calculated on the basis of the reference values from the literature (F4(28)). Blood and ovarian samples were collected for sex hormones and ovary redox status analysis. After 28-day exposure, changes were present both in prooxidants and antioxidants. However, after the 90-day exposure redox status imbalance was majorly caused by the disturbance of antioxidants. Changes in some parameters were observed even after exposure to the lowest doses. After 28-day exposure, the strongest dose-response relationship was found between hormones: LH and FSH and toxic metal(oid)s and, after 90-day exposure, between investigated redox status parameters: sulfhydryl groups, ischemia-modified albumin and nuclear factor erythroid 2-related factor 2 (Nrf2) and toxic metal(oid)s. Low obtained BMDLs and narrow Benchmark intervals for toxic metal(oid)s and some of the parameters might confirm the "no-threshold" paradigm. This study indicates possible detrimental effects of prolonged exposure to real-life mixtures of toxic metal(oid) on female reproductive function.

Attenuating effects of selenium and zinc against hexavalent chromium-induced oxidative stress, hormonal instability, and placenta damage in preimplanted rats

As a toxic metal, hexavalent chromium (CrVI) has effects on both the reproductive and endocrine systems. This study aimed to evaluate the protective effects of selenium (Se) and zinc (Zn) against the toxicity of chromium on the placenta in pregnant Wistar albino rats. Thirty pregnant Wistar rats were divided into control and four treated groups, receiving subcutaneously (s.c) on the 3rd day of pregnancy, K₂Cr₂O₇ (10 mg/kg body weight (bw)) alone, or in association with Se (0.3 mg/kg bw), ZnCl₂ (20 mg/kg bw), or both of them simultaneously. Plasma steroid hormones, placenta histoarchitecture, oxidative stress profile, and developmental parameters were investigated. These results showed that K₂Cr₂O₇ exposure induced a significant increase in the levels of both plasma estradiol (E₂) and placenta malondialdehyde (MDA), the number of fetal resorptions, and percent of post-implantation loss. On the other hand, K₂Cr₂O₇ significantly reduced developmental parameters, maternal body and placenta weight, and plasma progesterone (P) and chorionic gonadotropin hormone (β HCG) levels. However, K₂Cr₂O₇ significantly decreased the placenta activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH), and nonprotein sulfhydryl (NPSH). These changes have been reinforced by histopathological evaluation of the placenta. Se and/or ZnCl₂ supplementation provoked a significant improvement in most indices. These results suggest that the co-treatment with Se or ZnCl₂ strongly opposes the placenta cytotoxicity induced by K₂Cr₂O₇ through its antioxidant action.

Heavy Metal(loid) Accumulation in the Ovarian Tissue of Free-Ranging Queens and Bitches Inhabiting Highly Polluted Urban Environments

There is strong scientific evidence that exposure to environmental contaminants, such as heavy metal(loid)s (HMs), can impair female reproductive function. Pets, such as cats and dogs, who share the same habitat as humans, may be particularly useful sentinel models for detecting HMs in the ovary. In the present study, we compared the concentration of essential (Ems; Cu, Fe, Mn, Se, and Zn) and non-essential metal(loid)s (NEMs; Al, As, Cd, and Pb) in the ovarian tissues of free-ranging queens and bitches of different ages living in industrialized/highly polluted (south group) and non-polluted (north group) urban areas of the island of Sardinia, Italy. The results showed that both EMs and NEMs were present at detectable concentrations in feline and canine ovaries and their levels varied according to geographical areas and animal age. Among the EMs, Cu was found elevated in older queens and bitches inhabiting the southern area. Cadmium and lead were higher in feline and canine ovaries of older animals from the south compared to those living in the north. In addition, Cd and Pb concentrations increased in individuals of both species living in the south. These findings showed new perspectives for the use of pets as early warning sentinels of environmental pollution by HMs and for the risk of human exposure within a "One Health" approach. Pets may help to study the link between exposure to metals and female reproductive disturbances in mammals.

An Insight into the Impact of Serum Tellurium, Thallium, Osmium and Antimony on the Antioxidant/Redox Status of PCOS Patients: A Comprehensive Study

Humans exploit heavy metals for various industrial and economic reasons. Although some heavy metals are essential for normal physiology, others such as Tellurium (Te), Thallium (TI), antimony (Sb), and Osmium (Os) are highly toxic and can lead to Polycystic Ovarian Syndrome (PCOS), a common female factor of infertility. The current study was undertaken to determine levels of the heavy metals TI, Te, Sb and Os in serum of PCOS females (n = 50) compared to healthy non-PCOS controls (n = 56), and to relate such levels with Total Antioxidant Capacity (TAC), activity of key antioxidant enzymes, oxidative stress marker levels and redox status. PCOS serum samples demonstrated significantly higher levels of TI, Te, Sb and Os and diminished TAC compared to control (p < 0.001). Furthermore, there was significant inhibition of SOD, CAT and several glutathione-related enzyme activities in sera of PCOS patients with concurrent elevations in superoxide anions, hydrogen and lipid peroxides, and protein carbonyls, along with disrupted glutathione homeostasis compared to those of controls (p < 0.001 for all parameters). Additionally, a significant negative correlation was found between the elevated levels of heavy metals and TAC, indicative of the role of metal-induced oxidative stress as a prominent phenomenon associated with the pathophysiology of the underlying PCOS. Data obtained in the study suggest toxic metals as risk factors causing PCOS, and thus protective measures should be considered to minimize exposure to prevent such reproductive anomalies.

Puzzling relationship between levels of toxic metals in blood and serum levels of reproductive hormones: Benchmark dose approach in cross-sectional study

Reproductive disorders and infertility have become more common recently among the general population. Toxic metals are known as endocrine disruptors and as they are widespread in nature they may be linked to reproductive problems. This study was conducted as a cross-sectional study and its aim was to examine the dose–response relationship between cadmium, arsenic, mercury, chromium and nickel and serum hormone levels of testosterone (women) and estradiol and progesterone (men) using the Benchmark dose approach (BMD). Blood samples were collected from 218 women and 217 men digested in a microwave, and the levels of the tested metals were determined by atomic absorption spectrophotometry (AAS) or inductively coupled plasma-mass spectrometry (ICP-MS). Dose–response analysis was performed in PROAST software (version 70.1). The model averaging method was used to calculate the Benchmark dose interval (BMDI). A dose–response relationship has been established between all metals and hormones. The narrowest BMDI was found for the As-testosterone and Hg-testosterone. Levels estimated to produce the extra risk of testosterone serum levels disturbances of 10% were lower than median levels measured in the general population. Moreover, this research suggests the possibility of use of the BMD approach in analyzing data pool generated from extensive human-biomonitoring studies.

Environmental and occupational factors and higher risk of couple infertility: a systematic review study

Background

Infertility is a global health problem that represents an increasing trend due to new lifestyles following technological advances since individuals are facing more risk factors than before. The present systematic review study aimed to investigate the impact of environmental and occupational factors on reproductive parameters and increased risk of couple infertility.

