Association between Endocrine Disrupting Phenols in Colostrums and Maternal and Infant Health

Relationship between Eating Habits and 4-Nonylphenol Concentration in Breast Milk of Women in Slovakia

4-Nonylphenol belongs to the alkylphenol group of chemicals, and its high occurrence in the environment can cause an adverse effect on human health. Breast milk can serve as a marker to take measure of human exposure to these chemicals through different routes of exposure. In this work, the influence of selected factors (the kind of water drank by the mothers; the consumption of fish, pork, and beef; wearing gloves; using nail polish, gel nails, vitamins, and medication) on the concentration on 4-nonylphenol in 89 breast milk samples was studied. The concentrations of nonylphenol in breast milk were determined by HPLC with fluorescence detection. The lowest and highest concentrations of 4-nonylphenol in breast milk were 0.97 ng/mL and 4.37 ng/mL, respectively. Statistical significance was observed for the consumption of pork (p = 0.048) and fish (0.041) in relation to the 4-nonylphenol concentration. Certain parameters (use of gel nails, beef consumption, and vitamin supplementation) were at the border of statistical significance (p = 0.06). Other parameters did not show any statistical significance. The results showed that breast milk in Slovakia does not contain a harmful dose of 4-nonylphenol and does not cause health problems. But it is necessary to continue this research and perform extended screening on a larger number of samples.

Characterization of different contaminants and current knowledge for defining chemical mixtures in human milk: A review

Hundreds of xenobiotics, with very diverse origins, have been detected in human milk, including contaminants of emerging concern, personal care products and other current-use substances reflecting lifestyle. The routes of exposure to these chemicals include dermal absorption, ingestion and inhalation. Specific families of chemicals are dominant among human milk monitoring studies (e.g., organochlorine pesticides, bisphenol A, dioxins), even though other understudied families may be equally toxicologically relevant (e.g., food-processing chemicals, current-use plasticizers and flame retardants, mycotoxins). Importantly, the lack of reliable human milk monitoring data for some individual chemicals and, especially, for complex mixtures, is a major factor hindering risk assessment. Non-targeted screening can be used as an effective tool to identify unknown contaminants of concern in human milk. This approach, in combination with novel methods to conduct risk assessments on the chemical mixtures detected in human milk, will assist in elucidating exposures that may have adverse effects on the development of breastfeeding infants.

Mechanism of nonylphenol induced gastric inflammation through NF-κB/NLRP3 signaling pathway

Studies have found that the intake of environmental endocrine disruptors was positively correlated with the occurrence of gastric diseases. The aim of this study was to determine whether nonylphenol (NP) exposure can induce gastric inflammation and whether its mechanism was related to NF-κB/NLRP3 signaling pathway. In vivo, male SD rats were randomly divided into 4 groups (12 rats/group): control group (corn oil), NP low (0.4mg/kg), medium (4mg/kg), and high (40mg/kg) dose groups. After 33 weeks of NP chronic exposure, it was found pathological changes in gastric tissues, increase the release of inflammatory factors, and effects expressions of genes related to the NF-κB/NLRP3 signaling pathway. In vitro, the GES-1 cell experiments, which included four groups: control (0 µmol/L NP), L (2.5 µmol/L NP), M (40 µmol/L NP), and H (60 µmol/L NP), confirmed that NP increased the release of inflammatory factors in the cells, and up-regulated the expression of proteins related to NF-κB/NLRP3 signaling pathway. Furthermore, when pyrrolidinedithiocarbamate ammonium (PDTC) blocked the NF-κB signaling pathway, it was found that the expression of related proteins in the NF-κB/NLRP3 signaling pathway was decreased, and the release of inflammatory factors in GES-1 cells caused by NP was also attenuated. The results of this study indicated that NP can induce inflammation in the stomach in vivo and in vitro, and its mechanism was related to the NF-κB/NLRP3 signaling pathway. These findings provided a new perspective on the mechanism of inflammatory response induced by exposure to environmental endocrine disruptors. Also, these findings indicated that therapeutic strategies for the NF-κB/NLRP3 signaling pathway may be new methods to treat inflammatory diseases.

