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These models will allow us to expand knowledge about the first stages of development.
Two teams of scientists have created in the laboratory "structures similar" to early embryos from human cells, models that will expand knowledge about the first stages of development, the appearance of congenital problems at the beginning of life or new therapies for treat infertility.
Both works, presented this Wednesday in the journal Nature, now open new possibilities in the field of embryology, since, until now, researchers have faced important 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 which have been called "blastoids".
Blastocytes, they explain, are spherical structures formed by an outer layer of cells that surrounds a liquid cavity, in which a mass of embryonic cells is found.
The aforementioned mouse "blastoids" have allowed experts to replicate several aspects of their early development, but they present limitations in delving into the knowledge about the beginning of human life.
Although human blastocysts obtained after in vitro fertilization have provided researchers with valuable information to date, their availability and use are also very limited, they recall.
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 blastocysts with human cells, which will thus avoid the use of natural embryos. to carry out this type of studies.
Specifically, they reprogrammed fibroblasts, the main type of connective tissue cell, to produce three-dimensional models of human blastocytes, which they called "iBlastoids" ("induced blastoids").
They later confirmed that "iBlastoids" imitate the general architecture of blastocytes 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 several aspects of the early stages of implantation, the authors caution that "iBlastoids" should not be considered an "equivalent of human blastocytes."
Growing strategies
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 blastocyst-like structures from pluripotent stem cells, which have been called "human blastoids".
These "clusters of cells," Wu says, resemble human blastocysts in their morphology, size, number of cells, and the composition of different cell lineages.
Likewise, "human blastoids" are capable of generating embryonic and extraembryonic 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" are also not "equivalent" to the human originals, since, for example, they cannot give life to a viable embryo.
The two models described in Nature, they celebrate, manage to reproduce "key aspects" of early development, but they present a number of differences with respect to human embryos and, consequently, should not be considered as such.
