June 27, 2023

expert reaction to study of a model of human post-implantation development

A study published in Nature looks at the formation of self-patterning of human stem cells into post-implantation lineages.

Prof Roger Sturmey, Professor of Reproductive Medicine, Hull York Medical School, Senior Research Fellow, Maternal and Fetal Health, University of Manchester and Chair – Guideline working group of the G-SCBEM project, said:

“The work presented by Pedroza and colleagues is a remarkable study that has been carried out with great care.  The data show the development and detailed description of the generation of a stem cell-based embryo model that will allow researchers to carry out precise studies on how the founder lineages of the developing embryo can interact with each other. 

“Importantly, these data highlight similarities between stem cell-based embryo models and embryos proper – but also reveal subtle differences, which do distinguish these models from embryos proper.  In addition, the models described by Pedroza did not develop the cell lines that would be needed to develop placenta, necessary for these models to have developmental potential.

“This work describes an extremely important model to support our pursuit of understanding the cellular and molecular events that occur around the time that the early embryo implants into the uterus in early pregnancy. It further illustrates the necessity for a coherent set of guidelines supporting work of this nature.  Scientists, bioethicists and legal experts in the UK are proactively working toward this as part of the Cambridge Reproduction-led Governance of Stem Cell-Based Embryo Models project.”

Dr Darius Widera, Associate Professor in Stem Cell Biology and Regenerative Medicine, University of Reading, said:

“The peer-reviewed study by Pedroza and colleagues describes another elegant model of the early human embryo generated by the self-organization of human embryonic stem cells. These human embryo-like structures can help us understand the mechanisms that regulate early human development, which could lead to a better understanding of inborn diseases.

“Similar to the findings in several preprints published in the last two weeks, the generated structures resemble the human embryo up to 14 days after fertilization. However, it is important to note that these self-organized structures are neither synthetic nor identical to human embryos that develop naturally after fertilization.

“In addition, since the embryo-like structures described in this study lack certain features, they do not have the ability to develop further. Nevertheless, this research and other recent reports on models of the early human embryo highlight that a robust regulatory framework is urgently needed.”

Comment sent out by our colleagues at SMC Australia:

Dr Jason Limnios, Group Leader in the Human Pluripotent Stem Cells and Retinal Development Lab, and Research Fellow in the Clem Jones Centre for Regenerative Medicine, Bond University, said:

“Cells are always talking to each other by touch and secreted signals. This is especially true during early human development. The current wave of research into stem cell-derived embryo models (SEMs) allows scientists to investigate what is happening during the earliest stages of human development without the need for embryos.

“What Sozen’s lab created was not an actual embryo, but a collection of several cell types found in the early embryo. These cells communicate with each other to coordinate critical decisions; where to move, what kind of cell to become, how much to divide and so on. These models can be used to test the effect of different substances, viruses and toxins on normal development, share insights into the role of genes during development, and what happens when genes don’t function normally.

“Although SEMs aren’t embryos, it’s important that the public understand this type of research is carefully regulated in each country and is being done to ultimately improve human health.”

‘Self-patterning of human stem cells into post-implantation lineages’ by Monique Pedroza et al. was published in Nature at 16:00 UK time on Tuesday 27 June.

DOI: https://doi.org/10.1038/s41586-023-06354-4

Declared interests

Prof Roger Sturmey: “In addition to my joint academic appointments at The Hull York Medical School and Unversity of Manchester, I serve as the Chair of the Scientific Advisory Panel for the UK Association of Reproductive and Clinical Scientists (voluntary role). I am also a board member for the Association of Embryo Technology in Europe (AETE), a small scientific society concerned with assisted reproductive techniques in agriculture (voluntary role).”

Dr Darius Widera: “I have no conflict of interest.”

Dr Jason Limnios has not declared any conflicts of interest.