A model of a human embryo derived from stem cells has been created in the lab, a breakthrough that scientists say could help understand early human development and why and how some pregnancies fail.
This model embryo, derived from pluripotent stem cells, or stem cells capable of developing into different cell types, is an organized three-dimensional structure replicating some of the early human embryonic developmental processes, according to research from the University of Cambridge in the UK.
Such models, which allow experimental modeling of embryonic development during the second week of pregnancy, could also help researchers understand the developmental origins of organs and specialized cells such as sperm and eggs, the study published in the journal Nature said.
The second week of pregnancy in humans is when the embryo implants in the uterus. However, this is also the time when many pregnancies end.
“Our human embryo-like model, created entirely from human stem cells, allows us to access the developing structure at a stage that is normally hidden from us due to the implantation of a small embryo in the mother’s womb,” said Magdalena Zernicka-Goetz. , a professor in the Department of Physiology, Development and Neuroscience at Cambridge, who led the work.
Understanding these early developmental processes has the potential to reveal some of the causes of human birth defects and diseases and to develop tests for them in pregnant women, the study said.
Until now, the processes could only be observed in animal models, for example using zebrafish and mouse cells.
“This exciting development allows us to manipulate genes to understand their developmental roles in a model system. This will allow us to test the function of specific factors, which is difficult in the natural embryo,” said Zernicka-Goetz.
Until now, scientists have only been able to study the period of early human development using donated human embryos. This advance could reduce the need for donated human embryos in research.
Zernicka-Goetz said that while these models can mimic aspects of human embryo development, they cannot and will not develop to the postnatal equivalent in humans.
The new models, derived from human stem cells, do not have a brain or a beating heart, but include cells that would typically go on to form an embryo, placenta and yolk sac and develop to form the germ cell precursors that will form sperm and eggs.
Many pregnancies fail by the time these three types of cells organize to implant in the uterus and start sending each other mechanical and chemical signals that tell the embryo how to develop properly.
