Plastics and plastic additives as inducers of oxidative stress

8 pages, 1 figure, 2 tables.As plastics in the environment break down to smaller particles, contain additives, trap environmental pollutants and cross cell membranes, there is growing concern about the toxicological consequences for humans and vulnerable aquatic species. Recent studies have shown the ability of plastic additives to disrupt oxidative metabolism and cause damage to macromolecules as part of their mechanism of action. This article focuses on human and fish cell models because they serve to unravel the mechanisms of action of plastic additives and to predict the consequences of exposure. In addition, some in vivo studies revealing the action of plastics and its additives on oxidative stress parameters in aquatic organisms are reviewed. The selected works highlight an alteration of the oxidative stress balance as one accepted mechanism of action of plastics and warn about the negative consequences on humans and wildlife.This work was partially supported by Project references PGC2018-097513-B-I00 (MCIU/AEI/FEDER, UE) and CGL2016-76332-R (MINECO/FEDER, UE). C. Porte is a member of the SusPlast platform from the Spanish National Research Council (CSIC).With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe

Does exposure to testosterone significantly alter endogenous metabolism in the marine mussel Mytilus galloprovincialis?

31 p., figuras, tablas y bibliografíaMussels (Mytilus galloprovincialis) were exposed to different concentrations of testosterone (T: 20, 200 and 2000 ng/L) in a semi-static water regime (1-day dosing intervals) for up to 5 days in an attempt to see whether endogenous steroid levels and steroid metabolism were altered by exogenous exposure to testosterone. Whole tissue levels of total-testosterone (free + esterified) sharply increased in a concentrationdependent manner, from 2 ng/g in controls to 290 ng/g in organisms exposed to the highest concentration. In contrast, levels of free-testosterone were only significantly elevated at the high-exposure group (5-fold increase respect to controls). Increased activity of palmitoyl-CoA:testosterone acyltransferase (ATAT) was detected in organisms exposed to the highest concentration of testosterone, while those exposed to low and medium concentrations showed significant alterations in their polyunsaturated fatty acids profiles. The obtained results suggest that esterification of the excess of T with fatty acids might act as a homeostatic mechanism to maintain endogenous levels of free-T stable. Interestingly, a dose-dependent decrease in CYP3A-like activity was detected in T-exposed mussels together with a significant decrease in the metabolism of the androgen precursor androstenedione to dihydrotestosterone (5alfa-DHT). Overall, the work contributes to the better knowledge of androgen metabolism in mussels.This study was supported by the Spanish National Plan for Research (Project Ref CGL2008-01888/BOS). Denise Fernandes acknowledges a postdoctoral fellowship (SFRH/BPD/34289/2006) from the Portuguese Fundação para a Ciência e Tecnologia (FCT) of the Ministry of Science and Technology of Portugal.Peer reviewe

Las nuevas enfermedades y la contaminación química.

Hace varios años, un grupo de prestigiosos científicos, entre los que se contaban varios galardonados con el Premio Nobel, suscribieron el Llamamiento de París, en el que advertían de que la contaminación química está produciendo una pandemia silenciosa, que contribuye, entre otras cosas, al crecimiento del cáncer, de la infertilidad y de problemas en el sistema hormonal o en el aparato respiratorio o nervioso. En el mismo sentido se han expresado otros manifiestos científicos como la Declaración de Praga, esta última centrada en las alteraciones endocrinas. El hombre ha creado más de 100.000 sustancias químicas sintéticas que no estaban presentes en la naturaleza, y sólo una mínima parte de ellas ha sido debidamente evaluada en cuanto a sus posibles riesgos para la salud humana y el medio ambiente.Peer Reviewe

Evaluación de efectos biológicos asociados al vertido del "Prestige" en poblaciones de peces de interés comercial

2 pages.-- Número dedicado a: XVI Congreso Español de Toxicología, Cáceres, Spain, Sep 2005.Peer reviewe

Effects of endocrine disrupters on sex steroid synthesis and metabolism pathways in fish

