Cadmium delays puberty onset and testis growth in adolescents

Protective potential of naringenin and its nanoformulations in redox mechanisms of injury and disease

Increasing evidence suggests that elevated intracellular levels of reactive oxygen species (ROS) play a significant role in the pathogenesis of many diseases. Increased intracellular levels of ROS can lead to the oxidation of lipids, DNA, and proteins, contributing to cellular damage. Hence, the maintenance of redox hemostasis is essential. Naringenin (NAR) is a flavonoid included in the flavanones subcategory. Various pharmacological actions have been ascribable to this phytochemical composition, including antioxidant, anti-inflammatory, antibacterial, antiviral, antitumor, antiadipogenic, neuro-, and cardio-protective activities. This review focused on the underlying mechanism responsible for the antioxidative stress properties of NAR and its' nanoformulations. Several lines of in vitro and in vivo investigations suggest the effects of NAR and its nanoformulation on their target cells via modulating signaling pathways. These nanoformulations include nanoemulsion, nanocarriers, solid lipid nanoparticles (SLN), and nanomicelle. This review also highlights several beneficial health effects of NAR nanoformulations on human diseases including brain disorders, cancer, rheumatoid arthritis, and small intestine injuries. Employing nanoformulation can improve the pharmacokinetic properties of NAR and consequently efficiency by reducing its limitations, such as low bioavailability. The protective effects of NAR and its' nanoformulations against oxidative stress may be linked to the modulation of Nrf2-heme oxygenase-1, NO/cGMP/potassium channel, COX-2, NF-κB, AMPK/SIRT3, PI3K/Akt/mTOR, BDNF, NOX, and LOX-1 pathways. Understanding the mechanism behind the protective effects of NAR can facilitate drug development for the treatment of oxidative stress-related disorders.

Cadmium exposure during puberty damages testicular development and spermatogenesis via ferroptosis caused by intracellular iron overload and oxidative stress in mice

Cadmium (Cd) is a widespread environmental pollutant and a reproductive toxicant. It has been proved that Cd can reduce male fertility, however, the molecular mechanisms remain unveiled. This study aims to explore the effects and mechanisms of pubertal Cd exposure on testicular development and spermatogenesis. The results showed that Cd exposure during puberty could cause pathological damage to testes and reduce sperm counts in mice in adulthood. Moreover, Cd exposure during puberty reduced GSH content, induced iron overload and ROS production in testes, suggesting that Cd exposure during puberty may induce testicular ferroptosis. The results in vitro experiments further strengthened that Cd caused iron overload and oxidative stress, and decreased MMP in GC-1 spg cells. In addition, Cd disturbed intracellular iron homeostasis and peroxidation signal pathway based on transcriptomics analysis. Interestingly, these changes induced by Cd could be partially suppressed by pretreated with ferroptotic inhibitors, Ferrostatin-1 and Deferoxamine mesylate. In conclusion, the study demonstrated that Cd exposure during puberty maybe disrupted intracellular iron metabolism and peroxidation signal pathway, triggered ferroptosis in spermatogonia, and ultimately damaged testicular development and spermatogenesis in mice in adulthood.

Antioxidant Activity in Extracts from Zingiberaceae Family: Cardamom, Turmeric, and Ginger

An increase in life expectancy leads to a greater impact of chronic non-communicable diseases. This is even more remarkable in elder populations, to whom these become main determinants of health status, affecting mental and physical health, quality of life, and autonomy. Disease appearance is closely related to the levels of cellular oxidation, pointing out the importance of including foods in one's diet that can prevent oxidative stress. Previous studies and clinical data suggest that some plant-based products can slow and reduce the cellular degradation associated with aging and age-related diseases. Many plants from one family present several applications that range from the food to the pharmaceutical industry due to their characteristic flavor and scents. The Zingiberaceae family, which includes cardamom, turmeric, and ginger, has bioactive compounds with antioxidant activities. They also have anti-inflammatory, antimicrobial, anticancer, and antiemetic activities and properties that help prevent cardiovascular and neurodegenerative diseases. These products are abundant sources of chemical substances, such as alkaloids, carbohydrates, proteins, phenolic acids, flavonoids, and diarylheptanoids. The main bioactive compounds found in this family (cardamom, turmeric, and ginger) are 1,8-cineole, α-terpinyl acetate, β-turmerone, and α-zingiberene. The present review gathers evidence surrounding the effects of dietary intake of extracts of the Zingiberaceae family and their underlying mechanisms of action. These extracts could be an adjuvant treatment for oxidative-stress-related pathologies. However, the bioavailability of these compounds needs to be optimized, and further research is needed to determine appropriate concentrations and their antioxidant effects in the body.

