Transgenerational inheritance of chemical-induced signature: A case study with simvastatin

The hypothesis that exposure to certain environmental chemicals during early life stages may disrupt reproduction across multiple non-exposed generations has significant implications for understanding disease etiology and adverse outcomes. We demonstrate here reproductive multi and transgenerational effects, at environmentally relevant levels, of one of the most prescribed human pharmaceuticals, simvastatin, in a keystone species, the amphipod Gammarus locusta. The transgenerational findings has major implications for hazard and risk assessment of pharmaceuticals and other contaminants of emerging concern given that transgenerational effects of environmental chemicals are not addressed in current hazard and risk assessment schemes. Considering that the mevalonate synthesis, one of the key metabolic pathways targeted by simvastatin, is highly conserved among metazoans, these results may also shed light on the potential transgenerational effects of simvastatin on other animals, including humans.

Zebrafish (Danio rerio) life-cycle exposure to chronic low doses of ethinylestradiol modulates p53 gene transcription within the gonads, but not NER pathways

Parental full life-cycle exposure to ethinylestradiol (EE₂) significantly affects embryo development and survival. One of the possible mechanisms of action of EE₂ may involve the impairment of an organism's ability to repair DNA damage. DNA repair mechanisms have sophistically evolved to overcome DNA damaging hazards that threaten the integrity of the genome. In the present study, changes in the transcription levels of key genes involved in two of the most thoroughly studied DNA repair systems in mammals were evaluated in adult zebrafish (Danio rerio) gonad upon full life-cycle exposure to chronic environmentally low levels of EE₂ (i.e., 0.5, 1 and 2 ng/L EE₂). Real time PCR was used to analyse the expression levels of nucleotide excision repair genes (NER) as well as the tumor suppressor p53 and downstream selected effectors, i.e., p21 (cyclin-dependent kinase inhibitor), GADD45α (growth arrest and DNA damage induced 45, alpha), bax (bcl2-associated X protein) and p53 key regulator MDM2 (murine double minute 2 protein). NER genes transcription levels in gonads did not differ significantly among treatments. In contrast, the number of transcripts of p53 gene was significantly increased in male gonads at all EE₂ exposure concentrations and in females at 1 ng/L EE₂. Despite the increase in p53 transcripts, transcription levels of p21, GADD45α and bax genes were not affected upon EE₂ treatment, whereas MDM2 gene expression significantly increased in females at the intermediate EE₂ dose (1 ng/L). Overall, the present study indicate that chronic low levels of EE₂ significantly modulates the transcription of p53, a key gene involved in DNA repair, particularly in male zebrafish gonads, which supports the hypothesis of an impact of EE2 in male gonad DNA repair pathways.

Friend of GATA and GATA-6 modulate the transcriptional up-regulation of hepcidin in hepatocytes during inflammation

Hepcidin is an antimicrobial peptide hormone that plays a central role in the metabolism of iron and its expression in the liver can be induced through two major pathways: the inflammatory pathway, mainly via IL-6; and the iron-sensing pathway, mediated by BMP-6. GATA-proteins are group of evolutionary conserved transcriptional regulators that bind to the consensus motif-WGATAR-in the promoter region. In hepatoma cells, GATA-proteins 4 and 6 in conjunction with the co-factor friend of GATA (FOG) were shown to modulate the transcription of HAMP. However, it is unclear as to which of the GATA-proteins drive the expression of HAMP in vivo. In this study, using in vitro and in vivo approaches, we investigated the relevance of GATA and FOG proteins in the expression of hepcidin following treatment with IL-6 and BMP-6. We found that treatment of Huh7 cells with either IL-6 or BMP-6 increased the HAMP promoter activity. The HAMP promoter activity following treatment with IL-6 or BMP-6 was further increased by co-transfection of the promoter with GATA proteins 4 and 6. However, co-transfection of the HAMP promoter with FOG proteins 1 or 2 repressed the promoter response to treatments with either IL-6 or BMP-6. The effects of both GATA and FOG proteins on the promoter activity in response to IL-6 or BMP-6 treatment were abrogated by mutation of the GATA response element-TTATCT-in the HAMP promoter region -103/-98. In vivo, treatment of mice with lipopolysaccharide led to a transient increase of Gata-6 expression in the liver that was positively correlated with the expression of hepcidin. Our results indicate that during inflammation GATA-6 is up-regulated in concert with hepcidin while GATA-4 and FOG (1 and 2) are repressed.

