Scientists have experimented for centuries with using parts from animals to improve human health, but the technology has leapt ahead recently with advances in gene editing and immunology. Pigs have emerged as especially promising, because they are easy to breed and their organs are genetically similar to human organs.
Cross-species transplantation — or xenotransplantation — dates as far back as the 17th century.
A brief history of the advances that led to this week’s breakthrough.
1667 — In what is recognized as the earliest instance of animal-to-human transplantation, French physician Jean-Baptiste Denis performs the first animal-to-human blood transfusion, transferring lamb’s blood to a 15-year-old male patient. Further xenotransfusions performed by Denis meet mixed results, leading the practice to be banned in France for a number of years.
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19th century — Skin grafts between various species — such as frogs, rabbits, sheep, chickens, and pigeons — and humans gain popularity.
1838 — New York based ophthalmologist Richard Kissam transplants a pig cornea into a young Irishman with only one functional eye, but it fails within a month.
1906 — A surgeon from Lyon, France, conducts the first pig-to-human kidney transplant that results in the production of urine. The kidney fails after three days.
1963 — Dr. Keith Reemtsma of Tulane University transplants a rhesus monkey kidney to a human using an immunosuppression regimen, which prevents the body’s rejection of donor tissue or organs. Earlier attempts at xenotransplantation without immunosuppression resulted in poor survival rates. The patient survives for 63 days.
1964 — American surgeon James Hardy, who the previous year pioneered the first human lung transplant, conducts the first animal-to-human heart transplant using a chimpanzee heart. The patient dies within two hours.
The same year, Reemtsma transplants chimpanzee kidneys into 13 different patients, with survival lasting 11 days to nine months — the longest survival of any xenotransplant at this time.
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1968 — Dr. Donald Ross performs the first pig to human heart transplant in London. It lasts around five minutes.
1984 — “Baby Fae,” a month-old infant with an often fatal heart deformity, receives a baboon heart from Dr. Leonard Bailey in Loma Linda, Calif. Baby Fae lives for 21 days after the transplant, two weeks longer than anyone with a simian heart ever had before.
1992 — Surgeons at Cedars-Sinai Medical Center in Los Angeles implant a pig liver into a young, critically ill woman as she awaits a human donor. She dies after 36 hours.
1993 — A Swedish group headed by Carl Groth is the first to transplant pig islet cells, cells from the pancreas that produce insulin, into patients with diabetes, but there is no clinical benefit.
1996 — Cardiac surgeons transplant a pig’s heart into a human in India. The patient survives for seven days.
1998 — Researchers in Philadelphia share results one year after transplanting fetal brain cells from pigs into humans to treat Parkinson’s disease. This research marks the first time brain cells from an animal have been transplanted into a human.
2002 — After 12 Mexico City adolescents received pig cell transplants to treat diabetes, researchers present their findings: Half the patients required less insulin to keep their diabetes in check. One patient lived insulin-free for a year and another lived without the hormone supplements for six months.
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2021 — Doctors at NYU Langone Health in New York perform the first transplant of a genetically engineered pig kidney into a deceased human on a ventilator. It functioned well and showed no signs of rejection over a 54-hour observation period.
2022 — Doctors at the University of Maryland School of Medicine transplant a genetically modified pig’s heart into a 57-year old patient with end-stage heart disease. He lives for nearly seven weeks.
2023 — UMD doctors perform a second pig heart transplant in a 58-year-old patient with terminal heart disease. He lives for around two months.
Grace Gilson can be reached at grace.gilson@globe.com. Madeline Khaw can be reached at maddie.khaw@globe.com. Follow her @maddiekhaw.