Twelve people die each day waiting for a vital organ to be transplanted into them. The donor organs all come from persons who have been declared “brain dead,” a designation that remains controversial among ethicists.
But a medical breakthrough that was reported this week might eventually lead to a drastic reduction in both the number of people waiting for a donor organ and the need to excise vital organs from persons whose brains have completely ceased functioning — because of extreme trauma or drug overdoses — yet who are kept breathing mechanically.
The solution may well be organs from other animals, a procedure known as xenotransplantation, which has been studied for many years. In late September, a team of doctors at New York University/Langone Health in New York City successfully attached a pig kidney to a brain-dead woman who had shown signs of kidney dysfunction. The organ worked normally.
What made the procedure possible was a genetic modification of the donor pig to remove a gene that triggered rejection of its kidney by a human recipient.
Pig hearts and kidneys have been transplanted successfully into monkeys and baboons, but safety concerns precluded their use in humans, the New York Times said.
“We already use pig valves in humans. As long as it is safe, it should be fine,” Fr. Nicanor Austriaco, O.P., Professor of Biology & Professor of Theology at Providence College, said of the use of a pig kidney in a human, in an email to Aleteia. “My only concern is that this research is being done with apparently brain-dead patients. This is new because it is not clear who gives informed consent. I do not think that brain dead patients are truly dead … so this worries me that we are going in this direction.”
John F. Brehany, Executive Vice President of the National Catholic Bioethics Center, shared that concern. “ I would want to make sure that the brain death diagnosis was completely clear and valid,” he said in an email. “It may well have been. But the more that people start to do experimentation on human ‘cadavers’ on full life support based on brain death diagnoses, the more it may raise questions about the validity of brain death.”
Indeed, the fact that science could conduct an experiment on a “dead person” showing that the function of a living person was working seems contradictory.
The National Catholic Bioethics Center’s Fr. Tadeusz Pacholczyk, a neuroscientist and bioethicist, however, told USA Today that “there’s not a fundamental concern there, since this would be an instance of ‘donating one’s body to science’ after death.”
Fr. Pacholczyk, director of education at the NCBC, also sees “no insurmountable ethical problems with the surgery or pig-to-person transplant,” the newspaper said, pointing out that “animals have long been sacrificed for human benefit.”
New technologies
Genetically engineered pigs “could potentially be a sustainable, renewable source of organs — the solar and wind of organ availability,” said Dr. Robert Montgomery, the director of the N.Y.U. Langone Transplant Institute, who performed the procedure in September, according to the New York Times.
The combination of two new technologies — gene editing and cloning — has yielded genetically altered pig organs, and the kidney used in the NYU experiment was obtained by “knocking out a pig gene that encodes a sugar molecule that elicits an aggressive human rejection response,” explained the Times.
“Dr. Montgomery and his team also transplanted the pig’s thymus, a gland that is involved in the immune system, in an effort to ward off immune reactions to the kidney,” the paper said.
Dr. David Klassen, chief medical officer of the United Network for Organ Sharing, cautioned that many hurdles remain, however. Klassen warned that long-term rejection of organs occurs even when the donor kidney is well-matched, and “even when you’re not trying to cross species barriers.” Said the Times:
The kidney has functions in addition to clearing blood of toxins. And there are concerns about pig viruses infecting recipients, Dr. Klassen said: “It’s a complicated field, and to imagine that we know all of the things that are going to happen and all the problems that will arise is naïve.”
Nevertheless, the fact that, according to National Public Radio, “several biotech companies are in the running to develop suitable pig organs for transplant to help ease the human organ shortage” shows that there’s promise in the field. The NYU success is “a win for Revivicor, a subsidiary of United Therapeutics, the company that engineered the pig and its cousins, a herd of 100 raised in tightly controlled conditions at a facility in Iowa.”
Late last year, the Food and Drug Administration “approved the gene alteration in the Revivicor pigs as safe for human food consumption and medicine,” the radio network said.
