Estrogen-like activity of seafood related to environmental chemical contaminants

PCB cause global DNA hypomethylation of human peripheral blood monocytes in vitro

We have recently reported significant associations between exposure to polychlorinated biphenyls (PCB) and alterations on genome-wide methylation of leukocyte DNA of healthy volunteers and provided evidence in support of an etiological link between the observed CpG methylation variations and chronic lymphocytic leukemia. The present study aimed to elucidate the effects of PCB in human lymphocytes' methylome in vitro. Therefore, U937 cells and human peripheral blood monocytes (PBMC) were exposed in vitro to the dioxin-like PCB-118, the non-dioxin-like PCB-153, and hexachlorobenzene (HCB) and thorough cytotoxicity, genotoxicity and global CpG methylation analyses were performed. All compounds currently tested did not show any consistent significant genotoxicity at all exposure periods and concentrations used. On the contrary, extensive dose-dependent hypomethylation was observed, even at low concentrations, in stimulated PBMC treated with PCB-118 and PCB-153 as well as a small but statistically significant hypomethylation in HCB-treated stimulated cells.

Diet: A Source of Endocrine Disruptors

BACKGROUND

Food is indispensable for human life and determines the health and wellbeing of the consumer. As food is the source of energy for humans, it also emerges as one of the most important sources of exposure to deleterious chemicals both natural and synthetic. The food exposed chemicals cause a number of detrimental health effects in humans, with endocrine disruption being of serious concern amongst these effects. Such chemicals disrupting the health of endocrine system are known as endocrine-disrupting chemicals (EDCs). The food exposed EDCs need to be identified and classified to effectuate a cautious consumption of food by all and especially by vulnerable groups.

AIM

The aim of the present review was to discuss food as a source of exposure to common endocrine disruptors in humans. This review presents the occurrence and levels of some of the critical endocrine disruptors exposed through frequently consumed diets.

METHODS

The major source of data was PubMed, besides other relevant publications. The focus was laid on data from the last five years, however significant earlier data was also considered.

CONCLUSION

The food as a source of endocrine disruptors to humans cannot be neglected. It is highly imperative for the consumer to recognize food as a source of EDCs and make informed choices in the consumption of food items.

Evaluation of Environmental Quality of Mediterranean Coastal Lagoons Using Persistent Organic Pollutants and Metals in Thick-Lipped Grey Mullet

The evaluation of past and present anthropogenic impacts affecting the ecological quality status of transitional ecosystems is crucial from the perspective of protecting them from further deterioration, and to evaluate remediation and restoration measures. Contamination patterns of thick-lipped grey mullet from two Mediterranean coastal lagoons within a protected area in Italy were assessed and compared in order to evaluate their overall quality status and to collect information that can provide useful feedback on management choices aimed at enhancing environmental quality and biodiversity conservation. The quality status of the two lagoons was evaluated by an environmental assessment methodology based on indicators of direct and indirect human pressures, while a broad range of analyses were carried out to determine the presence and concentration of persistent organic pollutants (POPs) and metals in fish muscle tissue. A good quality status resulted for both lagoons, and an overall limited anthropogenic impact in the surrounding area. This could account for POPs and metal contamination levels found in mullet, although limited, and relating to their patterns. The overlap of results achieved with the two evaluation approaches can provide support for management choices in Mediterranean lagoon environments, especially for those committed to the protection and conservation of biodiversity.

The chronicles of the contaminated Mediterranean seas: a story told by the cetaceans' skin genes

Wild animals in their natural environment could provide a big source of information, but sampling can be very challenging, above all for protected species, like marine mammals. Nevertheless, significant data can be obtained sampling stranded animals right after their death, taking into account proper sampling time and methodology. RNA samples from the skin of 12 individuals including the species Stenella coeruleoalba, Tursiops truncatus, and Grampus griseus were used to test 4 potential gene markers of anthropogenic contaminants exposure. The individuals were sampled in 3 geographic areas: the Adriatic, Ionian and Tyrrhenian seas. Three out of the 4 genes tested showed higher expression in the samples collected from the Adriatic Sea. Minute skin samples tell the story of the specific geographic location where the marine mammal spent its life, thanks to the different impact on gene expression exerted by different contamination levels.

