Scientists create mouse embryos from stem cells without sperm or eggs

Comparison of native (top) and synthetic (bottom) mouse embryos, showing similar brain and heart formation.

Comparison of native (top) and synthetic (bottom) mouse embryos, showing similar brain and heart formation.
photo: Armaday and Hanford

British scientists say they have accomplished a feat of genetic engineering: creating ‘synthetic’ mouse embryos without the need for eggs or sperm cells. Embryos are made from stem cells and can start developing brains, hearts and other organs in as long as a week. The researchers believe their work could one day help answer why many human pregnancies fail early in development, and even inform future efforts to create lab-grown organs for transplantation.

The study of naturally developing embryos has provided scientists with countless insights into biology. But many aspects of early development are not readily observable in biology. Researchers have learned how to develop embryos already created in the lab to a certain extent, and how to produce artificial but simple embryos or individual organ models—advancements that help overcome some of these obstacles. However, the new study appears to be one of the first successful attempts to create functional mouse embryos from scratch.

Work, post Published in the journal Nature on Thursday, it is the culmination of years of research by scientists at the University of Cambridge. To create their embryos, they combined the three main types of embryonic stem cells in the right mixture and environment, allowing them to communicate with each other and mimic what happens naturally during embryonic development. From there, the cells begin to arrange themselves into the embryo’s basic structure and begin to progress through the early stages of development, including the formation of the yolk sac, brain and beating heart. Embryos survived for eight and a half days.

Technically, the team isn’t the first to claim to have created synthetic mouse embryos. On August 1, Israeli scientists post A paper in Cell details embryos made in their own lab. The UK authors noted that their work had gone through a review process for about a year, and even before the Israeli paper was submitted for publication, they believed their model was more complex than anyone else’s.

“This is really the first model that allows you to study brain development in the context of the entire developing mouse embryo,” study author Magdalena Zernicka-Goetz, professor of mammalian development and stem cell biology at Cambridge, found in a discussion.

Zernicka-Goetz and her team say the research should ultimately help pinpoint many of the causes of early pregnancy failure, even before people realize it.Estimated range, but 20% to 50% of pregnancies may end with abortion, while many embryos produced by in vitro fertilization may similarly fail to implant in the uterus or otherwise grow. If nothing else, just being able to study these earliest stages of growth up close can give scientists all kinds of information about how we came to be.

Zernicka-Goetz said: “This is an extremely complex stage of development that has enormous implications for the rest of our lives.”

The research could also have practical health implications, such as more precise detection of fetal defects in early pregnancy.Their past work has indicatedFor example, not all embryos diagnosed with defective cells go on to develop health problems because embryos can repair themselves to some extent. Finally, what we’ve learned here can even provide lessons on how to create fully functional synthetic organs.

However, this is all in its early stages, and there is no shortage of ethical issues arising from this and similar research directions.Last year, the International Society for Stem Cell Research easy Its guidelines for growing human embryos in the laboratory remove the hard 14-day limit, rather than evaluating it on a case-by-case basis. While these guidelines may not apply to simple models of human embryos, more complex versions that could one day be created by scientists like Zernicka-Goetz are likely.As far as they are concerned, the team has been working hard and planning further development Synthetic embryo.

However, the biggest challenge right now is creating synthetic mouse embryos that can survive early developmental stages in the lab (it takes about 20 days for a mouse to fully develop). Such advances will likely require the creation of artificial wombs or placenta-like structures, and scientists are also working hard on this.Last year, the same team from Israel Shows Embryos can be grown in a beaker for up to six days, and the Cambridge team says they are also working on their own method.

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