Xenotransplantation using pig organs as source for transplant has the potential to overcome
the severe shortage of human donor organs. Wide utilization of genetically-engineered pigs is enabling
progress to be made in pig-to-nonhuman primate experimental models. Novel, non-nephrotoxic
immunosuppressive regimens have largely overcome T cell rejection and a T cell-dependent elicited
antibody response. Recent advances in understanding of the biology of xenograft rejection and zoonotic
infections and the generation of alpha1,3-galactosyltransferase-gene knockout pigs have moved this
approach closer to the clinical application. However, inter-species coagulation dysregulation is proving
a major hurdle. Progress in islet xenotransplantation has been more encouraging controlling diabetes in
nonhuman primates up to 6 months, though this has usually been achieved using immunosuppressive
protocols that might not be clinically applicable. Further advances are required to overcome the
remaining barriers.
Keywords: Xenotransplantation, Coagulation Dysregulation, Pig, Genetically-Engineered, Nonhuman
Primate, Tolerance, Knock-Out, Hyperacute Rejection, Immunosuppression, Xenozoonosis.
