Prenatal exposure to per- and polyfluoroalkyl substances, fetal thyroid function, and intelligence quotient at 7 years of age: Findings from the Sheyang Mini Birth Cohort Study.

BACKGROUND: Prenatal exposure to per- and polyfluoroalkyl substances (PFASs) influences neurodevelopment. Thyroid homeostasis disruption is thought to be a possible underlying mechanism. However, current epidemiological evidence remains inconclusive. OBJECTIVES: This study aimed to explore the effects of prenatal PFAS exposure on the intelligence quotient (IQ) of school-aged children and assess the potential mediating role of fetal thyroid function. METHODS: The study included 327 7-year-old children from the Sheyang Mini Birth Cohort Study (SMBCS). Cord serum samples were analyzed for 12 PFAS concentrations and 5 thyroid hormone (TH) levels. IQ was assessed using the Wechsler Intelligence Scale for Children-Chinese Revised (WISC-CR). Generalized linear models (GLM) and Bayesian Kernel Machine Regression (BKMR) were used to evaluate the individual and combined effects of prenatal PFAS exposure on IQ. Additionally, the impact on fetal thyroid function was examined using a GLM, and a mediation analysis was conducted to explore the potential mediating roles of this function. RESULTS: The molar sum concentration of perfluorinated carboxylic acids (ΣPFCA) in cord serum was significantly negatively associated with the performance IQ (PIQ) of 7-year-old children (ß = -6.21, 95 % confidence interval [CI]: -12.21, -0.21), with more pronounced associations observed among girls (ß = -9.57, 95 % CI: -18.33, -0.81) than in boys. Negative, albeit non-significant, cumulative effects were noted when considering PFAS mixture exposure. Prenatal exposure to perfluorooctanoic acid, perfluorononanoic acid, and perfluorooctanesulfonic acid was positively associated with the total thyroxine/triiodothyronine ratio. However, no evidence supported the mediating role of thyroid function in the link between PFAS exposure and IQ. CONCLUSIONS: Increased prenatal exposure to PFASs negatively affected the IQ of school-aged children, whereas fetal thyroid function did not serve as a mediator in this relationship.

Do PFCAs drive the establishment of thyroid cancer microenvironment? Effects of C6O4, PFOA and PFHxA exposure in two models of human thyroid cells in primary culture.

BACKGROUND: Exposure to environmental pollutants is suspected to be one of the potential causes accounting for the increase in thyroid cancer (TC) incidence worldwide. Among the ubiquitous pollutants, per-polyfluoroalkyl substances (PFASs), were demonstrated to exert thyroid disrupting effects. Perfluoroalkyl carboxylates (PFCAs) represent a subgroup of PFAS and include perfluoro carboxylic acids (PFOA and PFHxA) and perfluoropolyether carboxylic acid (C6O4). The potential relationship between exposure to PFCAs and TC was not yet fully elucidated. This in vitro study investigated whether certain PFCAs (C6O4, PFOA, and PFHxA) can influence the composition of TC microenvironment. METHODS: Two models of normal thyroid cells in primary cultures: Adherent (A-NHT) and Spheroids (S-NHT) were employed. A-NHT and S-NHT were exposed to C6O4, PFOA or PFHxA (0; 0.01; 0.1, 1; 10; 100; 1000 ng/mL) to assess viability (WST-1 and AV/PI assay), evaluate spherification index (SI) and volume specifically in S-NHT. CXCL8 and CCL2 (mRNA and protein), and EMT-related genes were assessed in both models after exposure to PFCAs. RESULTS: PFHxA reduced the viability of both A-NHT and S-NHT. None of the PFCAs interfered with the volume or spherification process in S-NHT. CXCL8 and CCL2 mRNA and protein levels were differently up-regulated by each PFCAs, being PFOA and PFHxA the stronger inducers. Moreover, among the tested PFCAs, PFHxA induced a more consistent increase in the mRNA levels of EMT-related genes. CONCLUSIONS: This is the first evaluation of the effects of exposure to PFCAs on factors potentially involved in establishing the TC microenvironment. PFHxA modulated the TC microenvironment at three levels: cell viability, pro-tumorigenic chemokines, and EMT-genes. The results provide further evidence of the pro-tumorigenic effect of PFOA. On the other hand, a marginal effect was observed for C6O4 on pro-tumorigenic chemokines.

