title: Tissue hyperplasia: influence of a paclitaxel-eluting covered stent--preliminary study in a canine urethral model.
abstract: OBJECTIVE
  To evaluate a paclitaxel-eluting covered stent in reduction of tissue hyperplasia after stent placement in a canine urethral model.
  
  
  METHODS
  Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. Twenty paclitaxel-eluting polyurethane-covered stents (drug stents) and 20 polyurethane-covered stents (control stents) were placed alternately between the proximal and distal urethra in 20 male dogs. The dose of paclitaxel was approximately 1800 mug in each drug stent but absent in each control stent. Dogs were sacrificed either 4 (n = 10) or 8 (n = 10) weeks after stent placement. The percentage diameter of stenosis was assessed with follow-up retrograde urethrography and histologic findings obtained after sacrifice and compared between drug stents and control stents and between the proximal and the distal urethra.
  
  
  RESULTS
  Two drug stents partially migrated during retrograde urethrography immediately after stent placement; they were removed and replaced with a second stent during the same procedure. There was a strong tendency toward a lower percentage diameter of stenosis and numeric mean values of the four histologic findings, which indicates less formation of tissue hyperplasia in the proximal urethra than in the distal urethra. In particular, thickness of the papillary projection denoting the entire thickness of hyperplastic reaction was significantly less in drug stents than in control stents in the proximal urethra in the 8-week group (P = .016, Mann-Whitney U test).
  
  
  CONCLUSIONS
  Local delivery of paclitaxel via covered stents has the potential to reduce tissue hyperplasia secondary to stent placement in a canine urethral model. With stent placement, there are distinct differences of tissue hyperplasia between the proximal and distal urethra.
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Shin
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Song
authors.forename: Choong Gon
authors.initials: CG
authors.lastname: Choi
authors.forename: Soon Hong
authors.initials: SH
authors.lastname: Yuk
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Young Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Chang Jin
authors.initials: CJ
authors.lastname: Yoon
authors.forename: Tae-Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Ji-Yeon
authors.initials: JY
authors.lastname: Suh
authors.forename: Xu
authors.initials: X
authors.lastname: He
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage*; D004285:Dogs; D006965:Hyperplasia; D008297:Male; D017239:Paclitaxel / Q000008:administration & dosage*; D015607:Stents / Q000009:adverse effects; D014521:Urethra / Q000187:drug effects / Q000473:pathology*; D014525:Urethral Stricture / Q000188:drug therapy
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D017239:Paclitaxel