New technologies for organ replacement and augmentation.

The most common causes of disability and death are diseases of the heart, lungs, liver, kidneys, and pancreas, many of which are potentially treated by organ transplantation. The effect of organ dysfunction and failure will likely grow over time, and patients will increasingly expect "safer" transplants, in particular in cases of "preemptive transplantation." New technologies are being developed in part because of the limited availability of organs, and include transplantation with stem cells, tissue engineering, cloning, and xenotransplantation, which some researchers believe promise ready solutions. Although exciting, none of these approaches alone is likely to address the need for organ replacement. We propose that a melding of these new technologies adapted to the distinct challenges and imperatives of the various organs may address this daunting challenge.