Thursday, October 21

They develop the first embryo model from human cells

Two teams of scientists have created in the laboratory “similar structures” to early embryos from human cells, some models that will allow to expand the knowledge about the first stages of development, the appearance of congenital problems at the beginning of life or new therapies to treat infertility.

Both works, presented this Wednesday in the journal Nature, now open up new possibilities in the field of embryologyas, until now, researchers have faced significant challenges.

Recently, the authors recalled in a virtual meeting with the media, structures similar to the embryos of these animals that are in the blastocyst phase -which occurs about five days after fertilization- have been generated from mouse cells. – and that they have been called “blastoids”.

Blast cells, they explain, are spherical structures formed by an outer layer of cells that surrounds a liquid cavity, in which there is a mass of embryonic cells.

The aforementioned “blastoids” of mice have allowed experts to replicate various aspects of its early development, but have limitations to deepen knowledge about the beginning of human life.

Although human blasts obtained after in vitro fertilization have provided researchers, to date, valuable information, their availability and use are also very limited, they remember.

To overcome these obstacles, the team led by Argentine researcher José Polo, from Monash University (Australia), has generated, for the first time, “blastoids” similar to blastocytes with human cells, thus avoiding the use of natural embryos to carry out this type of study.

Specifically, they reprogrammed fibroblasts, the main type of connective tissue cell, to produce three-dimensional models of human blastocysts, which they have called “iBlastoids” (“induced blastoids”).

They later found that the “iBlastoides“They mimic the general architecture of blasts and are capable of giving rise to pluripotent and trophoblastic stem cells, a group of cells that provide nutrients to the embryo and develop as an important part of the placenta.

Although they also managed to mimic various aspects of the early stages of implantation, the authors caution that “iBlastoids” should not be viewed as a “equivalent of human blasts”.

Crop strategy

The second study, led by Jun Wu, from the University of Texas Southwestern (USA), presents the development of a three-dimensional culture strategy that allows the generation of blast-like structures from pluripotent stem cells, which they have called “human blastoids.”

These “sets of cells”, Wu exposes, they resemble human blasts in their morphology, size, number of cells, and in the composition of different cell lineages.

Likewise, “human blastoids” are capable of generating embryonic and extra-embryonic stem cells, while they can organize themselves into structures with characteristics typical of peri-implant human embryos.

Like José Polo, Jun Wu emphasizes that these “human blastoids” neither are they “equivalent” to the original human, since, for example, they cannot give life to a viable embryo.

The two models described in Nature, they celebrate, come to reproduce “key aspects” of early development, but present a number of differences from human embryos and, consequently, they should not be considered as such.

However, two independent experts, Yi Zheng y Jianping Fu, comment in an accompanying analysis article that, as protocols are optimized, these blastoids will more accurately mimic human blasts, which will raise bioethical questions.

“Consequently – they write – the continuous development of models of human embryos, including human blastoids, demands that public debates be opened on the scientific importance of these investigations, as well as on the social and ethical issues they raise. “

Polo states that there is still a long way to go to reach that point and that, for the moment, they “excited” about the “large number of applications” that already offer these two study models to better understand “the functions that many genes have in the early stages of development.”

“In addition, we are sure that it will lead us to understand, for example, infertility problems and how to solve them. Or how, since we can create hundreds of them (blastoids), they can affect toxins and viruses in those early stages “, he concludes.

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