Main body

Scopus, PubMed, SID, and Web of Science databases were searched for the available observational (i.e., cohort, case-control, and cross-sectional) systematic review, meta-analysis, and clinical trial studies between 2007 and 2019. To this end, keywords such as ‘Environmental exposure’, ‘Occupational exposure’, ‘Environmental pollutants’, ‘Environmental pollution’, ‘Couple infertility’, ‘Sterility’, and ‘Sub-fertility’ were used. The retrieved investigations examined the impact of environmental and occupational risk factors on reproductive indices and increased infertility risk. Totally, 66 out of 9519 papers were evaluated after considering the inclusion and exclusion criteria. The reported risk factors in the reviewed studies were heavy metals, cigarette smoking, and exposure to chemicals through consumer goods, urban life, and proximity to main roads. In addition, occupational factors included heavy physical activity, prolonged sitting, exposure to a hot environment, contact with formaldehyde, pesticides, insecticides, mechanical vibration, and contact with ionizing radiation, all of which affected the reproductive parameters. However, some researchers found no significant associations in this regard.

Short conclusion

In general, individuals with known impairments in reproductive parameters were more exposed to risk factors. Nonetheless, more studies are needed to determine the risk of infertility in the population.

Transition metallo-curcumin complexes: a new hope for endometriosis?

Endometriosis is a debilitating gynecological disorder in women of reproductive age. Laparoscopy, a minimally invasive surgical procedure, provides a definitive diagnosis of the disease. Current treatments, including hormonal therapy and pain medication, are often associated with undesirable side effects limiting their long-term usage. This calls for exploring newer diagnostic and therapeutic options with minimal side effects. Curcumin is an established anti-endometriotic agent with inherent fluorescent properties; however, poor bioavailability limits its clinical utility. To address this shortcoming, various transition metals were conjugated with curcumin to improve its stability, specificity and pharmacological properties. The chemical stability, hemocompatibility and ability of the synthesized metallo-curcumin complexes (MCCs) to ameliorate endometriotic lesions were investigated. While all of the MCCs exhibited low hemolytic activity, their chemical and biological activities were largely dependent on the nature of the metal ion conjugated to the curcumin molecule. Copper-curcumin and nickel-curcumin complexes demonstrated superior therapeutic efficacy evidenced by enhanced antioxidant activity, selective cytotoxicity and increased accumulation in endometriotic cells mediated by an energy-dependent active transport process.

Heavy metals and metalloids exposure and in vitro fertilization: Critical concerns in human reproductive medicine

Exposures to heavy metals and metalloids have been associated with decreased fecundity and fertility in couples conceiving via assisted reproduction. Heavy metals and metalloids can alter the homeostasis of critical hormones controlling sexual maturation by binding to critical hormones and receptors. This may disrupt the time course of sexual maturation directly or indirectly affecting reproductive competence in males and females. The present review aims to provide a summarized overview of associations between heavy metal exposure, reproductive concerns, and IVF outcomes. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in Google Scholar, Scopus, EMBASE and PubMed databases. Initial search produced 1,351 articles from which 30 articles were eligible to be included in the systematic review. From our results, 16 articles reported associations between selected heavy metals and IVF outcomes, while 14 articles summarized the role of heavy metals in reproductive concerns. For the studies on IVF outcomes, different human samples were examined for heavy metals. Heavy metals and metalloids (Pb, Hg, Cd, Cr, Mn, As) correlated negatively with oocyte fertilization/pregnancy rates in hair, follicular fluid, serum, urine and seminal plasma samples, while Cd and Hg in whole blood samples showed no associations. For the studies on reproductive concerns, high levels of heavy metals/metalloids were implicated in the following conditions: infertility (Cd, Pb, Ba, U), spontaneous abortion/miscarriage (Pb, Cd, Sb), congenital heart disease (Al, Mg, Cd), PCOS (As, Cd, Hg, Pb), endometriosis (Pb) and uterine leiomyomata (Hg). Taken together, the results of our study suggest that the impact of heavy metals and metalloids exposure on reproductive health may contribute to the failure rates of in vitro fertilization.

Assessment of Serum Elements Concentration and Polycystic Ovary Syndrome (PCOS): Systematic Review and Meta-analysis

Change in the levels of trace elements has been linked with PCOS pathogenesis by various studies, whereas some had reported no such association. Therefore, in order to evaluate association of eleven trace element (Cu, Zn, Cr, Cd, Se, Mn, Fe, Mg, Co, Ni and Pb) serum concentration with PCOS pathogenesis, current systematic review and meta-analysis has been carried out. Literature search was conducted using PubMed, Central Cochrane Library, Google Scholar and Science Direct databases with appropriate keywords. Studies published upto 3rd of September were evaluated for eligibility with suitable inclusion and exclusion criteria. Only case-control studies examining the association of serum trace element concentrations between PCOS cases and controls were selected. Present meta-analysis identified 32 articles with 2317 PCOS and 1898 controls. The serum Cu (MD = 15.40; 95% CI = 4.32 to 26.48; p = 0.006), Co (MD = 0.01; 95% CI = 0.01 to 0.02; p = 0.000), Cr (MD = 0.04; 95% CI = 0.00 to 0.07; p = 0.03) and Fe (MD = 12.98; 95% CI = 5.87-20.09; p = 0.0003) concentration is significantly higher, while lower concentration has been observed for Se (MD =  - 0.99; 95% CI =  - 1.31 to - 0.67; p = 0.000) and Mg (MD =  - 223.41; 95% CI =  - 391.60 to - 55.23; p = 0.009) among women with PCOS in comparison with the healthy group. Concentration of other elements which were analysed is not significantly related to PCOS. In short, PCOS women has higher serum concentrations of Cu, Co, Cr and Fe and lower concentrations of Se and Mg. Studies with sub-population of obese, non-obese and with and without insulin resistance are important to understand the pathomechanism of these elements in the syndrome.

Environmental and occupational exposure of metals and female reproductive health

Untainted environment promotes health, but the last few decades experienced steep upsurge in environmental contaminants posing detrimental physiological impact. The responsible factors mainly include the exponential growth of human population, havoc rise in industrialization, poorly planned urbanization, and slapdash environment management. Environmental degradation can increase the likelihood of human exposure to heavy metals, resulting in health consequences such as reproductive problems. As a result, research into metal-induced causes of reproductive impairment at the genetic, epigenetic, and biochemical levels must be strengthened further. These metals impact upon the female reproduction at all strata of its regulation and functions, be it development, maturation, or endocrine functions, and are linked to an increase in the causes of infertility in women. Chronic exposures to the heavy metals may lead to breast cancer, endometriosis, endometrial cancer, menstrual disorders, and spontaneous abortions, as well as pre-term deliveries, stillbirths. For example, endometriosis, endometrial cancer, and spontaneous abortions are all caused by the metalloestrogen cadmium (Cd); lead (Pb) levels over a certain threshold can cause spontaneous abortion and have a teratogenic impact; toxic amounts of mercury (Hg) have an influence on the menstrual cycle, which can lead to infertility. Impact of environmental exposure to heavy metals on female fertility is therefore a well-known fact. Thus, the underlying mechanisms must be explained and periodically updated, given the growing evidence on the influence of increasing environmental heavy metal load on female fertility. The purpose of this review is to give a concise overview of how heavy metal affects female reproductive health.

