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![Recently, By Conducting Two Studies, Researchers Have Raised Some Fundamental Ethical And Legal Questions About The Condition Of Human Embryos Grown In The Laboratory. The term "artificial embryo" is somewhat misleading, as this structure is not actually artificial, nor does it even closely resemble a natural embryo. Such a model resembles the original embryo, a small ball-like structure of cells created from the sperm that fertilizes the egg, but is actually made from stem cells grown in the lab. These stem cells originally came from a normal embryo, but still, such a structure has many differences with normal embryos. Therefore, some prefer to call this structure "embryo model based on stem cells". According to Nature , two teams of researchers have recently announced that they have grown embryo-like structures made entirely of human stem cells that are more advanced than any previous examples. These artificial embryos reached a stage equal to the growth of natural embryos about 14 days after fertilization. Compared to the past, such experiments can provide a good opportunity to research the process of human embryo development in the later stages. But still the ethical and legal questions about the status of "human embryo models" and how to monitor this process remain unanswered. The findings of recent research are described in two published studies by a team of researchers led by Magdalena Zernikagotz , a developmental biologist at the University of Cambridge, and another team led by stem cell biologist Jacob Hanna at the Weizmann Institute of Science. Both groups had previously presented their findings in scientific meetings. The controversial research made headlines after Zernikagotz presented the results at the annual meeting of the International Society for Stem Cell Research in Boston. What exactly have the researchers done and how different is their achievement? Both teams allowed artificial embryonic structures to form using human embryonic stem cells. Some of these structures were transformed into cellular models similar to the stem cells that form the placenta and the cells that form the yolk sac outside of a naturally developing embryo. The resulting embryo models show the structures and gene transcription profiles found in normal human embryos between 6 and 14 days after fertilization, the researchers say, until the start of a stage called gastrulation, during which the cells that make up the embryo in a layer between the amniotic cavity and the yolk sac are organized. Previously, researchers had made similar models using human and animal stem cells. Last year, Zernikagotz's team and Hanna 's team used similar techniques to create an artificial embryo model from mouse cells, progressing to the stage where vital organs such as the heart and brain begin to form. Until now, artificial human embryo models have not been this advanced, but last month Ali Brivanello , a stem cell biologist at the Rockefeller University in New York, and his colleagues reported in a study published in the BioArchive database that they had created human embryo models that showed signs of gastrulation. The equivalent of a normal embryo is observed around 12 days after conception. Recent studies show that researchers have created the most advanced human embryo models ever made. What is the importance of embryo survival for 14 days? 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: Because using real human embryos in research is ethically and technically challenging, we sought to develop a tool to answer specific questions about the second week of human embryo development.- 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. Why is the creation of human embryos scientifically controversial? 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 Martínez Arias, a developmental biologist at Pompeo Fabra University in Barcelona, believes that there is "nothing" in the research results described by Zernikagotz and his colleagues 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 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. What are the ethical concerns? 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, the embryo-like structures reported by Zernikagotz and Hanna 's groups must still respect the guidelines and rules for 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. Cell biologist Robin Lovellbudge of 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. "These models challenge the need to adhere to the principles of the 14-day rule," says Lovellbage, who is a member of the committee that recommended the reduction of these regulations in 2021 . Martínez Arias also believes that there are significant challenges to making long-lived human embryo models. He says that creating structures that can be developed in 21 days "will not be easy. "I would be surprised if [the human embryo models] could go further."](https://ded9.com/wp-content/uploads/2023/06/Controversy-over-the-creation-of-the-most-advanced-human-artificial-embryo-750x465.webp)