Extracellular Vesicles in Environmental Toxicological Studies: Association between Urinary Concentrations of Phthalate Metabolites and Exosomal miRNA Expression Profiles.

Phthalates are chemical compounds, mainly used as additives in plastics, which are known to induce harmful impacts to the environment and human health due to their ability to act as hormone-mimics. Few studies have been reported on the relationship between human exposure to phthalates and the level of circulating microRNAs (miRs), especially those miRs encapsulated in extracellular vesicles/exosomes or exosome-like vesicles (ELVs). We examined the relationship of ELV-miR expression patterns and urine of adult men with five phthalate metabolites (i.e., mono isobutyl phthalate, mono-n-butyl phthalate, mono benzyl phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-(2-ethylhexyl) phthalate) to identify potential biomarkers and relevant pathways. We found significant positive associations which were further confirmed by multivariable analysis. Overall, our analyses showed that the Σ phthalate metabolite concentration was associated with a significant increase in the expression level of two miRs found in ELV: miR-202 and miR-543. Different pathways including cancer and immune-related responses were predicted to be involved in this relationship. Analyzing the specific downstream target genes of miR-202 and miR-543, we identified the phosphatase and tensin homolog (PTEN) as the key gene in several converging pathways. In summary, the obtained results demonstrate that exposure to environmental phthalates could be related to altered expression profiles of specific ELV-miRs in adult men, thereby demonstrating the potential of miRs carried by exosomes to act as early effect biomarkers.

m6A-methylated Lonp1 drives mitochondrial proteostasis stress to induce testicular pyroptosis upon environmental cadmium exposure.

Cadmium (Cd) is a widely distributed typical environmental pollutant and one of the most toxic heavy metals. It is well-known that environmental Cd causes testicular damage by inducing classic types of cell death such as cell apoptosis and necrosis. However, as a new type of cell death, the role and mechanism of pyroptosis in Cd-induced testicular injury remain unclear. In the current study, we used environmental Cd to generate a murine model with testicular injury and AIM2-dependent pyroptosis. Based on the model, we found that increased cytoplasmic mitochondrial DNA (mtDNA), activated mitochondrial proteostasis stress occurred in Cd-exposed testes. We used ethidium bromide to generate mtDNA-deficient testicular germ cells and further confirmed that increased cytoplasmic mtDNA promoted AIM2-dependent pyroptosis in Cd-exposed cells. Uracil-DNA glycosylase UNG1 overexpression indicated that environmental Cd blocked UNG-dependent repairment of damaged mtDNA to drive the process in which mtDNA releases to cytoplasm in the cells. Interestingly, we found that environmental Cd activated mitochondrial proteostasis stress by up-regulating protein expression of LONP1 in testes. Testicular specific LONP1-knockdown significantly reversed Cd-induced UNG1 protein degradation and AIM2-dependent pyroptosis in mouse testes. In addition, environmental Cd significantly enhanced the m6A modification of Lonp1 mRNA and its stability in testicular germ cells. Knockdown of IGF2BP1, a reader of m6A modification, reversed Cd-induced upregulation of LONP1 protein expression and pyroptosis activation in testicular germ cells. Collectively, environmental Cd induces m6A modification of Lonp1 mRNA to activate mitochondrial proteostasis stress, increase cytoplasmic mtDNA content, and trigger AIM2-dependent pyroptosis in mouse testes. These findings suggest that mitochondrial proteostasis stress is a potential target for the prevention of testicular injury.

Integrative investigation of hematotoxic effects induced by low doses of lead, cadmium, mercury and arsenic mixture: In vivo and in silico approach.

