أول عملية زرع عضو ناجحة في العالم بين الكائنات الحية
January 11, 2022 - جراحون في الولايات المتحدة زرعوا قلب خنزير معدل وراثياً في جسم إنسان، مما يمثل خطوة جديدة في سعيهم الذي دام عقوداً لاستخدام أعضاء الحيوانات لعمليات الزرع المنقذة للحياة.
A Maryland man has become the first to receive a successful pig-to-human heart transplant. David Bennett, 57, is “still doing well” three days after the first-of-its-kind surgery and will continue to be monitored to determine whether the transplant, conducted at the University of Maryland, provides life-saving benefits, the university said in a statement.
The surgery took nine hours and saw doctors replace Bennett’s heart with one from a pig that had its genes edited specifically to provide organs to humans.
The pig, provided by Blacksburg, Virginia, company Revivicor, which raises pigs for transplant, was genetically modified in 10 different spots before birth.
One of the key reasons the human immune system rejects pig organs lies in genes responsible for producing an enzyme called alpha-1,3-galactosyltransferase (alpha-gal).
Since normal pig tissue contains active alpha-gal enzymes, antibodies in the human immune system interpret the transplanted tissue as a threat and cause an aggressive human rejection response.
Porcine DNA is genetically modified to eliminate the alpha-gal molecule from the embryos of cloned pigs. Six human genes are added to the pig DNA to prevent blood from coagulating in the heart, improve molecular compatibility and reduce the risk of rejection. Finally, scientists knock out two other genes -- one to stop the animal from growing too large and another to prevent the pig’s heart from continuing to grow after implantation.
The one-year-old pig that gave its heart to Bennett weighed about 109 kilograms; a standard male pig of the same age might weigh more than 200kg, said David Ayares, Revivicor’s executive vice president and chief scientific officer.
- Maryland man receives first successful pig-to-human heart transplant (UPI)
- FDA Approves First-of-its-Kind Intentional Genomic alteration to eliminate alpha-gal sugar on surface of pigs’ cells (FDA)
- The Future of Animal-to-Human Organ Transplants (Smithsonian)
- Timeline of the key events in xenotransplantation (ScienceLearn)