The plastic cellular states of liver cells

Adult liver cells have been considered restricted regarding their fate and lineage potential. That is, hepatocytes have been thought able only to generate hepatocytes and duct cells only duct cells. While this may be the case for the majority of scenarios in states of quiescence or homeostasis, evidence suggests that liver cells are capable of interconverting between cellular states of distinct phenotypic traits. This interconversion or plasticity, had been suggested by classical studies using cellular markers but recently, lineage tracing approaches have proven that cells are highly plastic and retain an extraordinary ability to respond differently to normal tissue homeostasis, tissue repair or when challenged to expand ex vivo or to differentiate upon transplantation. Stemness, as "self-renewal and multipotency", seems not to be limited to a particular cell type but rather to a cellular state in which cells exhibit a high degree of plasticity and can move back and forth in different phenotypic states. For instance, upon damage cells can de-differentiate to acquire stem cell potential that allows them to self-renew, repopulate a damaged tissue and then be able to undergo differentiation. In this review, we will discuss the evidence on cellular plasticity in the liver focusing our attention on two markers, EpCAM and Lgr5, which identify cells with stem cell potential. This article is protected by copyright. All rights reserved.