[Ethical aspects of xenotransplantation]

The motivation for research on animals as a source of cells, tissues and organs for human transplantation (xenotransplantation) is the scarcity of suitable donors for patients with end-stage organ failure. Use of animals in both experimental and clinical settings raise considerable ethical concerns, especially when non-human primates are used. The pig may represent an acceptable source animal for xenotransplantation and is today regarded as the animal of choice. Xenotransplantation seems defensible from an ethical perspective, but should not be performed in humans until preclinical animal-to-animal xenotransplantations have a predictable rate of success and the risk to society at large is negligible. For the individual patient and his or her next of kin involved, issues of autonomy and proper consent procedures must be given high priority. Safeguards must be established, for the patient and for society at large, in relation to health hazards from infectious organisms, particularly retroviruses. Public monitoring of research on and clinical use of xenotransplantation is mandatory.