title: Biocompatibility of new drug-eluting biodegradable urethral stent materials.
abstract: OBJECTIVE
  To investigate the effects of biodegradable stent material (poly-96L/4D-lactic acid [PLA]) on the production of cytokines and other inflammatory mediators in vitro and the biocompatibility of new drug-eluting biodegradable urethral stent materials in vivo. Indomethacin, dexamethasone, and simvastatin were used in the materials.
  
  
  METHODS
  The effects of the biodegradable stent material on cytokines and other inflammatory mediators were measured using the Human Cytokine Antibody Array and enzyme-linked immunosorbent assay in THP-1 cells, with bacterial lipopolysaccharide as a positive control. To assess the biocompatibility of the stent materials, we used muscle implantation. Biodegradable stent materials without drug-eluting properties and silicone and latex were used as controls. The measurements were done at 3 weeks and 3 months.
  
  
  RESULTS
  The PLA stent material induced production of inflammatory mediators, especially interleukin-8, tumor necrosis factor-alpha, and transforming growth factor-beta, in vitro. The increase in the production of these mediators with the PLA stent material was smaller than in the cells treated with lipopolysaccharide. In vivo, the effects of the biodegradable materials did not differ at 3 weeks, although, at 3 months, dexamethasone had induced more tissue reactions than had the other materials. At 3 months, fibrosis and chronic inflammatory changes were decreased in the biodegradable material groups compared with the positive control.
  
  
  CONCLUSIONS
  PLA stent material increased the production of cytokines and other inflammatory mediators less than did positive controls in vitro. The in vivo biocompatibility of the drug-eluting biodegradable materials was better than that of the positive controls. Drug-eluting biodegradable urethral stents could potentially offer a new treatment modality in the future.
authors: Department of Urology, Tampere University Hospital, Tampere, Finland. andres.kotsar@uta.fi
authors: Andres
authors: A
authors: Kotsar
authors: Riina
authors: R
authors: Nieminen
authors: Taina
authors: T
authors: Isotalo
authors: Joonas
authors: J
authors: Mikkonen
authors: Ilkka
authors: I
authors: Uurto
authors: Minna
authors: M
authors: Kellomäki
authors: Martti
authors: M
authors: Talja
authors: Eeva
authors: E
authors: Moilanen
authors: Teuvo L J
authors: TL
authors: Tammela
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002478:Cells, Cultured; D054855:Drug-Eluting Stents; D006801:Humans; D008297:Male; D008422:Materials Testing; D011817:Rabbits; D014521:Urethra / Q000601:surgery*