Assessment of drug induced developmental toxicity using human embryonic stem cells

Abstract

Embryonic stem (ES) cells are unique as they have the potential to be generated in large numbers and the ability to differentiate into the three germ layers via embryoid body (EB) formation. This property could be utilized as an index to study initial mammalian development. We have investigated the utility of a comprehensively characterized human ES (hES) cell line (ReliCellhES1) for testing the embryotoxic effects of compounds using cytotoxicity assays. Further, we performed real time gene expression analysis to check the alterations in germ layer markers expression upon drug treatment. The results show that assays using hES cells could serve as a reliable, sensitive and robust method to assess embryotoxic potential of compounds. They also provide a proof of concept that hES cells can be used as an in vitro model to demonstrate developmental toxicity, and to examine the germ layer-specific effects on differentiating EBs.

Human Pluripotent Stem Cells and Drug Discovery: A New Beginning

“…For instance, it was shown that while retinoic acid (RA) and 13-cis RA (13RA) exerted cytotoxic effects on hESCs, only the former compound induced cytotoxicity in mESCs despite both compounds being well-known agents of embryotoxicity 94 . However, testing for cytotoxicity is not a sufficient end-point to establish reproductive toxicity and hence incorporation of biomarkers to monitor changes in early lineage transcripts and cardiac development has been proposed 91,95 . In comparison to animal models, hPSCs have proven their effectiveness as an embryotoxic test system 96 .…”

“…In an attempt to address species variation, hPSCs have been proposed as suitable models for investigating embryotoxicity 91,93,94 . For instance, it was shown that while retinoic acid (RA) and 13-cis RA (13RA) exerted cytotoxic effects on hESCs, only the former compound induced cytotoxicity in mESCs despite both compounds being well-known agents of embryotoxicity 94 .…”

“…Acceptance of the mEST along with the WEC and MM test by the regulatory commission was therefore expected 78 ; however, the Scientific Advisory Committee (ESAC) of the ECVAM felt that these in vitro test systems were not adequate 79 . While several strategies have been implemented in attempts to improve mEST [80][81][82][83][84][85][86][87][88][89][90] , a major concern which remains is the species variation as it would be challenging to evaluate or interpret test results in a human context 91,92 .…”

Mouse and Human Embryonic Stem Cells: Can They Improve Human Health by Preventing Disease?

“…A second interesting study has evaluated the potential of hESC to provide information on toxic chemicals using two non-embryotoxic, two weakly embryotoxic, and two strongly embryotoxic chemicals [46]. Cytotoxic indices were determined using cells representing the embryo (hESC), fetus (human embryoid bodies) and adults (human foreskin fibroblasts).…”

Alternative models in developmental toxicology

“…The authors concluded that although this initial assay showed promise, additional research would be needed to standardize a human EST. Mehta et al [2008] attempted to increase the predictivity of the test by examining gene expression of each of the three germ layers as the endpoint of differentiation in a single hESC line. The authors concluded that the "implementation of the EST in regulatory test guidelines would demonstrate the importance of in vitro assays as valuable components of the risk/hazard assessment process" [Mehta et al 2008].…”