The effects of prenatal intraamniotic surfactant or dexamethasone administration on lung development are comparable to changes induced by tracheal ligation in an animal model of congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Lung surfactant deficiency contributes to the pathophysiology of congenital diaphragmatic hernia (CDH) and the high neonatal mortality rate. Acceleration of lung surfactant system maturation by prenatal administration of hormones has been described in animal models of CDH. However, in utero tracheal ligation (TL) is the best method to accelerate lung growth and reverse the pulmonary hypoplasia associated with CDH. Although this method offers promise, its application in humans is limited. The aim of this study was to investigate a new noninvasive therapeutic strategy, that is, the prenatal intraamniotic administration of exogenous porcine surfactant or dexamethasone, and compare it with the effects of TL in an animal model of CDH.

METHODS

Twenty-four pregnant New Zealand rabbits underwent surgery on gestational day 24 or 25 to create CDH in 26 fetuses. Five groups of animals were studied: (1) Control, nonoperated fetuses (n=14), (2) CDH (n=6), (3) CDH plus TL (n 6), (4) CDH plus intraamniotic administration of Curosurf (40 mg; n=6), and (5) CDH plus intraamniotic infusion of dexamethasone (0.4 mg; n=8). On gestational day 30, the fetuses were delivered by cesarean section. Functional studies (lung hysteresis curves and lung distensibility), weight and volume of lungs, histopathologic and histomorphometric analysis of lungs were performed.

RESULTS

The authors demonstrated that the hysteresis curve of CDH animals was shifted downward in comparison with controls. The analyses of curves standardized for lung weight indicated that intraamniotic administration of surfactant or dexamethasone improved lung compliance in comparison with controls and CDH fetuses, but TL had no effect on this parameter. Lung distensibility (maximum lung volume at 32 cm of water pressure per gram of lung) was reduced by CDH, but this parameter was increased by intraamniotic administration of drugs and not by TL (P< .05). CDH decreased the weight and volume of lungs (P< .05), and these changes were reversed only by TL, which prevented the herniation of the liver from the abdomen to the thorax. Histologically, CDH lungs treated with TL or intraamniotic administration of drugs demonstrated structural patterns similar to those of controls. Histomorphometric studies proved that CDH promoted significant thickening of septa walls (P< .05), and all the therapeutic methods could reverse this alteration to control values. The alveolar number per area in control lungs, CDH, and CDH plus TL lungs were similar, but in CDH plus surfactant and CDH plus dexamethasone lungs, the decreased number per area (P< .05) demonstrated that the alveolar airspace was increased.

CONCLUSION

From these data the authors conclude that intraamniotic surfactant or dexamethasone administration is capable of preventing pulmonary hypoplasia in fetuses with CDH, and thus, this method may be a substitute for TL.

Rex shunt for acute portal vein thrombosis after pediatric liver transplantation in children with biliary atresia

BACKGROUND/PURPOSE

Posttransplantation portal vein thrombosis (PVT) can have severe health consequences, and portal hypertension and other consequences of the long-term privation of portal inflow to the graft may be hazardous, especially in young children. The Rex shunt has been used successfully to treat PVT patients since 1998. In 2007, we started to perform this surgery in patients with idiopathic PVT and late posttransplantation PVT. Herein we have reported our experience with this technique in acute posttransplantation PVT.

METHODS

Three patients of ages 12, 15, and 18 months underwent cadaveric (n = 1) or living donor (n = 2) orthotopic liver transplantation (OLT). All patients had biliary atresia with portal vein hypoplasia; they developed acute PVT on the first postoperative day. They underwent a mesenteric-portal surgical shunt (Rex shunt) using a left internal jugular vein autograft (n = 2) or cadaveric iliac vein graft (n = 1) on the first postoperative day.

RESULTS

The 8-month follow-up has confirmed shunt patency by postoperative Doppler ultrasound. There have been no biliary complications to date.

CONCLUSIONS

The mesenteric-portal shunt (Rex shunt) using an autograft of the left internal jugular or a cadaveric vein graft should be considered for children with acute PVT after OLT. These children usually have small portal veins; reanastomosis is often unsuccessful. In addition, this technique has the advantage to avoid manipulation of the hepatic hilum and biliary anastomosis. Although this study was based on a limited experience, we concluded that this technique is feasible, with great benefits to and low risks for these patients.

