Viable iPSC mice: a step closer to therapeutic applications in humans?

Rapid advancements have occurred in induced pluripotent stem cell research within the 3 years since Yamanaka and colleagues first reprogrammed adult mouse fibroblasts to an embryonic stem cell-like state by the forced expression of a small cohort of transcription factors. Progress has been made in overcoming various technical obstacles, including oncogenic threat, that hinder the application of iPS cell technology as a therapeutic strategy in humans. Remaining hurdles include the low efficiency of iPS cell induction and the demonstration of complete developmental potential. This latter impediment now appears to have been overcome simultaneously by two groups (Kristen Baldwin and colleagues and Qi Zhou and colleagues), who have generated viable adult mice from tetraploid complementation assays using iPS donor cells. The generation of sufficiently reprogrammed iPS cells and mice will allow for adequate genomic and functional testing to evaluate their utility in research applications and patient-specific cell replacement therapies, which may include infertility.