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Pig heart transplant to human is an important milestone

   The University of Maryland Medical Center announced that a 57-year-old American man named David Bennett received a pig heart transplant in the United States on January 7. The operation lasted 7 hours and the patient is in good condition. The donor hearts used for transplantation were obtained from genetically modified pigs.
   Xenotransplantation has always been a huge challenge in medicine, and if a breakthrough can be achieved, it will become an effective and appropriate means of saving patients. Now, the successful transplantation of the world’s first genetically modified pig heart is an important milestone in human exploration. However, it remains to be seen what the follow-up effect will be. According to general requirements, the 5-year survival rate is now a basic criterion for the success of allogeneic organ transplantation. If the patient can survive for a period of time, it means that the pig heart or other organs of the pig is feasible for transplantation, which also clears the obstacle for the general clinical use of pig hearts and other organs in the future.
   In order for pig organs to become an organic part of the human body and function, there are still many problems to be solved: one is to solve the rejection reaction; To confirm whether pig hearts or other organs have the same functions as human organs, the fourth is an ethical issue.
   The pig heart used this time has adopted techniques to avoid rejection and achieved important results. The pig heart was harvested from a genetically modified pig provided by the regenerative medicine company Revivicor. The researchers made 10 genetic modifications to the pig, of which four genes were knocked out or inactivated, including those that cause aggressive rejection in humans. , the galactosyltransferase gene. In addition, a growth gene in this pig was also inactivated to prevent the pig’s heart from continuing to grow after the transplant. In addition, six human genes were inserted into the donor pig’s genome to prevent the human immune system from rejecting the pig’s organs.
   Even so, it remains to be seen and addressed in the future whether pig organs have other previously undiscovered genetic loci and molecules that may trigger immune rejection. At the same time, study whether pig organs contain other endogenous microorganisms and viruses that may cause harm to humans, such as endogenous retroviruses in pig organs.
   Functional compatibility issues also need to be observed and resolved. It is still unclear whether the pig’s heart can fully perform the functions of the human heart, including hormone secretion and metabolic balance. Hormones such as atrial natriuretic peptide (ANP) can not only protect blood vessels, but also inhibit cancer cell metastasis. But after the pig heart is transplanted, whether it can still secrete this hormone and be compatible with other human organs, tissues and systems.
   The transplanted pig heart generated pulse and blood pressure in Bennett’s body, and kept the patient alive, a success that rivals or even surpassed the first human heart transplant, which means that the easy availability of donor organs may save the future thousands of lives. If pig hearts are available for transplantation, ethical issues will also be addressed by formulating corresponding rules. In fact, when it comes to saving lives, survival is the first and greatest ethic.

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