Lung tissue is preserved in the Toronto XVIVO Lung Perfusion System developed at the Toronto General Hospital with the aim of repairing lungs prior to transplant. The technique allows for lungs to be removed from a donor and kept at body temperature while being assessed for function and transplant outcome.
Credit: Toronto General Hospital
A new out-of-body lung-repair technique developed at the Toronto General Hospital may dramatically increase the number of lungs that can be used in transplants and improve surgical outcome.
In an operating room at the hospital, the technology can keep a pair of human lungs slowly breathing inside a glass dome attached to a ventilator, pump, and filters. The lungs are maintained at normal body temperature of 37 °C and perfused with a bloodless solution that contains nutrients, proteins, and oxygen. The organs are kept alive in the machine, developed with Vitrolife, for up to 12 hours while surgeons assess function and repair them.
Normally, as few as one in ten lungs available for transplant is usable, and even those may not work properly when grafted. "The system allows you to assess the lungs, to diagnose what's wrong with them, and then repair them," says Shaf Keshavjee, who directs the hospital's Lung Transplant Program. "Therefore, we're transplanting lungs that have a more predictable outcome."
Some speculation besides transplants: A patient could be placed onto a lung machine. Their own lungs could be taken out and repaired and improved and then placed back into the original patient.
Other experts hail the Toronto technique but caution that more work is needed on how to fix lungs, stop the inflammatory response in grafting, and improve mortality in transplant patients.
"The Toronto system seems to re-create normal lung function outside the body," says Jacques-Pierre Fontaine of Brown University's cardiothoracic-surgery division. "If we can keep the organ outside the body longer with minimal ischemic damage, we can go farther to get a lung." However, says Fontaine, "the real test" will be how well the patients do with the transplanted lungs. "Proof will be in the survival data."
List of other videos of regenerative medicine and stem cell work from the McEwen Centre for Regenerative Medicine was established at University of Toronto
Vitrolife transplantation website