The modern era of whole organ transplantation began in 1962, when drugs were used in combination to treat patients after the technically easy operation of kidney transplantation. The simple kidney model continued for a long time to be the front-runner for advances in the four key elements of clinical transplantation, which could then be applied with minor adaptations for the extrarenal organs. The elements are (1) preservation, (2) tissue matching, (3) immunosuppression, and (4) surgical technique. This orderly progression changed within the last 10 years when the liver emerged as a focal organ of scientific inquiry.
For example, the liver has been central in testing better techniques of "slush" preservation. Such methods were introduced more than two decades ago, using a potassium-rich electrolyte solution or a plasmalike solution to cool kidneys by intra-arterial infusion, followed by refrigeration in an ice chest. Cadaveric kidneys could be cooled in this way for