Examination of Trace Metals and Their Potential Transplacental Transfer in Pregnancy

With the ever-growing concern for human health and wellbeing, the prenatal period of development requires special attention since fetuses can be exposed to various metals through the mother. Therefore, this study explored the status of selected toxic (Pb, Cd, Ni, As, Pt, Ce, Rb, Sr, U) and essential trace metals (Mn, Co, Cu, Zn, Se) in the umbilical cord (UC) sera, maternal sera, and placental tissue samples of 92 healthy women with normal pregnancies. A further aim focuses on the potential transplacental transfer of these trace metals. Based on the obtained levels of investigated elements in clinical samples, it was observed that all of the trace metals cross the placental barrier and reach the fetus. Furthermore, statistical analysis revealed significant differences in levels of toxic Ni, As, Cd, U, Sr, Rb, and essential Mn, Cu, and Zn between all three types of analyzed clinical samples. Correlation analysis highlighted As to be an element with levels that differed significantly between all tested samples. Principal component analysis (PCA) was used to enhance these findings. PCA demonstrated that Cd, Mn, Zn, Rb, Ce, U, and Sr were the most influential trace metals in distinguishing placenta from maternal and UC serum samples. As, Co, and Cu were responsible for the clustering of maternal serum samples, and PCA demonstrated that the Pt level in UC sera was responsible for the clustering of these samples. Overall, the findings of this study could contribute to a better understanding of transplacental transfer of these trace metals, and shed a light on overall levels of metal exposure in the population of healthy pregnant women and their fetuses.

Impact of Environmental Pollution on Female Reproduction

The increased pollution in the world atmosphere is a global concern. Water, air, and soil are polluted by various sources, such as farm fertilizer, sewage industrial waste products, fumes, and plastics, which in turn impact human health. Plastics and other mixtures of waste affect live in the water. Moreover, the ecosystem is disrupted by the use of heavy metal-containing chemicals in agriculture, and those are eventually consumed by humans. The consequences are a significant negative impact on health including reproductive health, which impairs fertility in the human population. Reproductive functions are severely affected by different chemicals which may interfere with hormonal functions. Greater consequences are faced by the women as the number of germ cells present in the ovary is fixed during fetal life, and which are nonrenewable. From the production of ovum to fertilization, to implantation, and finally continuation of pregnancy, all are affected by the heavy metals and endocrine disruptors. Lifestyle modifications such as consumption of organic foods, plastic product avoidance, separation of residential areas from industrial/agricultural areas, proper waste disposal, and so on, may help to improve the situation.

Potentials of orally supplemented selenium-enriched Lacticaseibacillus rhamnosus to mitigate the lead induced liver and intestinal tract injury

Lead is a metal that exists naturally in the Earth's crust and is a ubiquitous environmental contaminant. The alleviation of lead toxicity is important to keep human health under lead exposure. Biosynthesized selenium nanoparticle (SeNPs) and selenium-enriched Lactobacillus rhamnosus SHA113 (Se-LRS) were developed in this study, and their potentials in alleviating lead-induced injury to the liver and intestinal tract were evaluated in mice by oral administration for 4 weeks. As results, oral intake of lead acetate (150 mg/kg body weight per day) caused more than 50 times and 100 times lead accumulation in blood and the liver, respectively. Liver function was seriously damaged by the lead exposure, which is indicated as the significantly increased lipid accumulation in the liver, enhanced markers of liver function injury in serum, and occurrence of oxidative stress in liver tissues. Serious injury in intestinal tract was also found under lead exposure, as shown by the decrease of intestinal microbiota diversity and occurrence of oxidative stress. Except the lead content in blood and the liver were lowered by 52% and 58%, respectively, oral administration of Se-LRS protected all the other lead-induced injury markers to the normal level. By the comparison with the effects of normal L. rhamnosus SHA113 and the SeNPs isolated from Se-LRS, high protective effects of Se-LRS can be explained as the extremely high efficiency to promote lead excretion via feces by forming insoluble mixture. These findings illustrate the developed selenium-enriched L. rhamnosus can efficiently protect the liver and intestinal tract from injury by lead.

Heavy metal and metalloid - induced reproductive toxicity

Heavy metals and metalloid exposure are among the most common factors responsible for reproductive toxicity in human beings. Several studies have indicated that numerous metals and metalloids can display severe adverse properties on the human reproductive system. Metals like lead, silver, cadmium, uranium, vanadium, and mercury and metalloids like arsenic have been known to induce reproductive toxicity. Moderate to minute quantities of lead may affect several reproductive parameters and even affect semen quality. The ecological and industrial exposures to the various heavy metals and metalloids have disastrous effects on the reproductive system ensuing in infertility. This work emphasizes the mechanism and pathophysiology of the aforementioned heavy metals and metalloids in reproductive toxicity. Additionally, this work aims to cover the classical protective mechanisms of zinc, melatonin, chelation therapy, and other trending methods to prevent heavy metal-induced reproductive toxicity.

Metal elements associate with in vitro fertilization (IVF) outcomes in 195 couples

PURPOSE

Environmental factors may affecting reproductive function reduction and embryonic development. Couples who are exposed to heavy metals for a long time may affect the outcome of in vitro fertilization (IVF). To evaluate the effect of elements on IVF outcomes, a total of 195 couples undergoing IVF were included in this study.

METHODS

Elements including V, Cr, Mn, Ni, Cu, Zn, As, Mo, Cd, Ba, Hg, Tl, Pb were measured in serum and follicular fluid (FF) samples of female and semen samples of male by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Multiple linear regression were applied to evaluate the association between metal elements and semen quality parameters and the number of oocytes in MII stage. Poisson regression and the robust variance estimation of the generalized estimation equation were used to evaluate the association between elements and IVF outcomes.

