In January 2020, Zurich researchers, branded as the Liver4Life team, reported that they had radically extended the time a donor liver could remain viable in storage — by keeping some “poor quality” livers alive for a week.
This big story flew under the radar – probably because there was no real transplant at the time.
Rather, the study showed what was possible with a new perfusion machine miming many of the body’s functions, keeping the liver functioning for several days.
This week, the Liver4Life team reported successfully transplanting a liver into a cancer patient who had been kept viable in the machine for three days.
The transplant occurred about a year ago, and the unnamed male patient is still doing well.
Twelve hours max, usually
In standard practice, a donor’s liver is kept on ice in a cooler for up to 12 hours – with preservative chemicals to prevent inflammation, provide nutrients and maintain low sodium and high potassium levels in cells.
After 12 hours, the cells begin to leak and swell, and the organ loses its viability.
The machine performs several functions that keep the donor liver viable. Image: USZ
So the idea of extending the viability of a liver to a week is impressive. However, healthy livers suitable for a transplant are unlikely to need to be stored for several days.
The researchers noted, “There is a great need for functional donor livers. In Switzerland alone, two to three times as many people are waiting for a liver than can actually bented.”
The real value of this extended life and viability is that it gives time for poor-quality livers – those deemed unfit for transplant – to be rehabilitated and fit for a needy patient.
Making rejecting livers acceptable for transplantation
Like the livers in the 2020 experiment, the liver used in transplant surgery last year was initially rejected as a transplanted organ.
Rather than being thrown away, it was hooked up to the perfusion machine that “imitates the human body as closely as possible, to create ideal conditions for the human livers.”
Pierre-Alain Clavien, the transplant surgeon, with the unnamed patient. Photo: USZ
A pump replaces the heart, an oxygenator replaces the lungs, and a dialysis unit performs the functions of the kidneys.
In addition, “numerous infusions of hormones and nutrients fulfill the functions of the gut and pancreas”.
This mimicking involved moving the liver to the rhythm of human breathing, as happens naturally with the diaphragm.
For three days, the liver was treated with antibiotics, hormonal therapies, and drugs that optimized the liver’s metabolic function.
During this time, lengthy laboratory and tissue tests were performed without time constraints.
“In this way,” the researchers wrote, “it was possible to transform the liver into a good human organ, although it was not originally approved for transplantation due to its poor quality.”
Out of the lab and into a body
The transplant patient was on the Swiss waiting list for donor organs and suffered from a “rapidly progressing tumor”.
He later said, “I had little chance of getting a liver off the waiting list in a reasonable amount of time.”
The researchers explained that they had a rehabilitated liver available. Was he willing to try?
The man accepted, and the liver was transplanted in May 2021. The patient was able to leave the hospital a few days after the transplant and “is now doing well.”
The recovered liver seems to have exceeded expectations.
The authors note in their groundbreaking paper, “The transplanted liver showed normal function, with minimal reperfusion damage and the need for only a minimal immunosuppressive regimen.
“The patient quickly returned to a normal quality of life with no signs of liver damage, such as rejection or bile duct injury, according to a one-year follow-up.”
Of course, the process must be repeated in other patients. Liver4Life is already working on improving its perfusion machine.
If successful, to the point where the rehabilitation process is widely adopted, the researchers believe “that in the future a liver transplant, which is usually an emergency procedure, will be turned into a playable elective procedure.”