Trichostatin A Enhances Gap Junctional Intercellular Communication in Primary Cultures of Adult Rat Hepatocytes

The effects of histone deacetylase inhibitor Trichostatin A (TSA) on connexin (Cx) expression and gap junctional intercellular communication (GJIC) were investigated in primary cultures of adult rat hepatocytes. GJIC was monitored by using the scrape-loading/dye transfer method. Immunoblotting and immunocytochemistry were used to investigate Cx protein levels and localization. Cx gene expression was studied by means of quantitative reverse transcriptase-polymerase chain reaction. TSA increased Cx32 protein levels and affected negatively the Cx26 protein levels. The latter was preferentially located in the cytosol of cultured cells. TSA also promoted the appearance of Cx43 in the nuclear compartment of primary cultured hepatocytes. Overall, this resulted in enhanced GJIC activity. It is important to note that the time of onset of TSA treatment was crucial for the extent of its outcome and that the effects of TSA on Cx protein levels occurred independently of transcriptional changes. TSA differentially affects Cx proteins in primary rat hepatocyte cultures, suggesting distinct regulation and/or distinct roles of the different Cx species in the control of hepatic homeostasis. TSA enhances GJIC between primary cultured rat hepatocytes, an interesting finding supporting its use to further optimize liver-based in vitro models for pharmacotoxicological purpose

Use of 5-azacytidine in a proof-of-concept study to evaluate the impact of pre-natal and post-natal exposures, as well as within generation persistent DNA methylation changes in Daphnia

Short-term exposures at critical stages of development can lead to delayed adverse effects long after the initial stressor has been removed, a concept referred to as developmental origin of adult disease. This indicates that organisms’ phenotypes may epigenetically reflect their past exposure history as well as reflecting chemicals currently present in their environment. This concept has significant implications for environmental monitoring. However, there is as yet little or no implementation of epigenetics in environmental risk assessment. In a proof-of-principle study we exposed Daphnia magna to 5-azacytidine, a known DNA de-methylating agent. Exposures covered combinations of prenatal and postnatal exposures as well as different exposure durations and recovery stages. Growth, the transcription of genes and levels of metabolites involved in regulating DNA methylation, and methylation levels of several genes were measured. Our data shows that prenatal exposures caused significant changes in the methylome of target genes, indicating that prenatal stages of Daphnia are also susceptible to same level of change as post-natal stages of Daphnia. While the combination of pre- and postnatal exposures caused the most extreme reduction in DNA methylation compared to the control group. Furthermore, some of the changes in the methylation patterns were persistent even after the initial stressor was removed. Our results suggest that epigenetic biomarkers have the potential to be used as indicators of past chemical exposure history of organisms and provide strong support for implementing changes to the current regimes for chemical risk assessment to mimic realistic environmental scenarios

Environmentally relevant iron oxide nanoparticles produce limited acute pulmonary effects in rats at realistic exposure levels

Iron is typically the dominant metal in the ultrafine fraction of airborne particulate matter. Various studies have investigated the toxicity of inhaled nano-sized iron oxide particles (FeOxNPs) but their results have been contradictory, with some indicating no or minor effects and others finding effects including oxidative stress and inflammation. Most studies, however, did not use materials reflecting the characteristics of FeOxNPs present in the environment. We, therefore, analysed the potential toxicity of FeOxNPs of different forms (Fe3O4 , α-Fe2O3 and γ-Fe2O3 ) reflecting the characteristics of high iron content nano-sized particles sampled from the environment, both individually and in a mixture (FeOx-mix). A preliminary in vitro study indicated Fe3O4 and FeOx-mix were more cytotoxic than either form of Fe2O3 in human bronchial epithelial cells (BEAS-2B). Follow-up in vitro (0.003, 0.03, 0.3 µg/mL, 24 h) and in vivo (Sprague–Dawley rats, nose-only exposure, 50 µg/m3 and 500 µg/m3 , 3 h/d × 3 d) studies therefore focused on these materials. Experiments in vitro explored responses at the molecular level via multi-omics analyses at concentrations below those at which significant cytotoxicity was evident to avoid detection of responses secondary to toxicity. Inhalation experiments used aerosol concentrations chosen to produce similar levels of particle deposition on the airway surface as were delivered in vitro. These were markedly higher than environmental concentrations. No clinical signs of toxicity were seen nor effects on BALF cell counts or LDH levels. There were also no significant changes in transcriptomic or metabolomic responses in lung or BEAS-2B cells to suggest adverse effects