RESULTS

The statistical results showed that Cr had a significant negative correlation with total sperm concentration (TSC) and total motile sperm count (TMC), the correlation coefficients were -0.52 (-0.27∼1.43) and -0.4(-1.24, 0.45), respectively. At the same time, Ba was significantly correlated with TSC and TMC, the correlation coefficients were 0.1(-0.15∼0.34) and 0.12(-0.13, 0.36), respectively. Cr, Ba and Pb in follicular fluid (FF) had a significant positive correlation with the number of oocytes in MII stage. The correlation coefficients were 3.15 (0.79, 5.52), 1.54 (-0.27, 3.36), 12.27 (7.49, 17.04). The Tl level of FF was significantly associated with the high probability of blastocyst formation and high-quality blastocysts (RR: 2.83, 95 % CI: 0.92∼7.95; RR: 3.12, 95 % CI: 0.64, 12.84). The Hg level (RR: 3.98, 95 % CI: 0.78∼14.77) and the Ba level in serum (RR: 12.75 95 % CI: 1.31∼89.71) were significantly correlated with high-quality blastocysts. The levels of Ni, Cu, Mo in seminal plasma of men were significantly correlated with blastocyst formation and high-quality blastocysts (RR values were all greater than 1.5). In addition, the level of Ba was significantly correlated with the high probability of blastocyst formation (RR: 1.7, 95 % CI: 1.14∼2.52).

CONCLUSION

Our results reveal that Cr, Ba and Pb may affect TSC, TMC and MII oocytes. Moreover, Ba, Cr, As, Hg and Tl in serum and Mo in seminal plasma were related to fertilization results, good embryos, blastocyst formation, high-quality embryos, and pregnancy and live birth rates. Tl in FF may related to the quality of embryonic development, Ba was an important risk factor which closely related to the outcomes of IVF in both male and female. Through our detection and statistical analysis of clinical samples, it is shown that although not all elements will affect the outcome of IVF the key elements we have selected need to arouse our attention, which benifit to the diagnosis and prevention of clinical infertility.

Antioxidant status in relation to heavy metals induced oxidative stress in patients with polycystic ovarian syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a global health concern for women of reproductive age, as 6.5% of women worldwide are affected by this syndrome. PCOS is marked by hyperandrogenism, anovulation, menstrual abnormalities, and polycystic ovaries. Metals such as arsenic, cadmium, lead and mercury are considered to be systemic toxicants/human carcinogens and seem to have devastating effects on humans, even at minimal exposures. One of the probable aetiological factors for PCOS has been identified as oxidative stress. In view of the probable associations among oxidative stress, metal toxicity and PCOS, the present study examined the role of heavy metals in the generation of oxidative stress among females. This prospective study included 106 women (56 women diagnosed with PCOS and 50 women who were not diagnosed with PCOS as control women). There were no significant differences in the sociodemographic characteristics between the two groups except for the irregularity of menses and the presence of acne. The serum As, Cd, Pb, and Hg levels increased and the serum glutathione (GSH) and superoxide dismutase (SOD) levels diminished significantly in the PCOS group compared to the control group at P < 0.001. The SOD levels were negatively correlated with the As and Pb levels at P < 0.05. Additionally, the PCOS group exhibited a strong negative correlation between the GSH and As levels (P < 0.01), GSH and Pb levels (P < 0.05) and GSH and Hg levels (P < 0.01). Furthermore, the As levels were positively correlated with increased levels of Cd, Pb and Hg among PCOS women. Significant positive correlations were observed between Pb and Cd and between Cd and Hg at P < 0.001. The outcome of the study provides clear insight into the role of metal-induced oxidative stress, which plays a vital role in the pathophysiology underlying PCOS and suggests the use of these markers as prognostic tools to reduce the consequences of high-risk exposure to these metals among females.

Therapeutic effects of silver nanoparticle and L-carnitine on aerobic vaginitis in mice: an experimental study

Introduction: Aerobic vaginitis (AV) is a type of vaginal infection that occurs at the reproductive age of women. In this study, we aimed to study the possible anti-AV therapeutic effects of silver nanoparticles (AgNPs) and L-carnitine (LC) in the mouse model. Methods: AV model was established by intra-vaginal inoculation of 10⁸ CFU/mL Staphylococcus aureus and Escherichia coli (1:1) in adult NMRI mice. Susceptibilities of the bacteria were examined against AgNPs by inhibitory concentration (IC-50 and IC-90) and minimum biofilm inhibitory concentration (MBIC- 90) methods. The regimens therapy was intra-vaginal inoculation of AgNPs at MBIC- 90 and a daily injection of 250 mg/kg LC for two weeks. Mice were classified into healthy (control) and AV groups and then treated by LC, AgNPs, and AgNPs + LC. The vaginal smears were taken daily and tissue sections were prepared using the hematoxylin and eosin (H & E) method. Results: Minimum inhibitory concentrations (MICs) of AgNPs for E. coli, S. aureus, and their mixture were 250, 125, and 500 ppm, and their MBIC-90% were 500, 250, and 1000 ppm, respectively. The estrus cycle of mice treated with co-administration of AgNPs and LC was similar to the control group (P < 0.05). The results of histology also showed that infected mice were treated with AgNPs and LC, simultaneously. Conclusion: Single bacteria are more sensitive than their mixed model to these NPs. Co-administration of AgNPs as an antibacterial agent and LC as an antioxidant agent can treat AV in the infected mice.

Effect of Silver Nanoparticles and L-Carnitine Supplement on Mixed Vaginitis Caused by Candida albicans/ Staphylococcus aureus in Mouse Models: An Experimental Study

The evolution of antimicrobial-resistant pathogens is a global health and development threat. Nanomedicine is rapidly becoming the main driving force behind ongoing changes in antimicrobial studies. Among nanoparticles, silver (AgNPs) have attracted attention due to their versatile properties. The study aimed to investigate the effects of AgNPs and L-carnitine (LC) on mixed Candida albicans and Staphylococcus aureus in the mice vaginitis model. Study of antimicrobial activity of AgNPs evaluated by Minimum Inhibitory Concentration (MIC) and Minimum Biocidal Concentration (MBC) assays. AgNPs inhibited biofilm formation of microbial strains, which was tested by using crystal violet staining. In the current study, we evaluated the effects of AgNPs and LC in NMRI mice infected intravaginally with C. albicans/ S. aureus for two weeks. The proportion of mice in each stage of the estrous cycle (proestrus, estrus, metestrus, and diestrus) was examined. Histological properties were assessed by hematoxylin/ eosin (H&E) staining of formalin-fixed, paraffin-embedded vaginal tissue sections. Based on the results, MICs of AgNPs against S. aureus, C. albicans, and their combination were 252.3, 124.8, and 501.8 ppm, and their minimum biofilm inhibitory concentration (MBIC) was 500, 250, and 1000 ppm, respectively. The estrous cycle in the treated group was similar to the control. Vaginal histology and cytology showed that LC can improve tissue damages caused by vaginitis and AgNPs. This study demonstrates the promising use of AgNPs as antimicrobial agents and the combination of AgNPs/ LC could be a great future alternative in the control of vaginitis.

