title: Biodegradable rapamycin-eluting nano-fiber membrane-covered metal stent placement to reduce fibroblast proliferation in experimental stricture in a canine model.
abstract: OBJECTIVE
  The aim of the current study was to assess whether placement of the biodegradable rapamycin-eluting nano-fiber membrane-covered metal stent is followed by less fibroblast proliferation and tissue hyperplasia compared with bare stents in experimental stricture in a dog model.
  
  
  METHODS
  A total of 80 dog models of stricture were randomly divided into a control group (n = 20, no stent insertion), a bare stent group (BSG, n = 20, 1-week retention), and two drug-eluting stent sub-groups (DESG-1w, n = 20, 1-week retention; DESG-4w, n = 20, 4-week retention). Lower esophageal sphincter (LES) pressure, 5-minute barium height (5-mBH), and cardia diameter were assessed before, immediately after the procedure, and regularly thereafter for 6 months. Five dogs in each group were euthanized for histological examination at each follow-up assessment.
  
  
  RESULTS
  Stent insertion was well tolerated, with similar migration rates (0 % in BSG vs. 7.5 % in DESGs; P = 0.5441). At 6 months, LES pressure and 5-mBH improved in DESG-1w (26.70 ± 5.02 mmHg and 6.50 ± 2.98 cm) and DESG-4w (20.16 ± 5.50 mmHg and 1.54 ± 0.98 cm) compared with BSG (39.94 ± 5.22 mmHg and 11.1 ± 5.46 cm) (P < 0.05), with DESG-4w being more stable than DESG-1w (P < 0.05). The cardia maintained greater patency in the DESGs (7.10 ± 3.09 mm in DESG-1w; 9.16 ± 3.77 mm in DESG-4w) than in the BSG (1.86 ± 2.45 mm; P < 0.05). Reduced peak inflammatory reactions and scarring occurred in DESGs compared with the BSG (P < 0.05), with a better outcome in DESG-4w than in DESG-1w (P < 0.05).
  
  
  CONCLUSIONS
  In this experimental stricture model, rapamycin-eluting stents were more effective than bare stents for the reduction of fibroblast proliferation and tissue hyperplasia after stent placement. Furthermore, 4-week retention of the drug-eluting stent led to a better outcome than 1-week retention.
authors.affiliation: Department of Radiology, The Sixth Affiliated People's Hospital, Medical school of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Zhu
authors.forename: W G
authors.initials: WG
authors.lastname: Cui
authors.forename: Y S
authors.initials: YS
authors.lastname: Cheng
authors.forename: J
authors.initials: J
authors.lastname: Chang
authors.forename: N W
authors.initials: NW
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Yan
authors.forename: M H
authors.initials: MH
authors.lastname: Li
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002299:Cardia / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects*; D003251:Constriction, Pathologic / Q000139:chemically induced / Q000628:therapy; D004195:Disease Models, Animal; D004285:Dogs; D054855:Drug-Eluting Stents; D049630:Esophageal Sphincter, Lower / Q000473:pathology* / Q000503:physiopathology; D004940:Esophageal Stenosis / Q000473:pathology / Q000628:therapy*; D005260:Female; D005347:Fibroblasts / Q000502:physiology*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008297:Male; D008365:Manometry; D057139:Nanofibers; D011312:Pressure; D011897:Random Allocation; D020123:Sirolimus / Q000494:pharmacology*
chemical_list: D007166:Immunosuppressive Agents; D020123:Sirolimus