The use of biomarkers as integrative tools for transitional water bodies monitoring in the Water Framework Directive context - A holistic approach in Minho river transitional waters

The Water Framework Directive (WFD) provides an important legislative opportunity to promote and implement an integrated approach for the protection of inland surface waters, transitional waters, coastal waters and groundwaters. The transitional waters constitute a central piece as they are usually under high environmental pressure and by their inherent characteristics present monitoring challenges. Integrating water quality monitoring with biological monitoring can increase the cost-effectiveness of monitoring efforts. One way of doing this is with biomarkers, which effectively integrate physical-chemical status and biological quality elements, dealing holistically with adverse consequences on the health of water bodies. The new Marine Strategy Framework Directive (MSFD) already incorporates the biomarker approach. Given the recent activities of OSPAR and HELCOM to harmonize existing monitoring guidelines between MSFD and WFD the use of similar methodologies should be fostered. To illustrate the potential of the biomarker approach, juveniles of flounder (Platichthys flesus) were used to evaluate the quality of the Minho river-estuary water bodies. The use of juveniles instead of adults eliminates several confounding factors such changes on the biological responses associated with reproduction. Here, a panel of well-established biomarkers, EROD, AChE, SOD, CAT, GST, LPO, ENA and FACs (1-Hydroxyrene) were selected and measured along with a gradient of different physical conditions, and integrated with trace elements characterization on both biota and sediments. In general, a clear profile along the water bodies was found, with low seasonal and spatial variation, consistent with a low impacted area. Overall, the results support the use of both the battery of biomarkers and the use of juvenile flounders in the monitoring of the water quality status within the WFD.

Organotin levels in seafood from Portuguese markets and the risk for consumers

Because of their ubiquity in the aquatic environment, the antifouling agent tributyltin (TBT) and other organotins (OTs) accumulate through the food chain, resulting in the occurrence of OTs in seafood products. Despite a high number of studies on the negative impact of TBT in female prosobranch gastropods, few works exist in Europe reporting the levels of these compounds in edible parts of marine organisms used in Human diet. Therefore, within the scope of an EU project OT-SAFE the levels of several OTs were evaluated in the most relevant seafood products for Portuguese consumers. Butyltins (BTs) have been detected in all analysed groups (fish, crustaceans, bivalves, cephalopods), whereas triphenyltin, tricyclohexyltin, monooctyltin and dioctyltin could not be detected and tetrabutyltin was present above detection limits in a single sample. In general, levels of BTs in edible parts of fish, crustaceans and cephalopods collected in Portuguese markets during this study are in the lower range of that reported for these animal groups from other locations (i.e. below 30ngg(-1) wet weight). In contrast, moderate to high concentrations have been observed in bivalves (up to 275ng TBTg(-1) wet weight). While most samples showed TBT plus DBT levels below the tolerable average residue levels (TARL), which may indicate low risk for consumer, four bivalve samples displayed BT levels above TARL, thus indicating that higher bivalve consumer groups may be at risk. The results found are discussed in relation to the potential risk for consumers and integrated with recent finds on the molecular targets of OTs in mammals.

Oral fluids for the immunodiagnosis of Schistosoma mansoni infection

Saliva and oral transudate were evaluated for their potential as human specimens in the detection of IgG antibodies against soluble Schistosoma mansoni egg antigen (SEA). Preliminary laboratory testing of 49 subjects, 37 with parasitological proven infection and 12 negative controls, displayed 100% sensitivity in ELISA using serum and oral transudate and 94.6% using saliva. The specificity of the ELISA with serum was 100% versus 91.7% with both oral fluids. Significant Spearman rank correlations of anti-SEA IgG levels with egg counts were observed for serum, oral transudate and saliva (P < 0.05). The sensitivity of dot-ELISA was 100% for serum, 89% for transudate and 81% for saliva, and specificity was 100% for all 3 samples. The immunodiagnostic value of ELISA for the detection of anti-SEA IgG antibodies in oral transudate was further evaluated in 197 individuals from an endemic area of Brazil. The ELISA using serum and oral transudate showed sensitivities of 98.8% and 100% respectively and specificities of 67.8% and 64.3% respectively. Use of oral fluids for the diagnosis of S. mansoni infection was equivalent to sera with respect to test efficacy, offering an alternative to blood collection.

