Nature: for the first time, a mouse embryo with a heart was grown from stem cells and brain scientists at Cambridge University for the first time grew embryos from stem cells of mice that formed a brain, a beating heart and the beginnings of other organs of the body.
The results of the 10-year study are reported in an article published in the journal Nature.
During the experiment, biologists worked with three types of stem cells — embryonic stem cells (ESCs), trophoblast cells (TSCs) and iXEN cells. Scientists regulated the expression of certain sets of genes involved in embryogenesis, achieving self-organization of cells into structures that passed successive stages of development for 8.5 days. They developed contracting hearts, anterior and middle part of the brain, as well as a yolk sac.
For the successful development of the human embryo, proper interaction is necessary between the tissues that will become the embryo and the tissues that will connect the embryo with the mother. In the first week after fertilization, three types of stem cells develop: some eventually become the body’s own tissues, and the other two support the development of the embryo. One of these extraembryonic types of stem cells is the placenta, which connects the fetus to the mother and provides oxygen and nutrients; and the second is the yolk sac, where the embryo grows and from where it receives nutrients.
The spontaneous emergence of all living things was swollen and bubbled On March 7, 2017, scientists combined cultures of all three types of stem cells in the correct proportion and a suitable nutrient medium.
The authors call the formation of an almost full-fledged embryonic brain, which needs support from extraembryonic tissues, the main achievement of their research. Scientists also turned off a key gene responsible for the development of the neural tube, which is the precursor of the nervous system and the eyes. As a result, the synthetic embryos developed exactly the same defects as the animals with the corresponding mutation. This shows that grown embryos are similar to embryos obtained from fertilized germ cells.
The resulting embryos are a suitable platform for studying embryonic processes in vitro (in vitro). The researchers hope that they will help to understand why some embryos developing in the laboratory during in vitro fertilization survive and continue to develop into a full-fledged organism, while others die. It is known that a high risk of termination of pregnancy occurs at a time when three types of stem cells begin to send each other mechanical and chemical signals indicating to the embryo how to develop properly.
Since currently British legislation allows human embryos to be examined no later than 14 days after fertilization, scientists plan to grow synthetic embryos from human stem cells in order to conduct experiments at later stages of development. This will help to trace the key mechanisms of human organ development.