The effect of the lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) mixture (MIX) on hematotoxicity development was investigated trough combined approach. In vivo subacute study (28 days) was performed on rats (5 per group): a control group and five groups orally exposed to increasing metal(loid) mixture doses, MIX 1- MIX 5 (mg/kg bw./day) (Pb: 0.003, 0.01, 0.1, 0.3, 1; Cd: 0.01, 0.03, 0.3, 0.9, 3; Hg: 0.0002, 0.0006, 0.006, 0.018, 0.06; As: 0.002, 0.006, 0.06, 0.18, 0.6). Blood was taken for analysis of hematological parameters and serum iron (Fe) analysis. MIX treatment increased thrombocyte/platelet count and MCHC and decreased Hb, HCT, MCV and MCH values compared to control, indicating the development of anemia and thrombocytosis. BMDIs with the narrowest width were identified for MCH [pg] (6.030E-03 - 1.287E-01 mg Pb/kg bw./day; 2.010E-02 - 4.290E-01 mg Cd/kg bw./day; 4.020E-04 - 8.580E-03 mg Hg/kg bw./day; 4.020E-03 - 8.580E-02 mg As/kg bw./day). In silico analysis showed target genes connected with MIX and the development of: anemia - ACHE, GSR, PARP1, TNF; thrombocytosis - JAK2, CALR, MPL, THPO; hematological diseases - FAS and ALAD. The main extracted pathways for anemia were related to apoptosis and oxidative stress; for thrombocytosis were signaling pathways of Jak-STAT and TPO. Changes in miRNAs and transcription factors enabled the mode of action (MoA) development based on the obtained results, contributing to mechanistic understanding and hematological risk related to MIX exposure.

Chloroperfluoropolyether carboxylate compounds: A review.

Several new per- and polyfluoroalkyl substances (PFASs) have been synthesized to replace traditional (legacy) PFASs frequently without clear information on their structure, use and potential toxicity. Among them, chloroperfluoropolyether carboxylates (ClPFPECAs) are an emerging group used as processing aids in the production of fluoropolymers to replace the ammonium salt of perfluorononanoic acid (PFNA). The Solvay Company has produced ClPFPECAs as a mixture of six congeners (oligomers) since the mid-1990s, but other possible manufacturers and annual quantities synthesized and used worldwide are unknown. Initial studies to monitor their presence were conducted because of public authority concerns about suspect environmental contamination near fluoropolymer plants. As of 2015, these chemicals have been found in soil, water, vegetative tissues and wildlife, as well as in biological fluids of exposed workers and people, in research carried out mainly in the United States (New Jersey) and Italy. Analysis of wildlife collected even in non-industrialized areas demonstrated widespread occurrence of ClPFPECAs. From the analytical point of view, the (presumptive) evidence of their presence was obtained through the application of non-targeted approaches performed by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). Available toxicological data show that ClPFPECAs have similar adverse effects than the compounds which they have replaced, whereas their carcinogenic potential and reproductive damage are currently unknown. All these observations once again cast doubt on whether many alternatives to traditional PFAS are actually safer for the environment and health.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review.

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

NBR1-dependent autophagy activation protects against environmental cadmium-evoked placental trophoblast senescence.

Cadmium (Cd), a well-established developmental toxicant, accumulates in the placentae and disrupts its structure and function. Population study found adverse pregnancy outcomes caused by environmental Cd exposure associated with cell senescence. However, the role of autophagy activation in Cd-induced placental cell senescence and its reciprocal mechanisms are unknown. In this study, we employed animal experiments, cell culture, and case-control study to investigate the above mentioned. We have demonstrated that exposure to Cd during gestation induces placental senescence and activates autophagy. Pharmacological and genetic interventions further exacerbated placental senescence induced by Cd through the suppression of autophagy. Conversely, activation of autophagy ameliorated Cd-induced placental senescence. Knockdown of NBR1 exacerbated senescence in human placental trophoblast cells. Further investigations revealed that NBR1 facilitated the degradation of p21 via LC3B. Our case-control study has demonstrated a positive correlation between placental senescence and autophagy activation in all-cause fetal growth restriction (FGR). These findings offer a novel perspective for mitigating placental aging and placental-origin developmental diseases induced by environmental toxicants.

Intestinal carcinogenicity screening of environmental pollutants using organoid-based cell transformation assay.

