Researchers from the University of Texas Southwestern Medical Center, Dallas, and TransMedics, Andover, Massachusetts, believe there is a small-growing subset of transplanted livers. These livers are cumulatively more than a hundred years old. The researchers studied these livers so that they could identify the characteristics that determine why these organs are tough and lead the way to consider the potential expanse in the use of older liver donors. Furthermore, the research team at the University of Texas presented their findings at the Scientific Forum of the American College of Surgeons (ACS) Clinical Congress 2022.
As a part of their research, they used the United Network for Organ Sharing (UNOS) STAR data to identify the cumulative age of livers. Their age can be calculated by knowing the total initial age at transplant plus the post-transplant survival of at least a hundred years. As a result of their research, out of the 253,406 livers transplanted between 1990-2022, about twenty-five livers were considered to be centurion’s livers. Centurion’s livers are livers with a cumulative age of over a hundred years. The study author- Yash Kadakia- a medical student at UT said: “We looked at pre-transplant survival- essentially, the donor’s age as well as how long the liver went on to survive in the recipient. Further, we stratified out these remarkable livers with over a hundred-year survival and identified donor factors, recipient factors, and transplant factors involved in creating this unique combination where the liver was able to live to hundred years.”
For centurion’s livers, the average donor age was 84.7 years which is significantly higher compared to the 38.5 years for the non-centurion liver transplants. One of the significant factors that the researchers have noticed in livers that made it to a hundred is that they usually find an older average donor age as well as healthier donors. Impressively, the donors from the centurion group had a lower rate of diabetes and donor infections. As of 22nd September 2022, there are 11,113 patients on the waiting list for a liver transplant. While talking about how using older liver donors often could potentially expand the liver donor pool, Christine Hwang, MD, FACS, associate professor of surgery at UT Southwestern Medical Center said: “We previously tended to shy away from using livers from older donors. If we can sort out what is special amongst these donors, we could potentially get more available livers to be transplanted and have good outcomes.”
Transaminases are enzymes that play a key role in the liver & evidently, the Centurion liver donors had lower transaminases. These elevated transaminases can cause complications in liver transplantation. More to it- the recipients of centurion’s livers have significantly lower MELD scores (17 for the centurion group and 22 for the non-centurion group)- while a higher MELD score indicates a patient’s urgency for the transplant.
During the research, the researchers understood that no grafts in the centurion group were lost to a primary non-function or a vascular or biliary complication. Moreover, there was no significant difference in the rates of rejection at 12 months between the centurion and the non-centurion group. The outcomes for the centurion group had better allograft and patient survival. It is no secret that livers are resilient organs, and thus, Mr. Kadakia stated how they used older donors and paired them with better surgical techniques. Furthermore, he also stated how the researchers have advanced in immunosuppression and have better matching donor and recipient factors.
The study authors concluded by stating: “The donors were optimized, the recipients were optimized, and it takes that unique intersection of factors to result in a really good outcome. The existence of allografts over a hundred years old is revealing of the dramatic resilience of the liver to senescent events.”