Measuring lysosomal stability as an effective tool for marine coastal environmental monitoring

The use of lysosomal stability in the mussel, Mytilus galloprovincialis, as a potential biomarker of environmental contamination has been evaluated along the Portuguese coast. To this end, the neutral red retention (NRR) time was measured in mussel haemocytes gathered from nine different locations reflecting different degrees of anthropogenic contamination. Mussels collected in the vicinity of industrial and urban areas showed the lowest lysosomal stability. Additionally, no significant seasonal variability (winter-spring/summer) for NRR time was observed. In order to further support the usefulness of this method as an integrated tool for monitoring marine coastal environments, we compared the levels of xenobiotics in mussel tissues with the obtained NRR values. The results highlighted a consistent pattern, with the lowest lysosomal stability intimately correlated with the higher contaminant concentrations. In summary, this integrated approach further demonstrated that the NRR assay can provide useful and objective indications of the real health status of organisms subjected to different stress agents, being a valid option for environmental monitoring.

The effects of prenatal intraamniotic surfactant or dexamethasone administration on lung development are comparable to changes induced by tracheal ligation in an animal model of congenital diaphragmatic hernia: studies of lung glycogen content, elastic fiber density, and collagen content

BACKGROUND/PURPOSE

A new noninvasive therapeutic strategy, which consisted of prenatal intraamniotic administration of porcine surfactant or dexamethasone, was previously used to prevent the functional and structural immaturity of lungs associated with congenital diaphragmatic hernia (CDH), and its effects on lung development were comparable with the changes induced by tracheal ligation (TL). The purpose of this study is to verify if this novel therapeutic modality has any effect in the elevated concentration of lung glycogen and altered contents of lung elastic fiber and collagen promoted by CDH.

METHODS

A pilot study was performed to investigate in the rabbit model if the infused drugs in the amniotic cavity were aspirated by the CDH and non-CDH fetuses, and if there was correspondence between lung immaturity and high glycogen concentration in lung tissue. Experimental groups consisted of 50 pregnant rabbits that underwent surgery on gestational day 24 or 25 to create left-sided diaphragmatic hernias in 56 fetuses, which were divided in groups according to the procedures: CDH (n = 12), CDH plus TL (n = 16), CDH plus intraamniotic administration of Curosurf (40 mg, n = 12), and CDH plus intraamniotic administration of dexamethasone (n = 16). On gestational day 30, the fetuses were delivered by cesarean section, and 28 normal unoperated fetuses served as controls. The lungs were weighed and submitted to biochemical determination of glycogen, morphometric evaluation of elastic fibers, and colorimetric analysis of collagen.

RESULTS

In all CDH and non-CDH fetuses of the pilot study, the amniotic content was massively aspirated into the lungs and trachea. There was an increase in lung glycogen content of fetuses at 24 days' gestation in comparison with 20-day gestational age fetuses, followed by a decrease in the near full-term fetuses. In the fetuses of the experimental groups, CDH decreased the lung weight to body weight ratios of lungs ipsilateral to the hernia. These changes were reversed by TL but not by intraamniotic administration of surfactant or dexamethasone. Lung glycogen concentrations in the lungs of CDH fetuses were significantly higher than those in the control group. These changes were reversed by intraamniotic administration of surfactant but not by dexamethasone administration or TL. In the lungs ipsilateral to the hernia, surfactant administration promoted a significant decrease in glycogen content to levels lower than control lungs. CDH promoted a decrease in the linear density of elastic fibers in both lungs, ipsilateral and contralateral to the hernia. This alteration was partially corrected by TL and surfactant administration, although dexamethasone administration had no effect. The concentrations of collagen in both lungs were increased significantly by CDH, and these alterations could not be reversed by TL. In the lungs ipsilateral to the hernia, intraamniotic administration of surfactant or dexamethasone promoted a significant decrease in the lung concentration of collagen but not to control levels.

CONCLUSIONS

The positive effects of intraamniotic surfactant or dexamethasone administration on lung maturity of fetuses with CDH were observed. This therapy may be a substitute for TL.

Retinoid level dynamics during gonad recycling in the limpet Patella vulgata

Germ cell commitment and meiosis initiation are among the multitude of physiological roles of retinoic acid (RA) in vertebrates. Acting via receptor-mediated transcription, RA induces the expression of meiotic factors, triggering meiosis. Contrasting with vertebrates, invertebrate RA metabolism is scarcely understood. Still, some physiological processes appear to be conserved. Here we set to evaluate the role of retinoids in the gonad maturation process of the marine gastropod Patella vulgata. We found that retinoid concentration in gonadal tissue, namely RA, varies between breeding and resting specimens, with maxima attained in the latter. Additionally, we isolated and quantified the expression of both the retinoic acid receptor (RAR) and the retinoid X receptor (RXR) in gonads. In view of the stability of retinoid receptor expression, we suggest that the balance of RA levels operates through the enzymatic control of synthetic and catabolic processes. Overall, the reported data are supportive for a developmental role of RA during gonadal maturation in P. vulgata, which should be addressed in other protostome lineages.