The high incidence of colorectal cancer (CRC) is closely associated with environmental pollutant exposure. To identify potential intestinal carcinogens, we developed a cell transformation assay (CTA) using mouse adult stem cell-derived intestinal organoids (mASC-IOs) and assessed the transformation potential on 14 representative chemicals, including Cd, iPb, Cr-VI, iAs-III, Zn, Cu, PFOS, BPA, MEHP, AOM, DMH, MNNG, aspirin, and metformin. We optimized the experimental protocol based on cytotoxicity, amplification, and colony formation of chemical-treated mASC-IOs. In addition, we assessed the accuracy of in vitro study and the human tumor relevance through characterizing interdependence between cell-cell and cell-matrix adhesions, tumorigenicity, pathological feature of subcutaneous tumors, and CRC-related molecular signatures. Remarkably, the results of cell transformation in 14 chemicals showed a strong concordance with epidemiological findings (8/10) and in vivo mouse studies (12/14). In addition, we found that the increase in anchorage-independent growth was positively correlated with the tumorigenicity of tested chemicals. Through analyzing the dose-response relationship of anchorage-independent growth by benchmark dose (BMD) modeling, the potent intestinal carcinogens were identified, with their carcinogenic potency ranked from high to low as AOM, Cd, MEHP, Cr-VI, iAs-III, and DMH. Importantly, the activity of chemical-transformed mASC-IOs was associated with the degree of cellular differentiation of subcutaneous tumors, altered transcription of oncogenic genes, and activated pathways related to CRC development, including Apc, Trp53, Kras, Pik3ca, Smad4 genes, as well as WNT and BMP signaling pathways. Taken together, we successfully developed a mASC-IO-based CTA, which might serve as a potential alternative for intestinal carcinogenicity screening of chemicals.

Effects and mechanisms of N6-methyladenosine RNA methylation in environmental pollutant-induced carcinogenesis.

Environmental pollution, including air pollution, plastic contamination, and heavy metal exposure, is a pressing global issue. This crisis contributes significantly to pollution-related diseases and is a critical risk factor for chronic health conditions, including cancer. Mounting evidence underscores the pivotal role of N6-methyladenosine (m6A) as a crucial regulatory mechanism in pathological processes and cancer progression. Governed by m6A writers, erasers, and readers, m6A orchestrates alterations in target gene expression, consequently playing a vital role in a spectrum of RNA processes, covering mRNA processing, translation, degradation, splicing, nuclear export, and folding. Thus, there is a growing need to pinpoint specific m6A-regulated targets in environmental pollutant-induced carcinogenesis, an emerging area of research in cancer prevention. This review consolidates the understanding of m6A modification in environmental pollutant-induced tumorigenesis, explicitly examining its implications in lung, skin, and bladder cancer. We also investigate the biological mechanisms that underlie carcinogenesis originating from pollution. Specific m6A methylation pathways, such as the HIF1A/METTL3/IGF2BP3/BIRC5 network, METTL3/YTHDF1-mediated m6A modification of IL 24, METTL3/YTHDF2 dynamically catalyzed m6A modification of AKT1, METTL3-mediated m6A-modified oxidative stress, METTL16-mediated m6A modification, site-specific ATG13 methylation-mediated autophagy, and the role of m6A in up-regulating ribosome biogenesis, all come into play in this intricate process. Furthermore, we discuss the direction regarding the interplay between pollutants and RNA metabolism, particularly in immune response, providing new information on RNA modifications for future exploration.

F-53B mediated ROS affects uterine development in rats during puberty by inducing apoptosis.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs), as pollutants, can cause palpable environmental and health impacts around the world, as endocrine disruptors, can disrupt endocrine homeostasis and increase the risk of diseases. Chlorinated polyfluoroalkyl ether sulfonate (F-53B), as a substitute for PFAS, was determined to have potential toxicity. Puberty is the stage when sexual organs develop and hormones change dramatically, and abnormal uterine development can increase the risk of uterine lesions and lead to infertility. This study was designed to explore the impact of F-53B on uterine development during puberty. Four-week-old female SD rats were exposed to 0.125 and 6.25 mg/L F-53B during puberty. The results showed that F-53B interfered with growth and sex hormone levels and bound to oestrogen-related receptors, which affected their function, contributed to the accumulation of reactive oxygen species, promoted cell apoptosis and inhibited cell proliferation, ultimately causing uterine dysplasia.

Relationships between blood chromium exposure and liver injury: Exploring the mediating role of systemic inflammation in a chromate-exposed population.

