El gráfico muestra los pasos en la modificación genética de animales y una cronología de los xenotrasplantes.


Un hombre recibe un corazón de cerdo modificado genéticamente

By Duncan Mil

January 11, 2022 - Cirujanos en EUA trasplantaron a un humano un corazón de cerdo modificado genéticamente, un gran paso en los esfuerzos de décadas de uso de órganos de animales para salvar vidas humanas.

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.

PUBLISHED: 11/01/2022; STORY: Graphic News