An in vitro and in vivo comparison among three different human hepatic stem cell populations

An in vitro and in vivo comparison among three different human hepatic stem cell populations

Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00359
Approved funds: 
$2,252,835
Disease Focus: 
Liver Disease
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
Public Abstract: 
Because there is still considerable morbidity and mortality associated with the process of transplantation, and because more than a thousand people die each year while on the liver transplantation list, 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 assist device. Developing such a cell line from human embryonic stem cells (hESC) or from other human stem cell sources would provide a valuable tool for pharmacology studies, as well as for use in cell-based therapeutics. In the proposed studies, we will differentiate human embryonic stem cells or fetal liver cells or bone-marrow derived cells so that they act like liver cells in culture. Once it has been established that the cells are acting like liver cells by producing normal human liver proteins, and that they do not act like cancer cells, the cells will be injected into the livers of immunoincompetent mice that do not rejects human cells. Then we will evaluate whether the cells grow and thrive in the mouse livers, whether they still produce high levels of human liver-specific proteins, whether they produce tumors in the mouse livers, and whether they can replace damaged mouse liver cells with human cells. One of the ways this will be done is to label the cells with a marker gene and to image the marker gene in the livers of the mice with special x-ray machines that can distinguish a few hundred human cells in the mouse liver. Finally, we will infuse the human liver stem cells into the liver of monkeys to determine if they will grow in the monkey livers, because the monkeys are more similar to man. Such studies should be done in nonhuman primates before clinical studies are undertaken to employ these cells to replace abnormal liver cells in man. Our intent is these studies is to compare and contrast three types of stem cells to determine which will be the most effective cells to use in human studies. If the studies are successfully undertaken, we will establish a clinically useful and safe liver cell line that could be used to repopulate an injured liver in a safer and less expensive manner than with liver transplantation; moreover, all people who had liver failure or an inherited liver disease could be treated, because there would be an unlimited supply of liver cells.
Statement of Benefit to California: 
In California, as in all parts of the US, there are not enough livers available for transplantation for all the people who need them. The result is that many more people die of liver failure than is necessary. One way to improve this situation is the transplantation of liver cells rather than whole organ transplantation. We are attempting to develop liver cell lines from stem cells that will act like normal liver cells. If the cells that we develop function well and do not act like cancer cells in culture, we will then transplant them into special mouse models of liver disease and see if the human cells can rescue the mouse from its liver disease. As a final test, we will see if the cells function in primate livers. In our studies, we will compare human embryonic stem cells with adult stem cells to determine which will be the most effective cells to transplant into people. If the studies are successfully undertaken, it means that we will have a stem cell line that can then be employed in human studies to determine their safety and effectiveness.
Progress Report: 

Year 1

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) or from other human stem cell sources would provide a valuable tool for cell-based therapeutics. In the past year, we have improved on our ability to differentiate the hESC towards liver cells in culture. They are producing normal human liver proteins. They also are capable of metabolizing drugs and other substances in the same manner of normal liver cells in culture. This means that they have the most important attributes of normal liver cells. Also, we have employed these cells in clinically-relevant models using techniques that can then be adapted to future human clinical trials. Moreover, they do not produce tumors. In addition, we are employing adult stem cells derived from the bone marrow in collaborative studies with colleagues in Egypt. These stem cells have been differentiated so that they act like liver cells, and they have been transplanted into patients with advanced liver disease. The patients that have received the cells have improvement in their blood tests, and they are living longer than would have been expected without the transplantation. Thus we are making some progress in establishing 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 liver transplantation.

Year 2

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) or from other human stem cell sources would provide a valuable tool for cell-based therapeutics. In the past year, we have improved on our ability to differentiate the hESC towards liver cells in culture. They are producing normal human liver proteins. They also are capable of metabolizing drugs and other substances in the same manner of normal liver cells in culture. This means that they have the most important attributes of normal liver cells. Also, we have employed these cells in clinically-relevant models using techniques that can then be adapted to future human clinical trials. Moreover, they do not produce tumors. We have also worked to differentiate human induced pluripotent cells (hiPSC) to become liver-like cells in culture. The hiPSC behave very much like hESC, in that they are pluripotent. However, they are derived from adult somatic cells and thus do not have the ethical concerns associated with hESC. Our differentiation protocol has been successful in deriving cells that again have most of the important attributes of normal liver cells. Thus, we are hopeful that they also may be helpful for cell-based therapeutics in the future. In addition, we are employing adult stem cells derived from the bone marrow in collaborative studies with colleagues in Egypt. These stem cells have been differentiated so that they act like liver cells, and they have been transplanted into patients with advanced liver disease. The patients that have received the cells have improvement in their blood tests, and they are living longer than would have been expected without the transplantation. Thus we are making some progress in establishing 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 liver transplantation.

Year 3

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) or from other human stem cell sources would provide a valuable tool for cell-based therapeutics. In the past year, we have improved on our ability to differentiate the hESC towards liver cells in culture. They are producing normal human liver proteins. They also are capable of metabolizing drugs and other substances in the same manner of normal liver cells in culture. This means that they have the most important attributes of normal liver cells. Also, we have employed these cells in clinically-relevant models using techniques that can then be adapted to future human clinical trials. Moreover, they do not produce tumors. We have also worked to differentiate human induced pluripotent cells (hiPSC) to become liver-like cells in culture. The hiPSC behave very much like hESC, in that they are pluripotent. However, they are derived from adult somatic cells and thus do not have the ethical concerns associated with hESC. Our differentiation protocol has been successful in deriving cells that again have most of the important attributes of normal liver cells. Thus, we are hopeful that they also may be helpful for cell-based therapeutics in the future. Thus we are making some progress in establishing 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 liver transplantation.

Publications

© 2013 California Institute for Regenerative Medicine