
ReproTracker® is a state-of-the-art human stem cell-based in vitro assay that rapidly and reliably identifies developmental toxicity hazards of new drugs and chemicals. The assay captures the key cellular events of stem cell differentiation and early embryonic development. ReproTracker is used to investigate if compounds interfere with early embryonic development and the assay can quantitatively predict their teratogenic potential. ReproTracker can be used as an early-phase developmental toxicity screening platform, an alternative for animal-free teratogenicity testing of materials, or as a tool to extrapolate animal-derived results to humans.

Key Features
- Animal-free teratogenicity testing
- Highly sensitivity and specific identification of teratogenic compounds
- Predict in vivo teratogenicity and extrapolate it to humans
- More information with less compound compared to animal studies
- Visualization of the key cellular events of early embryonic development
- Extensively validated NAM for next generation testing
Reliable investigations of the developmental toxicity of chemicals in mammals requires a dynamic biological system that can represent and capture the key cellular events of embryonic development. The ability of human stem cells to recapitulate cellular differentiation during early embryonic development make them an attractive screening tool in detecting human teratogens. ReproTracker is a human induced pluripotent stem cells (hiPSCs)-based assay, which combines the assessment of functional/morphological changes with expression patterns of tissue-specific biomarkers to detect possible developmental toxicity responses of chemicals.
Highlights of ReproTracker:
- Unique in vitro screening platform for development toxicity identification
- Differentiation of hiPSCs towards cardiomyocytes, hepatocytes and neural rosettes
- Morphological and functional profiling of different tissues
- Biomarker expression analysis as a readout for teratogenicity
- Excellent predictor for developmental toxicity hazards
Schematic representation of hiPSCs differentiation towards cardiomyocytes, hepatocytes and neural rosettes in the ReproTracker assay
Typical applications of ReproTracker
- Early-phase of drug development: ReproTracker is validated alternative to expensive and time-consuming animal tests and can identify developmental toxicity hazards in an earlier stage and at a much lower cost.
- Better prediction for human safety: ReproTracker is a human stem cells-based assay and is more predictive of responses in humans.
- Late-phase in vitro screening: ReproTracker can be used to investigate the mode-of action of teratogenic compounds and extrapolate animal-derived results to humans.
Meet the study director for ReproTracker
Our study directors are the experts in the field to whom you can ask any question about our assays. From early screening to regulatory safety assessment, our study directors are able to listen to your questions and think along with you to provide a tailored solution. Here are some typical questions they often receive on ReproTracker in understanding where and how ReproTracker can be utilized in their strategies. Please feel free to ask your questions as well.
Can I meet you to talk about my study design?
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Will you also take me through the data after a project in a TC or meeting?
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Dr. Amer Jamalpoor
Study director for ReproTracker
Amer Jamalpoor obtained his Ph.D. degree in the field of human Toxicology and Pharmacology. His research focused on the development of in vitro screening platforms for predictive toxicology that utilize human stem cells combined with omics-based biomarker identification. Dr. Jamalpoor joined Toxys as a senior scientist, utilizing his expertise in molecular and cellular biology to run and commercialize the ReproTracker assay. Amer is instrumental in developing and extending the applicability domain of ReproTracker.
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The ReproTracker protocol consists of two phases. First, a broad dose range-finding is performed to select the compound concentrations that will be applied in differentiation protocols. Next, the hiPSCs are differentiated towards cardiomyocytes, hepatocytes, and neuronal rosettes in the presence of the test compound. During the differentiations, morphology/functionality of the differentiating cells are also properly monitored for any sign of adverse effects and morphological abnormalities are compared to unexposed cultures. Finally, developmental toxicity is investigated by quantitative gene expression profiling of selected biomarkers. Changes in biomarker expression are used to determine whether compounds have teratogenic properties.
