Japanese scientists grow working mini-livers for mice from stem cells

New breakthrough used non-embryonic stem cells and promises

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The Independent Online

Scientists in Japan have grown rudimentary functioning human livers from stem cells in a world first that promises to help alleviate the global shortage in transplant organs .

Grown from stem cells, these tiny pieces of human liver were then transplanted into mice, where they performed the organ’s normal functions such as cleaning toxins from the blood.

Whilst it make take another 10 years before wholly lab-grown livers can be used in transplants for human patients, the team responsible for the break-through say their work is an important proof of concept that will lead to growing more complex organs.

To create the liver tissues the researchers from Yokohama City University used human skin cells that had been chemically returned to an earlier stage of cell development. Known as ‘induced pluripotent stem cells’, these cells were then treated so they would grow into early-stage liver cells.

The cells grew over a two month period until they grew into “liver buds” five millimetres across – formations that are the precursors of a fully functioning liver. A scientist involved told the BBC that he was “completely gobsmacked” and “absolutely surprised” to see such development.

"To our knowledge, this is the first report demonstrating the generation of a functional human organ from pluripotent stem cells," the researchers wrote in the journal Nature.

The researchers’ use of ‘induced pluripotent stem cells’ (iPS) is also encouraging. Stem cells are the building blocks for human organs, but until recently have only been obtainable by harvesting them from human embryos.

This has caused controversy as it means the destruction of the embryo. As iPS cells are obtained from mature cellular material that is then ‘reprogrammed’ into an earlier state it means scientific research can avoid objections from groups such as religious conservatives, who object to stem cell research on moral grounds.

The breakthrough has been welcomed by scientists in the UK. In a statement issued by London’s Queen Mary University, professor of stem-cell biology Malcolm Alison said: “This opens up the distinct possibility of being able to create minilivers from the skin cells of a patient dying of liver failure.”

Kings College London’s senior lecturer in Stem Cell Science Dr Dusko Ilic echoed these sentiments, saying “The strategy is very promising, and represents a huge step forward. The promise of an ‘off-shelf liver’ seems much closer than one could hope even a year ago.”