Cadmium induced mouse spermatogonia apoptosis via mitochondrial calcium overload mediated by IP3R-MCU signal pathway

Cadmium (Cd) is a toxic metal and also a well-known reproductive toxicant. Cd could induce germ cells apoptosis in mouse testes, however, the mechanism remains unclear. This study designed in vitro using GC-1 spermatogonial (spg) cells to explore the cytotoxicity and the molecular mechanisms induced by cadmium chloride(CdCl₂). As expected, CdCl₂ elevated the levels of reactive oxygen species (ROS) and induced the release of AIF and Cyt-c from the mitochondria to the cytosol in spermatogonia. Correspondingly, CdCl₂ apparently increased the apoptotic rate in spermatogonia. Further researches found that CdCl₂ could activate IP₃R-MCU pathway, trigger Ca²⁺ transfer from endoplasmic reticulum to mitochondria, and cause mitochondrial Ca²⁺ overload. BAPTA acetoxymethyl ester (BAPTA-AM), a calcium chelator, almost completely attenuated IP₃R phosphorylation, inhibited the mRNA and protein expression levels of VDAC1, MCU and MCUR1 upregulated by CdCl₂, reduced the calcium ion content in the mitochondria. Moreover, BAPTA-AM could decrease the level of ROS, antagonize CdCl₂-induced release of AIF and Cyt-c from the mitochondria to the cytosol and alleviate CdCl₂-induced apoptosis in spermatogonia. As above, these results provided the evidence that CdCl₂ might induce apoptosis of spermatogonia via mitochondrial Ca²⁺ overload mediated by IP₃R-MCU signal pathway.

Cadmium exposure is associated with testosterone levels in men: A cross-sectional study from the China National Human Biomonitoring

BACKGROUND

Sex hormone disorders can cause adverse health consequences. While experimental data suggests that cadmium (Cd) disrupts the endocrine system, little is known about the link between Cd exposure and sex hormones in men.

METHODS

We measured blood cadmium (B-Cd), urine cadmium (U-Cd), serum testosterone and serum estradiol in men aged ≥18 years old participating in the China National Human Biomonitoring program, from 2017 to 2018. Urine cadmium adjusted for creatinine (Ucr-Cd) and the serum testosterone to serum estradiol ratio (T/E₂) were calculated. The association of Cd exposure to serum testosterone and T/E₂ in men was analyzed with multiple linear regression models.

RESULTS

Among Chinese men ≥18 years old, the weighted geometric mean (95% CI) of B-Cd and Ucr-Cd levels were 1.23 (1.12-1.35) μg/L and 0.53 (0.47-0.59) μg/g, respectively. The geometric means (95% CI) of serum testosterone and T/E₂ were 18.56 (17.92-19.22) nmol/L and 143.86 (137.24-150.80). After adjusting for all covariates, each doubling of B-Cd level was associated with a 5.04% increase in serum testosterone levels (β = 0.071; 95%CI: 0.057-0.086) and a 4.03% increase in T/E₂ (β = 0.057; 95%CI: 0.040-0.075); similar findings were found in Ucr-Cd.

CONCLUSIONS

In Chinese men, Cd may be an endocrine disruptor, which is positively associated with serum testosterone and T/E₂.

Risk factors on testicular function in adolescents

PURPOSE

Adolescence represents an important window for gonadal development. The aim of this review is to carry out a critical excursus of the most recent literature on endogenous and exogenous risk factors related to testicular function, focusing the research on adolescence period.

METHODS

A comprehensive literature search within PubMed was performed to provide a summary of currently available evidence regarding the impact on adolescence of varicocele, cryptorchidism, cancer, diabetes, lifestyle factors, endocrine disruptors, obesity and sexually transmitted diseases. We focused on human studies that evaluated a possible impact of these factors on puberty timing and their effects on andrological health.

RESULTS

Evidence collected seems to suggest that andrological health in adolescence may be impaired by several factors, as varicocele, cryptorchidism, and childhood cancer. Despite an early diagnosis and treatment, many adolescents might still have symptoms and sign of a testicular dysfunction in their adult life and at the current time it is not possible to predict which of them will experience andrological problems. Lifestyle factors might have a role in these discrepancies. Most studies point out towards a correlation between obesity, insulin resistance, alcohol, smoking, use of illegal drugs and testicular function in pubertal boys. Also, endocrine disruptors and sexually transmitted diseases might contribute to impair reproductive health, but more studies in adolescents are needed.

CONCLUSION

According to currently available evidence, there is an emerging global adverse trend of high-risk and unhealthy behaviors in male adolescents. A significant proportion of young men with unsuspected and undiagnosed andrological disorders engage in behaviors that could impair testicular development and function, with an increased risk for later male infertility and/or hypogonadism during the adult life. Therefore, adolescence should be considered a key time for intervention and prevention of later andrological diseases.