Amphibian Metamorphosis Assay: Investigation of the potential effects of five chemicals on the hypothalamic-pituitary thyroid axis of Xenopus laevis

2-Ethylhexyl 4-hydroxybenzoate (2-EHHB), 4-tert-octylphenol (4-OP), 4-nonylphenol-branched (4-NP), benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) were evaluated using a 21-day Amphibian Metamorphosis Assay (AMA). Xenopus laevis larvae were exposed nominally to each chemical at 3.6, 10.9, 33.0, and 100 μg/L, except 4-NP concentrations were 1.8, 5.5, 16.5 and 50 μg/L. Endpoints included mortality, developmental stage, hind limb length (HLL), snout-vent length (SVL), body weight (BW), and thyroid histopathology. BBP and 4-OP accelerated development compared to controls at the mean measured concentration of 3.5 and 39.8 μg/L, respectively. An increase in developmental stage frequency distribution was observed for 4-OP at 39.8 and 103 µg/L, BBP at all concentrations and DBP at 143 µg/L. Normalized HLL was increased on study day (SD) 21 for all tested substances except 4-NP. Histopathology revealed accelerated development and mild thyroid follicular cell hypertrophy at all BBP concentrations, but moderate severity at 105 μg/L. Increased BW occurred for all chemicals except 4-OP. Increased SVL was observed for 4-NP, BBP and DBP on SD 21. There was insufficient evidence that 4-NP and 2-EHHB affected the hypothalamic-pituitary thyroid axis, however, BBP, DBP and 4-OP showed potential effects on amphibian metamorphosis and thyroid activity, albeit through different lines of evidence.

Biomonitoring bisphenols, parabens, and benzophenones in breast milk from a human milk bank in Southern Spain

BACKGROUND

Human breast milk is considered the optimal source of nutrition for infants. Milk from breast milk banks offers an alternative to infant formulas for vulnerable hospitalized neonates most likely to benefit from exclusive human milk feeding. However, breast milk can also be a source of exposure to environmental contaminants, including endocrine-disrupting chemicals (EDCs).

AIM

To evaluate concentrations of phenolic EDCs, including bisphenols, parabens (PBs), and benzophenones (BPs), in samples from a human milk bank in Granada, Southern Spain and to explore sociodemographic, reproductive, and lifestyle factors related to their concentrations in the milk.

METHODS

Concentrations of three bisphenols [bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS)], four PBs [methyl- (MeP), ethyl- (EtP), propyl- (n-PrP), and butyl-paraben (n-BuP)], and six BPs [BP-1, BP-2, BP-3, BP-6, BP-8, and 4-hydroxy-BP] were determined in milk samples from 83 donors. Information on potential explanatory variables was gathered using the milk bank donor form and an ad hoc questionnaire. Multiple linear and logistic regression models were fitted.

RESULTS

Detectable concentrations were found of at least one of the analyzed compounds in all donor breast milk samples and at least five compounds in one-fifth of them. The most frequently detected compounds were MeP (90.5%), BP-3 (75.0%), EtP (51.2%), n-PrP (46.4%), and BPA (41.7%). Median concentrations ranged between <0.10 ng/mL (n-PrP, n-BuP, BP-1) and 0.59 ng/mL (BP-3). No sample contained detectable concentrations of BPF, BPS, or most BPs (BP-2, BP-6, BP-8, and 4- hydroxy-BP). Breast milk phenol concentrations were associated with parity, the utilization of deodorants, mouthwash, skin care products, and cosmetics, and the intake of nutritional supplements.

CONCLUSIONS

Results reveal the widespread presence of BPA, PBs, and BP-3 in donor breast milk samples, highlighting the need for preventive measures to enhance the benefits of breast milk from milk banks and from breastfeeding women in general.

Concentrations of bisphenols, parabens, and benzophenones in human breast milk: A systematic review and meta-analysis

BACKGROUND

Breast milk is the main source of nutrition for infants but may be responsible for their exposure to environmental chemicals, including endocrine-disrupting chemicals.

AIM

To review available evidence on the presence and concentrations of bisphenols, parabens (PBs), and benzophenones (BPs) in human milk and to explore factors related to exposure levels.

