title: Biodegradable biliary stents have a different effect than covered metal stents on the expression of proteins associated with tissue healing in benign biliary strictures.
abstract: BACKGROUND
  Benign biliary strictures (BBS) are primarily treated endoscopically with covered self-expandable metal stents (CSEMS). Biodegradable biliary stents (BDBS) may be the future of endoscopic therapy of BBS. The aim was to assess the expression of proteins related to tissue healing in BBS compared with the intact bile duct (BD), and to study the protein expression after therapy with CSEMS or BDBS.
  
  
  METHODS
  Pigs with ischemic BBS were endoscopically treated either with BDBS or CSEMS. Samples were harvested from pigs with intact BD (n = 5), untreated BBS (n = 5), and after six months of therapy with BDBS (n = 4) or CSEMS (n = 5) with subsequent histologic analysis. Two-dimensional electrophoresis with protein identification was performed to evaluate protein expression patterns.
  
  
  RESULTS
  In BBS, the expression of galectin-2 and annexin-A4 decreased, compared to intact BD. Treatment with biodegradable stents normalized galectin-2 level; with CSEMS therapy it remained low. Transgelin expression of intact BD and BBS remained low after BDBS treatment but increased after CSEMS therapy. Histologic analysis did not show unwanted foreign body reaction or hyperplasia in the BD in either group.
  
  
  CONCLUSIONS
  The expression of proteins related to tissue healing in BBS is different after treatment with biodegradable stents and CSEMS. Treatment with biodegradable stents may bring protein expression towards what is seen in intact BD. BDBS seem to have a good biocompatibility.
authors.affiliation: a Department of Gastroenterology and Alimentary Tract Surgery , Tampere University Hospital , Tampere , Finland ;
authors.forename: Antti
authors.initials: A
authors.lastname: Siiki
authors.affiliation: b Department of Medicine II , University of Heidelberg , Mannheim , Germany ;
authors.forename: Ralf
authors.initials: R
authors.lastname: Jesenofsky
authors.affiliation: c Karolinska University Hospital, Gastrocentrum , Huddinge , Sweden ;
authors.forename: Matthias
authors.initials: M
authors.lastname: Löhr
authors.affiliation: a Department of Gastroenterology and Alimentary Tract Surgery , Tampere University Hospital , Tampere , Finland ;
authors.forename: Isto
authors.initials: I
authors.lastname: Nordback
authors.affiliation: d Biomaterials and Tissue Engineering Group, BioMediTech and Department of Electronics and Communications Engineering , Tampere University of Technology , Tampere , Finland ;
authors.forename: Minna
authors.initials: M
authors.lastname: Kellomäki
authors.affiliation: e Department of Clinical Physiology and Nuclear Medicine , Kuopio University Hospital , Kuopio , Finland.
authors.forename: Heidi
authors.initials: H
authors.lastname: Gröhn
authors.affiliation: d Biomaterials and Tissue Engineering Group, BioMediTech and Department of Electronics and Communications Engineering , Tampere University of Technology , Tampere , Finland ;
authors.forename: Joonas
authors.initials: J
authors.lastname: Mikkonen
authors.affiliation: a Department of Gastroenterology and Alimentary Tract Surgery , Tampere University Hospital , Tampere , Finland ;
authors.forename: Juhani
authors.initials: J
authors.lastname: Sand
authors.affiliation: a Department of Gastroenterology and Alimentary Tract Surgery , Tampere University Hospital , Tampere , Finland ;
authors.forename: Johanna
authors.initials: J
authors.lastname: Laukkarinen
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001652:Bile Ducts; D001660:Biliary Tract Diseases / Q000601:surgery; D001672:Biocompatible Materials; D015180:Electrophoresis, Gel, Two-Dimensional; D011506:Proteins / Q000032:analysis*; D000069322:Self Expandable Metallic Stents; D013552:Swine; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D011506:Proteins
keywords: Biliary; ERCP (endoscopic retrograde cholangio-pancreatography); bioabsorbable; biodegradable; stent; stricture