Controversy over the creation of the most advanced human artificial embryo

Until now, artificial human embryo models have not been this advanced, but in the last month Ali Brivanlua stem cell biologist from Rockefeller University in New York and his colleagues in A study published in the BioArchive database reported the construction of human embryo models in which signs of gastrulation equivalent to normal embryos are observed at a time of about 12 days after fertilization. Recent studies show that researchers have created the most advanced human embryo models ever made.

Research on natural human embryos is carried out in accordance with an accepted guideline. This guideline, which is implemented in many countries, states that human embryos should not be cultured in the laboratory for more than 14 days. Therefore, researchers must use animal models to study the later stages of embryonic development, which do not necessarily represent the corresponding processes in humans.

Since in most countries artificial embryo models do not meet the official definition of embryo, they are not subject to such restrictions. Zernikagotz says:

Therefore, models older than 14 days can provide important insights into human embryonic development that are currently unavailable. For example, these embryos can be used to study developmental defects, or to investigate the causes of unwanted pregnancy termination.

The growth of artificial embryo models to the next stages of development has become a highly competitive issue and raises many arguments about the merits of the claims made.

It remains to be seen whether the claims made by the team of researchers in recent studies, none of which have yet been peer-reviewed, will hold up. Alfonso Martinez Arias A developmental biologist from Pompeo Fabra University in Barcelona, ​​believes that in the research results that Zernikagotz and his colleagues have explained that there is “nothing” that can be considered similar to the natural 14-day human embryo.

“What we can see are clumps of cells separated in parts, but there is no organized structure similar to a normal embryo,” Martínez-Arias added. He thinks that the overexpression of some of the genes needed to produce different types of protozoan cells “confuses the way the cells work,” and argues that these results do not add up to previous studies.

Zernikagotz It acknowledges the limitations of artificial embryo models for studying developmental processes. He believes that these structures do not explain all aspects of an embryo’s heritable traits, but serve as a complementary tool to investigate the differentiation of specific tissues during key stages of development.

In general, the results of studies about the status of artificial human embryo models and the issue of whether these models should be outside the rules related to natural human embryos or not, have provoked many discussions. Although artificial embryo models are not subject to the 14-day rule, embryo-like structures reported by groups Zernikagotz And Hana They must also respect the guidelines and rules regarding the human embryonic stem cells from which they are derived.

But other groups that have created artificial embryo models using “induced” stem cells derived from adult tissues do not follow such rules. Robin Lovellbudge The cell biologist from the Francis Crick Institute in London says these embryo models are “not supervised at all”.

Until now, no artificial embryo model has been created that has the ability to transform into a human. But a new study on monkey embryo models showed that such embryos can cause pregnancy if placed in the uterus; However, it ends automatically immediately after the implantation of the embryo.

Some researchers believe that a revised definition of the dream is needed to clarify this issue. For other researchers, the ultimate goal is to circumvent current limitations in embryo research.

Lowell Bej As a member of the committee that recommended the reduction of these regulations in 2021, he says: “These models challenge the need to adhere to the principles of the 14-day rule.” Martinez Arias also believes that there are significant challenges for making long-lived human embryo models. He says that creating structures that can be developed in 21 days “will not be easy. If [مدل‌های رویان انسانی] I will be surprised if they can go further.”