10 pages, 5 figures, 1 table.-- PMID: 15698553 [PubMed].The interactions of estrogenic (nonylphenol, dicofol, atrazine), androgenic (organotins, phthalates, fenarimol) and anti-androgenic compounds (vinclozolin, diuron, p,p′-DDE) with key enzymatic activities involved in both synthesis and metabolism of sex hormones was investigated. Carp testicular microsomes incubated in the presence of androstenedione and different xenobiotics evidenced higher sensitivity of 5α-reductase activity than 17β-hydroxysteroid dehydrogenase activity towards those chemicals. Dicofol, organotins and phthalates were among the most effective inhibitors. In contrast, ovarian synthesis of maturation-inducing hormones (20α- and 20β-hydroxysteroid dehydrogenase activities) were enhanced by nonylphenol, dicofol, fenarimol and p,p′-DDE. Metabolic clearance pathways of hormones were also affected. Fenarimol, nonylphenol and triphenyltin inhibited the glucuronidation of testosterone and estradiol at concentrations as low as 10, 50 and 100 μM, respectively. Triphenyltin, tributyltin and nonylphenol were also inhibitors of estradiol sulfation with IC50 values of 17, 18 and 41 μM. Overall, the data indicates the interaction of selected chemicals with key enzymatic pathways involved in both synthesis and metabolism of sex hormones. This interference might be one of the underlying mechanisms for the reported hormonal disrupting properties of the tested compounds, and might finally affect physiological processes such as gamete growth and maturation.This study was supported by the Spanish National Plan for Research under Project Ref. REN2002-01709/HID.Peer reviewe

Sex steroids and potential mechanisms of non-genomic endocrine disruption in invertebrates

16 pages, 6 tables, 2 figures.-- PMID: 17219086 [PubMed].-- Printed version published Feb 2007.The review reports on the presence and metabolism of sex steroids in several invertebrate species and provides detailed information on possible mechanisms of endocrine disruption other than the interaction with nuclear receptors. The presence of most vertebrate sex steroids in invertebrate tissues has been demonstrated by liquid or gas chromatography coupled to mass spectrometry. In addition, enzymatic pathways involved in the steroidogenic pathway have been described in at least some invertebrate phyla. Some endocrine disruptors induce alterations in these metabolic pathways and might lead to changes in steroid levels. Growing evidence suggests that estradiol can act through non-genomic pathways in molluscs, and that xenobiotics can as well interfere in these signalling casacades. In spite of these recent advances, most question marks on the action and function of sex steroids in invertebrates remain to be answered.This study was supported by the European Union (COMPRENDO-Project, EVK1-CT-2002-00129).Peer reviewe

Biliary PAH and Alkylphenol Metabolites, Biomarker Enzyme Activities, and Gene Expression Levels in the Deep-Sea Fish Alepocephalus rostratus