Hexavalent chromium and its compounds are prevalent pollutants, especially in the work environment, pose a significant risk for multisystem toxicity and cancers. While it is known that chromium accumulation in the liver can cause damage, the dose-response relationship between blood chromium (Cr) and liver injury, as well as the possible potential toxic mechanisms involved, remains poorly understood. To address this, we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury, including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and direct bilirubin (DBIL), and to evaluate the mediating effects of systemic inflammation. Platelet (PLT) and the platelet-to-lymphocyte ratio (PLR) were utilized as biomarkers of systemic inflammation. In the linear mixed-effects analyses, each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82% (0.11%, 1.53%) in TBIL, 1.67% (0.06%, 3.28%) in DBIL, 0.73% (0.04%, 1.43%) in ALT and 2.08% (0.29%, 3.87%) in AST, respectively. Furthermore, PLT mediated 10.04%, 11.35%, and 10.77% increases in TBIL, DBIL, and ALT levels induced by chromate, respectively. In addition, PLR mediated 8.26% and 15.58% of the association between blood Cr and TBIL or ALT. These findings shed light on the mechanisms underlying blood Cr-induced liver injury, which is partly due to worsening systemic inflammation.

Environmental Pollution and Risk of Childhood Cancer: A Scoping Review of Evidence from the Last Decade.

The long-term effects of environmental pollution have been of concern as several pollutants are carcinogenic, potentially inducing a variety of cancers, including childhood cancer, which is a leading cause of death around the world and, thus, is a public health issue. The present scoping review aimed to update and summarize the available literature to detect specific environmental pollutants and their association with certain types of childhood cancer. Studies published from 2013 to 2023 regarding environmental pollution and childhood cancer were retrieved from the PubMed database. A total of 174 studies were eligible for this review and were analyzed. Our search strategy brought up most of the articles that evaluated air pollution (29%) and pesticides (28%). Indoor exposure to chemicals (11%), alcohol and tobacco use during pregnancy (16%), electromagnetic fields (12%), and radon (4%) were the subjects of less research. We found a particularly high percentage of positive associations between prenatal and postnatal exposure to indoor (84%) and outdoor (79%) air pollution, as well as to pesticides (82%), and childhood cancer. Positive associations were found between leukemia and pesticides and air pollution (33% and 27%); CNS tumors and neuroblastoma and pesticides (53% and 43%); and Wilms tumor and other rare cancers were found in association with air pollution (50%). Indoor air pollution was mostly reported in studies assessing several types of cancer (26%). Further studies are needed to investigate the mechanisms underlying the potential associations between indoor/outdoor air pollution and pesticide exposure with childhood cancer risk as more preventable measures could be taken.

Pollutants to pathogens: The role of heavy metals in modulating TGF-ß signaling and lung cancer risk.

Lung cancer is a malignant tumor that develops in the lungs due to the uncontrolled growth of aberrant cells. Heavy metals, such as arsenic, cadmium, mercury, and lead, are metallic elements characterized by their high atomic weights and densities. Anthropogenic activities, such as industrial operations and pollution, have the potential to discharge heavy metals into the environment, hence presenting hazards to ecosystems and human well-being. The TGF-ß signalling pathways have a crucial function in controlling several cellular processes, with the ability to both prevent and promote tumor growth. TGF-ß regulates cellular responses by interacting in both canonical and non-canonical signalling pathways. Research employing both in vitro and in vivo models has shown that heavy metals may trigger TGF-ß signalling via complex molecular pathways. Experiments conducted in a controlled laboratory environment show that heavy metals like cadmium and arsenic may directly bind to TGF-ß receptors, leading to alterations in their structure that enable the receptor to be phosphorylated. Activation of this route sets in motion subsequent signalling cascades, most notably the canonical Smad pathway. The development of lung cancer has been linked to heavy metals, which are ubiquitous environmental pollutants. To grasp the underlying processes, it is necessary to comprehend their molecular effect on TGF-ß pathways. With a particular emphasis on its consequences for lung cancer, this abstract delves into the complex connection between exposure to heavy metals and the stimulation of TGF-ß signalling.

Photoreactivity of polycyclic aromatic hydrocarbons (PAHs) and their mechanisms of phototoxicity against human immortalized keratinocytes (HaCaT).