Temporal trends and risk assessment of polychlorinated biphenyls and heavy metals in a solid waste site in Taizhou, China

The solid wastes generated during the production of chemicals are important sources of polychlorinated biphenyls (PCBs) and heavy metals. However, few studies have been conducted regarding long-term monitoring of the risks and states of PCBs and heavy metal pollution from these sources. Herein, we reported the concentrations and risks posed by these pollutants at a chemical solid waste storage site in Taizhou, China, based on data collected before (in 2006) and after clearing the solid waste (in 2013). We examined the concentrations of 24 PCBs, including ten dioxin-like-PCB (DL-PCB) congeners (PCB77, 105, 114, 118, 123, 126, 156, 167, 169, and 189). Our data showed that the mean ∑24PCB concentrations in the soil, water, and plant samples were 6902.90 ng/g, 1637.58 ng/L, and 33.95 ng/g, respectively, in 2013. Furthermore, Cr was the most prevalent contaminant. The hazard quotient (HQ) values showed that Pb posed the highest risk in the soil samples, followed by Hg. The results of the reporter gene assay showed that soil extracts from S1, S2, S3, S4, S5, S6, and S9 exhibited potential estrogenic activities. A comparison of the data showed that the PCB pollution in some sites of this area was still serious. The data provided here are fundamentally useful for policy makers to regulate this type of storage site.

Estrogenic endocrine disruptors: Molecular mechanisms of action

A comprehensive summary of more than 450 estrogenic chemicals including estrogenic endocrine disruptors is provided here to understand the complex and profound impact of estrogen action. First, estrogenic chemicals are categorized by structure as well as their applications, usage and effects. Second, estrogenic signaling is examined by the molecular mechanism based on the receptors, signaling pathways, crosstalk/bypassing and autocrine/paracrine/homeostatic networks involved in the signaling. Third, evaluation of estrogen action is discussed by focusing on the technologies and protocols of the assays for assessing estrogenicity. Understanding the molecular mechanisms of estrogen action is important to assess the action of endocrine disruptors and will be used for risk management based on pathway-based toxicity testing.

Estrogenic evaluation and organochlorine identification in blubber of North Sea harbour porpoise (Phocoena phocoena) stranded on the North Sea coast

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using a luciferase reporter gene assay (RGA). None of the PCB 138, 153, or 180 or their mixture induced a response in the RGA. o,p′-DDT was the most potent xenoestrogen from the DDT group, inducing a response already at 80 ng/mL. From the HCH and HCB group, only β-HCH (at 400 and 2000 ng/mL) and δ-HCH (at 2000 ng/mL) displayed estrogenic activities. These 13 organochlorines were determined by GC-MS in 12 samples of North Sea harbor porpoise blubber. The PCBs were the main contaminants. Within each group, PCB 153 (6.0 × 10²~4.2 × 10⁴  μg/kg), p,p′-DDE (5.1 × 10²~8.6 × 10³  μg/kg), and HCB (7.6 × 10¹~1.5 × 10³  μg/kg) were the compounds found in highest concentrations. The hormonal activity of the porpoise blubber samples was also assayed in RGA, where two samples showed estrogenic activity, seven samples showed antiestrogenic activity, and one sample showed both estrogenic and antiestrogenic activity. Our results suggest that the 13 POPs measured by GC-MS in the samples cannot explain alone the estrogenicity of the extracts.

Contamination by hazardous substances in the Gulf of Naples and nearby coastal areas: a review of sources, environmental levels and potential impacts in the MSFD perspective

During the 7th FW EU Programme, a large group of research institutions with a strong tradition in marine science designed PERSEUS, a policy-oriented, marine research project aimed at identifying human-derived pressures and their impacts in the Southern European Seas. PERSEUS is about gathering and analyzing the data on our marine ecosystems and developing recommendations to assist policy makers in the implementation of the Marine Strategy Framework Directive (MSFD). In its initial phase, the project focuses on the analysis and evaluation of human pressures in selected coastal areas across the Mediterranean and Black Seas. This paper reports on the results about the chemical pollution pressure in the Gulf of Naples, one of the sites selected for the analysis, and surrounding waters of the Southern Tyrrhenian Sea. Based on a systematic up-to-date literature review, the paper brings together for the first time the available information on the presence, severity and distribution of contaminants on the site. In spite of methodological and sampling heterogeneity among studies, this review compiles the data in a harmonized and effective way, so that the current status, knowledge gaps and research priorities can be established. Thus, the review wishes not only to provide a contribution to the scientific community, but also to help to extract recommendations for mitigating pollution sources and risks in the area of concern. A similar process of analysis may be carried out for other areas and pressures in order to facilitate policy making at the European level.

