title: Stent-based tempamine delivery on neointimal formation in a porcine coronary model.
abstract: BACKGROUND
  Tempamine is one of new class of antioxidant agents, the nitroxides, which have shown a wide range of biological effects like suppressing free radical driven reactions to maintain cell functions. The objectives of this study were to evaluate the effect of a biodegradable polymer coated stent loaded with tempamine on in-stent neointimal formation.
  
  
  METHODS
  Stainless steel stents were dip coated in biodegradable elastomeric poly (ester-amide) (co-PEA) or in polymer solution mixed with 50% (wt%) and 100% (wt%) tempamine. One group 100% (wt%) tempamine loaded stents were further dip coated in co-PEA polymer to form a top layer. Stainless steel bare, polymer-only, and different doses tempanine coated stents were implanted into porcine coronary arteries with a stent to artery ratio 1.2:1. Histomorphometric analysis was performed at 5 days and 6 weeks respectively.
  
  
  RESULTS
  Histomorphometric analysis showed that the bare, polymer-only and tempamine-coated stents elicited a similar tissue response at 5 days. At 6 weeks, the peri-strut inflammation and neointimal hyperplasia of polymer-only stents were comparable to the bare stents. Compared to the bare stents, 50% tempanine coated stents had a trend to decrease the arterial injury (0.62 +/- 0.41 versus 0.34 +/- 0.18, P = 0.075) and neointimal hyperplasia (1.80 +/- 0.77 versus 1.27 +/- 0.39 mm2, P = 0.085). However, 100% tempanine coated showed significantly increased inflammatory response and neointimal formation.
  
  
  CONCLUSIONS
  These co-PEA polymer coatings showed a biocompatible performance. Loaded with 50% tempamine had a trend to decrease neointimal hyperplasia. The 100% tempamine for stent-based delivery may have potential cytotoxic effects to arterial wall. Using a co-PEA polymer topcoat could effectively abolish these side effects.
authors.affiliation: Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland 44195, USA. huangy@ccf.org
authors.forename: Yanming
authors.initials: Y
authors.lastname: Huang
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
authors.forename: Shengqiao
authors.initials: S
authors.lastname: Li
authors.forename: Xiaoshun
authors.initials: X
authors.lastname: Liu
authors.forename: Kwangdeok
authors.initials: K
authors.lastname: Lee
authors.forename: Eric
authors.initials: E
authors.lastname: Verbeken
authors.forename: Frans
authors.initials: F
authors.lastname: van de Werf
authors.forename: Ivan
authors.initials: I
authors.lastname: de Scheerder
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D020099:Coated Materials, Biocompatible; D003497:Cyclic N-Oxides / Q000008:administration & dosage / Q000494:pharmacology*; D016503:Drug Delivery Systems; D008855:Microscopy, Electron, Scanning; D011108:Polymers; D013193:Stainless Steel; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000187:drug effects*
chemical_list: D020099:Coated Materials, Biocompatible; D003497:Cyclic N-Oxides; D011108:Polymers; D013193:Stainless Steel; C015527:4-amino-TEMPO