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic compounds in the environment. They are produced by many anthropogenic sources of different origins and are known for their toxicity, carcinogenicity, and mutagenicity. Sixteen PAHs have been identified as Priority Pollutants by the US EPA, which are often associated with particulate matter, facilitating their dispersion through air and water. When human skin is exposed to PAHs, it might occur simultaneously with solar radiation, potentially leading to phototoxic effects. Phototoxic mechanisms involve the generation of singlet oxygen and reactive oxygen species, DNA damage under specific light wavelengths, and the formation of charge transfer complexes. Despite predictions of phototoxic properties for some PAHs, there remains a paucity of experimental data. This study examined the photoreactive and phototoxic properties of the 16 PAHs enlisted in the Priority Pollutants list. Examined PAHs efficiently photogenerated singlet oxygen and superoxide anion in simple solutions. Furthermore, singlet oxygen phosphorescence was detected in PAH-loaded HaCaT cells. Phototoxicity against human keratinocytes was evaluated using various assays. At 5 nM concentration, examined PAHs significantly reduced viability and mitochondrial membrane potential of HaCaT cells following the exposure to solar simulated light. Analyzed compounds induced a substantial peroxidation of cellular proteins after light treatment. The results revealed that a majority of the examined PAHs exhibited substantial reactive oxygen species photoproduction under UVA and violet-blue light, with their phototoxicity corresponding to their photoreactive properties. These findings improve our comprehension of the interactions between PAHs and human skin cells under environmental conditions, particularly when exposed to solar radiation.

Environmental cadmium inhibits testicular testosterone synthesis via Parkin-dependent MFN1 degradation.

Low testosterone (T) levels are associated with many common diseases, such as obesity, male infertility, depression, and cardiovascular disease. It is well known that environmental cadmium (Cd) exposure can induce T decline, but the exact mechanism remains unclear. We established a murine model in which Cd exposure induced testicular T decline. Based on the model, we found Cd caused mitochondrial fusion disorder and Parkin mitochondrial translocation in mouse testes. MFN1 overexpression confirmed that MFN1-dependent mitochondrial fusion disorder mediated the Cd-induced T synthesis suppression in Leydig cells. Further data confirmed Cd induced the decrease of MFN1 protein by increasing ubiquitin degradation. Testicular specific Parkin knockdown confirmed Cd induced the ubiquitin-dependent degradation of MFN1 protein through promoting Parkin mitochondrial translocation in mouse testes. Expectedly, testicular specific Parkin knockdown also mitigated testicular T decline. Mito-TEMPO, a targeted inhibitor for mitochondrial reactive oxygen species (mtROS), alleviated Cd-caused Parkin mitochondrial translocation and mitochondrial fusion disorder. As above, Parkin mitochondrial translocation induced mitochondrial fusion disorder and the following T synthesis repression in Cd-exposed Leydig cells. Collectively, our study elucidates a novel mechanism through which Cd induces T decline and provides a new treatment strategy for patients with androgen disorders.

Reproductive toxicity of cadmium stress in male animals.

Cadmium (Cd) is a common heavy metal pollutant in the environment, and the widespread use of products containing Cd compounds in industry has led to excessive levels in the environment, which enter the animal body through the food chain, thus seriously affecting the reproductive development of animals. Related studies have reported that Cd severely affects spermatogonia development and spermatogenesis in animals. In contrast, the reproductive toxicity of Cd in males and its mechanism of action have not been clarified. Therefore, this paper reviewed the toxic effects of Cd on germ cells, spermatogonia somatic cells and hypothalamic-pituitary-gonadal axis (HPG axis) of male animals and its toxic action mechanisms of oxidative stress, apoptosis and autophagy from the perspectives of cytology, genetics and neuroendocrinology. The effects of Cd stress on epigenetic modification of reproductive development in male animals were also analyzed. We hope to provide a reference for the in-depth study of the toxicity of Cd on male animal reproduction.

Influence of lead-induced toxicity on the inflammatory cytokines.

