Bioengineered Miniature Human Livers Have Been Successfully Transplanted Into Ill Rats

If scientists found a way to create liver transplants which are autologous, or made from the cells and tissues from the same individual, treatment of liver disease would drastically change. A bioengineered assembly and function of a human liver in vivo from induced pluripotent stem cells (iPSCs) have been previously done until a team of scientists were able to create miniature human livers.

Through time, research has advanced the methods for deconstructing and reconstruction liver cells from human iPCSs in an organ-like environment. A team from the University of Pittsburgh School of Medicine have bioengineered mini human livers and transplanted them into five rats.

The regenerated iPSC-derived mini liver was tested in vivo and continued to function for four days after auxiliary liver transplantation in rats with an impaired immune system. The human iPSCs donated by volunteers were mixed with hormones and other chemicals to create liver cells. Normally, it takes two years for human livers to mature from the moment of one's birth, while the researchers grew the mini livers in just a few weeks.

Previous experimental research on liver grafting was limited to only incorporating rodent cells. This is the first time that human stem cells were used not only for functional liver tissue, but for the vascular system and the bile duct network as well, connecting the liver, gallbladder, and pancreas to the small intestine.

Transplants are the Only Cure

Liver disease in the United States has been responsible for more than 30,000 deaths per year while 30 million people in the country have liver disorders. 'The only curative treatment for patients with terminal liver failure is liver transplantation,' explains the study.

Liver transplants are limited by the shortage of donors, expensive procedures, and immunosuppression, or induced suppression to an individual's immune system to help the donated organ survive after the transplant operation.

Since iPSCs can 'establish various types of tissue lineages,' immunosuppression is not required, thus unlimited availability of liver grafting is a possibility in the future. Four days later, the scientists dissected the five experimental rats with proof that the mini livers worked.

Results from the new study can also temporarily help patients with liver failure while waiting for a donor. This could battle the problem of about 14,000 Americans who may never receive a transplant. Also, someone with acute liver failure might not need an entire liver transplant, but maybe just a hepatic boost for a time and the scientists could one day make these developments as well.

Replacing Organ Donation

However, there were still imperfections. Evidence of poor blood flow was present, causing thrombosis and ischemia. It means that there are still serious issues with properly connecting the bioengineered liver grafts to animal vascular networks.

Although the team predicts that it may be another decade until good functioning liver transplants are engineered, this remains incredible progress. Alejandro Soto- Gutiérrez shared that 'You can make a whole organ that can be functional from one cell of the skin.'

Soto-Gutiérrez also said that 'The long-term goal is to create organs that can replace organ donation, but in the near future, I see this as a bridge to transplant.'