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A Metabolite-Based Biomarker Approach to Predict Developmental Toxicity Using Human Embryonic Stem Cells

Presented at the American College of Toxicology 33rd Annual Meeting, November 2012, in Orlando, Florida.

Birth defects are the largest cause of infant morbidity and mortality in the United States. Teratogens, defined as substances that cause fetal abnormalities during development, are responsible for 5-10% of all birth defects. The application of more predictive developmental toxicity screens would reduce the prevalence of birth defects and increase pharmaceutical and chemical safety. Human embryonic stem (hES) cell technology provides an innovative and robust alternative in vitro model system to predict developmental toxicity of chemicals. We have developed a targeted, rapid and highly predictive assay based on specific biomarker metabolites identified after analysis of metabolomics data obtained from hES cells exposed to 23 known human teratogens and non-teratogens. The metabolites were utilized to generate a high throughput assay that predicts the exposure level of a test agent at which hES cells respond in a manner indicating the potential teratogenicity. This new assay predicts the exposure level at which hES cells respond to treatment indicating the potential teratogenicity based on treatment level. We have tested this assay on a diverse set of compounds comprised of over 60 pharmaceuticals and environmental toxicants that exhibit a wide range of known developmental toxicity in animal models and man. hES cells were exposed to a 9-point dose curve of each compound. Spent media was collected and analyzed by high resolution LC-MS using a targeted metabolomics approach to determine the relative abundance of the biomarkers present in the model. We have built a database of the expected teratogenicity of the tested compounds in in vivo and in vitro tests to compare our results to. Our results show excellent concordance with both human and animal teratogenicity data and compare well to other commonly used in vitro assays for developmental toxicity. This new targeted biomarker approach continues to utilize LC/MS analysis while allowing for an 8-fold increase in instrument throughput and simplified analysis. This biomarker based assay is an attractive new quantitative model providing faster turn around and lower cost, while retaining high predictivity for early assessment of the developmental toxicity potential across a broad range of chemicals at multiple treatment levels in an all human derived system.

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