A team of scientists has vastly extended the time window in which a liver to be transplanted can be kept waiting to reach a patient.
By modifying a protocol necessary to conserve the liver of rodents, the scientists observed results so promising that they were tested on a human liver to be transplanted.
The liver of a donor had an average "life" of 9 hours, the new method brings this time to 27 hours. A sea of extra time to organize the operation, to increase the organ's transport range, to prepare the recipient.
A great, great discovery.
The research is supported byUSA National Institute of Bioengineering (NIBIB) and by other entities of the American National Institute of Health.
What happens to a liver to be transplanted
Like a glass that breaks when it gets too cold, cells often receive irreparable damage from the freezing process. The sensitivity of human cells involves the need to freeze a donor's liver below 4 ° C. This brings the useful time to a transplant to 9 hours, beyond which the damages of the cold become irreversible.
This is why it is often very difficult, and sometimes impossible, to get compatible organs to reach people waiting for a transplant.
"Delivering healthy organs in the window of time is one of the most complex aspects of organ transplantation," says Seila Selimovic, Ph.D, director of the NIBIB tissue engineering program. "Giving doctors and patients more time means saving a lot of people waiting for a transplant."
The first research
A study by Massachusetts General Hospital (MGH) in Boston led to a new technique to extend the preservation of rodent liver tissue below zero.
The result was obtained by adding a glucose compound, 3-OMG, and an ingredient, PEG-35kD, to the solution to preserve the tissues, at the base of some antifreeze.
The PEG substance lowers the freezing temperature of the cells and the 3-OMG acts as a protection. This allowed the rat livers to be stored at -6 ° C without freezing them. A process called "super cooling".
Unfortunately, the process did not work with human livers, which being 200 times larger presented more risk of ice crystal formation, rendering the organ useless.
The solution of the problem
In the paper published today in Nature Biotechnology, a research team at Harvard Medical School illustrated three corrective actions that resolved the problem.
First, limit the contact of the coolant with the air. The team removed oxygen from the container before pouring the liquid, eliminating any risk of crystals on the outer surface of the organ.
Second, two ingredients have been added to the original solution to specifically protect hepatocytes: trehalose helps protect cells and stabilizes their membranes. The glycerol supports the properties of the glucose contained in the original solution.
Third, a new organ transport method was developed. The previous one involved the manual pouring of the liquid on the organ. The current liquid is more viscous and to pour it they used the perfusion, a method to distribute it in a more uniform and capillary way.
This method will allow organs to travel even over long distances, reaching many more waiting patients.
