Researchers at the University of Minnesota Stem Cell Institute (SCI) have demonstrated, for the first time, the ability of adult bone marrow stem cells to differentiate in vitro as hepatocytes (liver cells) with hepatocyte phenotype and function.

"What we have seen is that adult stem cells cultured from the bone marrow of humans, mice and rats can be induced to differentiate into cells that look, stain and function like liver cells," said Catherine Verfaillie, M.D., director of the University of Minnesota Stem Cell Institute and author of the research. "Our lab shows, for the first time, clear indication that these stem cells function like liver cells in that they secreted three key elements: albumin, the most abundant protein made by the liver; urea, produced only by liver and kidney epithelium; and cytochrome P450, the major detoxifying enzyme in the liver."

According to Verfaillie, the benefits of the research could be broad. "These adult stem cells are indeed a good source of cells for patients with genetic diseases of the liver, such as alpha 1 antitrypsin deficiency, which affects 100,000 in the United States," she said. "It may also be helpful for some types of cirrhosis or acute liver failure due to medications. In addition, the cells might be used to create bio-artificial livers and replace the use of pig liver cells, which are a commonly used source of cells now. Much as dialysis machines can be a bridge for patients waiting for kidneys, a bio-artificial liver can help bridge a person from acute liver failure to transplant.

"The immediate benefit might well be to help pharmaceutical researchers and manufacturers screen for toxicity and efficiency of drugs prior to phase I clinical trials."

Verfaillie and her colleagues announced late last year that these cells, called multipotent adult progenitor cells (MAPCs), demonstrate the potential to differentiate beyond mesenchymal cells, into cells of visceral mesodermal origin, such as endothelium, as well as into cells with neuroectodermal phenotype and function.