Protective effect of C-phycocyanin and apo-phycocyanin subunit on programmed necrosis of GC-1 spg cells induced by H2 O2

C-phycocyanin (C-PC) is an effective antioxidant and has an important value in medical research. Oxidative stress is considered to be one of the main underlying mechanisms of cell death, and reducing oxidative stress is one of the strategies to enhance germ cell viability. Herein, we investigated the protective effect and the mechanism of C-PC and apo-phycocyanin subunit on oxidative stress damage induced by H₂ O₂ in GC-1 spg cells. C-PC genes were cloned into the pGEX-4T-1 vectorand transformed into Escherichia coli BL21 to achieve the efficient expression of C-PC subunit. GC-1 spg cells were treated with 600 μM H₂ O₂ for 24 h to establish the oxidative stress damage model. Cell viability was detected by CCK-8. The degree of oxidative stress was detected by testing Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and glutathione (GSH) and Malondialdehyde (MDA) levels. Reactive oxygen species (ROS) was evaluated utilizingby 2', 7'-dichlorofluorescent-diacetate (DCFH-DA). Mitochondrial membrane potential was determined by JC-1. Cell necrosis rate was detected by Annexin V-FITC/PI. Expression of protein was detected by western blot. We found that C-PC and GST-CPC β significantly inhibited H₂ O₂ -induced oxidative damage of GC-1 spg cells, improved the ability of antioxidation, reduced ROS overproduction, and mitochondrial membrane potential loss, and inhibited the RIP-1/RIP-3/ p-MLKL signaling pathway to reduce the necrosis rate. The results demonstrated that C-PC played a protective role against H₂ O₂ -induced cell damage, especially its β subunit. This study provides a theoretical basis for C-PC as a potential protective agent of reproductive system.

A Flavonoid-Rich Extract from Bergamot Juice, Alone or in Association with Curcumin and Resveratrol, Shows Protective Effects in a Murine Model of Cadmium-Induced Testicular Injury

It is known that cadmium damages testis structure and functionality. We examined the effects of nutraceuticals such as a flavonoid-rich extract of bergamot juice (BJe), alone or in association with curcumin (Cur) and resveratrol (Re), on mice testicular dysfunction caused by cadmium chloride (CdCl₂). Controversial data on the protective effects of Cur and Re are available, while no evidence on the possible role of BJe exists. Adult male C57 BL/6J mice were administered with CdCl₂ and treated with Cur, Re, or BJe alone or in combination for 14 days. Then, testes were removed and processed for molecular, structural, and immunohistochemical analyses. CdCl₂ increased the mRNA of IL-1β, TNF-α, p53, and BAX while reduced that of Bcl-2 and induced tubular lesions and apoptosis of germinal cells. Cur, Re, and BJe at 40 mg/kg significantly improved all of these parameters and events, although BJe at 20 mg/kg showed a lower protective effect. The association of Cur, Re, and BJe at both doses of 50/20/20 and 100/20/40 mg/kg brought each parameter close to those of the control. Our results indicate that the nutraceuticals employed in this study and their associations exert a positive action against Cd-induced testicular injury, suggesting a possible protection of testis functionality in subjects exposed to environmental toxicants.

Delay in puberty indices of Wistar rats caused by Cadmium. Focus on the redox system in reproductive organs

Puberty is a transitional period from juvenile stage to adulthood, followed by the functional maturation of gonads and reproductive organs. This period is sensitive to environmental pollutants like cadmium (Cd), a heavy metal that represents a serious health risk. Cd is an endocrine disruptor that interferes with reproduction by causing oxidative stress in the reproductive organs, affecting the sexual function and decreasing testosterone (T) levels. However, little research has been done on the effects of Cd on puberty markers and antioxidant systems. In this study, we evaluated the effects of Cd on puberty markers: preputial separation, testes descent and T levels, and the antioxidant activity (SOD, CAT, GSH/GSSG and TAC) in the seminal vesicles, testis and epididymis. Male Wistar pups were treated with 1 mg/kg Cd or saline solution by i.p. injection from day 1 to 35; the other treatment was administrated for 49 days. At the end of treatment, the animals were sacrificed, and the tissues of interest dissected, weighed and prepared for the respective assays. Cd treated rats from birth to puberty showed a delay onset in the puberty markers and a low weight in reproductive organs. Also, Cd induced differential effects on the redox system in reproductive organs and decreased T levels, these effects played a pivotal role in the delay of puberty markers onset (testes descent and preputial separation), affecting the development and sexual maturity of the male rats.

Linking molecular targets of Cd in the bloodstream to organ-based adverse health effects

The chronic exposure of human populations to toxic metals remains a global public health concern. Although chronic Cd exposure is linked to kidney damage, osteoporosis and cancer, the underlying biomolecular mechanisms remain incompletely understood. Since other diseases could also be causally linked to chronic Cd exposure, a systems toxicology-based approach is needed to gain new insight into the underlying exposure-disease relationship. This approach requires one to integrate the cascade of dynamic bioinorganic chemistry events that unfold in the bloodstream after Cd enters with toxicological events that unfold in target organs over time. To this end, we have conducted a systematic literature search to identify all molecular targets of Cd in plasma and in red blood cells (RBCs). Based on this information it is impossible to describe the metabolism of Cd and the toxicological relevance of it binding to molecular targets in/on RBCs is elusive. Perhaps most importantly, the role that peptides, amino acids and inorganic ions, including HCO₃^-, Cl^- and HSeO₃^- play in terms of mediating the translocation of Cd to target organs and its detoxification is poorly understood. Causally linking human exposure to this metal with diseases requires a much better integration of the bioinorganic chemistry of Cd that unfolds in the bloodstream with target organs. This from a public health point of view important goal will require collaborations between scientists from different disciplines to untangle the complex mechanisms which causally link Cd exposure to disease.

