Antonio Urries
Director of the Assisted Reproduction Unit at Quirónsalud Hospital in Zaragoza and president of the Association for the Study of Reproductive Biology (ASEBIR).
The first thing to note about the article is that what they have generated are not embryos per se, but "embryoid" structures capable of behaving like an embryo in its first days of development.
In this work, Li's team manages to generate blastoids from monkey embryonic stem cells, with similar characteristics to natural blastocysts, managing to maintain their long-term development and even their implantation in the uterus of surrogate macaque mothers and generating pregnancies with the presence of early gestational sacs.
Although it is true that this type of embryoid structures have already been successfully generated in humans with morphology and structures similar to natural embryos, their culture beyond day 14 and their implantation in a woman's uterus is not permitted due to ethical issues. Therefore, being able to carry out this type of research in a species as closely related to ours as the macaque monkeys is an ideal model for the detailed study of the early stages of development of such vital mammalian organs as the heart, brain and neural tube. The beginning of organogenesis.
On the other hand, it can help us to delve deeper into certain implantation mechanisms and understand why pregnancies fail, detecting those anomalies that can lead to miscarriages. It can also guide us in the development of "synthetic" organs and tissues for transplants and help us understand the origin of certain diseases.
Naturally, it has the limitations of being a technique in a very preliminary phase, the result of a very complicated and inefficient process (around 25%), but with great potential for the future and a very promising applicability in humans.