ananyo writes "Transplanting tiny 'liver buds' constructed from human stem cells restores liver function in mice, researchers have found. Although preliminary, the results offer a potential path towards developing treatments for the thousands of patients awaiting liver transplants every year. The liver buds, approximately 4 mm across, staved off death in mice with liver failure, the researchers report this week in Nature (abstract.). The transplanted structures also took on a range of liver functions — secreting liver-specific proteins and producing human-specific metabolites. But perhaps most notably, these buds quickly hooked up with nearby blood vessels and continued to grow after transplantation."