Cocoa-laden cadmium threatens human health and cacao economy: A critical view

In the recent decades, Cd burden in cocoa-based products threatened global food safety, human health and the future of chocolateries. Increased Cd bioavailability is an acute problem in cacao-based horticulture. Poverty, poor maintenance, unjustified traditional farming, and paucity of knowledge on Cd-binding propensity in cacao discourage the application of risk-mitigation measures. Progressive accumulation of Cd, with a half-life of 10-30 years, in the human body even at ultra-trace levels may lead to serious health complications. If Cd accumulates in the food chain through cocoa products, consequences in children, who are the primary consumers of chocolates, include morbidity and mortality that may result in a significant demographic transition by the year 2050. Developing cacao clones with an innate capability of taking up low Cd levels from soils, and site-specific Cd-cacao research might contribute to limiting the trophic transfer of Cd. This review highlights the possible routes for Cd uptake in cacao plants and discusses the measures to rescue the chocolateries from Cd pollution to promote "healthy" cacao farming. The potential human health risks of chocolate-laden Cd and mitigation strategies to minimize Cd burden in the human body are also presented. The challenges and prospects in Cd-cacao research are discussed as well.

Arbuscular Mycorrhizal Fungi as Potential Agents in Ameliorating Heavy Metal Stress in Plants

Heavy metal accumulation in plants is a severe environmental problem, rising at an expeditious rate. Heavy metals such as cadmium, arsenic, mercury and lead are known environmental pollutants that exert noxious effects on the morpho-physiological and biological attributes of a plant. Due to their mobile nature, they have become an extended part of the food chain and affect human health. Arbuscular mycorrhizal fungi ameliorate metal toxicity as they intensify the plant’s ability to tolerate metal stress. Mycorrhizal fungi have vesicles, which are analogous to fungal vacuoles and accumulate massive amount of heavy metals in them. With the help of a pervasive hyphal network, arbuscular mycorrhizal fungi help in the uptake of water and nutrients, thereby abating the use of chemical fertilizers on the plants. They also promote resistance parameters in the plants, secrete a glycoprotein named glomalin that reduces the metal uptake in plants by forming glycoprotein–metal complexes, and improve the quality of the soil. They also assist plants in phytoremediation by increasing the absorptive area, increase the antioxidant response, chelate heavy metals and stimulate genes for protein synthesis that reduce the damage caused by free radicals. The current manuscript focuses on the uptake of heavy metals, accumulation, and arbuscular mycorrhizal impact in ameliorating heavy metal stress in plants.

Biomarkers of exposure and early effect in three contaminated sites of southern Italy: protocols for etiological epidemiological studies

INTRODUCTION

Environmental pollution has been progressively becoming one of the main risk factors to human diseases. In particular, populations living in high-contaminated sites are particularly exposed to environmental toxicants, with consequent increased risks to human health. In Italy, there are currently ongoing three epidemiological etiological studies aimed at evaluating the association between exposure to inorganic and organic chemicals and presence of biological markers of early effects in population living in three National Priority Contaminated Sites (NPCSs). Specifically, the correlations concern preclinical indicators of liver disease in Priolo NPCS, thyroid diseases in Milazzo-Valle del Mela NPCS and cardiovascular risk and kidney damage in Crotone NPCS.

METHODS AND ANALYSIS

Overall, approximately 1300 subjects of both sexes will be enrolled in the three NPCSs according to specific inclusion criteria. For each subject, serum and urine specimens are collected, on which the determination of biological markers of exposure and early effects for the selected outcomes are performed. Individual information on environmental and occupational exposure, medical history, diet and life habits is obtained through questionnaires provided by web platform. In Milazzo-Valle del Mela and Crotone NPCSs, not invasive instrumental and imaging examinations are performed in order to evaluate further risk factors of thyroid carcinoma and cardiovascular disease, respectively.

ETHICS AND DISSEMINATION

The protocol studies have been approved by the Ethics Committees responsible for the three involved NPCSs: the Ethics Committee 'Catania 2' for the NPCS of Priolo (21 July 2017, n. 500/2017/CECT2), the Ethics Committee of the University Hospitals of Messina for the NPCS of Milazzo-Valle del Mela (19 February 2018, n.2/2018); the Ethics Committee of the Region of Calabria for the NPCS of Crotone (20 July 2017, n. 174). Results will be disseminated among policy-makers, citizens, stakeholders and scientific community through the organisation of conferences and events, and the publication on international peer/reviewed journals.