Basiliximab-chimeric anti-IL2-R monoclonal antibody in pediatric liver transplantation: comparative study

Basiliximab is a monoclonal antibody that binds to the alpha subunit (CD(25)) of the interleukin-2 receptor of activated T lymphocytes. The advantage of basiliximab in organ transplantation is the reduce possibility to calcineurin inhibitor dosages to avoid nephrotoxicity. Basiliximab has significantly reduced the incidence of acute rejection (AR) in renal transplant recipients; however, the results are uncertain in liver transplantation (LT). The objective of this investigation was to assess the effect of basiliximab to prevent AR in the first 6 months after pediatric LT. From March 2000 to October 2001, 32 recipients of a primary orthotopic cadaveric or living donor LT were given basiliximab by intravenous bolus injection on the day of transplantation (day 0) and on day 4. Four children who received one dose were excluded from the study. The rate and the intensity of AR episodes, the incidence of chronic rejection, serum creatinine level, incidence of infections, adverse side effects, and daily oral dosage of cyclosporine (Neoral) to maintain the target blood level of 850 to 1000 mg/dL at C2, 2 hours after the administration, were analyzed in the remaining 28 recipients. Results were compared to those obtained from a matched historical group (n = 28) of similar age, weight, and hepatic diseases distribution. None of the analyzed parameters was statistically significant (P >.05) except for the daily oral dose of cyclosporine (7 to 13 mg/kg/dose, P <.05). In our series, the addition of basiliximab to the immunosuppressive therapy did not reduce the incidence of AR in pediatric LT.

Simvastatin effects on detoxification mechanisms in Danio rerio embryos

The transcription and protein activity of defence mechanisms such as ABC transporters, phase I and II of cellular detoxification and antioxidant enzymes can be altered in the presence of emerging contaminants such as pharmaceuticals impacting the overall detoxification mechanism. The present work aimed to characterise the effects of simvastatin on the detoxification mechanisms of embryonic stages of Danio rerio. In a first approach, constitutive transcription of key genes involved in detoxification was determined. Embryos were collected at different developmental stages, and transcription patterns of genes coding for ABC transporters, phase I and II and oxidative stress were analysed. With exception of abcc2, all genes seem to be from maternal transfer (0-2 hpf). Embryos were then exposed to different concentrations of simvastatin (5 and 50 μg/L), verapamil and MK571 (10 μM; ABC protein inhibitors) and a combination of simvastatin and ABC inhibitors. mRNA expression levels of abcb4, abcc1, abcc2, abcg2, cyp1a, cyp3a65, gst, sod, cat was evaluated. Accumulation assays to measure ABC proteins activity and activity of EROD, GST, CAT and Cu/ZnSOD, were also undertaken. Simvastatin acted as a weak inhibitor of ABC proteins and increased EROD and GST activity, whereas Cu/ZnSOD and CAT activity were decreased. Simvastatin up-regulated abcb4 and cyp3a65 transcription (both concentrations), as well as abcc1 and abcc2 at 50 μg/L, and down-regulated gst, sod, cat at 5 μg/L. In conclusion, our data revealed the interaction of simvastatin with detoxification mechanisms highlighting the importance of monitoring the presence of this emerging contaminant in aquatic environments.

Organotin contamination in the Atlantic Ocean off the Iberian Peninsula in relation to shipping

Imposex in female snails, a bioindicator of TBT contamination, and the presence of organotins in snails' tissue and sediments were studied at nine sites off the western Iberian Peninsula. The study was part of a European project (acronym HIC-TBT) co-financed by the EU-LIFE programme, intending to investigate and communicate the impact of organotins from ships in marine ecosystems. Snails and sediments were sampled during two cruises in May/June 1999 and in January 2000 in areas of high, intermediate and low-shipping density. Imposex was found in female snails from several sampling sites, some of which had an imposex incidence of 100%. Differences in sensitivity were found between species; hence comparison of imposex levels between locations where different species were collected was not straightforward. Total organotin concentrations in sediments (sum of butyl and phenyltin compounds) ranged from 21 to 185 ng Sn g(-1) with higher values for most sites sampled in the vicinity of shipping lanes. Organotin concentration in snails' tissue ranged from <5 to 196 ng Sn g(-1), which are similar to those found in snails from other offshore areas contaminated by TBT. Overall, these results give further support to the recent ban on the use of organotin based antifouling paints to all ship size.

