New research suggests liver tissue grown from stem cells could one day replace the need for liver transplants.

A paper has been published in Archives of Toxicology showing that liver tissue implants supported liver function in mice with a type of liver disease. The team led by Professor Dave Hay from the MRC Centre of Regenerative Medicine at the University of Edinburgh, say the advance offers early-stage progress towards developing liver tissue implants for people.

The implants were produced by turning stem cells into cells with characteristics of liver cells in the lab. The cells grew into tiny balls in a dish for up to a year, but did not adopt the 3D structure of liver tissue.

Spheres of stem cell-derived liver cells (orange) placed on the scaffold. Credit: H Rashidi 2018.

A multi-disciplinary team including chemists and engineers helped to identify scaffold materials that could be used to provide a 3D backbone for the cells, including one material which is already approved for implants in people. The material was spun into a fibre mesh that formed a scaffold one centimetre square and just a few millimetres thick.

Liver cells grown from human stem cells were grown in the lab for 60 days before loading on to the mesh scaffold to form a 3D structure. When the implants were placed under the skin of mice, blood vessels grew into the scaffolds. Following the implant, the mice had human liver proteins in their blood, indicating that the tissue was functioning and had successfully integrated with the circulatory system.

Liver disease is the fifth biggest killer in the UK. A transplant is the only treatment for liver failure but many people die while waiting for an organ to become available.

The researchers tested the implants in mice with a potentially fatal genetic disease called tyrosinaemia, which causes defects that prevent the liver from breaking down toxic products. Affected mice with the liver implants showed fewer signs of liver damage than those that were implanted with an empty scaffold. They lost less weight and had fewer toxins in their blood.

This work could also reduce the need for animals in research by providing a tool for studying human diseases and testing drugs in the lab.

The study was funded by the UK Regenerative Medicine Platform and the Chief Scientist Office of Scotland.