Meet our EDC-MixRisk scientists and hear their story on what they are researching and why it matters. Joachim Sturve is assoc. professor and lecturer at the Department of Biological and Environmental Sciences at the University of Gothenburg, Sweden. He is an ecotoxicologist and the main focus of his research is on the effects of pollutants in aquatic organisms, primarily fish.


Hi Joachim – What your research group is researching in the experimental module of EDC-MixRisk?

We are studying the effects of EDC mixtures in fish, primarily zebrafish. The zebrafish genome matches approximately 70% to human orthologs, and they serve as a model species for biomedical research. Our work in EDC-MixRisk is divided into two parts. First, acute exposures with the aim to identify modes of action and possible biomarkers for this kind of exposures. Second, long-term transgenerational exposures with the aim to find epigenetic effects of EDC mixture. F0 generation of fish has been fed with low levels of EDC mixtures from larval stage until sexual maturity. Epigenetic alteration will be studied in the F1 and F2 generations.

 

What have you discovered so far and what your first results indicate?

The short turn acute studies have generated a lot of fascinating results and it is evident that the thyroid system is affected by these mixtures. We have identified specific components (genes) in the thyroid system which might be interesting for future studies. Epigenetic alterations in F1 and F2 generations will be studied during the fall of 2017.

 

What are the potential implications of your findings in a bigger picture?

In EDC-MixRisk, the various cell and animal models will be applied to epidemiological findings from two independent human cohorts. This gives a unique opportunity for collective data analysis comparing the reliability of experimental models in reproducing human health effects. Our results then again contribute to adding one more piece of the puzzle when it comes to EDCs effects on the thyroid system. They will hopefully also generate possible biomarkers for future screening and monitoring, which is relevant for risk assessment.

 


EDC-MixRisk will organize a workshop in Brussels, 25-26 September 2017. The aim of the workshop is to discuss the Adverse Outcome Pathway (AOP) approach and to explore the approach from the EDC-MixRisk perspective. The second day of the workshop will focus especially on aspects of societal impact and building key messages based on recent research results.


The EDC-MixRisk Consortium came together for its annual meeting in Stockholm, 15-17 May, to discuss the project’s progress and future activities.

The meeting was organized as a three-day event, combining an 1) Adverse Outcome Pathway  (AOP) workshop 2) a joint meeting between EDC-MixRisk and EDC-2020 to present scientific results and 3) one and half days dedicated for the EDC-MixRisk Consortium discussions.

The meeting was a great opportunity to learn more about an AOP approach and get highlights and glimpses of scientific results generated within the two projects, EDC-MixRisk and EDC-2020. Furthermore, the meeting provided a great forum to share lessons learned as well as to receive feedback and to discuss further ideas and plans with the Members of the Scientific Advisory Board.

The programme of the last one and half days of the meeting gave an overview of the project progress and on the tasks within the different modules. Also an update on management and dissemination activities was presented. The module breakout sessions drilled into the challenges, future plans and details of the work which were reported on the final day of the meeting.

The first results generated within the project have demonstrated the validity of project’s integrated approach – interaction between epidemiology and experimental toxicology, and the need to take mixture effects into account for risk assessment. It was summarized that overall, the project is progressing well and is largely on track in terms of its tasks and timeline.

The 2018 Consortium meeting will be held again in Stockholm, the hometown of the Project Coordinator, Prof. Åke Bergman.

 

 

 

 

 

 

EDC-MixRisk is a four-year project financed through the EU Commission’s programme Horizon 2020, which started in the spring of 2015. It involves participation from six Swedish Swetox-universities, as well as five European and one American. The project focuses on the effects of mixtures of endocrine disruptive chemicals (EDCs) on children.

The interdisciplinary and integrated research approach of EDC-MixRisk includes:

  • epidemiology of two child cohorts focused on three health domains (growth and metabolism, neurodevelopment, and sexual development)
  • a web of experimental toxicology and molecular biology approaches to determine multiple adverse health outcomes with pathways starting at the molecular level during early life exposure to EDC mixtures
  • regulatory toxicology for development of a transparent and systematic risk assessment framework. Together this interdisciplinary research, integrating epidemiologic and experimental evidence, will facilitate assessment of risk and societal impact ensuring better risk management for EDCs and their mixtures.

