Xenotransplantation: animal rights and human wrongs.

The first successful human-to-human organ transplant was performed in 1954 when a kidney was transferred between two identical twins. In the years since this groundbreaking operation improvements in transplant surgery and an increasing ability to control organ rejection using imunosupressive medication has made transplantation the treatment of choice for a new generation. Unfortunately, these advancements have resulted in transplantation becoming a victim of its own success, as waiting lists have increased along with the waiting time for donor organs. For these reasons the use of animal organs for human transplantation is seriously being considered. Two groups of animals have been considered as donors: non-human primates and large non-primates such as pigs. Whilst many researchers in this field are very optimistic about the future, many opponents are concerned about the effects on public health and the environment. The primary barrier to transplantation is immunological rejection. With xenotransplantation an additional mechanism of rejection called hyperacute rejection occurs. Immunosuppressive drugs cannot control hyperacute rejection. For this reason, the majority of xenotransplantation trials attempted to date in humans have used chimpanzee or baboon organs. However, the problem will occur with xenotransplantation into humans of organs from more distantly related species such a pigs. This article highlights the ethical issues associated with the use of animal organs, and the impact of xenotransplantation on animal communities.