The success of a liver transplant is significantly limited by the quality of the donor organ. Currently, this results in a severe shortage of acceptable organs, as many potential organs do not tolerate the static cold storage (SCS) of the conventional transplant procedure. Despite significant clinical advances in transplant procedures over the past 30 years, the mechanism for liver preservation has changed very little: the organ is flushed and placed on ice, lowering metabolic activity ten-fold in the hope of reducing damage. However, over time ischemic damage occurs, which reduces organ viability, and the cooling process renders any functional assessment of the initial or final health of the organ impossible.

To combat these problems the team behind Oxford-based OrganOx created the metra device, which is capable of storing a donor liver at physiological conditions of body temperature and blood perfusion.

Following success in animal models, the metra device was trialled in seven European transplant centres from 2014 to 2016. The results of the randomized trial of 220 liver transplants are published in Nature and show that the metra device’s Northothermic Machine Perfusion (NMP) resulted in a 50% lower level of organ injury and a 54% longer mean organ preservation time when compared to SCS. Comparing the normothermic and conventional preservation, the study also showed no significant differences in either bile duct complications, organ survival, or patient survival at one-year post-implantation.

As well as preserving the liver for up to 24 hours the OrganOx system also allows for a donor organ to be “test driven” with the metabolization of glucose, production of bile, and other functions of the donor liver being assessed prior to implantation. This results in a far more quantitative and accurate assessment of the organ’s fitness, which led to the improved performance seen, despite a 50% lower rate of organ discarding when compared to conventional preservation. Overall this led to 20% more livers being transplanted with the NMP system.

The team at OrganOx hope that these pivotal results will lead to increased numbers of organs being available for transplant, leading to shorter waiting lists and reduced patient mortality rates. “By changing the way the donor's livers are preserved and evaluated before they are transplanted, we expect to see more donor livers being transplanted. Our company is at the forefront of this exciting new technology, and we are also researching other applications for our platform to help address liver disease – which is predicted to become the largest cause of premature deaths by 2020.” Said Craig Marshall, CEO of OrganOx.

OrganOx was founded in 2008 as a spinout company from the Univeristy of Oxford by Professors Constantin Coussios and Peter Friend. The metra device is CE-marked for use in Europe and is currently undergoing clinical trials in the US and Canada.