Hepatic regeneration in living donor liver transplantation

Key Points 1. Active hepatocyte replication occurs after cadaveric transplantation to replace cells lost to ischemic and immunologic damage. Significantly more regeneration is also required after adult-to-adult living donor transplantation because of the small size of the graft. 2. The molecular mechanisms initiating regeneration are well described in animal models, which include priming with cytokines, activation of transcription factors, and expression of immediate early genes, which then cause the hepatocyte to progress through the cell cycle. 3. Certain factors have been shown to affect liver regeneration and recovery. These include ischemic injury, graft size, immunosuppression, steatosis, and donor age. Other factors that have been implicated are venous flow and gender. 4. Active regeneration in the living donor setting may affect other processes, including viral replication, the allo-immune response, drug metabolism, and recurrent hepatocellular carcinoma. More investigation is needed in these areas. Adult-to-adult living donor transplantation provides a unique opportunity to study human liver regeneration and return of normal liver function after resection.