Cellular and stromal components of an activated hepatic progenitor cell niche in dog and cat. Immunofluorescent double stainings of liver sections of canine chronic hepatitis and feline chronic neutrophilic cholangitis. PanCK or K19 was used as a marker for HPCs, activated stellate cells are visualized using αSMA staining and macrophages using MAC387 staining. Nuclei were counterstained with DAPI (blue). In canine and feline liver disease there is clear colocalization of activated HPCs with hepatic stellate cells, macrophages and laminin. [53, Unpublished observations section: Valtolina et al.].