American researchers have successfully restored dysfunctional human lungs for transplantation by supplying them with live pig blood.
- Connected to the blood supply of a live pig, lungs unsuitable for transplantation because they were too damaged regained their lung function within 24 hours.
Like many other transplant operations, lung transplantation does not escape the shortage of organs. The process is all the more delicate because as soon as an individual dies, their lungs begin to deteriorate due to oxygen deprivation and only remain viable within 6-8 hours of death. Eighty percent of the lungs proposed for transplantation are thus unsuitable for transplantation because they are damaged, swollen or soaked with liquid.
A discovery led by researchers from Columbia and Vanderbilt universities (USA), and published in the journal NatureMedicinecould prolong the life of explanted lungs up to 4 days after death and keep them functional.
Restoration of lung function in 24 hours
Working for eight years on a system to restore damaged lungs, the research team had already managed, in 2017, to restore the transverse circulation of lungs outside the body and, in 2019, to regenerate severely damaged pig lungs.
For this new trial, the researchers took six lungs unsuitable for transplantation from deceased patients. Each lung was placed in a plastic box hooked up to an artificial respirator. Then each lung was connected to a large vein from the neck of a live pig. Immunosuppressants were then added to the circulatory system consisting of the pig and the human lung.
After 24 hours of cross-circulation, the lungs were transformed: the lung cells were once again able to supply oxygen.
“The results sound like science fiction: within 24 hours the lungs appeared to be serviceable and lab tests confirmed they had been resuscitated”write the authors of the study in NatureMedicine.
A technology to refine
While further research is needed before this cross-circulation becomes a clinical reality, these early results are particularly encouraging and could significantly increase the number of viable lungs at transplantation.
“As a lung transplant surgeon, I have seen many patients not receive the lung transplants they desperately needed. I find this work intriguing and I hope this technology will make more donor lungs available”said Zachary Kon, director of the lung transplant program at NYU Langone Health, who was not involved in the study.
The results are all the more optimistic since the procedure does not seem to have any harmful effects on the pigs which were anesthetized. In a previous experiment, the animals could even move and feed while connected to the blood circulation device.
The ultimate goal is for this transverse circulation to be intra-human: a donor would then be able to restore his dysfunctional lung with his own blood supply.
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