The chest of the patient was opened on the Central line, Heparin was injected, and the heart-lung machine of the blood circulation of the patient connected. The body temperature was lowered to 34 degrees Celsius, the main artery pinched, then the surgeon cut out the heart.
This is the sober description of the beginning of heart transplantation, such as in an essay in the current issue of the journal "Nature". For people with heart failure in the terminal stage of a new heart is the only Chance for a cure – normally, this is not, however, report more in a trade magazine value.
In this case, however, the organ recipient was a baboon, and the donor is a pig. After the Transplantation, the monkey lived for 195 days, almost half a year before he was euthanized. Never before has a living creature has survived it with a donor heart of a foreign species for so long.
"The progress achieved is so relevant that the first clinical applications are considered."Gustav Steinhoff
University medicine Rostock
The Experiment will be celebrated by the professional world as a breakthrough. Experts who were not involved in the work, refer to the publication as a "groundbreaking", "impressive", "milestone", or "clinically relevant". "The progress achieved is so relevant that the first clinical applications of organs from genetically consider changes in pigs," says Gustav Steinhoff, head of the reference - and translation center for cardiac stem cell therapy at the University of Rostock.
Xenotransplantation is the name of the concept to resolve the chronic shortage of donor organs: organs from specially bred animals could extend the life of terminally ill people. If everything is going well, "we can go to maybe in three years in the clinic," says the Munich-based heart surgeon, Bruno Reichart, who transplanted a pig heart into the chest of the baboon. "In the clinker" means: Experiment with a people.
For the past 25 years, researchers try to put pig hearts in baboons. The previous survival record was 57 days. Eight years of this experiment. In "Nature" reports Reichart and his Team are now the same as you, to move the medical border between the species. They used genetically modified pigs in order to reduce the rejection reaction of the immune system of the baboon against the foreign Organ. They used a new method to the heart for Transfer to prepare. And they blocked with a drug, the growth of the pig heart, which would otherwise be too large for the chest of the baboons.
More transplants scheduled
According to this optimized Protocol five hearts in five baboons transplanted Reichart and his Team. One died early, two were killed after three months. So it had been with the ethics Commission. The two remaining animals were allowed to live in, 182 and 195 days. Four of the five animals seemed to tolerate the transplant well, with no severe infections due to the immunosuppression, stressed the Berlin transplant expert, Christoph Knosalla, in an accompanying commentary in "Nature".
for more transplants are planned Reichart. Because before Attempts start with people, must be confirmed by the successes. According to the guidelines of the International Society of Heart and Lung Transplantation first clinical Trials can be justified in principle, then, if 60 percent of the baboons to survive three months and the test series comprises at least ten animals that can survive for so long.
In Switzerland, the Federal office for health (BAG) would have to approve a transplant from pig to human. In the xenotransplantation regulation, it means that a permit could be granted if, among other things, "the quality and biological safety of genetically modified organs, tissues or cells, or of the resulting graft products are guaranteed to the patient or to the patient, as well as for human beings, animals and the environment".
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in Spite of the genetic adaptation of the donor pigs to reduce rejection reactions, will be instructed patients on medications that stop your immune system from attacking the foreign Organ. If the Doctors can use the same resources, as it Reichart now and his colleagues did, is still open. A first application for a license to practice medicine, the so-called Bridge to transplant. In the process, Doctors would have a life-threatening cardiac patients waiting for a suitable human donor organ, as a Bridge to the Transplantation of a pig to offer to heart.
another aspect must be clarified in each case, before a man comes as a receiver in consideration. In the genome of pigs lie dormant for many millions of years viruses called PERVs that have lost in the course of the Evolution of your activity. They represent a potential risk and should be removed from the genome of the donor pigs. That this is theoretically possible, have molecular shown biologists in the year 2017.
That such an act of violence is necessary at all, to doubt some of the experts. So Eckhard Wolf says, in the laboratory, the genetically modified pigs for rich arts grafts were created: "Probably just a PERV really need to get out", and there are already breeds of pigs without this virus remains in the genome. Other virus should be leftover as problematic, one could breed these out either or genetically cut out. Wolf is now working to continue to improve pigs genetically so that their hearts can beat in a human chest.
Created: 07.12.2018, 09:24 PM