Fred de Sam Lazaro reports there have been research breakthroughs recently that have triggered new interest in the possibility of ... xenotransplants.
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FRED DE SAM LAZARO: These newborn pigs are a milestone in biological craftsmanship. They are genetic clones, produced by PPL, the Scottish company that in 1997 created Dolly, the world's first cloned sheep.
Several biotech companies are developing such animals as potential sources of organs for humans. So far the big challenge has been rejection. But in recent months, at least two firms have managed to alter pig genes so that they no longer produce a certain sugar that scientists think is responsible for the vigorous rejection when pig cells are mixed with human tissue. The breakthrough has again revived interest in xenotransplantation.
The transfer of tissue or organs from one species into another is not a new idea. But the technology languished for decades. The most famous transplant was the case of Baby Fae. In 1984, she received a baboon heart but only survived for 20 days.
Xenotransplantation got new life in the '90s, as scientists learned how to alter genes; how to put human genes in animals so as to lessen rejection.
What hasn't changed over the years is the critical need for organs. Dr. David Cooper, transplant surgeon at Massachusetts General Hospital, says 16 patients die each day waiting for an organ.
Dr. DAVID COOPER (Transplant Surgeon, Massachusetts General Hospital): There are something like 80,000 people waiting at the moment in the U.S. for an organ of one sort or another. And this year there will be less than 20,000 organs available. So I think we have to look outside of the box, so to speak, and look to see what alternative sources there are.
DE SAM LAZARO: Primates such as chimpanzees and baboons were once considered a potential organ source. But their organs are typically smaller than human ones, and because they live in the wild they may carry many unknown diseases. The less exotic pig has many advantages.
Dr. COOPER: It is large enough to donate organs to the largest of humans. It breeds rapidly -- 10 or 12 in a litter. It's relatively easy and cheap to keep and house until you are ready to use the organs. Furthermore, we don't have so many ethical concerns about pigs. We actually slaughter 100 million pigs in the U.S. each year for food.
DE SAM LAZARO: Whether with pigs or baboons, xenotransplantation has raised many ethical concerns.
Dr. ALIX FANO (Campaign for Responsible Transplantation): While there are 80,000 people on the organ transplant list and we are sorry about that, there are 50 million people who don't have basic health care in this country.
DE SAM LAZARO: Alix Fano opposes xenotransplants for a variety of reasons. Besides the mistreatment of animals, Fano fears viruses, harmless in pigs, could "wake up" in humans. She cites the example of HIV, which moved from primates to humans.
Dr. FANO: Pig viruses could be transmitted to humans, could lay dormant for decades and then resurface later, creating a new global pandemic akin to AIDS. This is not science fiction or a paranoid fantasy. This is a reality. We know that in 1918, the swine influenza killed about 20 to 40 million people worldwide.
DE SAM LAZARO: Dr. Cooper discounts that possibility. He says transplant animals are carefully designed and nurtured -- if only because they are a huge financial investment.
Dr. COOPER: We have the opportunity to breed and house them under perfect conditions and to eradicate the infection from the strain of pigs. You can never say there is no risk, but my feeling is that if you've ruled out every known risk, you may have to take a leap into the unknown and say, "Well, we've ruled out every known risk, let's proceed cautiously."
Several biotech companies are developing such animals as potential sources of organs for humans. So far the big challenge has been rejection. But in recent months, at least two firms have managed to alter pig genes so that they no longer produce a certain sugar that scientists think is responsible for the vigorous rejection when pig cells are mixed with human tissue. The breakthrough has again revived interest in xenotransplantation.
The transfer of tissue or organs from one species into another is not a new idea. But the technology languished for decades. The most famous transplant was the case of Baby Fae. In 1984, she received a baboon heart but only survived for 20 days.Xenotransplantation got new life in the '90s, as scientists learned how to alter genes; how to put human genes in animals so as to lessen rejection.
What hasn't changed over the years is the critical need for organs. Dr. David Cooper, transplant surgeon at Massachusetts General Hospital, says 16 patients die each day waiting for an organ.
Dr. DAVID COOPER (Transplant Surgeon, Massachusetts General Hospital): There are something like 80,000 people waiting at the moment in the U.S. for an organ of one sort or another. And this year there will be less than 20,000 organs available. So I think we have to look outside of the box, so to speak, and look to see what alternative sources there are.
DE SAM LAZARO: Primates such as chimpanzees and baboons were once considered a potential organ source. But their organs are typically smaller than human ones, and because they live in the wild they may carry many unknown diseases. The less exotic pig has many advantages.
Dr. COOPER: It is large enough to donate organs to the largest of humans. It breeds rapidly -- 10 or 12 in a litter. It's relatively easy and cheap to keep and house until you are ready to use the organs. Furthermore, we don't have so many ethical concerns about pigs. We actually slaughter 100 million pigs in the U.S. each year for food.DE SAM LAZARO: Whether with pigs or baboons, xenotransplantation has raised many ethical concerns.
Dr. ALIX FANO (Campaign for Responsible Transplantation): While there are 80,000 people on the organ transplant list and we are sorry about that, there are 50 million people who don't have basic health care in this country.DE SAM LAZARO: Alix Fano opposes xenotransplants for a variety of reasons. Besides the mistreatment of animals, Fano fears viruses, harmless in pigs, could "wake up" in humans. She cites the example of HIV, which moved from primates to humans.
Dr. FANO: Pig viruses could be transmitted to humans, could lay dormant for decades and then resurface later, creating a new global pandemic akin to AIDS. This is not science fiction or a paranoid fantasy. This is a reality. We know that in 1918, the swine influenza killed about 20 to 40 million people worldwide.DE SAM LAZARO: Dr. Cooper discounts that possibility. He says transplant animals are carefully designed and nurtured -- if only because they are a huge financial investment.
Dr. COOPER: We have the opportunity to breed and house them under perfect conditions and to eradicate the infection from the strain of pigs. You can never say there is no risk, but my feeling is that if you've ruled out every known risk, you may have to take a leap into the unknown and say, "Well, we've ruled out every known risk, let's proceed cautiously."
Mr. JIM FINN: It was a very simple procedure. They drill a hole in the skull. I think it's right here. A quarter of an inch hole. And they put a six-inch needle in your brain, filled with pig cells, and they inject these fetal brain pig cells. And they pump them into your brain and hope for the best.
DE SAM LAZARO: Not even Finn's doctors are entirely sure whether it was the pig cells that caused the miracle. Others patients did not fare as well in his trial, which was suspended by the federal government after patients in a related study developed seizures. The uncertain economy has also slowed investment and research. But Dr. Cooper is confident the research will soon get back on track and that success will lead to wide public acceptance.
Dr. COOPER: I think I have no problems modifying a pig in the way we are trying to do it. But if you were going to change its psyche or its social behavior or its reproductive capacity and so on, then I would have some reservations.
DE SAM LAZARO: Scientists caution it will be a long wait before xenotransplants offer any potential to relieve the shortage of donor organs. Dr. Cooper says trials are scheduled to begin in the next few weeks in which pig organs will be transplanted into primates. This could, Cooper says, depending on how it goes, lead to trials in human patients in the next three years.
