Around 2 million people worldwide die from liver disease every year. Half of those deaths are due to complications of cirrhosis and the other half are due to viral hepatitis and hepatocellular carcinoma. Cirrhosis ranks as the 11th most common cause of death globally and liver cancer as the 16th leading cause of death. Together they account for 3.5% of all deaths.
In the UK alone, liver disease is the 5th biggest killer and the 3rd most common cause of premature death. All of these figures continue to rise making liver transplantation the second most needed solid organ transplantation in the world. Unfortunately, there are not enough of the organ to go around so less than 10% of global transplantation needs are met at current rates which is why so many people die.
Liver disease is caused by lifestyle issues such as obesity, viruses, alcohol and drug misuse, as well as by non-lifestyle issues such as autoimmune and genetic mediated disease. It is true that most causes of liver diseases are preventable, but for those that are diagnosed and it’s too late, there may soon be a way for the liver to regenerate itself. Meaning, they won’t have to wait for an available liver to save their life – the doctors will be able to treat their liver failure without the need for a transplant.
Researchers at King’s College London have pinpointed a cell that may be able to regenerate liver tissue. They used single cell RNA sequencing to identify it. The cell – a hepatobiliary hybrid progenitor (HHyP) – forms during our early development in the womb. However, it persists in our bodies as adults in small quantities. HHyP cells can grow into the two main cell types that make up the bulk of adult liver tissue (hepatocytes and cholangiocytes – bile duct epithelial cells) giving HHyPs stem cell-like properties. The research has been published in the journal Nature Communications.
Lead author, Dr. Tamir Rashid from the Centre for Stem Cells & Regenerative Medicine at King’s College, said in a statement:
For the first time, we have found that cells with true stem cell like properties may well exist in the human liver. 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 reprogram HHyPs within the body using traditional pharmacological drugs to repair diseased livers without either cell or organ transplantation.
The team examined HHyPs and found that they resemble mouse stem cells which have been found to rapidly repair mice liver following major injury, such as occurs in cirrhosis. The exact nature of these liver progenitor cells is still unclear but based on this new study, the researchers are a step closer towards understanding the process and perhaps one day harness its power.
The liver is the only internal human organ that holds the ability to regenerate after damage, unless it is continually hit with damage, whereupon full regeneration is prevented due to the development of scar tissue within the liver – known as cirrhosis. With further development and more research, the scientists hope to have the HHyP cells available for use someday in cell-based therapies for treating liver failure like this without the need for transplants.