Birth Cohorts in Highly Contaminated Sites: A Tool for Monitoring the Relationships Between Environmental Pollutants and Children's Health

Industrial areas are characterized by the dispersion of environmental stressors that could possibly have long-term detrimental effects on both human health and the environment. Environmental contamination has been indicated to be one of the major risks for reproductive health. In this context, the effects of environmental pollution on pregnant women living in heavily polluted areas is of special interest. In fact, fetal development is a crucial phase due to the dynamic interaction between the maternal/external environments and the developing organs and tissues. Moreover, following Barker's postulate of the intrauterine origin of health and disease, the events occurring in this time window could affect future health. Birth cohorts provide the most suitable design for assessing the association between early-life and possible long-term health outcomes in highly contaminated sites. By providing an assessment of the early life environment throughout the collection of biological samples, birth cohorts offer the opportunity to study in-depth several possible confounders and outcomes by means of questionnaires and follow-ups based on clinical evaluations and bio-specimen samplings. The exposome comprises the totality of exposures from conception onwards; the birth cohort approach allows the integration of the exposures as a whole, including those related to socioeconomic status, with "omics" data from biological samples collected at birth and throughout life. In the characterization of the "fetal exposome," the placenta represents a highly informative and scarcely considered organ. For this purpose, the "Neonatal Environment and Health Outcomes" (NEHO) birth cohort has been established by enrolling pregnant women residing in contaminated sites and in surrounding areas.

Cyanidin-3-O-glucoside restores spermatogenic dysfunction in cadmium-exposed pubertal mice via histone ubiquitination and mitigating oxidative damage

Cadmium (Cd) is an environmental contaminant found in soil, water, and food, and can cause oxidative stress and male reproductive damage. During puberty, the male reproductive system is very vulnerable to interference, however, the dysregulation of Cd on spermatogenesis in this period is ambiguous. The anthocyanin cyanidin-3-O-glucoside (C3G) is phytochemical rich in plants and fruits and has been shown to have remarkable anti-oxidant activity, making it an ideal nutrient for nutritional intervention. By modeling Cd-induced damage in male pubertal mice and feeding with C3G, we demonstrated that the C3G could rescue the amount and activity of sperm predominantly. Furthermore, C3G showed partial resistance to Cd-induced histone modification during spermiogenesis and prevented oxidative damage of the DNA in the sperm nucleus. Additionally, C3G mitigated the oxidative stress of testis to achieve the level coinciding with the control group. Meanwhile, Cd-induced mitochondrial apoptosis of sperm cells was reduced significantly via the MAPK signaling pathway in the presence of C3G. Collectively, our findings can offer a potential intervention for combating Cd-induced reproductive damage during puberty by taking anthocyanin as a dietary supplement.

Urinary cadmium and timing of menarche and pubertal development in girls

BACKGROUND

Cadmium (Cd) is a developmental toxicant that is released into the environment during industrial processes. Previous animal studies suggest that Cd may impact the onset of puberty.

OBJECTIVES

To determine whether Cd exposure, measured as urinary Cd concentration, was associated with ages at menarche and pubertal development.

METHODS

A cohort of 211 girls, ages 10-13 years at baseline, was followed for up to two years. Girls completed an interview and self-assessment of Tanner stages of breast development and pubic hair growth. They were followed monthly until menarche. Urinary Cd concentrations were measured in overnight urine specimens. Multivariable Cox regression was used to evaluate the association between urinary Cd and age at menarche and cumulative logit regression was used to evaluate the associations between urinary Cd and breast development and pubic hair growth.

RESULTS

The baseline geometric mean creatinine-adjusted Cd concentration was 0.22 μg/g creatinine (geometric standard deviation = 1.6) and decreased with increasing age (p-trend = 0.04). Cd levels were higher among Asian than White girls or girls of other/mixed race/ethnicity (p = 0.04). In multivariable analyses, girls with urinary Cd ≥ 0.4 μg/L were less likely to have attained menarche than girls with urinary Cd < 0.2 μg/L (hazard ratio = 0.42; 95% confidence interval, 0.23-0.78). Urinary Cd was negatively associated with pubic hair growth (p-trend = 0.01) but not with breast development (p-trend = 0.72) at baseline.

CONCLUSIONS

These findings suggest that a higher Cd body burden may delay some aspects of pubertal development among girls.

Body burdens of heavy metals associated with epigenetic damage in children living in the vicinity of a municipal waste incinerator

To evaluate the body burdens of heavy metals correlated with health impact on school-age children living around a waste incinerator. A total of 81 children from the exposure area and 95 from the control area were recruited in our study. We measured the blood levels of chromium (Cr), cadmium (Cd) and lead (Pb) by an inductively coupled plasma mass spectrometer (ICP-MS), conducted comet assays, calculated the percentage of 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5hmC) by MethylFlash methylated and a hydroxymethylated DNA quantification kit, and performed the flow cytometry to detect the expressions of surface antigens (including CD3⁺, CD19⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD16⁺ and/or CD56⁺) in peripheral lymphocytes. Besides, we measured hormonal levels, including triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH), and analyzed several regular hematological parameters. In addition, concentrations of heavy metals in environmental samples including rice, soils, vegetables, and drinking water were detected by ICP-MS. The mean blood levels of Cr, Cd, and Pb in the exposure group were all statistically higher than in the control group (2.57 vs. 0.79 μg/L; 1.83 vs. 1.81 μg/L; 44.00 vs. 32.31 μg/L, p < 0.01). The 5 mC and 5hmC levels in the exposure group were statistically lower (1.15% vs. 4.14%; 0.22% vs. 0.30%, p < 0.01), whereas the mean level of % tail DNA was statistically higher (10.10% vs. 8.62%, p < 0.01). Furthermore, the mean blood level of Cr and Pb was negatively correlated with the level of 5 mC (r = -0.279, r = -0.190, P < 0.05) in total population. In conclusion, children living in the vicinity of the municipal waste incinerator suffered increased body burdens of heavy metals (Cr, Cd, and Pb) associated with genotoxicity and epigenetic modifications.

