Background

Hepatic stellate cells (HSC) have recently been identified as liver-resident mesenchymal stem cells and are thought to contribute to liver repair and fibrogenesis [1]. Quiescent HSC are located in the space of Disse and store vitamin A in characteristic lipid droplets. During their activation HSC lose their vitamin A stores and adopt a myofibro-blast-like phenotype. This activation of HSC is necessary to enable hepatic differentiation and is accompanied by changes in the expression of many genes such as extracel-lular matrix protein encoding genes [2]. Some of these genes like Notch1 and Notch3 are regulated by epigenetic mechanisms. Their expression depends on the promoter DNA methylation and is changed during HSC activation [3]. The aim of the present study is a comprehensive ana-lysis of DNA methylation alterations during HSC activa