Machine keeps livers alive outside the body for a week
Science says that artificial organs made from human stem cells could potentially replace transplants in the future.
The possibility of transplant rejection by the recipient's immune system is one of the main challenges faced during the transplantation process. Another issue is organ preservation. From the moment the organ leaves the donor’s body, it is a race against time to ensure it can reach its destination hospital as a fully functional organ.
A study that has been published by the journal Nature Biotechnology describes a procedure where six human livers were successfully preserved outside the body for a full week.
Scientists from the University Hospital Zurich and the University of Zurich in Switzerland built a machine that not only managed to keep the organs alive for a week, but also repaired any damage.
A complex perfusion system
The basis of this technology consists of a perfusion system (a process involving pumping fluid through an organ or tissue) that allows blood and other fluids to be introduced intravenously, so that body functions can be imitated. A pump replaces the heart, an oxygenator the lungs, a dialysis unit the kidneys. Hormone and nutrient infusions do the job of the intestine and pancreas, and rhythmic movements imitate the diaphragm.
The team carried out tests on ten human livers, which were considered 'poor quality' and had been rejected for transplantation by all the European transplant centres.
“The success of this unique perfusion system — developed over a four-year period by a group of surgeons, biologists and engineers — paves the way for many new applications in transplantation and cancer medicine, helping patients with no liver grafts available,” said Pierre-Alain Clavien, president of the University Hospital of Zurich Department of Surgery and Transplantation.
When the project began in 2015, scientists could only preserve livers in the machine for twelve hours. The development of the perfusion process, both extended the duration that a liver can be stored, along with allowing for allows a wide range of restorative methods to take place, including repair of preexisting injury, cleaning of fat deposits in the liver, and even regeneration of partial livers.
Back in September 2019, a team of scientists from the Harvard Medical School and the University of Amsterdam published an article in the journal Nature Biotechnology describing a technique to keep a liver alive for up to 27 hours thanks to a cryopreservation process.
Currently, livers used for transplants are stored for a maximum of twelve hours, since that is the time in which the organ can be kept cold, at 4°C, without losing its viability.
The development of this perfusion technology offers a promising opportunity to facilitate the process of storing organs for longer, offering a new life for many patients with end stage liver disease or cancer.
