Transplanted hepatocytes: Wiped out or washed out?

Hope for the long-term effectiveness of hepatocyte transplantation (HTx) for metabolic liver disease in pediatric patients is based on the premise that hepatocytes in the main constitute a static population, quite unlike for example, the small bowel where there is constant turnover. However, several recent studies on the dynamics of hepatocyte turnover raise important questions about the long-term success of HTx. For example, a recent lineage tracing study in the mouse has demonstrated that, within a year, almost the total parenchymal population is replaced by new hepatocytes differentiating from Sox9-expressing interlobular bile ducts [1,2], suggesting that transplanted hepatocytes will inevitably be ‘washed out’ of the liver within the turnover time – in about 1year in the mouse.