22 pages, 3 figures, 3 tablesBiliary polycyclic aromatic hydrocarbon (PAH) and alkylphenol (AP) metabolites, hepatic gene expression, and corresponding enzyme activities were determined in the deep-sea fish Alepocephalus rostratus from two sites within the Mediterranean. Biliary metabolites included the hydroxylated PAH metabolites (OH-PAHs) 1-naphthol, 2-naphthol, 9-fluorenol, 9-phenanthrol, and 1-pyrenol and the APs 4-nonylphenol (NP) and 4-tert-octylphenol (OP). Five biomarker genes, namely, cytochrome P450 1A (CYP1A), vitellogenin (Vtg), catalase (CAT), Cu/Zn-superoxide-dismutase (Cu/Zn-SOD), and glutathione reductase (GR), were quantified using qRT-PCR. Moreover, corresponding enzyme activities (ethoxyresorufin-O-deethylase (EROD), CAT, SOD, and GR) were also determined. The ΣOH-PAHs detected ranged from 21.1 to 300.3 ng/g bile and were mainly composed of 1-naphthol. Both NP and OP metabolites were detected in all samples with concentrations ranging from 17.4 to 107.2 ng/g bile and 4.9 to 17.3 ng/g bile, respectively, and levels were significantly higher in samples from the western Mediterranean (WM) compared to those from the Catalan slope (CS). Accordingly, gene expression was significantly induced in male fish from the WM; however, these results were not reflected in enzyme activity levels. In particular, males caught at 2000 m in the WM exhibited 35-times higher Vtg levels compared to those from the CS, suggesting that endocrine-disrupting effects may potentially be occurring in such remote environments as the deep-seaThe present study was funded by the Spanish Science and Technology Ministry projects PROMETEO (CTM2007-66316-C02-02/MAR), BIOFUN (CTM2007-28739-E/MAR) and the HERMIONE project (EC-FP7 contract number 226354). Samuel Koenig holds a PhD grant (AFR 08/067) from the Fonds National de la Recherche (FNR), Luxembourg. The authors wish to thank the DeepMed Research Group (ICM-CSIC) and the R/V Garcia del Cid (CSIC) and R/V Sarmiento de Gamboa (CSIC) crews for helping with sampling. Furthermore, the authors acknowledge the help by R. Chaler, D. Fanjul, M. Comesaña with GC-MS instrumental analysis, as well as the technical assistance by N. Asker and M. Hultman with qPCR analysisPeer reviewe

Content and pattern of organic pollutants (PAHs, PCBs and DDT) in blue mussels Mytilus trossulus from the southern Baltic Sea

19 pages, 4 figures, 1 table.The objective of this work was to assess the contents and patterns of selected organic pollutants (polycyclic aromatic hydrocarbons - PAHs, polychlorinated biphenyls - PCBs, and chlorinated pesticides - DDT) in the southern part of the Baltic Sea proper, using blue mussels, Mytilus trossulus, as sentinel organisms. The mussels were collected from the Baltic Sea off Poland. The sampling programme focused on the mouths of the rivers Odra and Vistula, located respectively in the Pomeranian Bay and the Gulf of Gdansk, both known to be under anthropogenic pressure.This work was carried out within the framework of bilateral co-operation between the Institute of Oceanology, Sopot, Poland and the Institute of Chemical and Environmental Investigations (IIQAB/CID), Barcelona, Spain. It was also financially supported by the Institute of Oceanology statutory research project no. 2001/3.3.Peer reviewe

Low environmental levels of fluoxetine induce spawning and changes in endogenous estradiol levels in the zebra mussel Dreissena polymorpha

28 p., 3 figures and references.The pharmaceutical fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is often detected in municipal wastewater treatment plant effluents and surface waters within the ng/l range. There is, however, insufficient research evaluating potential hazards of fluoxetine in aquatic organisms at environmentally relevant concentrations. Taking into account that several SSRIs (fluoxetine, fluvoxamine) act as spawning inducers in bivalves, this study aimed at investigating the effects of fluoxetine exposure in the zebra mussel (Dreissena polymorpha) by assessing its potential to induce spawning at environmentally relevant concentrations (20 and 200. ng/l), as well as alterations of endogenous levels of testosterone and estradiol. Histological analyses of female and male gonads showed a concentration dependent decrease of oocyte and spermatozoan density, with a reduction in the number of oocytes per follicle of 40-70%, and spermatozoan density of 21-25%, relative to controls, following exposure to 20 and 200. ng/l of fluoxetine for 6 days, respectively. There was also a significant increase (1.5-fold) in the endogenous level of esterified estradiol in organisms exposed to 200. ng/l fluoxetine. Overall, the study shows that exposure to low levels of fluoxetine may effectively induce gamete liberation in the zebra mussel as well as alter endogenous levels of estradiol, and evidences the need of further investigating the potential of fluoxetine to alter the endocrine system of molluscs at environmentally relevant concentrations.This study was funded by the Ministerio de Medio Ambiente, Medio Rural y Marinom projects 041/SGTB/2007/1.1 and 042/RN08/03.4, the Spanish Ministry of Science and Education under Project Ref. CGL2008-01888/BOS, and a CSIC project (200930I037).Peer reviewe