To make his discovery, Fausto and his team isolated liver stem cells from human fetal tissue donated to research. They then grew the stem cells in the laboratory for up to six months and injected them in mice with damaged livers. The immune systems of the mice were suppressed to prevent rejection of the human cells. These cells, in turn, replaced thousands of damaged liver cells, far beyond Fausto’s expectations.

The team also manipulated the stem cells with special laboratory cultures to become cells of the bile duct, cartilage, bone, fat and blood vessels—cells that one day could have the potential to repair damaged tissue throughout the body.

“The significance of this research is that we were able to both isolate the liver stem cells and grow them into basic liver and bile-duct cells,” Fausto explains. “It was a delight when we witnessed these cells partially repopulating the damaged livers of the mice.”

Scientists have long believed that stem cells, derived from bone marrow, blood or embryos, are capable of repairing damaged tissue by taking on the identity of that organ’s cells—a phenomenon known as differentiation. Simply put, they can respond to the body’s needs and become virtually any type of cell. In recent years, research has expanded because of the promising regenerative potential of stem cells in treating a myriad of diseases.
 
“What we ended up finding in this study was a cell type that was a stem cell for liver lineage, but that could also become the cells of cartilage, fat, bile duct, bone and blood vessels,” Fausto says. “We found these cells to have an enormous capacity to differentiate.”

Throughout this experimental process, Fausto says the UW research team gained an unprecedented understanding of cell origins, human embryology and how the human liver is put together—knowledge, he says, which is “critical for future research.”

If the research moves forward successfully in coming years, the technique Fausto and his team developed could some day provide a new lease on life for liver patients who otherwise face a bleak prognosis.

But Fausto is quick to emphasize that this is only the beginning of a very long road, and clinical trials “are a long way off.”

Fausto is one of more than 80 faculty members who are part of the UW’s new Institute for Stem Cell and Regenerative Medicine. Regenerative medicine focuses on replacing damaged or dead cells either by introducing new cells into the body or by prompting the body to create new cells on its own.

The institute includes interdisciplinary teams of researchers in medicine, biology and engineering working together to unleash the tremendous power of stem cells and develop therapies—and, ultimately, cures. The mission: to move the long-touted regenerative powers of stem cells from the laboratory into the realm of viable human therapies. The targets: liver disease, heart failure, diabetes, Parkinson’s disease, spinal cord injury, stroke, Alzheimer’s disease, Lou Gehrig’s disease and loss of hearing or sight.