 

EDC-2020 is a five-year research program on endocrine disrupting chemicals financed by approx. one million euro a year by the Swedish Research Council Formas on behalf of the Swedish Government. The core of the project is five research areas and a training program. Eleven Swedish Swetox-universities have joint together in the efforts of EDC-2020.

EDC-2020 aims to:

  • create an enabling environment for strong research on EDCs and for scientific advances and innovations, which will benefit the field of toxicology-related sciences as a whole.
  • establish an overarching national program for research on EDCs, optimizing cooperation between national universities as well as with the Swetox facilities in Södertälje, and improve interdisciplinary research.
  • establish an international EDC collaboration platform including world-leading experts and to link students in toxicological sciences across the country.

The research performed in EDC-MixRisk helps to expand our knowledge on mixtures of endocrine disrupting chemicals. Meet our EDC-MixRisk scientists and hear their story on what they are doing and why it is important. This time in line is Efthymia Kitraki (PhD), professor of Biology and Head of the Laboratory of Basic Biomedical Sciences, in the School of Health Sciences University of Athens, Greece. Her experimental approaches include in vivo manipulations and behavioural testing of small rodents, followed by in vitro analysis of the tissues using cellular and molecular techniques.

What is the focus of your research group in EDC-MixRisk?

Our research group is studying the effects of in utero exposure of mice to mixtures of EDCs. The exposed offspring of both sexes are tested at postnatal days 21(weaning) and 90 (adulthood).

We are mainly interested in the potential effects of Mixture N1 (neurodevelopment) on the neuroendocrine axis of stress response.

Additional goals are: investigation of the potential effects of Mixture G1 (growth and metabolism) on the development of brain areas implicated in cognition and of Mixture S (sexual development) on the gonadal function.

What have you discovered so far?

We had a first set of mixtures, mixtures G0 (growth and metabolism), N0 (neurodevelopment), and S0 (sexual development) as they, in the respective dilution, reflect a “typically-measured” mixture of EDCs in the SELMA mothers. Given the inability to use Mixtures N0 and G0 (due to different kinetics of persistent and non-persistent compounds in the same mixture) we are presently studying the effects of Mix S0. Anogenital distance (AGD) is used as a measurement of genital development. Preliminary results show alterations in AGD and AGD/bw (AGD index), especially in male offspring at concentrations 0.4mM and 4mM of Mix S0 (stock 1M), but not at 20mM. Experiments are ongoing by exposing animals at 0.02mM (corresponds to SELMA levels). Analyses of gonadal histology and expression of steroidogenesis- and differentiation-related genes are in process.

What are the potential implications of your findings?

The detected alterations in AGD index are in line with those observed in the SELMA study for the boys exposed in utero to a mixture comprised mainly by the same ‘bad’ chemicals. Our preliminary data are also in compliance with the literature on the effects of individual components of our Mixture S0 in rodents. The observed alterations of AGD index, a biomarker of prenatal exposure to endocrine disruptors, if linked to molecular/hormonal indices of gonadal dysfunction in our study, could provide a pathway of adversity due to exposure to this mixture.

 


2nd International Fresenius MIXTOX Conference “Toxicity of Chemical Mixtures: Risk, Hazard and Exposure Assessment” will be organized in Cologne, Germany 8‐9 June 2017. Prof. Åke Bergman, EDC-MixRisk Coordinator, will give some insights and provide an overview of EDC-MixRisk at the conference. The title of his talk is EDC-MixRisk – a novel approach for assessing EDCs.

More information and programme of the conferece is available here.


A very recently published study carried out by CNRS flags that exposure to endocrine disrupting chemicals (EDCs) causes changes in thyroid hormone signalling, which may disturb brain development. Frog embryos were exposed to a mixture of 15 chemicals commonly present in the fluid of a human mother’s womb.

