An international group of scientists has created a synthetic human embryo model that mimics a natural embryo between seven and 14 days old to study an early phase of human life development, a process known as gastrulation in which the fertilized egg is transformed in a structure with three differentiated germinal layers from which all the tissues and organs of the individual will be formed.
The research that has achieved this scientific milestone has been led by scientists from the University of Cambridge (United Kingdom) and the California Institute of Technology (USA) and directed by Magdalena Zernicka-Goetz, who published in August last year Nature magazine how they had managed to reproduce outside the womb and without using eggs or sperm what happens in the early stages of mouse development.
Now, and according to the British newspaper The Guardian, they have reported on the technique with human material during the annual meeting of the International Society for Stem Cell Research in Boston (United States). Researchers have succeeded in generating model embryos resembling those found in the early stages of human development from stem cells, a breakthrough that may help study genetic disorders and understand why miscarriages occur.
“This work may provide an important tool to study early development, while reducing reliance on human embryos for this type of research.”
The details of the study have not yet been published in a scientific journal, although the draft has been published on the bioRxiv repository. Zernicka-Goetz has explained in the presentation that the culture of embryos has reached a stage that goes somewhat beyond the equivalent of 14 days of development of a natural embryo. “We can create models similar to human embryos by reprogramming cells [troncales embrionarias]”, he said at the meeting, according to The Guardian.
Better understand infertility and abortion
These synthetic embryos are not intended to be used clinically, as it would be illegal to implant them into a woman’s uterus, and it is also not known whether these structures have the ability to continue to mature beyond the early stages of development. The objective of the research is to help scientists better understand the development period of the “black box”, that first stage in which human life is gestated and which is known by this name because it is only allowed to cultivate embryos in the laboratory up to a legal limit of 14 days. They then return to the research much later by looking at the scans that are done during the pregnancy and on the embryos donated for research.
“Our human model is the first three-lineage human embryo model to specify amnion and germ cells, egg and sperm precursor cells,” Żernicka-Goetz told The Guardian. “It’s beautiful and created entirely from embryonic stem cells.”
Roger Sturmey, Professor of Reproductive Medicine at Hull York Medical School (United Kingdom) and principal investigator of Maternal and Fetal Health at the University of Manchester (United Kingdom) has given his opinion on this scientific milestone in statements to SMC Spain. “The work published in The Guardian builds on a growing base of research showing that stem cells can, under highly specialized laboratory conditions, be engineered to form a structure resembling the embryonic stage called a blastocyst. In normal development, the blastocyst is an important structure, as it is around this time that the embryo begins the process of implantation in the uterus and pregnancy is established.”
According to this expert, “we know very little about this stage of human development, but it is a time when many pregnancies are lost, especially in the context of IVF [fecundaciones in vitro]. Therefore, models are urgently needed to allow us to study this period to help understand infertility and early pregnancy loss. Today, we can say that these ‘synthetic embryos’ share a number of characteristics with blastocysts, but it is important to recognize that the way synthetic embryos form is different from what happens when a normal embryo forms a blastocyst.”
Therefore, he warns: “Much work remains to be done to determine the similarities and differences between synthetic embryos and embryos that are formed from the union of an egg and a sperm. This work by Zernicka-Goetz has not yet been fully appreciated by the scientific community, but it offers interesting perspectives to answer these questions and may provide an important tool to study early development while reducing reliance on human embryos. for this type of research. Given the nature of this work, UK lawyers, ethicists and scientists are currently working to establish a set of voluntary guidelines to ensure that synthetic embryo research is conducted responsibly.”
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