title: Portal fibroblasts: Underappreciated mediators of biliary fibrosis.
abstract: Portal fibroblasts are an important yet often overlooked nonparenchymal cell population in the liver. They are distinct from hepatic stellate cells, yet like stellate cells differentiate in the setting of chronic injury to fibrogenic myofibroblasts, playing an important role in collagen production in the fibrotic liver. Portal fibroblasts (PFs) are located adjacent to bile duct epithelia and thus play a particularly significant role in biliary fibrosis. New data suggest that they may also have key functions independent of fibrogenesis. This review addresses the definition and characteristics of PFs as well as their signaling pathways, interactions with the biliary epithelium, and contributions to liver pathobiology.
  
  
  CONCLUSIONS
  PFs are an important and multifunctional nonparenchymal cell population in need of further study.
authors.affiliation: Section of Digestive Diseases, Department of Medicine, Yale University School of Medicine, New Haven, CT, USA. jonathan.dranoff@yale.edu
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Dranoff
authors.forename: Rebecca G
authors.initials: RG
authors.lastname: Wells
mesh_terms: D000818:Animals; D002450:Cell Communication; D002454:Cell Differentiation; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000209:etiology*; D011168:Portal System / Q000473:pathology*; D015398:Signal Transduction