A human liver deemed not viable for transplant has been repaired by an innovative perfusion machine and subsequently transplanted into a patient who continues to do well a year after the groundbreaking surgery.
The technique, called “ex situ normothermic perfusion,” was developed by a team of researchers from University Hospital Zurich, ETH Zurich, Wyss Zurich, and the University of Zurich. A scientific paper detailing the remarkable achievement was published today in Nature Biotechnology.
“Our therapy shows that by treating livers in the perfusion machine, it is possible to alleviate the lack of functioning human organs and save lives,” Pierre-Alain Clavien, a study co-author and a surgeon at the University Hospital Zurich, said in a press release.
More studies of the technique are needed, but this medical advance stands to expand the number of livers available for transplantation and allow surgeries to be scheduled days in advance. Under normal clinical conditions, a liver can only be sustained on ice for around 12 hours once it’s outside of the body. In this case, the liver was preserved for three days outside of the body prior to transplantation, in what is a medical first. The patient is doing well one year after the surgery, which was performed in May 2021.
Two years ago, the Liver4Life research team used the system to sustain a liver outside of the body for seven days, setting the stage for an actual human transplant. The perfusion device works by mimicking the human functions to the greatest extent possible. The machine supplies the liver with a blood substitute at normal body temperatures; a pump acts as the heart; an oxygenator serves as the lungs; a dialysis machine performs kidney duties; and hormones and nutrient infusions mimic the intestines and pancreas.
The liver used in the groundbreaking surgery was originally not approved for transplantation, but the perfusion machine, by applying a steady cocktail of drugs, brought the organ to a viable state.
The patient was previously diagnosed with advanced cirrhosis, severe portal hypertension, and other serious liver conditions. He also had cancer and was on a waiting list for a donor liver. The patient consented to the experimental procedure and, following the surgery, was fit enough to leave the hospital after just a few days. “I am very grateful for the life-saving organ,” said the patient. “Due to my rapidly progressing tumor, I had little chance of getting a liver from the waiting list within a reasonable period of time.”
The transplanted liver appears to be functioning normally and with minimal damage. The patient was administered a basic immunosuppressant during the first six weeks following surgery and showed no signs of rejection or other forms of complications.
“The interdisciplinary approach to solving complex biomedical challenges embodied in this project is the future of medicine,” explained Mark Tibbitt, professor of macromolecular engineering at ETH Zurich. “This will allow us to use new findings even more quickly for treating patients.”
The authors of the paper say more research is needed, including studies with more patients, more extended observational periods, and with more institutions involved. Still, it’s a promising start, as the new technique could make more livers available, while allowing for scheduling flexibility with transplant recipients.