Exploring the origin of the development: totipotent stem cells.

As the origin of the development, a fertilized egg owns the ability to generate a whole new organism, including both embryonic and extraembryonic tissues, representing the highest developmental potency, totipotency. For more than 40 years, pluripotent stem cells, with differentiation potential weaker than that of totipotent cells, have been easily derived from inner cell mass and maintained in vitro. Until now, capturing totipotent stem cells is still challenging. Recently, the stable culture of mouse and human totipotent blastomere-like cells was achieved for the first time using spliceosomal repression. Subsequently, other methods, particularly epigenetic manipulation, have also succeeded in culturing mouse totipotent stem cells. These advancements provide an excellent system for studying early embryonic development and offer new possibilities for regenerative medicine. However, the in vitro culture of totipotent stem cells has only been recently realized, and much further exploration is needed in this field. This review aims to compare different totipotent stem cells and discuss their potential applications in regenerative medicine and disease modeling.