Toxicity assessment of metallic nickel nanoparticles in various biological models: An interplay of reactive oxygen species, oxidative stress, and apoptosis

Nickel nanoparticles (Ni-NPs) are widely used for multiple purposes in industries. Ni-NPs exposure is detrimental to ecosystems owing to widespread use, and so their toxicity is important to consider for real-world applications. This review mainly focuses on the notable pathophysiological activities of Ni-NPs in various research models. Ni-NPs are stated to be more toxic than bulk forms because of their larger surface area to volume ratio and are reported to provoke toxicity through reactive oxygen species generation, which leads to the upregulation of nuclear factor-κB and promotes further signaling cascades. Ni-NPs may contribute to provoking oxidative stress and apoptosis. Hypoxia-inducible factor 1α and mitogen-activated protein kinases pathways are involved in Ni-NPs associated toxicity. Ni-NPs trigger the transcription factors p-p38, p-JNK, p-ERK1/2, interleukin (IL)-3, TNF-α, IL-13, Fas, Cyt c, Bax, Bid protein, caspase-3, caspase-8, and caspase-9. Moreover, Ni-NPs have an occupational vulnerability and were reported to induce lung-related disorders owing to inhalation. Ni-NPs may cause serious effects on reproduction as Ni-NPs induced deleterious effects on reproductive cells (sperm and eggs) in animal models and provoked hormonal alteration. However, recent studies have provided limited knowledge regarding the important checkpoints of signaling pathways and less focused on the toxic limitation of Ni-NPs in humans, which therefore needs to be further investigated.

Crude oil and public health issues in Niger Delta, Nigeria: Much ado about the inevitable

The importance of crude oil has come at a great cost. In many developing economies of the world, it can be described as the bitter-sweet crude for its double-edged impacts on the welfare, wellness and wellness of the people. Agitations and restiveness remain characteristic features of Niger Delta following claims of exploitation and neglect of the local population by the multinationals. Literature on the environmental and public health impacts of crude oil was searched from relevant databases such as google scholar, Science Direct, Scopus and PubMed. This paper is a translational scientific and toxicological insight on what should be done by the major players rather than casting unending aspersions. Since living near oil spills and crude oil production sites is an environmental stressor occasioned by exposure to both chemical pollutants and physical menace that are all detrimental to health, cumulative risk assessment CRA is proposed as a viable approach for a comprehensive understanding of the size of this problem. Multinational oil companies should support development of Environmental Medicine Research which will in turn generate data on both how to harness the natural resources to combat the public health issues associated with oil exploration and the mitigation and remediation of the environment. This endeavor will create a waste-to-wealth program that will pacify the restiveness in oil exploring communities. It will be interesting to know that in the same environment that breeds the elephant-in-the-parlor lies the natural antidotes to check-mate the public health malady.

Potential Role of Zinc in the COVID-19 Disease Process and its Probable Impact on Reproduction

COVID-19 (coronavirus disease 2019) is the current world health crisis, producing extensive morbidity and mortality across all age groups. Given the established roles of zinc in combating oxidative damage and viral infections, zinc is being trialed as a treatment modality against COVID-19. Zinc also has confirmed roles in both male and female reproduction. The possible depletion of zinc with the oxidative events of COVID-19 is especially relevant to the fertility of affected couples. This review aims to present the pathophysiology of COVID-19, especially in relation to reproductive function; the role of zinc in the COVID-19 disease process; and how zinc depletion in concert with cytokine storm and reactive oxygen species production could affect reproduction. It also highlights research areas to better the understanding of COVID-19 and its impact on fertility and potential ways to mitigate the impact.

Female Fertility and Environmental Pollution

A realistic picture of our world shows that it is heavily polluted everywhere. Coastal regions and oceans are polluted by farm fertilizer, manure runoff, sewage and industrial discharges, and large isles of waste plastic are floating around, impacting sea life. Terrestrial ecosystems are contaminated by heavy metals and organic chemicals that can be taken up by and accumulate in crop plants, and water tables are heavily contaminated by untreated industrial discharges. As deadly particulates can drift far, poor air quality has become a significant global problem and one that is not exclusive to major industrialized cities. The consequences are a dramatic impairment of our ecosystem and biodiversity and increases in degenerative or man-made diseases. In this respect, it has been demonstrated that environmental pollution impairs fertility in all mammalian species. The worst consequences are observed for females since the number of germ cells present in the ovary is fixed during fetal life, and the cells are not renewable. This means that any pollutant affecting hormonal homeostasis and/or the reproductive apparatus inevitably harms reproductive performance. This decline will have important social and economic consequences that can no longer be overlooked.

Body Representations of Internal Pollution: The Risk Perception of the Circulation of Environmental Contaminants in Pregnant and Breastfeeding Women in Spain

In this article, we analyze how pregnant and breastfeeding women perceive the inside of their bodies as well as their thoughts regarding the accumulation and elimination of chemical compounds present in food, and how these are then transmitted to the fetus. We explore different social perceptions of risk regarding the circulation of chemical compounds inside the body using qualitative research based on the technique of body mapping, comprised of women’s figures of their bodies in combination with comments on the figures, food diaries and narratives from in-depth interviews. We examine how these 41 women (21 pregnant and 20 breastfeeding) perceive the body’s internal mechanisms during the stages of pregnancy and breastfeeding, as well as the circulation of chemical contaminants within it. The body mapping technique allowed us to analyze participants’ knowledge of internal pollution, a little-understood process in society. Thanks to these pregnant and breastfeeding women, who made an effort to represent and reflect on these new risks, this study shows that scientists and obstetricians need to collaborate with women in order to better understand and publicize the risks of internal pollution.

Effects of oral exposure to arsenite on arsenic metabolism and transport in rat kidney

Nephrotoxicity is within the recognized toxic effects of arsenic. In this study we assessed the effect of arsenite on the renal capacity to metabolize and handle arsenicals in rats exposed to drinking water with 0, 1, 5, or 10 ppm sodium arsenite for ten days. Arsenite treatment did not affect the gene expression of the main enzyme catalyzing methylation of arsenite, As3mt, while it reduced the expression of GSTO1 mRNA and protein. Arsenite decreased the expression of Aqp3, Mrp1, Mrp4, and Mdr1b (i.e., transporters and channels used by arsenic), but not that of Aqp7, Glut1, Mrp2, and Mdr1a. The protein abundance of AQP3 was also reduced by arsenite. Arsenite increased urinary NGAL and FABP3 and decreased Klotho plasma levels, without alteration of creatinine, which evidenced early tubular damage. Renal Klotho mRNA and protein expressions were also downregulated, which may exacerbate renal damage. No effect was observed in selected miRNAs putatively associated with renal injury. Plasma PTH and FGF23 were similar between groups, but arsenite decreased the renal expression of Fgfr1 mRNA. In conclusion, exposure to arsenite alters the gene expression of proteins involved in the cellular handling of arsenical species and elicits tubular damage.

Depression, changes in peripheral blood cell count, and changes in selected biochemical parameters related to lead concentration in whole blood (Pb-B) of women in the menopausal period

THE AIM

The aim of this study was to assess the severity of depression, vasomotor symptoms, changes in peripheral blood cell count, and selected biochemical parameters in relation to the concentration of lead in whole blood of women in the perimenopausal period.

