The authors of this review outline recent progress and the future potential of xenotransplantation - the use of animal organs, tissues or cells in humans. The review draws particular attention to preclinical models of transplantation from pigs to non-human primates. The following topics are discussed:

• Introduction
• Pig organs
• Pancreatic islets from pigs
• Pig neuronal cells
• Pig hepatocytes
• Pig corneas
• Pig red blood cells
• Strategies to resolve the remaining barriers
• Coagulation dysfunction
• T-cell response
• Physiology
• Safety
• Regulatory, legal, and ethical issues