Lead (Pb2+) is a hazardous heavy metal that is pervasive in the human environment as a result of anthropogenic activity, and poses serious health risks, particularly in children. Due to its innumerable unique physical and chemical properties, it has various applications; therefore, it has become a common environmental pollutant. Lead may cause oxidative stress, and accumulating evidence indicates that oxidative stress influences the pathophysiology of lead poisoning, also called plumbism. The immune system is continually exposed to various environmental pathogens and xenobiotics, including heavy metals such as lead, and appears to be one of the most vulnerable targets. After being exposed to lead, cells are subjected to oxidative stress as a result of reactive oxygen species (ROS) production. When the generation and consumption of ROS are out of equilibrium, various cell structures, particularly phospholipids are disrupted leading to lipid peroxidation. Various inflammatory signalling pathways are activated as a consequence, along with reduced disease resistance, inflammation, autoimmunity, sensitization and disruption of the cell-mediated and humoral immune systems. Lead negatively affects the metabolism of cytokines, including the interleukins IL-2, IL-1b, IL-6, IL-4, IL-8, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN), as well as the expression and functioning of inflammatory enzymes such as cyclooxygenases. However, the cause of toxicity depends on the kind of lead, dosage, route of entry, exposure period, age, host and genetic predisposition.

Stima dei decessi attribuibili all'inquinamento da NO2, PM10 e PM2,5 nella Città di Milano nel 2019.

BACKGROUND: there is growing evidence that exposure to environmental pollutants affects health, including mortality, chronic diseases, and acute diseases. The World Health Organisation has recently revised downwards the safety thresholds for exposure to environmental pollutants. The City of Milan (CoM) has particularly high levels of pollution; this is due both to the presence of various emission sources and to climatic and orographic conditions. OBJECTIVES: to describe the health effects of exposure to pollutants, measured by deaths due to environmental exposure to NO2, PM10, and PM2.5 in 2019. DESIGN: observational study. Using a pollutant concentration estimation model, annual mean values of NO2, PM10, and PM2.5 were estimated for the CoM in 2019. The number of deaths attributable to each exposure was estimated using risk functions available in the literature; the values recommended by the new World Health Organisation guidelines were used as counterfactual exposure limits. SETTING AND PARTICIPANTS: the population assisted by the Agency for Health Protection of Milan and resident in the CoM on 01.01.2019, aged 30 years or older. The place of residence was georeferenced and the population was followed up until 31.12.2019. Deaths and their causes were obtained from the Causes of Death Registry. MAIN OUTCOME MEASURES: deaths attributable to exposure from non-accidental causes, cardiovascular diseases, respiratory diseases, and lung cancer were estimated. RESULTS: in 2019, the estimated annual average level of NO2 was 36.6 µg/m3, that of PM10 was 24.9 µg/m3, and that of PM2.5 was 22.4 µg/m3, with levels varying across the city area. Concerning exposure to NO2, in 2019 10% of deaths for natural causes were estimated to be attributable to annual mean levels of NO2 above 10 µg/m3. As regard PM2.5, 13% of deaths for natural causes and 18% of deaths from lung cancer were attributable to an annual mean level above 5 µg/m3. The impact of exposure to particulate matter on mortality does not seem to be the same in all the areas of the CoM. CONCLUSIONS: the health impact of exposure to airborne particulate matter in the CoM population is high. It is important that citizens, policy-makers, and stakeholders address this issue, because of its impact on both health and healthcare costs.

Genotoxicity responses of single and mixed exposure to heavy metals (cadmium, silver, and copper) as environmental pollutants in Drosophila melanogaster.

Heavy metals are now persistently present in living things' environments, in addition to their potential toxicity. Therefore, the aim of this study was to utilize D. melanogaster to determine the biological effects induced by different heavy metals including cadmium chloride (CdCl2), copper (II) sulfate pentahydrate (CuSO 4.5 H2O), and silver nitrate (AgNO3). In vivo experiments were conducted utilizing three low and environmentally relevant concentrations from 0.01 to 0.5 mM under single and combined exposure scenarios on D. melanogaster larvae. The endpoints measured included viability, reactive oxygen species (ROS) generation and genotoxic effects using Comet assay and the wing-spot test. Results indicated that tested heavy metals were not toxic in the egg-to adult viability. However, combined exposure (CdCl2+AgNO3 and CdCl2+AgNO3+CuSO 4.5 H2O) resulted in significant genotoxic and unfavorable consequences, as well as antagonistic and/or synergistic effects on oxidative damage and genetic damage.