Mini human livers grown from stem cells successfully implanted into rats

Organ transplants save lives, but there are hurdles to overcome. For one, there’s a constant shortage of donors and, even when one is found, the patient’s immune system often rejects the new tissue.

Growing a replacement organ from a patient’s own cells could solve both problems. It can be done on demand when a patient needs one, and the organ won’t be rejected because the immune system recognizes the cells as “self.”

In the new proof-of-concept study, researchers from the University of Pittsburgh grew livers from human cells and then transplanted them into rats. First, human skin cells are collected from volunteers. Then, these are reprogrammed into IPSCs, essentially returning them to a state where they can be differentiated into whatever types of cells are needed.

In this case, that’s liver cells. These human liver cells were then seeded into a rat liver that had had all its own cells stripped out. This leaves the scaffold behind for the new cells to stick to, retaining the original structure of the organ.

The researchers then transplanted these mini-human livers into five rats and monitored their condition for four days. In all cases, the new organs were working the whole time. They were secreting bile acids and urea, and the team detected human liver proteins in the rats’ blood serum.