ReproTracker experimental design
Cytotoxicity of a compound is determined during the first stage of the ReproTracker protocol. Based on this, test concentrations are selected for the differentiations. During differentiations of the hiPSCs into heart, liver and neural lineages, the morphology, including toxicity, is assessed. At the end of differentiation, also contraction of the cardiomyocytes is determined to confirm proper differentiation. Finally, at different stages of hiPSCs differentiation, expression of various biomarkers is determined. Significant reduction in biomarker expression will lead to classification of a compound as teratogenic.
Teratogenic compounds
Exposure to thalidomide markedly declined cardiac contractions and disrupted both hepatocyte and neural rosette morphology, and significantly decreased expression of the selected biomarker genes (AFP, MYH6). Based on the assay criteria, thalidomide is classified as a teratogen.
Non-teratogenic compounds
Folic acid (B vitamin) had no effect on the morphology, nor on expression of the selected biomarker genes in the differentiated cells. Based on the assay criteria, folic acid is classified as a non-teratogen.
Results from a ReproTracker study are summarized in the table to indicate the effects of compounds on the differentiation of stem cells into the different cell lineages. Also, the lowest observed adverse effect levels (LOAEL) are indicated that can be used for extrapolation to in vivo exposure levels.
Project report
The project report contains the protocol, technical details, cytotoxicity testing/dose range finding results, biomarker expression with test
compounds, morphological analysis with test compounds, and LOAEL concentrations of the compounds. We are happy to share the dummy report with you. Please click here to request for a dummy report.
ReproTracker has been extensively validated with various libraries (ICH, EURL ECVAM) of well-established teratogenic and non-teratogenic compounds with different mechanism of actions. ReproTracker identified in vivo teratogenic compounds with an accuracy of 85% (sensitivity 85%, specificity 84%).
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Meet the study director for ReproTracker
Our study directors are the experts in the field to whom you can ask any question about our assays. From early screening to regulatory safety assessment, our study directors are able to listen to your questions and think along with you to provide a tailored solution. Here are some typical questions they often receive on ReproTracker in understanding where and how ReproTracker can be utilized in their strategies. Please feel free to ask your questions as well.
Can I meet you to talk about my study design?
Click for the answer
Will you also take me through the data after a project in a TC or meeting?
Click for the answer

Dr. Amer Jamalpoor
Study director for ReproTracker
Amer Jamalpoor obtained his Ph.D. degree in the field of human Toxicology and Pharmacology. His research focused on the development of in vitro screening platforms for predictive toxicology that utilize human stem cells combined with omics-based biomarker identification. Dr. Jamalpoor joined Toxys as a senior scientist, utilizing his expertise in molecular and cellular biology to run and commercialize the ReproTracker assay. Amer is instrumental in developing and extending the applicability domain of ReproTracker.
Can you help with selecting relevant controls for my substances?
Click for the answer
Click here to send your question!
What endpoints are covered by the assay?
ReproTracker detects disruption of stem cell differentiation and early embryonic development. The assay combines the functional/morphological changes and expression of the selected biomarkers in three embryonic lineages (endo-, meso-, and ectoderm) to reveal the developmental toxicity of chemicals.
What is a typical application of ReproTracker?
ReproTracker is an in vitro assay to predict in vivo teratogenicity. The assay is typically applied as an early-phase developmental toxicity screening tool, as an alternative to short-term in vivo testing or as a human follow-up test to investigate inter-species differences and extrapolate animal-derived results to humans.
How do you classify compounds as teratogens?
Compounds are classified as in vitro teratogens when the differentiation of hiPS cells into functional heart, liver or neural cell lineages is disrupted. This disruption is defined by reduction in gene expression of selected biomarkers as well as functional and morphological changes that are induced by the test compound.
What type of chemistry has been tested in the assay?
ReproTracker has been validated with a wide range of chemistry including pharmaceuticals, (agro)chemicals, cosmetics ingredients, and food ingredients.
How is the assay validated?
ReproTracker has been extensively validated using various reference compound libraries as suggested by ICH and EURL ECVAM. These libraries exist of well-established teratogenic and non-teratogenic compounds with different mechanism of actions.
What is the sensitivity and specificity of the assay?
