Miniature liver grown from stem cells

Researchers from Wake Forest University Baptist Medical Center have created a tiny, functional liver grown from stem cells. It's not big enough to process a half-time beer (Go Giants!), or much of anything else, but it's an interesting start.

The researchers presented their laboratory-grown liver, which is about the size of a walnut, at a meeting of the American Association for the Study of Liver Diseases.

Growing fully formed organs out of stem cells is thought to be a distant goal of stem cell research. That's because of the complexity of organs. Of the possible stem cell therapies that are expected to reach clinical trial, most involve transplanting a single cell type -- retinal cells for macular degeneration, nerve support cells for spinal cord injury, or insulin-producing cells for diabetes. Whole organs contain a complicated network of cell types that all have to work together in order for an organ to function.

The Wake Forest group took an existing liver and stripped it of all the liver cells, leaving behind the support structures like connective tissue and blood vessels. Onto that they placed liver stem cells, which then grew in a bioreactor to create a tiny new liver.

The BBC quotes Shay Stoker, who led the research, saying there's a long way to go before this tiny proof-of-principle is ready to replace organ donations:

"Not only must we learn how to grow billions of liver cells at one time in order to engineer livers large enough for patients, we must determine whether these organs are safe to use."

That's many years of laborious time in the lab condensed into a single sentence. Scaling the liver up and proving its safety will be significant hurdles. Still, it's exciting to see these first steps toward what might one day be an alternative for thousands of people currently waiting on donated organs. 

A.A.