Miniature human livers have been successfully grown in the laboratory, heralding the possibility of customized transplant organs. US scientists have created working livers the size of a walnut, they said yesterday at the annual meeting of the American Association for the Study of Liver Diseases in Boston.
Like pretty much all organ transplants, there are never even close to enough replacement livers for those who need them, and it can be an agonizing wait for patients and families as they hope to secure a donor organ. In theory, there’s a better way to do this – grow replacement organs in labs, and then transplant those into the patients. That remains just a dream – but it now looks quite a bit more realistic after a breakthrough at Wake Forest’s Institute for Regenerative Medicine.
“We are excited about the possibilities this research represents, but must stress that we’re at an early stage and many technical hurdles must be overcome before it could benefit patients,” said the project director, Associate Professor Shay Soker from the Wake Forest Institute for Regenerative Medicine in North Carolina.
“Not only must we learn how to grow billions of liver cells at one time in order to engineer livers large enough for patients, but we must determine whether these organs are safe to use in patients.”
His colleague, Pedro Baptista, said: “Our hope is that once these organs are transplanted, they will maintain and gain function as they continue to develop.”
In developing the procedure, the researchers simultaneously triggered the hope of creating organs on demand and the wrath of opponents of stem-cell research. The technology, which will take at least five years to move from the laboratory to hospitals, also opens up the prospect of growing other replacement organs, including kidneys or pancreases, for patients who are able to donate stem cells.
Artificially grown livers could be transplanted into patients or used to test the safety of experimental drugs. “This would more closely mimic drug metabolism in the human liver, something that can be difficult to reproduce in animal models,” Dr Baptista said.
To create these miniature livers, the researchers took animal livers and treated them so that all their cells were removed, leaving only the collagen support structure behind. They then added immature human liver cells as well as cells vital for the creation of new blood vessels. After a week spent in a bioreactor that provided a constant stream of nutrients, the miniature livers displayed all the functions of a normal liver, not to mention continued cell growth.
This is very good news, and its possible similar approaches could be used to engineer artificial kidneys and pancreases.