The pig is currently regarded as the most suitable source of organs for future xenotransplantation into man for several reasons. First, this species has many anatomical and physiological similarities with man. Second, the pig has a short gestation period (around 115 days) and produces large litters, of 10 offspring or more, that grow rapidly to the size necessary for xenografting into human adults. Third, pigs can easily be bred under qualified pathogen-free conditions, such that the majority of zoonotic agents can be eliminated. Fourth, this animal is widely used for food. In this respect, it is worth mentioning that approximately 90 million pigs are reared and slaughtered each year in the United States to provide meat and other products. Therefore, as a source of organs for clinical purposes, the pig carries fewer ethical objections than the use of non-human primates. On the ethical issues surrounding xenotransplantation, a recent enquiry by the Nuffield Council on Bioethics (an independent body that analyses the ethical issues raised by new developments in medicine and biology), concluded in 1996 that "the use of genetically modified pigs for the routine supply of organs for xenotransplantation is ethically acceptable".
Given these considerations, a consensus has developed in the scientific community working in this field, that the pig is the preferred donor species for future clinical xenotransplantation. |