Approximately 79,000 people are on the organ transplant list in the United States. And every day, ten of these individuals pass away and 3,000 new patients are added to the list. Primarily, ailing patients need a new heart, liver, pancreas, lung or kidney, and the reality is that there are not enough organ donors to meet the growing need.
Xenotransplantation – a word that describes animal-to-human organ, tissue and cell transplants – could possibly help alleviate the shortage of lifesaving donor organs. Originally, scientists looked to animals that had comparable sized organs to humans. In the early 1960s, chimpanzee kidneys were the first reported xenotransplantation attempts. And over the years, scientists have also attempted to transplant baboon organs (like the heart, liver and kidneys).
Pig organs and tissues are a current xenotransplantation research focus because pigs have a remarkably similar biochemical profile to human beings. Additionally, pigs breed easily and birth litters, making them a viable non-primate xenotransplantation option.
A groundbreaking medical study in Melbourne, Australia found that pig lungs were kept alive when fueled with human blood. These pigs were genetically modified with human DNA to control blood clotting and minimize organ rejection in human recipients.
In the report, human blood entered the pig lungs without oxygen and came out with oxygen, concluding that the lungs were functioning successfully with human blood. Then, the lungs were hooked up to a machine with a ventilator that mimics human breathing and circulation, a standard process with traditional lung transplants. While past studies failed to succeed in this critical step, these human DNA-altered pig lungs continued to work even after several hours on the machine.
Pig lung transplants in human patients could be a reality in as little as five years. Some medical experts believe that xenotransplantation will provide the gift of life to patients that may die otherwise. There’s the argument that many people eat pigs for meat, so why not use their organs to save human lives? Is it be possible that the transplant waiting list will virtually disappear in the future with the help of animal organs? In a Hanover University School of Medicine’s poll of over 1,000 individuals, 77% of people reported that they would be willing to accept an animal organ if they needed a transplant. And when informed of the possible xenotransplantation risks? That statistic dropped to just 58 percent.
However, despite the potential benefits of xenotransplantation, hurdles remain and doctors are divided on the issue. There’s the consideration that these animals could transmit diseases to the human population. Some think that genetically modifying pigs is an unethical practice. Researching animal-to-human organ transplants is highly expensive. And xenotransplantation does not offer a guarantee of extended life – irreversible and fatal tissue and organ failure is a real possibility. And other critics are just freaked out about the idea of a “part human, part animal” walking among us.
While xenotransplantation is a current hot topic, the use of animal parts in medical procedures is not a new issue. Pig heart valve transplants are commonplace throughout the United States, and medical teams are researching whether animal cells can assist the human pancreas in producing insulin. Additionally, there is interest and study on the possibility of pig skin helping humans with severe burns.
Learn more about the xenotransplantation debate.