The transplant procedure has been subject to tests on pig and human lungs

A pioneering new technique can patch-up normally discarded damaged lungs and make them suitable for transplant patients, scientists have shown.

The two-step procedure, which involves gene therapy, has been successfully tested on pig and human lungs.

In future it could double the number of donor organs available to transplant patients, say the Canadian scientists. They believe it may be possible to treat other transplant organs, such as kidneys and hearts, the same way.

Clinical trials are now planned in which consenting, critically-ill patients will be given the "refurbished" lungs if no other organs are available.

More than 80% of potential donor lungs suffer inflammation and injury as a result of brain death and intensive care complications that render them unsuitable for transplantation, according to the researchers.

Damaging inflammation, caused by an over-active immune response, also commonly occurs after transplant surgery.

The new approach involves first preserving the lungs at normal body temperature inside a protective "dome" and pumping a solution of oxygen, proteins and nutrients over the damaged tissues.

The technique, known as the Toronto XVIVO Lung Perfusion System, allows the injured cells to begin repairing themselves and prepares them for stage two in the treatment process.

Next, a common cold virus is used to carry a gene called IL-10 into the lungs. This has the effect of significantly improving blood flow and the lungs' ability to carry out the all-important function of gas exchange - taking in oxygen and getting rid of carbon dioxide.

The "IL-10 effect" lasted for 30 days in human lungs, the scientists found. Helping the organ to function better at the start should lead to more predictable, safer outcomes, shorter periods of mechanical ventilation, and less time spent in intensive care units, they said.