"We have proven that in humans there are stem cells for the liver in the bone marrow," says Neil Theise, M.D., Associate Professor of Pathology at New York University School of Medicine, the lead author of the new study. "These cells potentially could be used as a source of cells for liver transplants, as a pool of cells for the development of an artificial liver, and in gene therapy to treat many liver diseases," he says.
Stem cells were long thought to be limited to organs that supply fresh sources of new cells throughout life, such as blood cells from the bone marrow and skin cells from skin. And cells from bone marrow, for example, couldn't become anything but blood cells.
The liver, too, supplies new recruits -- even if half of the organ is removed from the body, it regenerates with breathtaking speed -- but researchers have disagreed for many years about the origins of the liver's newfound cells. Some suspected there might be hepatic stem cells, but they lacked proof of their existence -- until now. (The ancient Greek myth of Prometheus is based on the liver's ability to regenerate. Each day a giant eagle eats the liver of Prometheus, who is bound by chains to a rock. And each day the liver subsequently grows back to its original size.)
"This is an exciting finding, and incredibly surprising because the bone marrow has never been considered as a source of liver cells," says D
Contact: Deborah Miller
New York University Medical Center and School of Medicine