LONDON, Feb 4 (IANS): Following a medical breakthrough, pig lungs could be transplanted into humans to overcome a shortage of donor organs, a media report said on Thursday citing Australian scientists.
Scientists have paved the way for animal-human transplants in as little as five years, after keeping pig lungs alive and functioning with human blood, the 'Daily Mail' reported on its website.
The breakthrough came after scientists at Melbourne's St Vincent's Hospital were able to remove a section of pig DNA called the Gal gene, which made the pig organs incompatible with human blood.
Professor Tony D'Apice, who has been breeding pigs for possible transplants since 1989, said human DNA was added to the engineered animals to control blood clotting and rejection in humans.
Glenn Westall, from the Alfred Hospital in Melbourne, said the world-first discovery meant pig-human lung transplants were a real prospect. He said: "Five to six hours into the experiment they seemed to be working as well as they were at the start.
"The blood went into the lungs without oxygen and came out with oxygen, which is the exact function of the lungs. It showed that these lungs were working perfectly well and doing as we were expecting them to do ... This is a significant advance compared to experiments that have been performed over the past 20 years."
The Alfred scientists removed the lungs and hooked them up to a machine mimicking the human circulation system under a process mirroring that used for traditional lung transplants. The machine uses a ventilator to cause the lungs to 'breathe' while a pump acting as a heart allows blood to flow through the lungs.
Previous attempts to combine unmodified pig lungs and human blood ended abruptly two years ago when blood clots began forming almost immediately, causing the organs to become so blocked no blood could pass through. But when the genetically modified lungs were used at the end of last year the results were overwhelming, fuelling hopes of clinical trials in five to 10 years.
Westall said: "Where before we saw the system crash and the lungs destroyed within 10 minutes, the lungs seemed to be working perfectly well at the end of our experiment after many hours.
"This is a major advance but there remain significant hurdles."
The full results of the research are being kept a secret before being announced at a world transplant meeting in Vancouver in August.
The possibility of animal-to-human transplants - xenotransplantation - has divided the medical ethics community.
Medical ethicist Associate Professor Nicholas Tonti-Filippini said such transplants had the potential to bring animal diseases into the human population. He said the creation of genetically modified pigs was not ethically acceptable, explaining: "It is basically a human-pig, a hybrid, or whatever you want to call it.
"It is about whether the community is prepared to accept a part human, part animal."
