The journal published two studies natural Acting generation in vitro The “similar structure” is similar to the embryo at the blastocyst stage, that is, when the embryo develops 5 or 6 days after fertilization. These works can help understand the shortcomings in the early development and the development of neo-assisted reproductive therapy, but they still have great limitations.
A few days later Fertilization of egg, This becomes Bacillus embryo.It’s about Embryos about 5 or 6 days old A complex cell structure is proposed, which is composed of approximately 200 cells. This is the first stage where embryo and extra-embryonic cell types can be easily detected. The defect is one of the causes of the defect. Spontaneous abortion Two out of every three monozygotic twins occur at this stage.
But despite the Embryonic development In recent years, their understanding has been limited due to the lack of appropriate models.Donated human blastocysts for research In vitro fertilization (IVF) has played a big role, but its availability and use are limited.
Recently, the explosive structure of a mouse is called Blastocyst, Can simulate all aspects of early mouse development. However, so far there has been no report that human cells produce blastocysts like blastocysts.
IBlastoids represents an accessible, scalable and manageable model system, which is valuable for many applications. It will allow the research and treatment of early developmental diseases to be screened, and has great potential in understanding infertility and early pregnancy loss.
One First job, Published in the magazine this week natural And from Monash University (Australia) successfully reprogrammed human fibroblasts (the main cell type found in connective tissue) to produce a three-dimensional model of human blastocysts in the laboratory, which they called iBlastoids (induced blastocysts) ).
The researchers found that the structure formed by iBlastoids is similar to the morphology of human blastocysts, and can produce pluripotent and trophoblast stem cells (they provide nutrients to the embryo and become an important part of the placenta). They can also simulate all aspects of the initial implantation phase.
“Our data shows that iBlastoids represents an accessible, scalable and manageable model system that is valuable for many applications in basic research and transformation methods. They affirmed that it will allow Developmental disease research and treatment screening, and it has great potential in understanding infertility and early pregnancy abortion.
Yes, the author pointed out that iBlastoids should not be considered equivalent to human blastocysts. He explained: “The important thing is that the blastocyst model cannot generalize our ignorance of human preimplantation development.” Teresa Rayon,the scientist Francis Crick Institute. “Embryonic implantation can help generate hypotheses that should be tested in human embryos, but it will not replace the need to use preimplantation embryos to solve some unknown problems.”
These models are not embryos
One Second independent study, Also published in natural From University of Texas Southwestern Medical Center (United States) revealed a three-dimensional culture strategy that makes it possible to generate human blastocysts from human pluripotent stem cells.
The morphology, size, cell number and composition of various cell lineages of human blastocysts are similar to those of human blastocysts. In addition, the authors discovered that protein kinase C signaling-which is involved in embryonic development-is in the formation of the blastocyst cavity.
Rayon said: “Human blastocysts will help to accurately analyze the interactions between the stem cell populations that make up the blastocyst without the need to donate embryos.” “In addition, blastocysts can study specific mutations, signaling molecules or morphology in the blastocyst. The process occurs and is very useful for simulating embryo implantation.”
Despite the good results, they also emphasized that human blastocysts are not equivalent to blastocysts and blastocysts. Cannot produce viable embryos. Therefore, although these two models reproduce key aspects of early human development, they have many differences from real human embryos, so they should not be regarded as such.
As pointed out Peter Rugg-Gunn, of Barbraham Institute (United Kingdom), the next step should be to optimize the conditions to improve the formation efficiency of the explosive structure. The current level is very low: “Only one in ten attempts are successful, and the rate of formation is also high. It is asynchronous. .
In order to take full advantage of this discovery, more control of the process and less variation will be required. He also said that it is also important in future research to determine which aspects of early human development can generalize explosive structures.
For its part, Martin Johnson, Professor Emeritus of Reproductive Sciences Cambridge University (UK) pointed out how the author chose to stop the development of these embryos before they formed the original stripes, thereby respecting the 14-day rule stipulated by the country’s law.
“Despite the fact that blastocysts are not classified as human embryos, and by analogy with mouse blastocysts with comparable yields, they cannot have complete developmental potential. Obviously, the authors hope that their work will be obtained before passing this line. Public recognition. He concluded that scientists will have to explain the limitations and potential benefits of this technology.