Report from the ESTIV2008 Congress

ESTIV2008, the 15th International Congress on In Vitro Toxicology, was held on September 25-28, 2008, at Djurönäset, Stockholm, Sweden. The congress was jointly organized by the European Society of Toxicology In Vitro (ESTIV), the Scandinavian Society for Cell Toxicology (SSCT) and Expertrådet AB, Sweden.

 

Because of the large scale of this meeting (over 300 participants from 35 countries, 60 oral presentations and 120 posters), the former INVITOX workshops, held every second year, have been upgraded this year to the ESTIV2008 Congress. The programme of the congress including 10 sessions covered different topical fields of in vitro toxicology, e.g. use of embryonic stem cells for developmental toxicology, in vitro models for allergy testing, environmental and tissue-specific toxicity, kinetics and metabolism-mediated toxicity, models for predicting acute systemic toxicity, new strategies in neurotoxicology, as well as new approaches for validation and implementation of alternative methods. Owing to a large volume of information, only a few topics are presented in this brief overview. Proceedings from the Congress will be published in Toxicology in Vitro (TIV). 
      
     At the first day of the meeting, the Scandinavian Society for Cell Toxicology (SSCT) organized a special symposium on methods in cell toxicology , chaired by Hasso Seibert (Germany). This type of training session on the methodological issues has been arranged at the SSCT annual meetings since 2006.  This year the symposium was focused on the use of human cell models. The invited speaker, Roland Grafström (Sweden) presented a survey of the usefulness and limitations of using normal and transformed human cell cultures for predicting toxicity. He also described the role of exposure conditions, different sensitivity of toxicity end-points and the application of computational toxicology, e.g. genome-scale analyses and bioinformatics processing, for complementing traditional testing strategies. Daniella Steel (Sweden) presented an innovative cardiotoxicity model using human embryonic stem cells (hESC) derived cardiomyocytes, expressing cardiac specific markers, for toxicity testing of new therapeutic drugs. Other speakers were Lousie Sivertsson(Sweden), giving an overview on the use of human cell models in hepatoxicity, and Carolina Bredhult (Sweden), presenting a human cell culture method for evaluating effects of endocrine disrupters.

     A whole session was dedicated to the use of embryonic stem cells (ESC) for developmental in vitro toxicology (invited speaker, Martina Klemm, Germany). The use of mammalian ESC, and especially of human ESC for risk assessment of embryotoxic chemicals is a promising approach since such test systems are most relevant to humans. The hESC have a capability to differentiate into various organotypic cell cultures (e.g. cardiomyocytes, neural cells, muscle cells etc.). The prediction of toxicity by hESC models is usually very good and avoids in vivo animal studies.

    The session “In vitro models in aquatic and ecotoxicology” (invited speaker, Kristin Schirmer, Switzerland) was focused on the importance of alternative tests, such as fish cell lines, for developing in vitro models for risk assessment.       
     Several presentations were devoted to skin sensitization and allergy testing, especially, in the light of changes in EU legislation (REACH; 7th Amendment to the European Cosmetics Directive).
Gavin Maxwell (United Kingdom), invited speaker in the session “Topical toxicity and in vitro tests for allergy inducing compounds”, spoke about the development of new in vitro models as a collaborative effort within The European Cosmetic Association (COLIPA) and as a part of an EU FP6 project (Sens-it-iv). Evaluation of a skin irritation model (EPISKIN) for assessment of skin irritation of industrial enzymes was presented by S.G. Elvig-Jørgensen (Denmark). A human corneal model for testing eye irritating chemicals was presented by Maria Engelke (Germany) and Heléne Lindegren (Sweden) described an in vitro alternative based on TRPV1 (transient receptor potential vanilloid type 1)-expressing neuroblastoma SH-SY5Y cells for classification of mild eye irritating products.

     New achievements in cell toxicology will not be possible without implementation of new strategies, based on molecular biological techniques, e.g., gene expression analysis (microarray), comet assays, RNA analysis etc.
The usefulness of these methods was discussed in the session “New in vitro models and strategies: Gen ontology categorization and bioinformatics processing in cell culture phenotyping and toxicity testing”. Roland Grafström (Sweden) talked about the use of computational analysis of gene expression data for studying how well transformed human oral epithelium cell lines retain normal functions and how these methods could provide information on how the transformed states should be used for studies of normal cell function. The use toxicogenomics in the H295R and MCF-7 cell lines for screening and classification of endocrine disrupters was discussed by Caroline Vanparys (Belgium). 