Common classification schemes for PCB congeners and the gene expression of CYP17, CYP19, ESR1 and ESR2

BACKGROUND

Reliable techniques to measure polychlorinated biphenyl (PCB) congeners make the clearer definition of their effects on human health possible. Given that PCBs are classified as endocrine disrupters, we sought to explore the expression of some key genes involved in sex steroid metabolism.

OBJECTIVES

To examine common classification schemes of PCB congeners and determine whether exposure to groups classified by mechanism of action alter the gene expression (GE) of CYP17, CYP19, and ESR1 and ESR2.

METHODS

GE and exposure to various classifications of lipid-adjusted PCB congeners were examined in 139 daughters of the Michigan Fisheaters' Cohort. Using mixed models analyses and adjusting for age, menopausal status, and current use of oral contraceptives and hormone replacement therapy, GE data were regressed on exposure to PCB congener groupings based on mechanism of action.

RESULTS

Three novel findings are elucidated: first, that up-regulation of CYP19 expression is associated with exposure to PCB groupings containing dioxin-like, potentially anti-estrogenic, immunotoxic congeners, including PCB IUPAC #74, #105, #118, #138, #156, #157, #158, #167, and #170 from this cohort. Second, that exposure to similar congeners (PCB IUPAC #105, #156, #157, #158, and #167 in this cohort) but using a classification based solely on hormonal mechanisms of action is associated with increased expression of ESR2. Third, that increased expression of CYP17 is of borderline significance when associated with exposure to PCB IUPAC #118, #138, and #156.

CONCLUSIONS

These findings are both counter-intuitive and intriguing. Rather than exhibiting anti-estrogenic effects alone, they suggest that these congeners up-regulate the major enzyme involved in estrogen synthesis and tend to confirm previous findings of links between AhR and ER signaling pathways. Replication of these findings, expansion of the number of genes examined, exploration of mixtures of environmental chemicals, and subsequent study of health outcomes in a larger cohort are future priorities.

Accumulation of organochlorine contaminants in loggerhead sea turtles, Caretta caretta, from the eastern Adriatic Sea

We analyzed 15 polychlorinated biphenyls (PCBs) and five organochlorine pesticides (OCPs) in fat tissue of 27 loggerhead sea turtles (Caretta caretta) from eastern Adriatic Sea with the curved carapace length ranging from 25.0 to 84.5 cm. The PCB profile was dominated by hexa- and hepta-chlorinated congeners, with PCB-153 (median: 114.9 ng g⁻¹ wet mass), PCB-138 (80.0 ng g⁻¹ w.m.), and PCB-180 (26.7 ng g⁻¹ w.m.) detected with the highest levels. Toxic mono-ortho congeners PCB-118, PCB-105 and PCB-180 with dioxin-like toxicity were found in > 70% samples. 4,4'-DDE (81.0 ng g⁻¹ w.m.) prevailed the OCP signature, accounting for 80% of the total DDTs. A significant increasing trend in accumulation with size was found for PCB-52 (r(s) = 0.512, p < 0.01) and PCB-114 (r(s) = 0.421, p < 0.05). Comparison of our results with organochlorine contaminant (OC) pattern in some prey taxa suggest that contamination occurs primarily through the food web, with biomagnification factors of 0.14-6.99 which were positively correlated with the octanol-water partition coefficient (logK(ow); p < 0.05). This study, based upon a fairly large sample size collected mostly from incidentally captured animals over a short time period (June 2001-November 2002), present a temporal snapshot of OC contamination in wild, free-ranging loggerheads from Adriatic feeding grounds and provide a baseline for monitoring the regional OC trends in this endangered species.

