Researchers worldwide conduct vital research involving the understanding of the very early development of humans inside the womb using human embryos. Research of the type uses surplus embryos donated by people who have undergone in vitro fertilization. However, the amount of research conducted into these early stages of human development is extremely limited by the availability of embryos.
Limits are also placed on this type of research by ethical time limits on how long embryos can develop, which is currently set at 14 days. However, researchers at Caltech may have created a structure that could help get around the limitations placed on research from embryo availability and ethical time limits. Whereas natural human embryos are formed from a combination of sperm and egg, the embryo-like structures created by Caltech are made from human stem cells.
Caltech researchers are clear that there are key differences between natural embryos and their embryo-like structures. However, their creation will allow critical research to be conducted into human development without needing donated human embryos. The scientists created their embryo-like structures using a type of pluripotent stem cell able to become a distinct type of cell that can self-assemble into a structure that has a morphology that’s very similar to an embryo.
Natural embryos have distinct embryonic and extra-embryonic tissues. The pluripotent stem cells used in the structure were isolated from actual human embryos by other researchers and maintained in a laboratory environment. When presented with the correct conditions, the stem cells can recall how to assemble themselves into an embryo-like structure. The basic structure of an embryo appears to be an inbred property of the cells.
However, researchers note the memory of the cells is either not completely precise, or scientists simply lack the best method to help the cells recover their memory. That means additional work is required before human stem cells can achieve the same developmental accuracy seen with mouse stem cell counterparts. Nevertheless, the breakthrough could eliminate the need for donated embryos in the future.