Because there is still considerable morbidity and mortality associated with the process of whole liver transplantation, and because more than a thousand people die each year while on the liver transplantation list, and tens of thousands more never get on the list because of the lack of available livers, it is evident that improved and safer liver transplantation would be valuable, as would approaches that provide for an increased number of transplantations in a timely manner. A technology that might address these issues is the development of a human liver cell line that can be employed in liver cell transplantation or in a bioartificial liver. Developing such a cell line from human embryonic stem cells (hESC) would provide a valuable tool for pharmacology studies, as well as for use in cell-based therapeutics. The objective of this proposal is to focus a team effort to determine which differentiated hESC will be the most effective liver-like cells in cell culture and in animal studies, and to then use the best cells in clinical trials of cell transplantation in patients with advanced liver disease.
In the past year, we have been able to differentiate hESC so that they act like liver cells in culture. The cells are acting like liver cells by producing normal human liver proteins, and they metabolize drugs in a manner similar to liver cells, and they do not cause tumors when transplanted. Now we are ready to assess the cells in clinically-relevant models using techniques that can then be adapted to future human clinical trials. The intent in these studies is to determine which will be the most effective cells to use in human clinical trials. Once this is determined, the best cells can then be employed in human patients.
If the studies are successfully undertaken, we will have established a clinically useful and viable liver cell line that could be used to repopulate an injured liver in a safer and less expensive manner than with whole liver transplantation. Moreover, all people who have liver failure or an inherited liver disease could be treated, because there would be an unlimited supply of liver cells.