University of Exeter researchers have discovered a simple and efficient approach to recreate the early structures of the human embryo from stem cells in the lab.
Studying the natural development of the human embryo is challenging in vivo. In addition, very few embryos are available for research in vitro. As a result, researchers have relied on the observations and experiments within other mammals, particularly the mouse. While development follows a similar program in all mammals, there are still many distinct features between species. For example, the regulation of blastocyst formation is different in humans and in mice.
In recent years, researchers have generated blastocyst-like structures (blastoids) from mouse stem cells. This work has progressed to the recent manufacturing of human blastoids. However, in order to be a useful model, blastoids have to accurately recapitulate the cellular organisation and lineage composition of the natural human blastocyst.
Human embryo model
In this study, published in Cell Stem Cell, researchers investigated the potential of human naïve stem cells to generate blastoids that show high fidelity to the human embryo. In a previous study, researchers found that human naïve pluripotent stem cells could give rise to the three founding lineages of the blastocyst.
Now, researchers arranged the stem cells into clusters and briefly introduced two molecules known to influence how cells behave in early development. The team found that 80% of the clusters organised themselves after 3 days into structures that mimicked the natural blastocyst stage of an embryo. Furthermore, single-cell transcriptome analyses showed that these artificial embryos had the same active genes as the natural embryo.
The researchers next hope to understand how to extend the development of these embryos for a few days to study the critical period when an embryo implants into the womb. This period is critical to help understand why embryos fail to develop properly. Thus, this new technique has important implications for studying IVF and infertility.
Image credit: By Science Photo Library – canva