Scientists at King's College London have sniffed out a type of cell that may be able to regenerate liver tissue. With further tweaking and many more years of research, it’s hoped the cells could someday be used in cell-based therapies for treating liver failure without the need for transplants.
Reporting in the journal Nature Communications, the team detail the analysis of a new type of cell called a hepatobiliary hybrid progenitor (HHyP). HHyP appears to be a progenitor cell capable of transforming into the two types of cells that make up the bulk of liver tissue (hepatocytes and bile duct epithelial cells) in a similar fashion to a stem cell. The cell is thought to be used during early development in the womb, but also seems to exist in small quantities in adults.
"For the first time, we have found that cells with true stem cell like properties may well exist in the human liver," lead author, Dr Tamir Rashid from the Centre for Stem Cells & Regenerative Medicine at King’s College, said in a statement. "This, in turn, could provide a wide range of regenerative medicine applications for treating liver disease, including the possibility of bypassing the need for liver transplants."
"We now need to work quickly to unlock the recipe for converting pluripotent stem cells into HHyPs so that we could transplant those cells into patients at will. In the longer term, we will also be working to see if we can reprogramme HHyPs within the body using traditional pharmacological drugs to repair diseased livers without either cell or organ transplantation," said Rashid.
The liver is the only internal human organ that holds the ability to regenerate after damage, whether it’s from physical injury, disease, obesity, or drug abuse. In fact, as little as a quarter of the original liver mass can regenerate back to its full size. However, if the liver is continually hit with damage, full regeneration is prevented due to the development of scar tissue within the liver, known as cirrhosis.
Most intriguing of all for the researchers, the HHyP cells closely resemble the progenitor cells mice use to regenerate their liver after chronic injury. The exact nature of the liver progenitor cells that make regeneration possible in humans has long remained a hazy subject. Now, based on these findings, researchers are a bit closer to understanding the process and perhaps one day harness its power.
"Previous attempts to address fundamental questions surrounding the presence and nature of liver stem/progenitors have been hampered by the lack of correlation between mouse and human models and the limited resolution of lineage tracing strategies," the researchers wrote in their study. "By contrast, the combination of carefully selected human tissue and single-cell analysis performed here has facilitated the identification of a hybrid progenitor population from human foetal liver."