Prenatal Cadmium Exposure Is Negatively Associated With Adiposity in Girls Not Boys During Adolescence

Introduction: Cadmium is a pervasive toxic metal that remains a public health concern and exposure in early life has been associated with growth deficits in infancy and childhood. Growth during adolescence also may be sensitive to effects of cadmium exposure, given the changes in distribution of lean and adipose tissue that vary by sex during puberty. This study examines whether prenatal and concurrent cadmium exposures are associated with adiposity measures at ages 8-15 years in a well-characterized birth cohort. Methods: The sample included 185 participants from the ELEMENT birth cohorts in Mexico City with complete data on urinary cadmium exposures, anthropometry and covariates [child age and sex, household socioeconomic status, and maternal smoking history and body mass index (BMI)]. Maternal third trimester and adolescent urines were analyzed for cadmium using an Inductively Coupled Plasma Mass Spectrometer. Trained personnel obtained anthropometry including height, weight, waist circumference and subscapular, suprailiac, and triceps skinfold thickness. BMI z-scores for age and sex were calculated using the World Health Organization's reference standard. Linear regression models were used to estimate the association of prenatal and concurrent urinary cadmium levels with adolescent anthropometry, adjusting for covariates. Results: Among 87 males and 98 females, median age was 10 years (IQR 9 -11 years). Pregnant women and children had median urinary cadmium concentrations of 0.19 μg/L (IQR 0.12- 0.27 μg/L) and 0.14 μg/L (IQR 0.11- 0.18 μg/L), respectively. Regression models showed inverse relationships between prenatal cadmium exposure and adolescent adiposity. An IQR increase in prenatal cadmium was associated with percent decreases in BMI z-score (-27%, p = 0.01), waist circumference (-3%, p = 0.01), and subscapular (-11%, p = 0.01), suprailiac (-11%, p = 0.02), and triceps (-8%, p < 0.01) skinfold thickness. When stratified by sex, these relationships remained statistically significant in females but not males. Conclusions: Prenatal cadmium exposure was negatively associated with measures of both abdominal and peripheral adiposity in girls, but not in boys. These results emphasize the sex-dependent effects of in utero cadmium exposure on adiposity in adolescence.

Flavocoxid, a Natural Antioxidant, Protects Mouse Kidney from Cadmium-Induced Toxicity

Background

Cadmium (Cd), a diffused environmental pollutant, has adverse effects on urinary apparatus. The role of flavocoxid, a natural flavonoid with antioxidant activity, on the morphological and biochemical changes induced in vivo by Cd in mice kidney was evaluated.

Methods

C57 BL/6J mice received 0.9% NaCl alone, flavocoxid (20 mg/kg/day i.p.) alone, Cd chloride (CdCl₂) (2 mg/kg/day i.p.) alone, or CdCl₂ plus flavocoxid (2 mg/kg/day i.p. plus 20 mg/kg/day i.p.) for 14 days. The kidneys were processed for biochemical, structural, ultrastructural, and morphometric evaluation.

Results

Cd treatment alone significantly increased urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; reduced GSH, GR, and GPx; and induced structural and ultrastructural changes in the glomeruli and in the tubular epithelium. After 14 days of treatment, flavocoxid administration reduced urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; increased GSH, GR, and GPx; and showed an evident preservation of the glomerular and tubular structure and ultrastructure.

Conclusions

A protective role of flavocoxid against Cd-induced oxidative damages in mouse kidney was demonstrated for the first time. Flavocoxid may have a promising antioxidant role against environmental Cd harmful effects on glomerular and tubular lesions.

Cadmium exposure and cognitive abilities and behavior at 10 years of age: A prospective cohort study

BACKGROUND

We have previously reported inverse associations of prenatal and childhood cadmium exposure with cognition in 5-year-old Bangladeshi children.

OBJECTIVES

To assess if cadmium exposure affected cognition and behavior in the Bangladeshi children at 10 years.

METHODS

Cadmium exposure was assessed by urinary concentrations at 10 (n = 1498) and 5 years of age (n = 1453), and of the mothers in early pregnancy (n = 1299), measured by ICP-MS. Cognitive abilities were assessed with Wechsler Intelligence Scale for Children (4th edition) and behavior with the parent-rated Strengths and Difficulties Questionnaire.

