Liver Buds to the Rescue

Some 16,000 ailing Americans are waiting to receive a liver transplant. But due to a shortage of viable livers, it’s likely that fewer than 7,000 transplants will be performed in 2013. In Japan, where the shortage is worse, the number of people in need of new livers is 10 times as great as the number of deceased donors who could provide one.

Source: http://discovermagazine.com

That gap motivated stem cell biologist Takanori Takebe and his colleagues at the Department of Regenerative Medicine at Yokohama City University in Japan to find an alternate solution. This year they succeeded in generating mini-livers, or liver buds, from stem cells that were taken from human skin and reprogrammed to an embryonic state. (Embryonic stem cells are notable because they can morph into virtually any cell type in the body.)

When mixed with two other types of cells, the fabricated primitive liver cells organized themselves into three-dimensional structures, complete with blood vessels. In effect, Takebe’s team re-created the process by which a human embryo begins to form a functioning liver. 

Transplanted into a mouse, the human liver buds, about 5 millimeters long, exhibited many functions of the mature organ, such as metabolizing sugars and drugs. When the scientists disabled the mouse’s own liver, the human buds kept the animal alive for two months. A person with liver failure would require an infusion of “tens of thousands” of liver buds, Takebe says.

Until the buds can be generated from the skin of each individual patient, recipients will have to rely on immune-suppressing drugs to avoid rejection, just as they would with the transplant of an entire organ. Replacement liver buds might be available to human patients in a decade or less. — Jeff Wheelwright…………………more here