Supercooling and machine perfusion allow transplantation of rat livers preserved for up to four days
A system developed by investigators at the Massachusetts General Hospital (MGH) Center for Engineering in Medicine allowed successful transplantation of rat livers after preservation for as long as four days, more than tripling the length of time organs currently can be preserved. The team describes their protocol – which combines below-freezing temperatures with the use of two protective solutions and machine perfusion of the organ – in a Nature Medicine paper receiving advance online publication.
In a system developed at the Mass. General Hospital Center for Engineering in Medicine, perfusion of a rat liver with preservative solutions before and after supercooling helped enable successful transplantation after up to four days.
Credit: MGH Photography Department
"To our knowledge, this is the longest preservation time with subsequent successful transplantation achieved to date," says Korkut Uygun, PhD, of the MGH Center for Engineering in Medicine (MGH-CEM), co-senior author of the report. "If we can do this with human organs, we could share organs globally, helping to alleviate the worldwide organ shortage."
Once the supply of oxygen and nutrients is cut off from any organ, it begins to deteriorate. Since the 1980s, donor organs have been preserved at temperatures at or just above freezing (0˚ Celsius or 32˚ Fahrenheit) in a solution developed at the University of Wisconsin (UW solution), which reduces metabolism and organ deterioration ten-fold for up to 12 hours. Extending that preservation time, the authors note, could increase both the distance a donor organ could safely be transported and the amount of time available to prepare a recipient for the operation.
Keeping an organ at below-freezing temperatures, a process called supercooling, could extend preservation time by further slowing metabolism, it also could damage the organ in several ways. To reduce those risks the MGH-CEM protocol involves the use of two protective solutions – polyethylene glycol (PEG), which protects cell membranes, and a glucose derivative called 3-OMG, which is taken into liver cells.
After removal from donor animals, the livers were attached to a machine perfusion system – in essence, an 'artificial body' that supports basic organ function – where they were first loaded with 3-OMG and then flushed with a combination of UW and PEG solutions while being cooled to 4˚C (40˚ F). The organs were then submerged in UW/PEG solution and stored at -6˚C (21˚F) for either 72 or 96 hours, after which the temperature was gradually increased back to 4˚C. The organs were then machine perfused with UW/PEG solution at room temperature for three hours before being transplanted into healthy rats.
All of the animals that received organs supercooled for 72 hours were healthy at the end of the three-month study follow-up period. Although only 58 percent of animals receiving organs supercooled for 96 hours survived for three months, analysis of several factors done while the organs were being rewarmed could distinguish between the organs that were and were not successfully transplanted.
"This ability to assess the livers prior to transplantation allows us to determine whether the supercooled organ is still good enough for transplantation," explains study co-author Bote Bruinsma, MSc, of the MGH-CEM. "Even among the livers preserved for four days, if we had only used those in which oxygen uptake, bile production and the flow of perfusion solution were good, we would have achieved 100 percent survival."
While much work needs to be done before this approach can be applied to human patients, extending how long an organ can safely be preserved may eventually allow the use of organs currently deemed unsuitable for transplant, notes Martin Yarmush, MD, PhD, founding director of MGH-CEM and co-senior author of the paper. "By reducing the damage that can occur during preservation and transportation, our supercooling protocol may permit use of livers currently considered marginal – something we will be investigating – which could further reduce the long waiting lists for transplants." Yarmush and Uygun are both on the faculty of Harvard Medical School.
Lead author of the Nature Medicine report is Tim Berendsen, MD, formerly of the MGH Center for Engineering in Medicine and now at the University Medical Center at Utrecht, the Netherlands. Additional co-authors are Catheleyne Puts, Nima Saeidi, Berk Usta, Basak Uygun, Maria-Louisa Izamis and Mehmet Toner, all of the MGH-CEM. The study was supported by National Institutes of Health grants R01EB008678, R01DK096075, R01DK084053, R00DK080942 and R00DK088962 and funds from Shriners Hospitals for Children. Several patents covering the work described in this paper are pending.
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $785 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, transplantation biology and photomedicine.
Cassandra Aviles | Eurek Alert!
LISA: Scientists introduce a new method of statistical inference in neuroimaging (fMRI)
16.10.2018 | Max-Planck-Institut für biologische Kybernetik
Researchers demonstrate first example of a bioelectronic medicine
09.10.2018 | Northwestern University
Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.
Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...
Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles
Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...
When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.
We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...
Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...
Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...
17.10.2018 | Event News
16.10.2018 | Event News
02.10.2018 | Event News
18.10.2018 | Life Sciences
18.10.2018 | Earth Sciences
18.10.2018 | Life Sciences