RESULTS

In multivariable-adjusted models, urinary cadmium at 10 years was inversely associated with Full scale IQ and most of the sub-scales. Associations were mainly observed in boys, in whom the difference in Full scale IQ was 7.0 scores (95% CI: -11, -2.7), corresponding to 0.21 SD, when comparing those in the highest (range: 0.30-2.6 μg/L) and lowest tertile of urinary cadmium (0.036-0.18 μg/L). Urinary cadmium at 5 years was inversely, but not significantly, associated with IQ. Children in the highest exposure tertile at 10 years also had poorer Prosocial behavior scores. The association appeared strongest in girls, in whom the corresponding OR for Prosocial scores in relation to cadmium exposure at 10 years and prenatally was 0.58 (95% CI: 0.34, 0.99) and 0.48 (95% CI: 0.25, 0.93), respectively.

CONCLUSION

Childhood cadmium exposure was associated with lower intelligence in boys, and there were indications of altered behavior in girls for both prenatal and childhood exposures. Findings are of concern as similar exposure levels are common world-wide.

Cadmium-Induced Oxidative Stress Impairs Glycemic Control in Adolescents

Experimental evidence suggests that cadmium (Cd) boosts oxidative stress that may result in toxicity on the endocrine system also in humans. The aim of this study was to investigate the glycemic control and oxidative stress markers in male adolescents with increased urinary levels of cadmium. We investigated 111 males, aged 12–14 years, living in a polluted area of Sicily and a control age-matched population (n = 60) living 28–45 km far from the polluted site. Malondialdehyde (MDA), total antioxidant activity (TAC), metallothionein-1A (MT-1A) gene expression, insulin resistance by the homeostatic model assessment (HOMA-IR), and urinary cadmium were investigated. Cd levels were significantly higher in adolescents living in the polluted area than in control age-matched subjects. Adolescents with elevated Cd levels had a significant increase in MDA, MT-1A, and HOMA-IR and reduced TAC compared to the control group. A robust correlation was found between urinary cadmium and MT-1A, HOMA-IR, and MDA whereas an inverse correlation was identified between urinary cadmium and TAC. This study indicates that cadmium burden alters glycemic control in adolescents and suggests that oxidative stress plays a key role in cadmium-induced insulin resistance, increasing the risk of developing metabolic disorders.

Oxidative Stress: Harms and Benefits for Human Health

Oxidative stress is a phenomenon caused by an imbalance between production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products. ROS can play, and in fact they do it, several physiological roles (i.e., cell signaling), and they are normally generated as by-products of oxygen metabolism; despite this, environmental stressors (i.e., UV, ionizing radiations, pollutants, and heavy metals) and xenobiotics (i.e., antiblastic drugs) contribute to greatly increase ROS production, therefore causing the imbalance that leads to cell and tissue damage (oxidative stress). Several antioxidants have been exploited in recent years for their actual or supposed beneficial effect against oxidative stress, such as vitamin E, flavonoids, and polyphenols. While we tend to describe oxidative stress just as harmful for human body, it is true as well that it is exploited as a therapeutic approach to treat clinical conditions such as cancer, with a certain degree of clinical success. In this review, we will describe the most recent findings in the oxidative stress field, highlighting both its bad and good sides for human health.

Metals, hormones and sexual maturation in Flemish adolescents in three cross-sectional studies (2002-2015)

Sex hormone levels and timing of sexual maturation are considered important markers for health status of adolescents in puberty, and previous research suggests they might be influenced by metal exposure. In three campaigns of the Flemish Environment and Health Study (FLEHS I 2002-2006; FLEHS II 2007-2011 and FLEHS III 2012-2015), data were collected on internal exposure to metals (Cd, Cu, Pb, Cr, Mn, Tl, Ni, Sb, Hg, As and As species) and sexual maturation in 2671 14-15years old adolescents. All metals were measured in blood and/or urine, except total- and methylmercury which were measured in hair samples. Sex hormone levels were measured in blood serum of adolescent males of the cohorts of FLEHS I and FLESH II. The use of a uniform methodology in successive campaigns allows to confirm associations between exposure and health in different cohorts and over time. Furthermore, mathematical and statistical density correction methods using creatinine or specific gravity were tested for urinary markers. Significant associations between sex hormones and maturity markers were observed in the FLEHS I and II campaigns, when both were assessed together. Regardless of the applied correction method, creatinine correction systematically introduced bias due to associations of creatinine with sex hormones and maturation markers, especially in adolescent males, while this is not the case for specific gravity. A series of exposure-response associations were found, but several involving Cd, Pb, As, Tl and Cu persisted in different FLEHS campaigns. The effects of Pb and Cu on luteinizing hormone, (free) testosterone, (free) oestradiol and maturation support a xenoestrogenic agonistic action on the feedback of oestradiol to the hypothalamus-pituitary-gonadal axis. Our results suggest that specific care should be taken when selecting urine density correction for investigating associations with hormonal and maturation markers in adolescent males. Furthermore, the possibility of xenoestrogenic effects of certain metals in environmentally exposed adolescents warrants further investigation.