The results of the study demonstrate that a short exposure to the mixture (3 days) affected thryoid hormone signalling, but also altered brain gene expression, reduced neuron volume and inhibited tadpole movement. Furthermore, these findings can be placed in the context of recent epidemiological studies showing that small variations in maternal thyroid hormone during early pregnancy impact children’s IQ.

Professor Barbara Demeneix, an author of the paper and work package leader in EDC-MixRisk, says:

“Undisturbed thyroid signalling is essential for normal brain development in all vertebrates. Since thyroid hormone is exactly the same in frogs and humans, these findings should prompt rapid action to remove these harmful chemicals from the market.”

 

The results are published by Nature in a peer-reviewed paper in Scientific Reports entitled “Human amniotic fluid contaminants alter thyroid hormone signalling and early brain development in Xenopus embryos”. The full article is available here.

 



Dr. Pauliina Damdimopoulou’s group focuses on reproductive toxicology and recently, they have been working on a new technique obtained from Dr. Claus Andersen’s laboratory in Copenhagen. They have been isolating structures from within the ovary called follicles, which consist of supporting and nourishing cells surrounding the growing egg.

The group has successfully modified the technique learned in Copenhagen to isolate follicles from bovine and human ovaries, specifically focusing on an area of tissue called the cortex which contains the most follicles. The next step is culturing follicles for long periods of time, such as several days or weeks, so that the effects of chemical mixtures on egg development and health can be tested. The research will increase our understanding on whether chemicals can affect women’s fertility.

A growing follicle after 5 days of culture. The egg can be seen in the centre of several layers of supporting cells.

 

 

 

 

For more information on the research team:
http://swetox.se/en/research/pauliina-damdimopoulou/


The position is linked to EDC-MixRisk project and it is open at the Department of Environmental Science and Analytical Chemistry, Stockholm University. The Postdoctoral Fellow will contribute to the work package that concerns the development of a transparent and systematic risk assessment procedure that can integrate epidemiological and experimental research to facilitate the assessment of risk for EDCs and their mixtures.

Main responsibilities will include:
(1) To perform a risk assessment case study with a single chemical, using the recently proposed SYRINA framework for EDC risk assessment. SYRINA is described here: http://ehjournal.biomedcentral.com/articles/10.1186/s12940-016-0156-6. The case study includes performing all the steps outlined in SYRINA for a selected case chemical. The process will also be presented and discussed with all other scientists involved in the project.
(2) Together with other scientists in EDC-MixRisk, further develop the SYRINA framework to encompass also mixtures.

For more information, click here.


Meet our EDC-MixRisk scientists working behind the scenes. Prof. Chris Gennings shares her insights into the project. She is Professor of Biostatistics at the Icahn School of Medicine at Mount Sinai, NY, USA and her research focuses particularly on the design and statistical analysis methodologies for studies of chemical mixtures.

Hi Chris – What are you researching in EDC-MixRisk?

We are using the SELMA pregnancy cohort data to identify mixtures of endocrine disrupting chemicals (EDCs) measured in early pregnancy that are associated with health effects in each of three health domains for the children: neurodevelopment, metabolism and growth, and sexual development. Our strategy includes evaluation of chemicals across a wide range of chemical classes. Once the sets of ‘bad actors’ are identified, we calculate a ‘typical mixture’ from the SELMA cohort data for each health domain using pharmacokinetic modeling.  These mixtures are then constructed and experimentally evaluated across the consortium.

 

What are the key results so far?

Important results so far include the identification of bad actors that are detected in all or nearly all of the pregnant women in the SELMA cohort. Second, these identified chemicals come from multiple chemical classes, indicating that focusing on single chemical classes may underestimate risk. Further, we have detected health effects from each of the three health domains, indicating the potential comorbidity associated with exposures to EDCs.

 

What these findings could implicate?

The strategy we use for identifying bad actors is based on the simultaneous evaluation of mixtures of chemicals related to a health effect, i.e., the so-called ‘mixture effect’. An advantage of this strategy is the inference is focused towards detecting the mixture effect and thereby has more power to find it. Single chemical analyses may not indicate statistically significant associations; but combining across components we detect higher signal. The potential consequences are that we may identify that current regulatory guidelines, which generally focus on single chemicals or single chemical classes, are not adequately protective.