METHODS

A systematic review was carried out using Medline, Web of Science, and Scopus databases, conducting a comprehensive search of peer-reviewed original articles published during the period 2000-2020, including epidemiological and methodological studies. Inclusion criteria were met by 50 studies, which were compiled by calculating weighted detection frequencies and arithmetic mean concentrations of the chemicals. Their risk of bias was assessed using the ROBINS-I checklist.

RESULTS

Among the 50 reviewed studies, concentrations of bisphenols were assessed by 37 (74.0%), PBs by 21 (42.0%), and BPs by 10 (20.0%). Weighted detection frequencies were 63.6% for bisphenol-A (BPA), 27.9-63.4% for PBs, and 39.5% for benzophenone-3 (BP-3). Weighted mean concentrations were 1.4 ng/mL for BPA, 0.2-14.2 ng/mL for PBs, and 24.4 ng/mL for BP-3. Mean concentrations ranged among studies from 0.1 to 3.9 ng/mL for BPA, 0.1 to 1063.6 ng/mL for PBs, and 0.5 to 72.4 ng/mL for BP-3. The highest concentrations of BPA and PBs were reported in samples from Asia (versus America and Europe). Higher BPA and lower methyl-paraben concentrations were observed in samples collected after 2010. Elevated concentrations of these chemicals were associated with socio-demographic and lifestyle factors in eight studies (16.0%). Two epidemiological studies showed moderate/serious risk of bias.

CONCLUSIONS

This systematic review contributes the first overview of the widespread presence and concentrations of bisphenols, PBs, and BPs in human breast milk, revealing geographical and temporal variations. The methodological heterogeneity of published studies underscores the need for well-conducted studies to assess the magnitude of exposure to these chemicals from human milk.

Bisphenols and Thyroid Hormone

In recent decades, attention has been directed toward the effects of bisphenol A (BPA) on human health. BPA has estrogenic activity and is regarded as a representative endocrine disruptor. In addition, mounting evidence indicates that BPA can disrupt thyroid hormone and its action. This review examined human epidemiological studies to investigate the association between BPA exposure and thyroid hormone levels, and analyzed in vivo and in vitro experiments to identify the causal relationship and its mechanism of action. BPA is involved in thyroid hormone action not only as a thyroid hormone receptor antagonist, but also through several other mechanisms. Since the use of bisphenols other than BPA has recently increased, we also reviewed the effects of other bisphenols on thyroid hormone action.

Preliminary study on bisphenol A levels and possible exposure history of mother and exclusively breastfed infant pairs

The aims of this study were to determine bisphenol A (BPA) levels in breast milk and urine specimens of healthy mother and exclusively breastfed infant pairs having no known BPA exposure, and also to examine the relationship between BPA levels and possible BPA exposure history. Forty mothers and their 1-2-month-old exclusively breastfeed infant were included in the study. The questionnaires about sociodemographic characteristics and possible BPA exposure history were filled out. Breast milk and urine samples were taken. BPA analyses of these samples were conducted using high-performance liquid chromatography coupled with mass spectrometry. All mother-infant pairs showed detectable BPA concentrations. The geometric means of BPA levels in breast milk, maternal urine, and infant urine were determined as 0.12 μg/L (0.03-0.59), 0.12 μg/L (0.03-0.73), and 0.13 μg/L (0.02-0.44), respectively. Infants whose mothers were consuming yoghurt in plastic containers had relatively higher urinary BPA levels (p = 0.00). Mothers consuming hot beverages in plastic glass showed higher breast milk BPA levels (p = 0.033). There were no statistical associations between BPA levels and the use of plastic materials and tools (p > 0.05).Conclusion: The measurable BPA concentrations in all breast milk specimens of healthy mothers may reflect possible exposure from dietary or non-dietary sources. Exclusively, breastfed healthy infants without any known BPA exposure may be exposed to BPA from their mothers through breastfeeding. What is Known: • Fetuses, neonates and infants are exposed to BPA from their mothers through placental transfer and breastfeeding. • Breast milk is considered a continuous low-level exposure to BPA. What is New: • BPA was detected in 100% of maternal urine, infant urine, and breast milk in healthy mother-infant pairs having no known BPA exposure. • The measurable amount of BPA in breast milk and infant urine may reflect possible BPA exposure of mother-infant pairs.

