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Glossary / Life sciences and medicine

Xenotransplantation

Transplanting organs or tissues from animals into humans. Today the main candidates are kidneys and hearts from genetically modified pigs.

Pig organs are close to human size and can be produced in numbers, so they have long been studied as a way to relieve organ shortages. The biggest obstacle is the human immune system attacking pig cells as foreign. Pigs have therefore been engineered with the genes for the main targets knocked out and human genes added.

In 2022 a report described genetically modified pig kidneys transplanted into brain-dead recipients and working for several days[1]. Transplants into living patients followed, some functioning for months, but chronic rejection has not yet been brought under control.

Related terms

  • Carbohydrate antigenA sugar chain on the cell surface that the immune system uses as a target. In xenotransplantation the key example is α-Gal, present in pigs but absent in humans.
  • Antibody-mediated rejectionRejection in which the recipient produces antibodies against a transplanted organ, and those antibodies attack the organ's blood vessels and gradually impair it.
  • ImmunosuppressionUsing drugs to weaken the immune system so that it does not reject a transplanted organ.

Sources

  1. R. A. Montgomery, J. M. Stern, B. E. Lonze, et al., “Results of Two Cases of Pig-to-Human Kidney Xenotransplantation,” N. Engl. J. Med. 386, 1889–1898 (2022).