Identifying the gaps: Resources and perspectives on the use of nuclear receptor based-assays to improve hazard assessment of emerging contaminants

Biological control of key processes, such as development and reproduction, is largely ascribed to a superfamily of ligand-dependent and independent transcription factors named Nuclear Receptors (NRs). Given their ability to accommodate ligands, NRs are prime targets of man-made compounds that mimic or antagonise the action of endogenous ligands. Accordingly, NRs occupy a prominent role in OECD and EPA guidelines for testing and assessment of Endocrine disrupting chemicals (EDCs). Although NR assays are already a key instrument in the OECD Conceptual Framework for Testing and Assessment of EDCs, the focus is mostly on vertebrate NRs. Here, we address the chief knowledge gaps in the field. More specifically, we (1) verify the growing availability of genomes/transcriptome projects, (2) highlight gaps in the identification and characterization of metazoan NR and in the establishment of (3) life cycle and (4) toxicity testing protocols. An overall bias towards vertebrates and selected invertebrate groups, notably Arthropoda, Annelida and Mollusca, was observed. Hence, if we aim to improve risk assessment of EDCs and emerging pollutants at an ecosystems scale, and understand their mode of action (MOA), we must establish a framework to include a broad phylogenetic sampling of Metazoans.

Imposex and butyltin contamination off the Oporto Coast (NW Portugal): a possible effect of the discharge of dredged material

Imposex in the gastropod Hinia reticulata, a bioindicator for tributyltin (TBT) contamination, was investigated in locations at different distances from the Oporto harbour-dredged material discharge site. The degree of imposex found was inversely related to the distance to the discharge site, the highest imposex frequency being found closest to the discharge area. However, the levels of imposex found were low when compared with those reported for H. reticulata populations from moderately TBT-contaminated areas. Despite detectable levels of dibutyltin (DBT) and monobutyltin (MBT) in snail tissues (total butyltins ranging from 84 to 410 ng/g Sn dry wt.), TBT was below detection limit in all snail samples collected in open sea.

The last frontier: Coupling technological developments with scientific challenges to improve hazard assessment of deep-sea mining

The growing economic interest in the exploitation of mineral resources on deep-ocean beds, including those in the vicinity of sensitive-rich habitats such as hydrothermal vents, raise a mounting concern about the damage that such actions might originate to these poorly-know ecosystems, which represent millions of years of evolution and adaptations to extreme environmental conditions. It has been suggested that mining may cause a major impact on vent ecosystems and other deep-sea areas. Yet, the scale and the nature of such impacts are unknown at present. Hence, building upon currently available scientific information it is crucial to develop new cost-effective technologies embedded into rigorous operating frameworks. The forward-thinking provided here will assist in the development of new technologies and tools to address the major challenges associated with deep sea-mining; technologies for in situ and ex situ observation and data acquisition, biogeochemical processes, hazard assessment of deep-sea mining to marine organisms and development of modeling tools in support of risk assessment scenarios. These technological developments are vital to validate a responsible and sustainable exploitation of the deep-sea mineral resources, based on the precautionary principle.

The use of the shanny Lipophrys pholis for pollution monitoring: a new sentinel species for the northwestern European marine ecosystems

The contamination of aquatic ecosystems by organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is a matter of great concern. Mussels have been extensively used as sentinel species in a large number of monitoring programs. However, the use of bivalves as the sole species has some limitations, because they are not as responsive as fish to Aryl Hydrocarbon Receptor agonists. Hence, for many marine areas, there is the need to validate new sentinel fish species that can be used in the assessment of pollution by organic contaminants. The shanny Lipophrys pholis is an intertidal fish that combines many characteristics required in a sentinel species: is abundant and easy to catch, has a wide geographical distribution and restrict home range. After larvae recruitment to the intertidal rocky shores, they remain in the same area for the rest of the life-cycle, thus reflecting local pollutants exposure. In order to evaluate the species sensitivity to organic contaminants under field conditions, L. pholis were collected at six sites reflecting different degrees of anthropogenic contamination. The induction of two biomarkers extensively validated in the assessment of PAHs contamination ethoxyresorufin-O-deethylase activity (EROD) and Fluorescent Aromatic Compounds (FACs) was evaluated. In parallel, mussels were collected at the same locations and levels of 16 PAHs and selected heavy metals determined. Overall, the specimens collected in the urban areas showed a significant induction of EROD and FACs (up to a six-fold induction) if compared with the reference sites. Additionally, a positive correlation was observed between the biomarkers and PAHs levels in mussel tissues. Even though further validation is currently in progress, the available data indicate that L. pholis is responsive to organic contaminants such as PAHs, suggesting its future integration in monitoring programmes designed to evaluate the presence of these contaminants in European marine ecosystems.

