title: Polymer stent coating for prevention of neointimal hyperplasia.
abstract: OBJECTIVE
  Restenosis has been the principal limitation of bare metal stents. Based upon the presumption that platelet and inflammatory cell recruitment initiate neointimal proliferation, we explored a novel polymer coating that reduces cell-stent interactions. The purpose of the present study was to investigate the effect of poly(L-lysine)-graft-poly(ethyleneglycol) (PLL-g-PEG) adsorbed to stent surfaces to reduce neointimal hyperplasia in the porcine restenosis model.
  
  
  RESULTS
  Seven animals were instrumented each with 2 stainless steel stents (15 mm length, 2.5-3.5 mm diameter), randomly implanted in 1 major epicardial coronary artery. One stent was dip-coated with PLL-g-PEG, whereas the other stent served as the uncoated control stent. All animals were sacrificed after 6 weeks for histological examination. Neointimal hyperplasia was significantly less (-51%) in the PLL-g-PEG-coated stents (1.15 +/- 0.59 mm2) than in the uncoated control stents (2.33 +/- 1.01 mm2; p < 0.001). Conversely, lumen size was larger in the PLL-g-PEG-coated stents (2.91 +/- 1.17 mm2) than in the uncoated stents (2.04 +/- 0.64 mm2; p < 0.001). High magnification histomorphologic examination revealed no signs of inflammation or thrombus formation in either stent group.
  
  
  CONCLUSIONS
  Polymeric steric stabilization of stents with PLL-g-PEG significantly reduces neointimal hyperplasia in the porcine restenosis model. Reduction of cell-stent interactions mediated by PLL-g-PEG appear to improve biocompatibility of stainless steel stents without evidence of adverse inflammatory or prothrombotic effects.
authors.affiliation: Department of Cardiology, University Hospital Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Billinger
authors.forename: Felix
authors.initials: F
authors.lastname: Buddeberg
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hubbell
authors.forename: Donald L
authors.initials: DL
authors.lastname: Elbert
authors.forename: Thomas
authors.initials: T
authors.lastname: Schaffner
authors.forename: Daniel
authors.initials: D
authors.lastname: Mettler
authors.forename: Stephan
authors.initials: S
authors.lastname: Windecker
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meier
authors.forename: Otto M
authors.initials: OM
authors.lastname: Hess
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation / Q000379:methods; D000818:Animals; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000627:therapeutic use*; D023903:Coronary Restenosis / Q000209:etiology / Q000517:prevention & control / Q000628:therapy*; D003328:Coronary Thrombosis / Q000517:prevention & control; D004195:Disease Models, Animal; D005260:Female; D006965:Hyperplasia / Q000150:complications / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000627:therapeutic use*; D011107:Polylysine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015607:Stents / Q000009:adverse effects; D013552:Swine; D017539:Tunica Intima / Q000473:pathology*
chemical_list: D020099:Coated Materials, Biocompatible; C443714:polylysine-graft-(poly(ethylene glycol)); D011107:Polylysine; D011092:Polyethylene Glycols