The association of protein intake (amount and type) with ovarian antral follicle counts among infertile women: results from the EARTH prospective study cohort

OBJECTIVE

To evaluate the association between protein intake (amount and type) and antral follicle count (AFC).

DESIGN

Prospective cohort.

SETTING

Academic fertility centre.

POPULATION

Two hundred and sixty-five women undergoing fertility treatments at an academic fertility centre and participating in an ongoing study on environment and reproductive health.

METHODS

We measured AFC in ultrasonographic evaluation among women undergoing infertility treatments. Women completed a previously validated semi-quantitative food frequency questionnaire. We used Poisson regression to evaluate the relation between protein intake and AFC while adjusting for age, body mass index, race, smoking status, and total energy intake.

MAIN OUTCOME MEASURES

Antral follicle count.

RESULTS

Among 265 women (mean age: 35.0 ± 3.9 years, 85% Caucasian), total protein intake (% energy) was unrelated to AFC. When protein from different food sources was considered separately, we found a negative association between dairy protein intake and AFC. The mean AFC was 14.4% (3.9-23.7%) lower for women in the highest quintile of dairy protein intake than for women in the bottom quintile after adjusting for potential confounders (P-trend = 0.04). This association was stronger among women who had never smoked (P-trend = 0.002) but was not observed among previous smokers (P-trend = 0.36). There were no associations between protein intake from either non-dairy animal or vegetable sources and AFC.

CONCLUSION

Higher dairy protein intake (≥5.24% of energy) was associated with lower antral follicle counts among women presenting for infertility treatment. These findings should be further investigated in prospective studies also designed to clarify the biology underlying the observed associations.

TWEETABLE ABSTRACT

Higher dairy protein intake was associated with lower antral follicle counts in an infertile population.

Computational insights into the molecular interactions of environmental xenoestrogens 4-tert-octylphenol, 4-nonylphenol, bisphenol A (BPA), and BPA metabolite, 4-methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene (MBP) with human sex hormone-binding globulin

Environmental contamination has been one of the major drawbacks of the industrial revolution. Several man-made chemicals are constantly released into the environment during the manufacturing process and by leaching from the industrial products. As a result, human and animal populations are exposed to these synthetic chemicals on a regular basis. Many of these chemicals have adverse effects on the physiological functions, particularly on the hormone systems in human and animals and are called endocrine disrupting chemicals (EDCs). Bisphenol A (BPA), 4-tert-octylphenol (OP), and 4-nonylphenol (NP) are three high volume production EDCs that are widely used for industrial purposes and are present ubiquitously in the environment. Bisphenol A is metabolized in the human body to a more potent compound (MBP: 4-Methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene). Epidemiological and experimental studies have shown the three EDCs to be associated with adverse effects on reproductive system in human and animals. Sex hormone-binding globulin (SHBG) is a circulatory protein that binds sex steroids and is a potential target for endocrine disruptors in the human body. The current study was done in order to understand the binding mechanism of OP, BPA, NP, and MBP with human SHBG using in silico approaches. All four compounds showed high binding affinity with SHBG, however, the binding affinity values were higher (more negative) for MBP and NP than for OP and BPA. The four ligands interacted with 19-23 residues of SHBG and a consistent overlapping of the interacting residues for the four ligands with the residues for the natural ligand, dihydrotestosterone (DHT; 82-91% commonality) was shown. The overlapping SHBG interacting residues among DHT and the four endocrine disruptors suggested that these compounds have potential for interference and disruption in the steroid binding function.

Effects of Low-Dose Bisphenol A on DNA Damage and Proliferation of Breast Cells: The Role of c-Myc

BACKGROUND

Humans are exposed to low-dose bisphenol A (BPA) through plastic consumer products and dental sealants containing BPA. Although a number of studies have investigated the mammary gland effects after high-dose BPA exposure, the study findings differ. Furthermore, there has been a lack of mechanistic studies.

OBJECTIVE

The objective of this study was to investigate the effect and the mechanism of low-dose BPA in mammary gland cells.

