New method triple length of time organs can be preserved for transplantation -
supercooling and perfusion machine allows the rat liver transplantation preserved up to four days
a system developed by researchers at the Massachusetts General Hospital (MGH) engineering Centre in medicine has enabled the successful transplantation after conservation rat liver during the period of four days, more than triple the length time members currently can be preserved. The team described their protocol - which combines temperatures below the freezing point with the use of two protection solutions and infusion machine of the body - in a document Nature Medicine receive the publication advance online
"in. our knowledge, this is the longest conservation time with after a successful transplant to date," said Korkut Uygun, PhD, of the Center medical engineering MGH ( MGH-CEM), co-lead author of the report. "If we can do that with human organs, we could share organs worldwide, helping to mitigate the shortage of organs in the world."
When the supply of oxygen and nutrients is cut off from any body, it begins to deteriorate. Since the 1980s, the organ donors were kept at or temperatures just above freezing (0˚ 32˚ Celsius or Fahrenheit) in a solution developed at the University of Wisconsin (UW solution), which reduces the metabolism and organ deterioration ten times for a maximum 12 hours. the extension of the shelf life, the authors note, could increase both the distance of a donor organ can safely be transported and the amount of time available to prepare a recipient for the operation.
Keep an organ below freezing temperatures, a process called supercooling, could extend the shelf life by slowing the metabolism again, it could also damage the body in many ways. To reduce these risks the MGH-CEM protocol involves the use of two protection solutions -. Polyethylene glycol (PEG), which protects cell membranes, and a glucose derivative called 3-OMG, who is caught in liver cells
After the removal of donor animals, livers were tied a machine perfusion system - in essence, an "artificial body" that supports the basic body function - where they were first charged with 3-OMG, then rinsed with a combination of UW solutions and PEG while being cooled at 4 ° C (40˚ F). The organs were then immersed in the solution UW / PEG and stored at -6C (21F) for either 72 or 96 hours, whereupon the temperature was gradually increased back to 4 ° C then organs were perfused with the machine UW solution / PEG at room temperature for three hours before being transplanted into healthy rats.
All animals received for 72 hours supercooling organs were healthy at the end of three months of study follow-up period. Although only 58 percent of animals receiving supercooling bodies for 96 hours survived for three months, the analysis of several factors, then, that the bodies were warmed could distinguish between bodies that have been and are successfully transplanted .
"The ability to assess the livers before transplantation to determine if the body is supercooled still good enough for transplantation," says co-author Bote Bruinsma, MSc, of the MGH-CEM. " even among livers preserved for four days, had we used only those in which the oxygen consumption, bile production and flow of the infusion solution were good, we would have reached 100 percent survival. "
Although much work needs to be done before this approach can be applied to human patients, extending the duration of an organ can be preserved safely may eventually allow the use of organs currently deemed unfit transplantation, notes Martin Yarmush, MD, PhD, founding director of the MGH-CEM and co-lead author. "by reducing the damage that may occur during storage and transportation, our supercooling protocol may allow use livers currently considered marginal - something we're investigating. - which could further reduce long waiting lists for transplants " Yarmush Uygun and are both on the faculty of Harvard Medical School.
The principal author of Nature Medicine report Tim Berendsen, MD, formerly of medical engineering MGH Center and now at the University Medical Center Utrecht, the Netherlands -Low. Additional co-authors are Puts Catheleyne, 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 document are pending.
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