METHODS

The study sample consisted of 233 women from the general population of the West Pomeranian Province (Poland) in age between 44-65 years. The intensity of menopausal symptoms was examined using the Blatt-Kupperman Index, and the severity of depression using the Beck Depression Inventory. The following biochemical data were evaluated: concentrations of glucose, triglycerides, HDL, C-reactive protein, glycated haemoglobin, cortisol, insulin, blood cell count, and lead concentration in whole blood (Pb-B).

RESULTS

A whole blood Pb concentration below 5 μg/dl was found in 55 subjects (23.61 %), in 142 women (60.94 %) it ranged from 5 to 10 μg/dl, while in 36 women (15.45 %) was higher than 10 μg/dl. There was a strong positive correlation between Pb concentration in the blood of the examined women and the severity of depressive symptoms (Rs=+0.60, p = 0.001). The lowest mean values for total leukocytes (5.07 ± 1.22 thousand/μl) and neutrophils (2.76 ± 0.86 thousand/μl) were found in women with Pb concentration above 10 μg/dl (p < 0.05). There was a significant negative correlation between the number of total leukocytes (r=-0.45, p = 0.002) and neutrophils (r=-0.50, p = 0.001) and blood Pb concentration. Analysis showed statistically significant differences in glucose concentration (p < 0.05) between groups. Blood glucose was higher in women with Pb-B <5 and between 5-10 μg/dl than in women with Pb-B >10 μg/dl.

CONCLUSION

Exposure to Pb may be a factor playing a significant role in the development of depressive symptoms in menopausal women. It may also be associated with glucose metabolism disorders and immunosuppression in women during this period of life.

Female Infertility Associated with Blood Lead and Cadmium Levels

Lead and cadmium are known to be potential female reproductive toxins. However, studies on the relationship between these metals and infertility are limited. This study examines the association between self-reported infertility and blood lead and cadmium levels in US women by comparing metal levels in infertile and pregnant women. Data on blood lead, blood cadmium, and infertility from women aged 20–39 years who participated in the 2013–2014 and 2015–2016 National Health and Nutrition Examination Surveys were analyzed (n = 124, ‘pregnant’ n = 42, ‘infertile’ n = 82). Blood lead and cadmium levels were measured using inductively coupled plasma mass spectrometry, and infertility and pregnancy status were assessed using a self-reported questionnaire. Low blood lead and cadmium levels (geometric mean of blood lead = 0.50 µg/dL and blood cadmium = 0.26 µg/L) were positively associated with self-reported infertility after adjusting for confounding effects (odds ratio (OR) for lead per two-fold increase in blood metal levels = 2.60; 95% confidence interval (95% CI), 1.05–6.41 and OR for cadmium per two-fold increase = 1.84; 95% CI, 1.07–3.15). Although our findings require confirmation, they suggest that even low blood cadmium and lead levels may be deleterious to female fecundity.

Sensor-as-a-Service: Convergence of Sensor Analytic Point Solutions (SNAPS) and Pay-A-Penny-Per-Use (PAPPU) Paradigm as a Catalyst for Democratization of Healthcare in Underserved Communities

In this manuscript, we discuss relevant socioeconomic factors for developing and implementing sensor analytic point solutions (SNAPS) as point-of-care tools to serve impoverished communities. The distinct economic, environmental, cultural, and ethical paradigms that affect economically disadvantaged users add complexity to the process of technology development and deployment beyond the science and engineering issues. We begin by contextualizing the environmental burden of disease in select low-income regions around the world, including environmental hazards at work, home, and the broader community environment, where SNAPS may be helpful in the prevention and mitigation of human exposure to harmful biological vectors and chemical agents. We offer examples of SNAPS designed for economically disadvantaged users, specifically for supporting decision-making in cases of tuberculosis (TB) infection and mercury exposure. We follow-up by discussing the economic challenges that are involved in the phased implementation of diagnostic tools in low-income markets and describe a micropayment-based systems-as-a-service approach (pay-a-penny-per-use-PAPPU), which may be catalytic for the adoption of low-end, low-margin, low-research, and the development SNAPS. Finally, we provide some insights into the social and ethical considerations for the assimilation of SNAPS to improve health outcomes in marginalized communities.

Endocrine Disruptors Induced Distinct Expression of Thyroid and Estrogen Receptors in Rat versus Mouse Primary Cerebellar Cell Cultures

The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain the hormonal and neuronal milieu during tissue development. This complex system can be influenced by endocrine disruptors (ED)—substances that can alter the hormonal regulation even in small concentrations. By now, thousands of substances—either synthesized by the plastic, cosmetic, agricultural, or medical industry or occurring naturally in plants or in polluted groundwater—can act as EDs. Their identification and testing has been a hard-to-solve problem; Recent indications that the ED effects may be species-specific just further complicated the determination of biological ED effects. Here we compare the effects of bisphenol-A, zearalenone, and arsenic (well-known EDs) exerted on mouse and rat neural cell cultures by measuring the differences of the ED-affected neural estrogen- and thyroid receptors. EDs alters the receptor expression in a species-like manner detectable in the magnitude as well as in the nature of biological responses. It is concluded that the interspecies differences (or species specificity) in ED effects should be considered in the future testing of ED effects.

Review of the nature of some geophagic materials and their potential health effects on pregnant women: some examples from Africa

The voluntary human consumption of soil known as geophagy is a global practice and deep-rooted in many African cultures. The nature of geophagic material varies widely from the types to the composition. Generally, clay and termite mound soils are the main materials consumed by geophagists. Several studies revealed that gestating women across the world consume more soil than other groups for numerous motives. These motivations are related to medicinal, cultural and nutrients supplementation. Although geophagy in pregnancy (GiP) is a universal dynamic habit, the highest prevalence has been reported in African countries such as Kenya, Ghana, Rwanda, Nigeria, Tanzania, and South Africa. Geophagy can be both beneficial and detrimental. Its health effects depend on the amount and composition of the ingested soils, which is subjective to the geology and soil formation processes. In most cases, the negative health effects concomitant with the practice of geophagy eclipse the positive effects. Therefore, knowledge about the nature of geophagic material and the health effects that might arise from their consumption is important.

