Scientists have developed a specialized machine which can keep a human liver alive outside the body for one week. An incredible possibility proposed by the researchers is to take a donated liver, break it up into several pieces, and regrow them in the perfusion machine.
Until now, livers could be stored safely outside the body for only a few hours. The amounts of nutrients, blood, and oxygen are automatically adjusted by algorithms, meaning the machine doesn't require constant supervision, according to a study in Nature Biotechnology.
"This is a different type of machine that we [had] to develop to reach seven days", said Prof Pierre-Alain Clavien, co-author of the research from University Hospital Zurich. After seven days of treatment with the machine, six of the 10 livers had been restored to full function.
The machine keeps the liver at body temperature (37 degrees Celcius/98.6 degrees Fahrenheit), and removes bile from it.
The technology could boost the number of livers available for transplantation and even offer new approaches to treating diseases such as liver cancer. The basis for this technology is a complex perfusion system, mimicking most core body functions close to physiology. The machine simulates normal bodily functions, such as delivering blood and oxygen, managing glucose levels and red blood cell counts, and removing waste products, among other things. For example, medical staff may be able to fix pre-existing injuries, clean fat deposits in the liver or even regenerate parts of the organ.
However in 2018 researchers in the United Kingdom reported a system that allows livers to be kept at body temperature for 24 hours, a move that the lead author said at the time "improved both the transplant success rate as well as the number of livers available for transplant". The machine was developed with a series of pig livers. Alternatively, human livers may also be kept metabolically active for up to 24 hours by supplying oxygenated fluids and normothermic blood via a machine.
However, Clavien said the system would be used for livers initially stored on ice but deemed too poor quality for immediate transplantation, and that in future it may also be used to boost the quality of marginal livers.
"Overall, the results. are promising and suggest that machine perfusion for 1 week may support viability of human livers, although testing with higher-quality livers and transplantation of perfused livers into recipients will be required to fully assess the potential of our approach", wrote the authors in the study. Prof. Philipp Rudolf von Rohr, Professor of Process Engineering at ETH Zurich and co-leader of the project said, "The biggest challenge in the initial phase of our project was to find a common language that would allow communication between the clinicians and engineers".
The team found that all 10 livers lost weight during the course of the week and four deteriorated.