Liver Stem Cell Treatments

Last Updated (Tuesday, 18 November 2008 00:29) Saturday, 15 March 2008 15:49

Organs - Liver

Liver Stem Cell Treatments

There are still several issues when it comes to implanting stem cells in human livers, and scientists say that current problems have been related to immunological reactions against the cells as well as difficulty with how to introduce the stem cells into the liver. However now a novel protein marker has been found that identifies rare adult liver stem cells, whose ability to regenerate injured liver tissue has the potential for cell-replacement therapy.

 

In the United States, Dr. Fausto and his team of research scientists are trying to identify stem cells in human livers that could be used to help people with liver failure. They are hoping to find a cell that is a stem cell for the liver, and to inject those cells and repopulate livers that have been injured. "The idea is if you could have cells that could be introduced into the patient, it could either be a permanent solution to help the liver regenerate itself or at least serve as a bridge until transplantation can be done" says Dr. Fausto.

 

In May 2005, a research team at London's Hammersmith Hospital did a trial using patients' own stem cells to treat their chronic liver disease. They were attempting to reverse cirrhosis of the liver by harnessing and enhancing the body's own repair mechanism. They used adult stem cells extracted from patients' bone marrow to generate new tissue in damaged areas. It involved taking blood from the patient and separating it into its component parts. Stem cells were isolated from the white blood cells and injected into the hepatic artery in the liver, while the red blood cells were returned to the body through the arm. The outcome of this is currently unknown.

 

Nov 2008 - A novel protein marker has been found that identifies rare adult liver stem cells, whose ability to regenerate injured liver tissue has the potential for cell-replacement therapy.

 

For the first time, researchers at the University of Pennsylvania School of Medicine led by Linda Greenbaum, MD, Assistant Professor of Medicine in the Division of Gastroenterology, have demonstrated that cells expressing the marker can differentiate into both liver cells and cells that line the bile duct

 

In the future, this marker will allow for the isolation and expansion of these stem cells, which could then be used to help patients whose livers can no longer repair their own tissue.The findings appear in the journal Hepatology.

 

"In a healthy liver, proliferation of mature liver and bile-duct lining cells is sufficient to maintain the necessary size and function of the organ," explains Greenbaum. "This even works when the liver is confronted with mild and acute injury, but the situation changes when injury to the liver is chronic and severe."

For chronic injury, the liver uses a back-up system that stimulates stem cells to proliferate and eventually differentiate into new liver cells. Greenbaum and colleagues found that these dual-potential stem cells can be identified and potentially isolated from other liver cells because they uniquely express the protein Foxl1. The team showed that in two mice models of liver injury, stem cells and their descendents were marked by the expression of FoxL1. The researchers propose to use this marker to isolate the Foxl1-bearing stem cells and transplant them back into damaged livers to restore function.

 

"At this point, we haven't identified the molecular targets that are regulated by Foxl1 in the liver stem cell," says Greenbaum. The researchers also do not yet know what signals activate the expression of Fox l1 and how exactly it is related to liver function. But, they finally have a molecular handle on identifying liver stem cells, which have remained elusive to scientists. "This work has significant implications for cell-replacement therapies of chronic liver disease in the future," says Greenbaum.

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