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!
PET identifies which prostate cancer patients can benefit from salvage radiation treatment
05.12.2017 | Society of Nuclear Medicine and Molecular Imaging
Designing a golden nanopill
01.12.2017 | University of Texas at Austin, Texas Advanced Computing Center
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences