NEW insights into how the liver regenerates during tissue damage or normal cellular turnover have been revealed by researchers from Stanford University, California, USA. The research could lead to new treatments for conditions caused when the organ is unable to function properly, such as cirrhosis and liver cancer, and may also help explain how liver cancer develops.
Until now, there has been limited understanding of how organ regeneration occurs or the cells responsible for causing liver cancer. In a mouse model, the team observed that unusually high levels of telomerase were expressed in around 3–5% of all liver cells, which were distributed evenly throughout the liver’s lobules. They found that these cells proliferate to create clumps of new liver cells during regular cell turnover or following damage to the liver. This may help explain how the liver has the unique ability to fully regenerate from as little as 25% of its original mass.
The researchers also discovered that these cells express fewer metabolic genes, which could be a way of protecting and enabling them to pass on a more pristine genome to their daughter cells.
The study could prove to be of vital significance in understanding what happens when the organ stops functioning properly. “The liver is a very important source of human disease,” commented Prof Steven Artandi, Stanford University. “It’s critical to understand the cellular mechanism by which the liver renews itself. We’ve found that these rare, proliferating cells are spread throughout the organ, and that they are necessary to enable the liver to replace damaged cells. We believe that it is also likely that these cells could give rise to liver cancers when their regulation goes awry.”
The team believe the findings provide a new target for the development of treatments to help enable the smooth regeneration of livers. “You could imagine developing drugs that protect these telomerase-expressing cells or ways to use cell therapy approaches to renew livers,” added Prof Artandi. “On the cancer side, I think that these cells are very strong candidates for cell of origin. We are finally beginning to understand how this organ works.”
James Coker, Reporter
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