Scientists in the United States have announced that for the first time in the world they have successfully transplanted not one but two genetically modified pig kidneys into a man who was brain dead.
Transplanting animal organs into humans - known as xenografts - promises to increase the number of available organs and thus prevent the thousands of deaths that occur each year in people who are on long waiting lists for transplants but ultimately fail, as supply can not meet the demand of the various institutions in a timely manner.
Doctors, led by Professor Jamie Locke of the University of Alabama School of Medicine, who published the report in the American Journal of Transplantation, reported that the pig's kidneys after transplantation were transplanted. , produced urine and were not immediately discarded (within the next 77 hours). It was preceded by the modification and addition of a total of ten genes, so that the animal's kidneys could be accepted by the human body.
The first attempts at genetically modifying pigs to reduce the possibility of their organs being rejected by humans began in the early 2000s. genome of pigs, so as to overcome the biological barriers created by evolution in its course. In this case, four pig genes were inactivated and six human genes were added.
"A revolutionary moment in the history of medicine that represents a paradigm shift and is an important milestone in the field of xenografting, which is the best solution to the crisis of organ shortage," said Dr. Locke, director of the Department of Integrated Transplantation. University of Alabama, which is a pioneer in transplantation in the US and internationally. "The new study provides additional knowledge that could not exist with animal models and brings us closer to a future in which the supply of organs will meet the frightening demand," he added.
Until now, kidneys from genetically modified pigs had only been tested in other large experimental animals (primates). The medical team announced that the experimental transplant met all the requirements to be considered a phase 1 clinical trial. of United Therapeutics Corp.
The recipient was 57-year-old Jim Parsons, who was a potential organ donor during his lifetime, but his organs were not suitable for donation. His family gave him permission to keep his brain dead body in mechanical support, in order to perform the test transplant of the pig's kidneys, after the removal of his own organs.
The lifespan of pigs is usually 30 years, while they have organs similar in size to human ones, so they can be used more widely in transplants. However, additional research and testing is needed before xenografting can be used to address the current shortage of organs. It remains to be confirmed that a pig kidney can be tolerated in the human body environment, as a transplanted kidney is extremely sensitive to its new environment. For example, pigs have lower blood pressure than humans.
The first test in humans, however, went well in the beginning and in the surgery there were no complications such as severe bleeding. In just 23 minutes, one transplanted pig kidney began to produce human urine, but the other to a much lesser extent, without scientists knowing why there was this difference between the two organs. Because the experiment ended after about three days, the researchers also could not be sure whether the kidneys of the animals would be rejected over a longer period of time - weeks or months.
Millions of people around the world suffer from severe kidney failure and need transplantation, as for many people hemodialysis is a temporary solution. But the waiting list for transplants can be from five to ten years, with the result that several kidney patients (5% to 15% per year) die in the meantime. The experience of transplants so far has shown that kidney recipients live longer and have a better quality of life than those on dialysis (only 35% of the latter have an eight-year survival). On the other hand, a kidney transplant works well in 95% of cases, thus treating end-stage renal disease.
The first experimental chimpanzee kidney transplant in 13 patients with end-stage renal disease was performed in 1963-64 in the United States, at a time when chronic dialysis was not yet available. Despite the close genetic affinity of chimpanzees and humans, no patients lived more than nine months and almost all died within a few weeks. The idea that pigs would be a better solution than chimpanzees first appeared in the 1980s.
1954 was preceded by the first successful human-to-human kidney transplant between two twins. The transplanted kidney operated for eight years. In 1962, with the help of immunosuppression, the first kidney transplant was performed among non-genetically related patients.
Source: RES-EAP