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A pig heart’s fantastic drift

  Not long ago, for the first time in American medicine, a pig heart was successfully transplanted into the body of a 57-year-old heart patient. Three days after the surgery, the patient is still doing well.
  This is the first human attempt to transplant an organ from across species, into a living person. The patient was diagnosed with heart failure and arrhythmia – and after a heart transplant operation, a genetically edited pig heart was restored to the patient’s chest after doctors evaluated and sought his consent.
  After the surgery, the patient was able to breathe on his own and was hooked up to a heart-lung machine that assisted the new heart. Although it is not possible to say that the operation was a complete success, this could be the beginning of a revolution in organ transplantation: not surprisingly, cross-species organ transplants will enter formal clinical trials in the future.
  In retrospect, a number of genetically edited pig organs have been transplanted in monkeys with good results. It is important to note that the vast majority of previous xenotransplantation cases have ended in failure – mainly due to rejection of animal organs by the human body. Although humans are similar to other primates such as monkeys and orangutans in terms of physiology, anatomy and metabolism, rejection can be easily managed, the long generation gap, low reproduction rate and high breeding cost of primates make it difficult to meet the demand for human organ transplants. In contrast, compared to primate organs, pig organs can grow to adult organ size in as little as 6 months after the pig is reared. Not only are the organ sizes, anatomical features, and physiological and biochemical characteristics of pigs very similar to those of humans, but they also have shorter growth cycles and high reproduction rates, making them recognized by the scientific community as ideal donors for allogeneic organ transplantation.
  By now, porcine heart valves and porcine pancreatic cells have been used for human transplantation, and porcine skin has also been used as a temporary graft for burn victims. A little earlier, surgeons in New York even successfully transplanted kidneys grown in genetically modified pigs into human patients (attached to the patient’s blood vessels and kept outside the body).
  Although the pathobiological response to xenograft transplantation between pigs and humans is complex, developments in gene editing and cloning technologies have accelerated this research process over the past decade, bringing relief to countless patients waiting on organ transplant waiting lists. For example, the pig heart that was used for this transplant was genetically edited so that sugars in the cells that would cause a rapid rejection reaction were removed. The surgeon who performed the surgery also said that he had repeatedly experimented with transplanting pig hearts into about 50 baboons over a five-year period before proposing them to patients.
  The shortage of human organs available for transplantation has long been acute. Data from the Shared United Network, an organization that coordinates organ procurement in the United States, shows that in 2021, a record 3,800 heart transplants were performed across the country. The U.S. federal government also has data showing that more than 100,000 people are waiting for organ transplants in the country, and that more than 6,000 people die each year before receiving them.
  So, as Bennett, a 57-year-old patient, said on his last day before surgery, “It was death or transplant. I know it’s an attempt in the dark, but I have no choice.”

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