embryonic stem cell test

/Tag:embryonic stem cell test

Detection of the Embryotoxic Potential of Cyclophosphamide by Using a Combined System of Metabolic Competent Cells and Embryonic Stem Cells

Susanne Bremer, Cristian Pellizzer, Sandra Coecke, Martin Paparella and Paolo Catalani

In order to develop a method for detecting metabolism-mediated embryotoxicity, differentiating embryonic stem (ES) cells were exposed to the well-known proteratogen, cyclophosphamide (CPA). CPA was tested in a scientifically validated embryonic stem-cell test (EST), and in the newly developed reporter-gene assay for developmental cardiotoxicity. Both assays gave false-negative results. Because no metabolic competence (cytochrome P450 [CYP] activity) was found in the ES cells under the selected culture conditions, a simple biotransformation system was combined with the reporter-gene assay. As the metabolic pathway of CPA is well characterised, the genetically engineered mammalian cell line V79, transfected with CYP2B1 cDNA, was selected as a biotransformation system. CYP2B1 is responsible for transforming CPA into teratogenically active metabolites. The supernatants of genetically engineered V79 cells were analysed in the reporter-gene assay for developmental cardiotoxicity. In preliminary experiments, the combined system was able to detect the embryotoxic potential of the proteratogen, CPA.
You need to register (for free) to download this article. Please log in/register here.

The ECVAM International Validation Study on In Vitro Embryotoxicity Tests: Results of the Definitive Phase and Evaluation of Prediction Models

Elke Genschow, Horst Spielmann, Gabriele Scholz, Andrea Seiler, Nigel Brown, Aldert Piersma, Madeleine Brady, Nicole Clemann, Hannele Huuskonen, Francoise Paillard, Susanne Bremer and Klaus Becker

From 1996 to 2000, ZEBET (Centre for Documentation and Evaluation of Alternative Methods to Animal Experiments at the BgVV, Berlin, Germany) coordinated the European Centre for the Validation of Alternative Methods (ECVAM) prevalidation and validation study on three embryotoxicity tests: a) a test employing embryonic stem cell lines (EST); b) the micromass (MM) test; and c) the postimplantation rat whole-embryo culture assay (WEC test). The main objectives of the study were to assess the performance of these three in vitro tests in discriminating between non-embryotoxic, weakly embryotoxic and strongly embryotoxic compounds. Phase I of the study (1997) was designed as a prevalidation phase, for test protocol optimisation, and for the establishment of a comprehensive database of in vivo and in vitro data on embryotoxic compounds. Phase II (1998-2000) involved a formal validation trial, conducted under blind conditions on 20 test compounds selected from the database, which were coded and distributed to the participating laboratories. In the preliminary phase of the validation study, six chemicals out of the 20, which showed embryotoxic potential, were tested. These results were used to define new biostatistically based prediction models (PMs) for the MM and WEC tests, and to evaluate those developed previously for the EST. As a next step, the PMs were evaluated by using the results for the remaining 14 chemicals of the definitive phase of the validation study. The three in vitro embryotoxicity tests proved to be applicable to testing a diverse group of chemicals with different embryotoxic potentials (non-embryotoxic, weakly embryotoxic, and strongly embryotoxic). The reproducibility of the three in vitro embryotoxicity tests were acceptable according to the acceptance criteria defined by the Management Team. The concordances between the embryotoxic potentials derived from the in vitro data and from the in vivo data were good for the EST and the WEC (PM2) test, and sufficient for the MM test and the WEC (PM1) tests according to the performance criteria defined by the Management Team before the formal validation study. When applying the PM of the EST to the in vitro data obtained in the definitive phase of the formal validation study, chemicals were classified correctly in 78% of the experiments. For the MM and the WEC tests, the PMs provided 70% and 80% (PM2) correct classifications, respectively. And, very importantly, an excellent predictivity (100%, except for PM1 of the WEC test, with 79%, considered as good) was obtained with strongly embryotoxic chemicals in each of the three in vitro tests.
You need to register (for free) to download this article. Please log in/register here.

Development of a Testing Strategy for Detecting Embryotoxic Hazards of Chemicals In Vitro by using Embryonic Stem Cell Models

Susanne Bremer, Cristian Pellizzer, Sarah Adler, Martin Paparella and Jan de Lange

The importance of developing in vitro tests for embryotoxicity is discussed, and ECVAM's work with its collaborators is summarised. Studies are in progress to find new endpoints for use in the scientifically validated embryonic stem (ES) cell test, so that the potential for chemical effects on endodermal, mesodermal and/or ectodermal differentiation can be identified. This involves, inter alia, the use of genetically modified ES cells.
You need to register (for free) to download this article. Please log in/register here.

Validation of the Embryonic Stem Cell Test in the International ECVAM Validation Study on Three In Vitro Embryotoxicity Tests

Elke Genschow, Horst Spielmann, Gabriele Scholz, Ingeborg Pohl, Andrea Seiler, Nicole Clemann, Susanne Bremer and Klaus Becker

A detailed report is presented on the performance of the embryonic stem cell test (EST) in a European Centre for the Validation of Alternative Methods (ECVAM)-sponsored formal validation study on three in vitro tests for embryotoxicity. Twenty coded test chemicals, classified as non-embryotoxic, weakly embryotoxic or strongly embryotoxic on the basis of their in vivo effects in animals and/or humans, were tested in four laboratories. The outcome showed that the EST can be considered to be a scientifically validated test, which is ready for consideration for use in assessing the embryotoxic potentials of chemicals for regulatory purposes.
You need to register (for free) to download this article. Please log in/register here.