Recent advances in pig-to-human organ and cell transplantation

Xenotransplantation using pigs offers the prospect of an unlimited number of organs and cells for clinical transplantation. A major step forward has been achieved with the introduction of pigs homozygous for α1,3-galactosyltransferase gene-knockouts that do not express the major antigenic target for primate antipig antibodies (i.e., Galα1,3Gal). Heterotopic heart transplants have survived for 2 – 6 months in baboons. However, other immune and pathophysiologic barriers remain, including: i) anti-non-Gal antibodies and cells of the innate immune system; and ii) thrombogenesis associated with incompatibilities in the coagulation–anticoagulation systems of pig and primate. Further genetic modification of the organ-source pig to overcome these barriers is being undertaken.