October 31, 2006

stem cell scientists react to news of ‘minature liver grown in lab’

University of Newcastle scientists have reported growing functioning liver tissue using stem cells extracted from umbilical cord blood.

Professor Malcolm Alison, Centre for Diabetes and Metabolic Medicine, Queen Mary’s School of Medicine and Dentistry, said:

“The ability to ‘grow a liver’ outside the body is the ultimate dream of hepatologists wishing to cure young people with metabolic liver disease and people with virally- or alcohol-induced liver cirrhosis. Unfortunately there are not enough spare livers around to meet the increasing demands for liver transplantation; thus the excitement generated by the claims of the Newcastle scientists.

“Many groups, including the Newcastle one, have been able to turn stem cells from the blood into cells that look like liver cells (hepatocytes), but these have been difficult to expand in culture into a mass of cells that was therapeutically useful, moreover hepatocytes in culture are notorious for rapidly loosing their functional abilities, thus quickly rendering them useless. The new claim is that they have created a ‘mini-liver’ which would be a complex 3-D structure that could make all sorts of useful blood proteins such as albumin and blood coagulation functions and at the same time cleanse the blood of excretory products such as bile pigments (an excess in the blood gives you jaundice – yellow eyes).

“Unfortunately, these claims have not been validated by external experts in the field, and the public should not get too carried away with these claims until the data has been so-called peer-reviewed. An artificial human liver would also be very useful for testing new drugs, reducing the need for animal testing and also for studying viral liver disease (HBV and HCV) which are very much on the increase in the UK and cannot be studied in rodent livers. Of course, as the Newcastle group admit, we are still many years away from creating a ‘transplantable’ liver suitable for a person with untreatable liver disease.”

Dr Stephen Minger, Director, Stem Cell Biology Laboratory, Kings College London, said:

“This research hasn’t been through the proper scientific channels yet – it hasn’t been peer reviewed. So other scientists in the field of stem cell biology don’t know what has been done, and it is impossible to know whether this work is meaningful or not.”