Assessment of an application on a detoxification process of groundnut press cake for aflatoxins by ammoniation

12 p.-2 fig.-2 tab.Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on an application for a detoxification process of groundnut press cake for aflatoxins by ammoniation. Specifically, it is required that the feed decontamination process is compliant with the acceptability criteria specified in the Commission Regulation (EU) 2015/786 of 19 May 2015. The CONTAM Panel assessed the data provided by the feed business operator with respect to the efficacy of the process to remove the contaminant from groundnut press cake batches and on information demonstrating that the process does not adversely affect the characteristics and the nature of the product. Although according to the literature the process may be able to reduce aflatoxin levels below the legal limits, the Panel concluded that the proposed decontamination process, on the basis of the experimental data submitted by the feed business operator, cannot be confirmed for compliance with the acceptability criteria provided for in Commission Regulation (EU) 2015/786 of 19 May 2015. The Panel recommended sufficient sample testing before and after the process, under the selected conditions, to ensure that the process is reproducible and reliable and to demonstrate that the detoxification is not reversible. In addition, genotoxicity testing of extracts of the treated feedingstuff and of the identified degradation products would be necessary. Finally, information on the transfer rate of AFB1 to AFM1 excretion in milk for animals fed the ammoniated product, in comparison to the starting material and on the ammoniation process changes of the nutritional values of the feed material should be provided.The Panel wishes to thank Federico Cruciani and Carina Wenger for the support provided to this scientific output, and the hearing expert Professor Dr Wayne L Bryden, for the overview on aflatoxin inactivation by ammoniation.Peer reviewe

Risk assessment of chlorinated paraffins in feed and food

The Panel wishes to thank the hearing expert: Kerstin Krätschmer and EFSA staff member: Kelly Niermans for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data in food and human milk and data on the toxicity of CPs, and supported the data collection for the Comprehensive European Food Consumption Database.Peer reviewedPublisher PD

Evaluation of the shucking of certain species of scallops contaminated with domoic acid with a view to the production of edible parts meeting the safety requirements foreseen in the Union legislation

Acknowledgements: The Panel wishes to thank the following hearing experts for the support provided to this scientific output: Marina Nicolas and Micheal O'Mahony. The Panel wishes to acknowledge all European competent institutions, Member State bodies and other organisations that provided data for this scientific output.Peer reviewedPublisher PD

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

Panel members: Margherita Bignami, Laurent Bodin, James Kevin Chipman, Jesus del Mazo, BettinaGrasl-Kraupp, Christer Hogstrand, Laurentius (Ron) Hoogenboom, Jean-Charles Leblanc, Carlo StefanoNebbia, Elsa Nielsen, Evangelia Ntzani, Annette Petersen, Salomon Sand, Dieter Schrenk, TanjaSchwerdtle, Christiane Vleminckx and Heather Wallace Requestor: European Commission Question number: EFSA‐Q‐2018‐00433 Acknowledgements: The Panel wishes to thank the hearing experts: Cathy Fernandes and Henri Schroeder, and EFSA staff members: Kelly Niermans and Federico Cruciani, for the support provided to this scientific output. The Panel wishes to acknowledge all European competent institutions and Member State bodies that provided consumption and occurrence data for this scientific output. Data: All annexes on occurrence and exposure data, as well as the protocol used to produce this Scientific opinion, cross‐referenced in the text, are available on the EFSA Knowledge Junction at: https://doi.org/10.5281/zenodo.4475651Peer reviewedPublisher PD

Evaluation of the shucking of certain species of scallops contaminated with lipophilic toxins with a view to the production of edible parts meeting the safety requirements foreseen in the Union legislation

Acknowledgements: The Panel wishes to thank the following hearing experts for the supportprovided to this scientic output: Laurent Guillier, Mari na Nicolas and Micheal O’Mahony. ThePanel wishes to acknowledge all European competent institutions, Member State bodies and otherorganisations that provided data for this scientic outputPeer reviewedPublisher PD

Risk assessment of aflatoxins in food

© 2020 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.Peer reviewedPublisher PD