Another use for ES cells was discussed by Elena Cattaneo, Ph.D., founder of Dialectica (www.dialectica.com). According to Dr. Cattaneo, it is difficult to culture 100% neural stem cells capable of producing neurons, which is why Dialectica is using mouse ES cells to determine if these have better utility in this application.
“Our mouse ES-derived, neural cell line has been through 170 passages, yet it is still neurogenic and contains approximately 80 percent neurons,” Dr. Cattaneo stated. “Action potential is present in these cells that also express sodium channels and the major inhibitory neurotransmitter, GABA, which means they could be a useful model for identifying compounds to treat conditions including Huntington’s disease.”
Like Dialectica, Axiogenesis (www.axiogenesis.com) is using mouse ES cells but for toxicity testing rather than compound screening. Heribert Bohlen, Ph.D., founder and CEO of Axiogenesis, explained the rationale for developing in vitro testing. “Animal-based toxicity testing is mandatory prior to the registration of a new compound. Current EU regulations require testing on 100 animals at several doses, a process that can take up to six months to complete and be as much as 30 percent of the registration cost.
“Our in vitro method, RETOX, uses mouse ES cells transfected with a vector containing a green fluorescent protein (GFP) marker and an actin promoter. During the in vitro cell-differentiation process into cardiac cells, GFP expression begins, and the cells fluoresce,” Dr. Bohlen continued.
“Adding toxic or teratogenic compounds at this point alters the amount of fluorescent cardiac cells produced, which can be measured by fluorometry, microscopy, or cytofluorometry.”
Dr. Bohlen presented data to show that RETOX was able to correctly identify the category of 93% of 70 known toxic compounds tested, and even detected the teratogenic effect of thalidomide. He also discussed a case study where Grunenthal (www.gruenthal.com) used RETOX to screen 30,000 compounds for E15,000 and saved E55, 000 on the cost of animal testing.
“If we can get RETOX accepted in a regulatory setting, it could save the lives of millions of lab animals every year and reduce testing costs by billions of euros,” Dr. Bohlen concluded.