title: Silver-nanoparticle-coated biliary stent inhibits bacterial adhesion in bacterial cholangitis in swine.
abstract: BACKGROUND
  One of the major limitations of biliary stents is the stent occlusion, which is closely related to the over-growth of bacteria. This study aimed to evaluate the feasibility of a novel silver-nanoparticle-coated polyurethane (Ag/PU) stent in bacterial cholangitis model in swine.
  
  
  METHODS
  Ag/PU was designed by coating silver nanoparticles on polyurethane (PU) stent. Twenty-four healthy pigs with bacterial cholangitis using Ag/PU and PU stents were randomly divided into an Ag/PU stent group (n=12) and a PU stent group (n=12), respectively. The stents were inserted by standard endoscopic retrograde cholangiopancreatography. Laboratory assay was performed for white blood cell (WBC) count, alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) at baseline time, 8 hours, 1, 2, 3, and 7 days after stent placements. The segment of bile duct containing the stent was examined histologically ex vivo. Implanted biliary stents were examined by a scan electron microscope. The amount of silver release was also measured in vitro.
  
  
  RESULTS
  The number of inflammatory cells and level of ALT, IL-1beta and TNF-alpha were significantly lower in the Ag/PU stent group than in the PU stent group. Hyperplasia of the mucosa was more severe in the PU stent group than in the Ag/PU stent group. In contrast to the biofilm of bacteria on the PU stent, fewer bacteria adhered to the Ag/PU stent.
  
  
  CONCLUSIONS
  PU biliary stents modified with silver nanoparticles are able to alleviate the inflammation of pigs with bacterial cholangitis. Silver-nanoparticle-coated stents are resistant to bacterial adhesion.
authors.affiliation: Department of Digestive Endoscopy Center, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China. fanzhining@njmu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Tang
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Zhi-Ning
authors.initials: ZN
authors.lastname: Fan
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001422:Bacterial Adhesion / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D015415:Biomarkers / Q000097:blood; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000295:instrumentation*; D002761:Cholangitis / Q000097:blood / Q000175:diagnosis / Q000382:microbiology / Q000628:therapy*; D020099:Coated Materials, Biocompatible; D016207:Cytokines / Q000097:blood; D004195:Disease Models, Animal; D005240:Feasibility Studies; D018836:Inflammation Mediators / Q000097:blood; D053758:Nanoparticles; D011140:Polyurethanes; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012834:Silver / Q000008:administration & dosage*; D015607:Stents / Q000382:microbiology*; D013552:Swine; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D020099:Coated Materials, Biocompatible; D016207:Cytokines; D018836:Inflammation Mediators; D011140:Polyurethanes; D012834:Silver; D000410:Alanine Transaminase