   In the session “Kinetic and metabolism-mediated toxicity”, the role of metabolic competence of in vitro systems was underlined, as well as the importance of developing new PK-PD models  (invited speaker, Olavi Pelkonen, Finland). Another speaker from this session, Bas J Blaauboer (the Netherlands) described important issues which need to be taken in consideration for the interpretation of in vitro toxicity data. For example, the actual (free) concentration of a compound in the in vitro system, and the most important factors determining the distribution of a compound, such as lipophilicity, the intrinsic clearance, plasma protein binding and oral absorption.

     Gastro-intestinal toxicity and hepatotoxicity testing were extensively discussed in several presentations. Jürgen Borlak (invited speaker, Germany) outlined the usefulness of toxicogenomics and gene expression profiling for detection of early signs of liver toxicity. A successful application of human intestinal Caco-2 cell line for studies of absorption, metabolism and toxicity was presented (Manuela Natoli, Italy; Laura Turco, poster; Italy). Pilar Prieto (Italy) presented the results of an ECVAM prevalidation study of two in vitro models (Caco-2/ATCC and Caco-2/TC7) for the prediction of gastrointestinal absorption, showing that both models were more reliable for passive diffusion than for active transport, indicating that further characterization of the models are needed. One poster described the suitability of HEPAC2 cells, primary human hepatocytes which could be maintained serum-free during several weeks, for the toxicity testing of xenobiotics by use RNA-expression profiles (Anett Ullrich, Germany).

Per Arturson (invited speaker, Sweden) described the development of in vitro models for studying passive and active drug transport processes in the human intestine and liver. In such models it is possible to study the role of transport proteins in toxic drug – drug interaction. Also computer based models were described.

     New strategies in neurotoxicity were discussed by Anna Forsby (invited speaker, Sweden) in her lecture “Neuronal in vitro models for the estimation of acute systemic toxicity”. She demonstrated the usefulness of the human neuroblastoma SH-SY5Y cell line for the testing of toxic chemicals: 23 chemicals from ACuteTox project were tested for 50 neuronal endpoints, and evaluated.  Agnieszka Kinsner (Italy) summarized ECVAM ongoing activities on acute toxicity to meet the 2009 deadline for a testing and marketing ban of cosmetic products with ingredients tested on animals. She presented the ACuteTox project and its main purposes: to develop and pre-validate a testing strategy to fully replace acute oral toxicity testing in animals, as well as a follow-up to the ICCVAM/ECVAM validation study on the prediction of acute toxicity by cytotoxicity tests.

Michael Sjöström (invited speaker, Sweden) presented a validation strategy, used in ACuteTox project for analysis of in vitro data and for in vitro-in vivo modeling.
     The results of validation of several skin irritation models, such as the SkinEthic’ Reconstructed Human Epidermis model (RHE) and EpiDerm Skin Irritation Test (SIT), were presented by Nathalie Alépée (France) and Helena Kandarová (Slovakia), respectively.

     The Björn Ekwall Memorial Lecture was given by Professor Erik Walum (Biovitrum AB, Sweden) who is the Björn Ekwall Memorial Award winner 2008. The title of his lecture was: “Relevance of in vitro cell responses to drugs and chemicals for predicting human toxicity. Reflections in the spirit of Björn Ekwall.”

     In many presentations during the congress, advances in the development of alternative in vitro models replacing animal experimentation were demonstrated, and the application of these models was presented. New trends in in vitro toxicology have been outlined, e.g., the use of human neural and embryonic stems cells in the toxicity testing of teratogenic/embryogenic chemicals, implementation of organotypic cell models, new strategies in metabolism-mediated toxicity assessment, and development and validation of predictive in vitro models for acute toxicity evaluation.  The needs for speeding up the validation and implementation of in vitro methods for toxicity testing were discussed and the importance of involving different stakeholders, such as authorities and end-users early in the development was underlined.  

In summary, the meeting was a great success. The number of participants reached all time high. The beautiful surroundings in the Stockholm archipelago positively influenced also the scientific atmosphere of  the meeting. 
                           
Cecilia Clemedson
Ada Kolman
Stockholm, October 21, 2008