|Red region in this 9 day old mouse embryo shows embryonic stem cells (ESC) within the extra-embryonic yolk sac, a tissue type that ESC usually can’t form. (Photo Credit: Sophie Morgani, University of Copenhagen.)|
It is all about potency. And no, that is not a male boasting about the power of sperm. It is about the power of cells to become various tissues. The very earliest cells in an embryo are called “totipotent” (toti = all) because they can become any tissue of the body, but also the placenta and yolk sac needed to foster the developing fetus. Embryonic stem cells are harvested at a point when the cells have lost the ability to form those supportive tissues, so they are dubbed pluripotent (pluri= many). Now, a Danish team at the University of Copenhagen has found a way to regress embryonic stem cells so that they regain the ability to form placenta and yolk sac.
Why would we want to do that? It gives researcher a great way to study normal development of these critical supportive structures. Issues with the placenta often lead to miscarriages, and this work could point to ways to avoid those abnormalities and allow more women to carry babies to term.
The work was published in Cell Reports online late last week and the university posted this press release, quoting the first author, Sophie Morgani, a Ph.D. student:
This new discovery is crucial for the basic understanding of the nature of embryonic stem cells and could provide a way to model the development of the organism as a whole, rather than just the embryonic portion. In this way we may gain greater insight into conditions where extra-embryonic development is impaired, as in the case of miscarriages.
Many in the field of stem cell science gain particular satisfaction when research in the field works toward improving the chances for bringing new life into the world. Although embryonic stem cells come from dot-sized early embryos left over from in vitro fertilization (IVF) procedures, stem cell scientists are often accused of destroying life. CIRM grantee Stanford’s Renee Reijo Pera’s work with stem cells has led to a method that will allow IVF clinics to better determine which of the many eggs fertilized in any one procedure are most likely to develop into a healthy fetus. She talks about that work in this video.