Rapid-behaviour responses as a reliable indicator of estrogenic chemical toxicity in zebrafish juveniles

Whereas biochemical and molecular parameters have been well recognised as important "signposts" of individual disturbance to endocrine disrupting chemical's (EDCs) exposure, behavioural endpoints are yet greatly overlooked as a routine tool in environmental risk assessment of EDCs. However, life histories are intimately associated with numerous inter- and intra-specific interactions, which invariably depend on the performance of effective behaviours. Within fish species, one of the most important factors influencing energy turnover earlier in the development is locomotor activity. This essential trait reflects the organism's ability to generate and coordinate the metabolic energy required for both reproductive and non-reproductive behaviours. Inappropriate movement responses due to toxic effects of contaminants may ultimately impact important ecological variables. Therefore, in the present study, the swimming bursts of zebrafish juveniles exposed for 40 d to the synthetic estrogen ethinylestradiol (EE(2)), tested at environmentally relevant concentrations (nominal concentrations of 0.5, 1 and 2 ng L(-1)), were investigated in order to address the potential of rapid-behaviour patterns as an effective response indicator of estrogenic endocrine disrupting chemical's exposure. This synthetic estrogen was selected due to its high prevalence in aquatic ecosystems, ability to mimic natural estrogens and proven record of causing negative effects in fish reproduction. The behavioural responses were compared with established endpoints used in the screening of EE(2) effects at adulthood. Results indicate that zebrafish juveniles' swimming activity was significantly decreased upon EE(2) exposure. Since reduced locomotion of zebrafish may impact foraging, predator avoidance, drift and transport, and even interfere with social and reproductive behaviours, a fitness decline of wild fish populations can ultimately be hypothesized. Furthermore, behavioural endpoints were found to display higher sensitivity to EE(2) than either vitellogenin gene induction or reproductive parameters determined at adulthood. Overall, the findings of this work not only demonstrate the power of high-throughput behavioural responses, able to act as sensitive early warning signals of EDC exposure, but also highlight the potential of behavioural endpoints in providing a more comprehensive and non-invasive measure of EDC's exposure.

Simvastatin modulates gene expression of key receptors in zebrafish embryos

Nuclear receptors (NR) are involved in the regulation of several metabolic processes and it is well known that these constituents may be modulated by different chemicals classes, including pharmaceuticals that may activate or antagonize NR. In mammals, some pharmaceuticals modulate the transcription of pregnane X receptor, Pxr, peroxisome proliferator activated receptor, Ppars, and aryl hydrocarbon receptor, Ahr, affecting mRNA expression of genes belonging to various regulatory pathways, including lipid metabolism and detoxification mechanisms. The aim of this study was to determine the effects of simvastatin (SIM), an anticholesterolemic drug, on selected NR and AhR mRNA transcription levels during zebrafish early development. Embryos were collected at different development stages (0, 2, 6, 14, 24, 48, and 72 hr post fertilization (hpf)) and mRNA of all target NR was detected at all time points. Embryos (1 and 24 hpf) were exposed to different concentrations of SIM (5 or 50 μg/L) in two differing assays with varying exposure times (2 or 80 hr). The transcription levels of ahr2, raraa, rarab, rarga, pparαa, pparβ1, pparγ, pxr, rxraa, rxrab, rxrbb, rxrga, rxrgb, as well as levels of cholesterol (Chol) were measured after exposure. SIM exerted no marked effect on Chol levels, and depending upon exposure duration mRNA levels of NR and AhR either increased or decreased. After 2 hr SIM treatment in 24 hpf embryos, transcription of ppars, pxr, and ahr was up-regulated, while after 80 hr mRNA levels of pxr and ahr were decreased with no marked changes in ppars. Data demonstrate that SIM produced alterations in gene expression of NR which are involved in varying physiological functions and that may disturb regulation of different physiological processes which might impair fish survival and ecosystems regeneration.