Polydeoxyribonucleotide, an Adenosine-A2A Receptor Agonist, Preserves Blood Testis Barrier from Cadmium-Induced Injury

Cadmium (Cd) impairs blood-testis barrier (BTB). Polydeoxyribonucleotide (PDRN), an adenosine A_2A agonist, has positive effects on male reproductive system. We investigated the effects of PDRN on the morphological and functional changes induced by Cd in mice testes. Adult Swiss mice were divided into four groups: controls administered with 0.9% NaCl (1 ml/kg, i.p., daily) or with PDRN (8 mg/kg, i.p. daily), animals challenged with Cd chloride (CdCl₂; 2 mg/kg, i.p, daily) and animals challenged with CdCl₂ (2 mg/kg, i.p., daily) and treated with PDRN (8 mg/kg, i.p., daily). Experiments lasted 14 days. Testes were processed for biochemical, structural, and ultrastructural evaluation and hormones were assayed in serum. CdCl₂ increased pERK 1/2 expression and Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) levels; it decreased testosterone (TE) and inhibin-B levels and induced structural damages in extratubular compartment and in seminiferous epithelium, with ultrastructural features of BTB disruption. Many TUNEL-positive germ cells were present. CdCl₂ increased tubular TGF-β3 immunoreactivity and reduced claudin-11, occludin, and N-cadherin immunoreactivity. PDRN administration reduced pERK 1/2 expression, FSH, and LH levels; it increased TE and inhibin-B levels, ameliorated germinal epithelium changes and protected BTB ultrastructure. Few TUNEL-positive germ cells were present and the extratubular compartment was preserved. Furthermore, PDRN decreased TGF-β3 immunoreactivity and enhanced claudin-11, occludin, and N-cadherin immunoreactivity. We demonstrate a protective effect of PDRN on Cd-induced damages of BTB and suggest that PDRN may play an important role against Cd, particularly against its harmful effects on gametogenesis.

Blood Cadmium Level Associates with Lower Testosterone and Sex Hormone-Binding Globulin in Chinese men: from SPECT-China Study, 2014

Cadmium is a widespread environmental pollutant. We aimed to determine whether blood cadmium level (BCL) associates with reproductive hormones in a cross-sectional study. Our data were from SPECT-China. We selected 5690 participants (2286 men and 3404 women), aged 18 years and older, among whom 1589 were postmenopausal women. BCL, blood lead level, total testosterone (TT), estradiol (E2), sex hormone-binding globulin (SHBG), luteinizing hormone, and follicle-stimulating hormone were measured. Results showed that BCL was significantly higher in men (median 1.90 μg/L) than that in women (median 1.56 μg/L). The median level of cadmium in postmenopausal women was 1.40 μg/L. In men, BCL was negatively correlated with TT (Spearmen coefficient = -0.057, P < 0.01) and SHBG (Spearmen coefficient = -0.098, P < 0.01), but in postmenopausal women, this correlation was not observed. In linear regression, after full adjustment for blood lead level, age, body mass index, residence area, economic status, and smoking, TT and SHBG were still negatively associated with BCL in men. Additionally, the association between BCL and TT levels was modified by BMI group (P for interaction = 0.041). However, from base model to fully adjusted model, BCL was not associated with TT and E2 in postmenopausal women. In conclusion, men had higher BCL than women in China, and BCL was associated with TT and SHBG in Chinese men, which may have important implications for male reproductive health. Concerted efforts are warranted to reduce adult cadmium exposure.

Confusion about Cadmium Risks: The Unrecognized Limitations of an Extrapolated Paradigm

BACKGROUND

Cadmium (Cd) risk assessment presently relies on tubular proteinuria as a critical effect and urinary Cd (U-Cd) as an index of the Cd body burden. Based on this paradigm, regulatory bodies have reached contradictory conclusions regarding the safety of Cd in food. Adding to the confusion, epidemiological studies implicate environmental Cd as a risk factor for bone, cardiovascular, and other degenerative diseases at exposure levels that are much lower than points of departure used for setting food standards.

OBJECTIVE

The objective was to examine whether the present confusion over Cd risks is not related to conceptual or methodological problems.

DISCUSSION

The cornerstone of Cd risk assessment is the assumption that U-Cd reflects the lifetime accumulation of the metal in the body. The validity of this assumption as applied to the general population has been questioned by recent studies revealing that low-level U-Cd varies widely within and between individuals depending on urinary flow, urine collection protocol, and recent exposure. There is also evidence that low-level U-Cd increases with proteinuria and essential element deficiencies, two potential confounders that might explain the multiple associations of U-Cd with common degenerative diseases. In essence, the present Cd confusion might arise from the fact that this heavy metal follows the same transport pathways as plasma proteins for its urinary excretion and the same transport pathways as essential elements for its intestinal absorption.

CONCLUSIONS

The Cd risk assessment paradigm needs to be rethought taking into consideration that low-level U-Cd is strongly influenced by renal physiology, recent exposure, and factors linked to studied outcomes.

CITATION

Bernard A. 2016. Confusion about cadmium risks: the unrecognized limitations of an extrapolated paradigm. Environ Health Perspect 124:1-5; http://dx.doi.org/10.1289/ehp.1509691.