METHODS

We evaluated DNA damage following BPA exposure using the comet assay and immunofluorescence staining, and used cell counting and three-dimensional cultures to evaluate effects on proliferation. We examined the expressions of markers of DNA damage and cell-cycle regulators by immunoblotting and performed siRNA-mediated gene silencing to determine the role of c-Myc in regulating BPA's effects.

RESULTS

Low-dose BPA significantly promoted DNA damage, up-regulated c-Myc and other cell-cycle regulatory proteins, and induced proliferation in parallel in estrogen receptor-α (ERα)-negative mammary cells. Silencing c-Myc diminished these BPA-induced cellular events, suggesting that c-Myc is essential for regulating effects of BPA on DNA damage and proliferation in mammary cells.

CONCLUSIONS

Low-dose BPA exerted c-Myc-dependent genotoxic and mitogenic effects on ERα-negative mammary cells. These findings provide significant evidence of adverse effects of low-dose BPA on mammary cells.

Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons

DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

Androgen and Progesterone Receptors Are Targets for Bisphenol A (BPA), 4-Methyl-2,4-bis-(P-Hydroxyphenyl)Pent-1-Ene--A Potent Metabolite of BPA, and 4-Tert-Octylphenol: A Computational Insight

Exposure to toxic industrial chemicals that have capacity to disrupt the endocrine system, also known as endocrine disrupting chemicals (EDCs), has been increasingly associated with reproductive problems in human population. Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol) and 4-tert-octylphenol (OP; 4-(1,1,3,3-tetramethylbutyl)phenol) are among the most common environmental contaminants possessing endocrine disruption properties and are present in plastics, epoxy resins, detergents and other commercial products of common personal and industrial use. A metabolite of BPA, 4-Methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP) is about 1000 times more biologically active compared to BPA. Epidemiological, clinical, and experimental studies have shown association of BPA and OP with adverse effects on male and female reproductive system in human and animals. The endocrine disruption activity can occur through multiple pathways including binding to steroid receptors. Androgen receptor (AR) and progesterone receptor (PR) are critical for reproductive tract growth and function. Structural binding characterization of BPA, MBP, and OP with AR and PR using molecular docking simulation approaches revealed novel interactions of BPA with PR, and MBP and OP with AR and PR. For BPA, MBP, and OP, five AR interacting residues Leu-701, Leu-704, Asn-705, Met-742, and Phe-764 overlapped with those of native AR ligand testosterone, and four PR interacting residues Leu-715, Leu-718, Met-756, and Met-759 overlapped with those of PR co-complex ligand, norethindrone. For both the receptors the binding strength of MBP was maximum among the three compounds. Thus, these compounds have the potential to block or interfere in the binding of the endogenous native AR and PR ligands and, hence, resulting in dysfunction. The knowledge of the key interactions and the important amino-acid residues also allows better prediction of potential of xenobiotic molecules for disrupting AR- and PR-mediated pathways, thus, helping in design of less potent alternatives for commercial use.

Alterations in the rat serum proteome induced by prepubertal exposure to bisphenol a and genistein

Humans are exposed to an array of chemicals via the food, drink and air, including a significant number that can mimic endogenous hormones. One such chemical is Bisphenol A (BPA), a synthetic chemical that has been shown to cause developmental alterations and to predispose for mammary cancer in rodent models. In contrast, the phytochemical genistein has been reported to suppress chemically induced mammary cancer in rodents, and Asians ingesting a diet high in soy containing genistein have lower incidence of breast and prostate cancers. In this study, we sought to: (1) identify protein biomarkers of susceptibility from blood sera of rats exposed prepubertally to BPA or genistein using Isobaric Tandem Mass Tags quantitative mass spectrometry (TMT-MS) combined with MudPIT technology and, (2) explore the relevance of these proteins to carcinogenesis. Prepubertal exposures to BPA and genistein resulted in altered expression of 63 and 28 proteins in rat sera at postnatal day (PND) 21, and of 9 and 18 proteins in sera at PND35, respectively. This study demonstrates the value of using quantitative proteomic techniques to explore the effect of chemical exposure on the rat serum proteome and its potential for unraveling cellular targets altered by BPA and genistein involved in carcinogenesis.