Mercury chloride exposure induces DNA damage, reduces fertility, and alters somatic and germline cells in Drosophila melanogaster ovaries

Mercury exposure has been shown to affect the reproductive system in many organisms, although the molecular mechanisms are still elusive. In the present study, we exposed Drosophila melanogaster Canton-S adult females to concentrations of 0 mM, 0.1 mM, 0.3 mM, 3 mM, and 30 mM of mercury chloride (HgCl₂) for 24 h, 48 h, or 72 h to determine how mercury could affect fertility. Alkaline assays performed on dissected ovaries showed that mercury induced DNA damage that is not only dose-dependent but also time-dependent. All ovaries treated for 72 h have incorporated mercury and exhibit size reduction. Females treated with 30 mM HgCl₂, the highest dose, had atrophied ovaries and exhibited a drastic 7-fold reduction in egg laying. Confocal microscopy analysis revealed that exposure to HgCl₂ disrupts germinal and somatic cell organization in the germarium and leads to the aberrant expression of a germline-specific gene in somatic follicle cells in developing egg chambers. Together, these results highlight the potential long-term impact of mercury on germline and ovarian cells that might involve gene deregulation.

The geochemistry of geophagic material consumed in Onangama Village, Northern Namibia: a potential health hazard for pregnant women in the area

Ingestion of geophagic materials might affect human health and induce diseases by different ways. The purpose of this study is to determine the geochemical composition of geophagic material consumed especially by pregnant women in Onangama Village, Northern Namibia and to assess its possible health effects. X-ray fluorescence and inductively coupled plasma mass spectrometry were used in order to determine the major, and trace elements as well as anions concentrations of the consumed material. The geochemical analysis revealed high concentrations of aluminium (Al), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), sodium (Na), and silica (Si); and trace elements including arsenic (As), chromium (Cr), mercury (Hg), nickel (Ni) and vanadium (V) as well as sulphate (SO₄^2-), nitrate (NO₃^-), and nitrite (NO₂^-) anions comparing to the recommended daily allowance for pregnant women. The pH for some of the studied samples is alkaline, which might increase the gastrointestinal tract pH (pH < 2) and cause a decrease in the bioavailability of elements. The calculated health risk index (HRI > 1) revealed that Al and Mn might be a potential risk for human consumption. Based on the results obtained from the geochemical analysis, the consumption of the studied material might present a potential health risk to pregnant women including concomitant detrimental maternal and foetal effects.

Effect on the offspring of pregnant females CD-1 mice treated with a single thallium(I) application

Thallium (Tl) is a highly toxic metal for human beings; higher amounts found in diverse fluids of pregnant women are associated with low birth weight and preterm birth. However, experimental data concerning their effects on the embryonic development of mammalian organisms are limited. Hence, in the present work, TI(I) acetate of 0, 4.6, 9.2, or 18.5 mg/kg body weight were administered by intraperitoneal injection to groups of 10 pregnant CD-1 mice on the 7th gestational day, and animals were sacrificed on day 18 of gestation. The fetuses obtained showed some variations, such as trunk bent over (18.5 mg/kg), tail variations (all doses), forelimbs malrotation and hind limbs (all doses). Skeletal examination of the fetuses showed a delay in the ossification of skull bones, ribs, and limbs (all doses). In conclusion, the Intraperitoneal injection of Tl(I) acetate to pregnant mice induced morphological variations and a delay of the fetus ossification.

Placental levels of metals and associated factors in urban and sub-urban areas of Seville (Spain)

Environmental exposure to metals among women, revealed their adverse effects on pregnancy. The fetus is exposed to these toxic elements only via the placenta which are able to accumulate there or cross it, compromising the protective functions of this organ. Numerous studies have shown associations between the prenatal exposition to some metals and an impact on cognitive, motor and intellectual development of the child. Sixty two placental samples were taken at delivery to determine the mineral content (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, V, Zn) by ICP-OES. Among these metals, essential ones (B, Ca, Cu, Fe, Mg, Mn, Mo, Na, Zn) can have health beneficial effects at low levels however, in high concentration are potentially toxic. On the other hand, elements such as Al, Cd, Pb, are classified as toxic metals, no matter what its concentration is. The aim of this study is to find the potential relationships between these metals levels, newborn's parameters, pregnancy details and the epidemiologic information obtained using a questionnaire data from the participant pregnant women from Seville (Spain). The main maternal determinant of detectable placenta Cd levels was smoking during pregnancy. Other maternal factors that may affect placenta metal levels were gestational age (Al, B, Ba, and Pb) or dietary supplement (Fe). It has to be stressed that our results have to be interpreted with caution, because of the small study group and the low exposure levels, along with the lack of information on potential sources of exposure to these metals. The use of placenta samples obtained at delivery can be considered strength of this study since the concentration of some metals in placenta can indicate the extent of maternal exposure during gestation.

Effect of Low-Dose Exposure to Toxic Heavy Metals on The Reproductive Health of Rats A Multigenerational Study

The aim of this investigation was to evaluate the effects of the exposure to low doses of lead, mercury and cadmium dissolved in drinking water (200× above maximal permissible dosage) on the reproductive potency of 200 Wistar rats (100 males and 100 females of F1 generation) and their progeny. Ten groups of rats were formed according to their exposure to heavy metals, including one control group without exposure. The females gave births between weeks 13 and 78 of the experiments. Reproduction parameters, such as number of litters, total number of newborns, number of newborns per litter, and number of weanlings were assessed weekly. The results demonstrated that the number of litters and newborns were higher after exposure to mercury and lower after exposure to lead. The number of weanlings and their share from newborns were the highest after exposure to cadmium and the lowest after exposure to mercury. A sex-specific effect of metals was related to the reproductive success.

Evaluation of trace elements associated with antioxidant enzymes in blood of primary epithelial ovarian cancer patients

Epithelial ovarian cancer (EOC) has been associated with oxidative stress (OS) due to epithelial inflammation which makes ovaries more vulnerable to the deleterious effects of reactive oxygen species (ROS). However, antioxidant enzymes (AOEs) such as manganese-superoxide dismutase (Mn-SOD), copper,zinc-superoxide dismutase (Cu,Zn-SOD) and glutathione peroxidase (GPx1) protect cells against the biological damage of ROS-induced OS and support cancer prevention by maintaining normal cell cycle progression, inhibiting proliferation, tumor invasion, angiogenesis, inflammation or inducing apoptosis. In the present study, we aimed to measure the levels of trace elements [manganese (Mn), copper (Cu), zinc (Zn) and selenium (Se)] which are structurally and/or functionally associated with the AOEs by inductively coupled plasma/mass-spectrometry (ICP/MS) in blood samples of patients with EOC (M, n = 26) and compare the data with healthy subjects (C, n = 46). Serous EOC (M1, n = 18) data were also evaluated according to the tumor grading [well or moderately well differentiated (G 1-2) vs. poorly differentiated or undifferentiated (G3)] and staging of disease [stage I-II (SI-II) vs. stage III (SIII)]. We obtained; i) The Mn and Se levels of M were significantly lower than C, ii) only Mn levels were changed [(G3_(Mn) < G 1-2 _(Mn)] in M1, iii) significant correlations were observed between [Cu and Zn levels (r = 0.701, p = 0.036) in G 1-2 and (r = 0.686, p = 0.041) in G3; Cu and Se levels (r = 0.960, p = 0.000) in G3; Mn levels and Mn-SOD expression (r = 0.551, p = 0.006) in M, (r = 0.857, p = 0.007) in G 1-2 and (r = 0.690, p = 0.056) in G3; Se levels and erythrocyte GPx1 activity (r = 0.660, p = 0.053) in G 1-2 ; Se levels and erythrocyte Cu,Zn-SOD activity (r = 0.693, p = 0.038) in G3]. The study revealed that trace elements, particularly low Mn and Se levels along with high Cu/Se ratios might be of value in all histologic subtypes of EOC. Although Mn level was important in terms of discriminating tumor grades, positive correlation between Cu-Se levels was also remarkable in patients with G 1-2 tumors of M1. Moreover, high erythrocyte Cu/Se ratios might be a favourable marker for EOC.

