SCIENTISTS in Scotland have repaired a damaged liver in a mouse by transplanting stem cells grown in the laboratory.

It is the first time researchers have restored function to a severely damaged liver in a living animal using stem cells.

Their findings pave the way for cell-based therapies that could one day replace the need for liver transplants in humans.

It comes as figures reveal a decline in the number of patients in Scotland who successfully received an organ transplant in the last year.

Researchers from the Medical Research Council (MRC) Centre for Regenerative Medicine at Edinburgh University transplanted liver stem cells into mice with liver failure. They found that over several months major areas of the liver were regrown from these cells, improving the structure and function of their livers.

A normal, healthy liver is naturally able to repair and regenerate itself, but once patients develop conditions such as cirrhosis and acute liver failure it becomes damaged beyond repair.

Hepatitis C, alcohol abuse and non-alcoholic fatty liver disease - a build up of fat typically brought on by obesity - are the most common causes of cirrhosis of the liver

Within the liver, hepatocytes are the essential cells that make many proteins and break down toxins, and while they have been used for transplantation their use has been limited as they don’t grow well under laboratory conditions.

Liver stem cells overcome this as they can be grown under laboratory conditions and have the flexibility to change into hepatocytes or other important types of liver cells.

This is the first time that researchers have proven that liver stem cells can regrow the liver to such an extent. If they can show the same effect with human cells then they may be useful as a treatment for liver failure.

Transplanting such cells into patients with liver failure could one-day offer an alternative to liver transplants.

Professor Stuart Forbes, of the MRC Centre for Regenerative Medicine at Edinburgh University, said: “Revealing the therapeutic potential of these liver stem cells brings us a step closer to developing stem cell based treatments for patients with liver disease. It will be some time before we can turn this into reality as we will first need to test our approach using human cells. This is much needed as liver disease is a very common cause of death and disability for patients in the UK and the rest of the world.’’

In the long term, scientists hope to find a way of stimulating the patient’s own stem cells to repair the damaged liver using medicines.

The research was funded by the Medical Research Council, the UK Regenerative Medicine Platform and the Wellcome Trust. It is published in the journal Nature Cell Biology.

Dr Rob Buckle, Director of Science Programmes at the MRC, said: “This research has the potential to revolutionise patient care by finding ways of co-opting the body’s own resources to repair or replace damaged or diseased tissue. Work like this, building upon a precise understanding of the underlying human biology and supported by the UK Regenerative Medicine Platform, will give doctors powerful new tools to treat a range of diseases that have no cure, like liver failure, blindness, Parkinson’s disease and arthritis.”

Meanwhile, the NHS Blood and Transplant service revealed that the number of patients successfully receiving organ transplants in Scotland fell by by 9 per cent to 360 in the 12 months to March this year.

The number of deceased donors in Scotland also fell from 106 to 98 over the same period, while the number of living donors fell slightly to 81.