News of the first transplant of a pig’s heart into a human was widely reported last week, raising hope that the procedure could one day help alleviate the shortage of organs. In decades of experimentation with xenotransplantation, the transplantation of organs from one species to another, no human recipient of a nonhuman organ has survived for more than a few months. Most have died within hours or days from rejection, infection, or both. Like the recipient of the pig’s heart, many previous patients were dying and were not eligible for an organ transplant through conventional channels. But before we forge ahead with clinical trials of xenotransplantation we should be concerned about several issues: the potential to spread pathogens, exploitation of human research participants, and animal welfare.
Early research on xenotransplantation used organs from monkeys and chimpanzees, who are the closest phylogenetic and evolutionary relatives to humans. That research ended because of concerns about the transmission of pathogens, including retroviruses, some of which are readily transmitted from nonhuman primates to humans. The U.S. Food and Drug Administration effectively banned the... see more