Associations of environmental exposures to methylmercury and selenium with female infertility: A case-control study

BACKGROUND

Methylmercury exposure is a common health risk resulting from daily fish intake. However, studies addressing the link between methylmercury and infertility are limited and also inconsistent. In addition, no previous epidemiological studies have accounted for the interaction between methylmercury and selenium. We aimed to investigate the association between environmental exposures to metals and female fertility.

METHODS

This case-control study included 98 infertile women receiving fertility treatment (infertile group) and 43 female workers in their thirties (control group) who provided blood samples and returned a questionnaire on lifestyles and dietary characteristics. Blood levels of mercury, lead, cadmium, arsenic, manganese, zinc, and selenium were compared between the groups. Spearman correlation analyses between anti-Müllerian hormone and the metals were conducted.

RESULTS

The mean selenium level in blood (± SD) and the selenium/mercury molar ratio were significantly lower in the infertile group (189 ± 25 μg/L and 94.6 ± 44.3, respectively) than in the control group (200 ± 25 μg/L and 118.4 ± 70.5). By contrast, blood mercury levels after adjusting for blood selenium and age were significantly higher in the infertile group than in the control group. Multiple logistic regression analyses with the adjustment for the other metals and potential confounders confirmed significant associations of infertility with elevated mercury and reduced selenium levels. No significant correlations were observed between anti-Müllerian hormone and metals.

CONCLUSIONS

Methylmercury and selenium exposures appear to have adverse and protective effects on female fertility, respectively. This is the first report to suggest the antagonistic interaction between methylmercury and selenium in relation to human female fertility.

Toxicological and nutritional status of trace elements in hair of women with in vitro fertilization (IVF) pregnancy and their 9-month-old children

The objective of the present study was to assess toxic and nutritional trace element and mineral status in hair of women with IVF pregnancy and their children. Inductively-coupled plasma mass-spectrometry was used to assess hair trace element levels of 50 women with IVF pregnancy and 158 controls with spontaneous pregnancy and their children. Women with IVF pregnancy were characterized by significantly elevated hair As, Hg, Li, K, Na, and reduced Fe, Si, and Zn contents. Children from IVF pregnancy had significantly lower values of hair Cr, Fe, Mg, Sr, and Al content when compared to the control values, whereas hair Hg and Mo levels were higher. Hair trace element levels were associated with pregnancy complications and infertility, but not newborn characteristics. The results suggest the need for preconceptional monitoring and correction of the levels of toxic and essential elements in women in order to improve the course pregnancy and child development.

Thiacalix[4]arenes Remove the Inhibitory Effects of Zn Cations on the Myosin ATPase Activity

Numerous female reproductive abnormalities are caused by uterine smooth muscle (myometrium) disorders. Heavy metals have an adverse effect on the contractility of the uterine smooth muscle. Although zinc is an essential biogenic element for most of the organisms, high doses of this element are toxic. The study of 0.5-5 mM Zn2+ effect on myosin S1 ATPase activity from the uterus found that 5 mM Zn2+ cations have the most pronounced inhibitory effect. The calculation of the kinetic parameters (Km and Vmax, ATP) revealed that the apparent maximum velocity of the hydrolysis ATP catalyzed by myosin in the presence of 5 mM Zn2+ decreased by 1.6 times. The value of Кm for ATP hydrolysis by myosin S1 in the presence of Zn2+ does not change statistically, although it tends to decrease. It was determined that uterine myosin S1 ATPase activity does not depend on the concentration of Mg2+ in the presence of 5 mM Zn2+. Also, it was demonstrated that tetrahydroxythiacalix[4]arene-tetrasulfosphonate (C-798) and tetrahydroxythiacalix[4]arene-tetraphosphonate (C-800) restored myosin S1 ATPase activity to the control level in the presence of 5 mM Zn2+. One of the most probable mechanisms of restoring the action of these thiacalix[4]arenes protective effect is based on its ability to chelate heavy metal cations from the incubation medium. The molecular docking of C-798 and C-800 into the myosin S1 region showed that these thiacalix[4]arenes could interact with Zn cation bond by myosin amino acid residues near the ATPase active site. Therefore, thiacalix[4]arenes may weaken the interaction between this cation and myosin S1. It was speculated that the obtained results could be used for further research with the aim of using this thiacalix[4]arenes as pharmacological compounds in the case of poisoning with high concentrations of zinc.

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.

The Metal Neurotoxins: An Important Role in Current Human Neural Epidemics?

Many published studies have illustrated that several of the present day neurological epidemics (autism, attention deficit disorder, Alzheimer's) cannot be correlated to any single neurotoxicant. However, the present scientific examination of the numerous global blood monitoring databases for adults that include the concentrations of the neurotoxic elements, aluminum (Al), arsenic (As), lead (Pb), manganese (Mn), mercury (Hg), and selenium (Se) clearly indicate that, when considered in combination, for some, the human body may become easily over-burdened. This can be explained by changes in modern lifestyles. Similar data, solely for pregnant women, have been examined confirming this. All these elements are seen to be present in the human body and at not insignificant magnitudes. Currently suggested minimum risk levels (MRL) for humans are discussed and listed together with averages of the reported distributions, together with their spread and maximum values. One observation is that many distributions for pregnant women are not too dissimilar from those of general populations. Women obviously have their individual baseline of neurotoxin values before pregnancy and any efforts to modify this to any significant degree is not yet clearly apparent. For any element, distribution shapes are reasonably similar showing broad distributions with extended tails with numerous outlier values. There are a certain fraction of people that lie well above the MRL values and may be at risk, especially if genetically susceptible. Additionally, synergistic effects between neurotoxins and with other trace metals are now also being reported. It appears prudent for women of child-bearing age to establish their baseline values well before pregnancy. Those at risk then can be better identified. Adequate instrumental testing now is commercially available for this. In addition, directives are necessary for vaccination programs to use only non-neurotoxic adjuvants, especially for young children and all women of child-bearing ages. Additionally, clearer directives concerning fish consumption must now be reappraised.

Risk assessment of environmental exposure to heavy metals in mothers and their respective infants

Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α₁-microglobulin (α₁-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α₁-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (p_trend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.