Synthetic embryos — those two words just don’t seem to go together, do they? Two recent reports in the journals Cell and Nature describe research that has done just that. Both groups started with single cells and provided the right conditions to stimulate the cells to grow into embryos. These studies were both performed with mouse cells and produced mouse embryos in the lab. While these embryos only developed for eight days, this represents about half the time to full development for normal mouse babies in a pregnant mouse. Think of the sinister company in the Alien series growing replicates of the heroine Ripley in the lab!
The groups used similar approaches to each other with comparable results, but they each used different cells. One approach used stem cells that were manipulated into what is called a naïve state. This means that the cells would be capable of growing into any cell in a mouse body. From the naïve state, specific genes in one set of cells were switched on that would allow them to form the placenta. Another set of the same cells were treated to form the yolk sac that provides nutrition to the early developing embryo. The third set of cells were those that formed the embryo.
In the other study, scientists started with cells destined to become either the yolk sac, placenta or the embryo itself, rather than starting with naïve stem cells. Special rotating incubation chambers were used to continuously bathe the cells in nutrient media and encourage their interaction. The interaction between the cells is key. While the cells are growing, they exchange chemicals to signal each cell to continue on the developmental journey. The communication goes in all directions and it is necessary for the yolk sac and placenta to optimally serve the growing embryo. The embryo has to signal its support structures to obtain what it needs as it grows into a baby mouse. Talk about a community effort!
Over the more than 8 days of development, the embryos developed recognizable features. They developed a heart that began beating, formed a digestive tract and began to assemble a central nervous system with a forebrain and a mid-brain.
After the eighth day, the embryos died. The scientists are still trying to figure out why development stopped and the embryos died. It could be that the embryos needed additional signaling from the mother’s tissues that were not present in the lab environment. There were also some tissue defects and organizational issues in the developing tissues. Another issue was that few cells started or continued on the path to form an embryo. While complete embryos were not developed, the progress toward a complete fetal mouse was remarkable.
This is an area to watch carefully as scientists work on further studies and improve the efficiency of embryo formation. Human development is so remarkably complex, it will likely be some time before we see Ripley emerging from a culture chamber. But who knows what advances will come next?
Medical Discovery News is hosted by professors Norbert Herzog at Quinnipiac University, and David Niesel of the University of Texas Medical Branch. Learn more at www.medicaldiscoverynews.com.
Internet forum rules ... Real names required. No pseudonyms or partial
names allowed. Stand behind what you post. Keep it clean. Don't use obscene, vulgar,
lewd, racist or sexually-oriented language. Don't threaten. Threats of harming another
person will not be tolerated. Be truthful. Don’t knowingly lie about anyone or
anything. Be nice. No racism, sexism or any sort of -ism
that is degrading to another person. Be brief. Keep posts to 150 words or less. Edit yourself. No more than two posts per thread
and stay on topic. Do not link to sites outside galvnews.com. Be aware. All posts are property of The Daily News
and may be republished in print. Be proactive. Use the "Report" link on
each comment to let us know of rule violations.
(0) comments
Welcome to the discussion.
Log In
Internet forum rules ...
Real names required. No pseudonyms or partial names allowed. Stand behind what you post.
Keep it clean. Don't use obscene, vulgar, lewd, racist or sexually-oriented language.
Don't threaten. Threats of harming another person will not be tolerated.
Be truthful. Don’t knowingly lie about anyone or anything.
Be nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be brief. Keep posts to 150 words or less.
Edit yourself. No more than two posts per thread and stay on topic. Do not link to sites outside galvnews.com.
Be aware. All posts are property of The Daily News and may be republished in print.
Be proactive. Use the "Report" link on each comment to let us know of rule violations.