Monitoring of polychlorinated biphenyl contamination and estrogenic activity in water, commercial feed and farmed seafood

We evaluated the concentration and congener distribution of seven "target" polychlorinated biphenyls (PCBs) present in water collected in different aquaculture farms of the Mediterranean area, commercial feeds, and farmed seafood. PCBs were present in feed and in tissues of all the analysed organisms at levels ranging from 1.96 ng g(-1) to 124.00 ng g(-1) wet weight, and in 10.5% of the water samples, at levels from under detection limit to 33.0 ng l(-1) with total PCB concentrations significantly higher in samples from the Tyrrhenian Sea than the Adriatic Sea. PCB congener distribution in tissues resembled that of feed, suggesting that commercial feed is an important source of PCBs. The estrogenicity of organic extracts of the samples was also evaluated by using an in vitro yeast reporter assay. Estrogenic activity higher than 10% of the activity induced by 10 nM 17 beta-estradiol was observed in 20.0% of seafood samples and 15.8% of water samples. Seafood and water samples from the Tyrrhenian Sea were more frequently estrogenic than the Adriatic ones (16.45 versus 4.08%). A significant correlation of total PCB concentrations on biological activity was observed for sea bass and mussels from the Adriatic Sea (p < 0.045 and p < 0.04, respectively), and for sea bass of the Tyrrhenian Sea (p = 0.05). These results indicate the need of an integral approach in the exposure assessment to potential toxic compounds for human via food.

Characterisation of bioactive compounds in infant formulas using immobilised recombinant estrogen receptor-alpha affinity columns

In this study, the use of recombinant estrogen receptor alpha (ERalpha)-based affinity columns was reported, for the isolation and the identification of estrogenic substances present in complex matrices, focusing on bioactive compounds present in foodstuff. The capability of affinity columns to trap high, but also low-affinity radio-labelled ligands (17beta-estradiol, genistein and bisphenol A) was demonstrated. Three pooled samples of infant formulas (milk-based, hypoallergenic and soy-based formulas for infants aged 0-4 months) from a EU market basket were prepared by the CASCADE Network of Excellence. After determining the estrogenic activity of these food samples, human recombinant ERalpha ligand binding domain (LBD) based affinity columns combined with suitable analytical methods (high resolution LC-MS/MS) were used to identify the bioactive compounds present in the soy-based formula extract, namely phytoestrogens (genistein and daidzein) involved in the agonistic activity measured. Incubations of genistein with liver microsomes were carried out and the extracts analysed following the same protocol, demonstrating that hERalpha affinity columns can also be used for trapping active metabolites. This approach combining bioluminescent cell lines with this useful tool based on hERalpha-LBD affinity columns thus allowed the purification and the concentration of both known and unknown estrogenic ligands prior to investigation of their structure using LC-MS.

Potential human health risks from metals (Hg, Cd, and Pb) and polychlorinated biphenyls (PCBs) via seafood consumption: estimation of target hazard quotients (THQs) and toxic equivalents (TEQs)

Edible marine species (fish, cephalopod molluscs, crustaceans) from the Adriatic Sea were analyzed for content in heavy metals (Hg, Cd and Pb) and polychlorinated biphenyls (PCBs). Health risks to human via dietary intake of seafood were assessed by the target hazard quotients (THQs) and the toxic equivalent factors (TEFs). Mercury maximum concentrations corresponded to fish (0.07-1.56 microg g(-1)w.w.), followed by cephalopod molluscs (0.10-0.55 microg g(-1)w.w.), and crustaceans (0.27-0.33 microg g(-1)w.w.). Cadmium levels in cephalopods (0.18-0.59 microg g(-1)w.w.) were higher than those in fish (0.01-0.05 microg g(-1)w.w.) and crustaceans (0.02-0.04 microg g(-1)w.w.), while for Pb the concentrations were generally low (fish: ND-1.18 microg g(-1)w.w., cephalopods: ND-0.17 microg g(-1)w.w., crustaceans: ND-0.03 microg g(-1)w.w.). For PCBs, concentrations in fish, cephalopods and crustaceans ranged between 141 and 3,406 ng g(-1)l.w., 190 and 542 ng g(-1)l.w., and 202 and 429 ng g(-1)l.w., respectively. Cd and Pb THQ values as well as estimates of PCB TEQ exposure indicated the absence of health risks through consumption of the various seafood. In contrast, mercury TEQs values due to consumption of certain fish species (albacore, rosefish and thornback ray) indicated that human health risk might be of concern.