An extraordinary new study has detailed the development of a nearly complete mouse embryo – with muscles, blood vessels and a tiny beating heart – grown in a lab dish out of stem cells. The research presents the most sophisticated “embryo in a dish” created to date, offering essential new innovations on the road to growing replacement human organs in a lab.
The new research comes out of the Thisse Lab at the University of Virginia School of Medicine. Led by Christine and Bernard Thisse, the scientists have been working for years to find a way to build functional embryos out of stem cells.
Creating an embryo in a lab dish out of stem cells is obviously not a simple process. Several different types of stem cells are needed, and then directing those cells to develop into the correct organized structure at the right moments has proved challenging.
Over the past few years the Thisse lab has overcome several hurdles, initially creating zebrafish embryos before moving onto more complex mammals. Christine Thisse explains her team’s breakthrough presents the first mammalian embryo of this complexity ever built solely from stem cells.
"We found a way to instruct aggregates of stem cells to initiate embryonic development,” she says. “In response to this controlled instruction, the aggregates develop into embryo-like entities in a process that recapitulate the embryonic steps one-by-one. What is amazing is that we can get the variety of tissues that are present in an authentic mouse embryo."
So far the research has not progressed to the point of producing a fully mature mouse embryo. In this study embryonic development halted at a stage equivalent to the middle phase of gestation. Bernard Thisse says although development of certain brain regions is still a hurdle to be overcome they are confident of soon being able to generate complete “embryo-like entities.”
"The embryoids we are currently producing lack the anterior brain domains," he notes. "However, with the techniques we have developed, we should be able, at some point, to manipulate molecular signals that control embryo formation, and this should lead [to] generating embryo-like entities containing all tissues and organs including the anterior brain."
The primary goal of this research is to grow functional human organs for transplants. The Thisses suggest this new breakthrough brings that reality one step closer by demonstrating that complex tissue organization can be achieved through tailored control over stem cell growth.
Other outcomes include better ways to model diseases using detailed lab-grown organoids. But how much further can this kind of research go?
“This model holds the potential for further manipulating gradients, modeling diseases, performing drug screening and even for development of a human counterpart,” the researchers conclude in the new study.
The new study was published in the journal Nature Communications.
Source: University of Virginia