Validation has shown that ReproTracker has an 85% accuracy for identification of in vivo teratogenicity, with a sensitivity of 85% and specificity of 84%.
How much compound is needed to perform the assay?
Compound requirement depends strongly on the toxicity and maximum soluble concentration. Typically, 20-100 mg is sufficient for a full test, including a dose finding and two independent biological test repeats.
How long does it take to receive a report?
Depending on the size of the project, it takes approximately 8-10 weeks to complete a full ReproTracker study and deliver a final report.
What type of solvent can be used?
ReproTracker has been validated with DMSO, water, and PBS as solvents.
What is the top-concentration that is tested, and how is this determined?
The top concentration that is applied in ReproTracker is determined by the toxicity of the compound. The dose that induced 20-40% cytotoxicity is selected as top concentration. Alternatively, the maximum soluble concentration is used. In case no toxicity is observed, 1mM is used as top concentration.
How many compound concentrations are tested?
In the standard ReproTracker protocol, 5 concentrations, typically in 2-fold dilution steps, are tested. Customization of the protocol can be discussed with the study director.
Can you share a sample report?
Yes, please contact us for a sample report via info@toxys.com
Meet the study director for ReproTracker
Our study directors are the experts in the field to whom you can ask any question about our assays. From early screening to regulatory safety assessment, our study directors are able to listen to your questions and think along with you to provide a tailored solution. Here are some typical questions they often receive on ReproTracker in understanding where and how ReproTracker can be utilized in their strategies. Please feel free to ask your questions as well.
Can I meet you to talk about my study design?
Click for the answer
Will you also take me through the data after a project in a TC or meeting?
Click for the answer

Dr. Amer Jamalpoor
Study director for ReproTracker
Amer Jamalpoor obtained his Ph.D. degree in the field of human Toxicology and Pharmacology. His research focused on the development of in vitro screening platforms for predictive toxicology that utilize human stem cells combined with omics-based biomarker identification. Dr. Jamalpoor joined Toxys as a senior scientist, utilizing his expertise in molecular and cellular biology to run and commercialize the ReproTracker assay. Amer is instrumental in developing and extending the applicability domain of ReproTracker.
Can you help with selecting relevant controls for my substances?
Click for the answer
Click here to send your question!
Service
We perform ReproTracker as a service for our clients. You can send your compounds and receive a full report within 8-10 weeks. It is also possible to request a ReproTracker test via scientist.com. Are you interested in receiving a quote or do you have any questions? Please reach out!
Practical information
Compound requirement
- 20-100 mg test material requested
- Top concentration tested in ReproTracker is 1 mM or 1 mg/ml
Turn around time
- 8-10 weeks
Throughput
- Testing up to 20 compounds per week
Type of solvents compatible with the assay
- DMSO
- PBS
- Water
A standard ReproTracker test includes
- Extensive dose range finding
- Two biological repeats
- Compound tested at five concentrations
- Positive and negative control compounds included
Next steps after sharing your interest in ReproTracker
Meet the study director for ReproTracker
Our study directors are the experts in the field to whom you can ask any question about our assays. From early screening to regulatory safety assessment, our study directors are able to listen to your questions and think along with you to provide a tailored solution. Here are some typical questions they often receive on ReproTracker in understanding where and how ReproTracker can be utilized in their strategies. Please feel free to ask your questions as well.
Can I meet you to talk about my study design?
Click for the answer
Will you also take me through the data after a project in a TC or meeting?
Click for the answer

Dr. Amer Jamalpoor
Study director for ReproTracker
Amer Jamalpoor obtained his Ph.D. degree in the field of human Toxicology and Pharmacology. His research focused on the development of in vitro screening platforms for predictive toxicology that utilize human stem cells combined with omics-based biomarker identification. Dr. Jamalpoor joined Toxys as a senior scientist, utilizing his expertise in molecular and cellular biology to run and commercialize the ReproTracker assay. Amer is instrumental in developing and extending the applicability domain of ReproTracker.
Can you help with selecting relevant controls for my substances?
Click for the answer
Click here to send your question!