Environmental risk assessment of accidental marine spills: A new approach combining an online dynamic Hazardous and Noxious substances database with numerical dispersion, risk and population modelling

The foreseen rise on maritime transportation of Hazardous and Noxious Substances (HNS) increases the likelihood of accidents, leading to a higher risk of chemical spillage that can have severe ecological impacts. Considering the lack of information on HNS spills, the response to these events is less well established than those involving oil. Moreover, a paramount knowledge of the physicochemical and ecotoxicological properties of the substance involved is required for an effective environmental risk assessment and response to an HNS spill. In the present work, a new online interface, in which a dynamic HNS database feeds a chemical numerical dispersion model, was developed with the aim to improve predictions regarding the behaviour and environmental risk of HNS spills on marine ecosystems. Potential impacts to pelagic organisms were characterized by coupling model outputs with toxicity risk ratios. Furthermore, a simple population model was developed, foreseeing impacts at the ecological level. The integration of the developed tools establishes an innovative framework, which aims to improve predictions related to HNS plumes' behaviour and potential hazards to the marine environment and associated ecosystem services. Further, this new approach fosters an improved preparedness and response to coastal pollution incidents, enhancing effective decision making and management by competent authorities.

The evolutionary road to invertebrate thyroid hormone signaling: Perspectives for endocrine disruption processes

Thyroid hormones (THs) are the only iodine-containing hormones that play fundamental roles in chordates and non-chordates. The chemical nature, mode of action and the synthesis of THs are well established in mammals and other vertebrates. Although thyroid-like hormones have been detected in protostomes and non-chordate deuterostomes, TH signaling is poorly understood as compared to vertebrates, particularly in protostomes. Therefore, the central objective of this article is to review TH system components and TH-induced effects in non-vertebrate chordates, non-chordate deuterostomes and protostomes based on available genomes and functional information. To accomplish this task, we integrate here the available knowledge on the THs signaling across non-vertebrate chordates, non-chordate deuterostomes and protostomes by considering studies encompassing TH system components and physiological actions of THs. We also address the possible interactions of thyroid disrupting chemicals and their effects in protostomes and non-chordate deuterostomes. Finally, the perspectives on current and future challenges are discussed.

Vitellogenin gene expression in the intertidal blenny Lipophrys pholis: a new sentinel species for estrogenic chemical pollution monitoring in the European Atlantic coast?

The presence of estrogenic chemicals (ECs) in the aquatic environment is a growing problem. While most attention was initially given to fresh water and estuarine ecosystems, it is now evident that coastal marine areas are also vulnerable to these pollutants. The use of vitellogenin induction in male fish, a specific biomarker of EC exposure, has been the most widely applied methodology. However, in some occasions, the high mobility and migratory behaviour of common sentinel fish species makes data interpretation difficult. Hence, there is the need to validate new sentinel marine fish species which should display, among other features, a strong homing behaviour. The shanny, Lipophrys pholis, is an intertidal fish that combines many of the required characteristics for a sentinel species: abundance and easy of catch, wide geographical distribution and restricted home range. Thus, in order to evaluate, in the field, the species sensitivity to ECs, L. pholis males were collected at two sites reflecting different degrees of anthropogenic contamination. The vitellogenin II gene (VTGII) was isolated and its liver expression evaluated by RT-PCR in the field samples. A significant induction of gene expression was observed in the specimens collected in the urban area, if compared to the reference site, which suggests exposure to ECs. Moreover, a 21-days laboratory exposure to environmental relevant concentrations of ethinylestradiol (EE2) was also performed. A significant induction of L. pholis VTGII gene in EE2 exposed males was observed suggesting similar sensitivity to that of other marine/estuarine fishes. Even though further validation is currently in progress, the available data indicates that L. pholis is responsive to ECs, thus favouring its future integration in monitoring programmes designed to evaluate the presence of ECs in European marine ecosystems.

Urogenital papilla feminization in male Pomatoschistus minutus from two estuaries in northwestern Iberian Peninsula

Recently, male urogenital papilla feminization (UGPF) in the sand goby Pomatoschistus minutus was reported in several UK estuaries with high levels of estrogenic compounds. The fact that this species is also common in southern European estuaries, together with its life-cycle characteristics, prompted us to investigate P. minutus UGPF in the northwestern of Iberian Peninsula. Specimens of P. minutus were periodically sampled during 2004 at several locations in two estuaries (Minho and Lima). Evidence for UGPF was recorded in both estuaries, the highest incidence being observed in the Lima estuary (50%). Estrogen levels (17beta-estradiol and estrone) above 100 pg/l were observed in both estuaries, the higher concentrations being found in the Lima estuary. Overall, the results suggest a relationship between the feminization of male P. minutus urogenital papilla and the presence of estrogenic compounds. In the future, more in-depth studies are required in order to use P. minutus as a sentinel species for estrogenic compound monitoring in estuaries.