By Akshaiyaa V S
Researchers at the MERLN institute and the Hubrecht Institute in the Netherlands have been successful in growing model mouse embryos by combining stem cells.
Usually, a sperm and an egg cell are necessary for the formation of a fetus, and this can be done either naturally or through artificial means. However, researchers have successfully skipped this step by using stem cell lines, giving hopes to couples with fertility issues and helping doctors and scientists alike understand the early days of life better.
Nicolas Rivron, who leads the research group said he had his moment of epiphany when he realised that other labs were able to cultivate the outer part of the stem cells, which would later become the placenta and the inner part, which would grow to become an embryo, separately.
“By combining these mouse stem cells, we have now succeeded in creating embryo structures in the laboratory,” he said. He added that the artificial embryos, nicknamed “blastoids”, were able to implant themselves in the uterus, just as naturally as the normally developing ones.
How it works
The developing embryo in the first few days after fertilization forms a blastocyst, which is a cluster of around 100 cells, and these inner cells later become the beginning of an embryo while the outer shells form the placenta. Taken from mice, the trophoblast cell – which later becomes the placenta and the embryonic cell is grown separately under laboratory conditions. The embryonic cell is observed to be the chatty type – communicating with the placenta and helping it to self-organize and implant itself in the uterus. These artificial blastocysts were called “blastoids.”
When the experiment was conducted in mice, the artificial embryo attached itself to the mouse’s womb and cell division took place just like it would in normal embryos. The only shortfall was the lack of a third type of stem cell which would provide nourishment for the growing embryo and optimization of the system for its proper development into a fully-grown fetus.
Though the experiment is successful in mice, research is going on to further develop the embryo and also to test its reliability for human uteruses.
Significances of the discovery
The first few weeks of any pregnancy are the most critical, as the possibility of a miscarriage is the highest during those days. Minor problems developed at an early stage have fatal life-long consequences in the developing fetus or in extreme cases, even termination of pregnancy.
The cell development during this blastocyst phase influences the success rate of the pregnancy and the health of the baby post-childbirth. Studying the murky early stages, thus, would focus on the intricate molecular structure of the blastocyst, enabling researchers to understand early embryonic development and test drugs to treat complications which arise. Additionally, usage of embryonic cells to test drugs can help minimize the use of animals in laboratory research.
Testing medicines require a lot of samples and till now, research has been performed using limited leftover samples from IVF treatments. Also, scientists have to strictly adhere to the “14- day rule”, where they stop experimenting after 14 days since an embryo develops a primitive neural network after the deadline and may experience “pain” if experiments were performed further.
Though the deadline is the same in case of the artificially created embryos too, having abundant quantities of stem cells enables research to be conducted at a faster pace. Since stem cells are available in surplus, generating a surfeit of embryos is made easy. Artificially creating embryos and facilitating their growth would also help save the endangered species of the world.
Although it is unclear about the scope of the response of human uteruses to blastoids created from stem cells, if successful, the research can bring a ray of hope to the society and to couples struggling with fertility issues.