The journal Nature reports today that Japanese scientists used human stem cells to create “liver buds” — tiny precursors to full-fledged livers — that were then implanted into mice and functioned much like regular livers.
In other words, it appears that we’ve come our closest yet to actually building a solid-tissue human organ from stem cells. It will likely be a decade or more until this advance might help the many patients waiting desperately for transplants, but for now, stem cell experts say this is a significant breakthrough in regenerative medicine.
JH: So first of all, what did the researchers do here?
Well, what they did not do is use those politically controversial embryonic stem cells. These were what’s called “induced pluripotent stem cells,” they’re adult cells that have been kind of “reprogrammed” to be able to develop into various cell types.
What the researchers did was to mix together three types of human stem cells, and they found — to their own surprise, the first time they observed it — that the cells self-organized, or self-assembled, into a three-dimensional liver bud. A liver bud is normally found in an early embryo, and it later develops into a full-fledged liver. Continue reading