title: Development of a novel prohealing stent designed to deliver sirolimus from a biodegradable abluminal matrix.
abstract: BACKGROUND
  We aimed to demonstrate that, by separating endothelial progenitor cell capture from sirolimus delivery through the application of drug to the abluminal surface of the stent, the degree of endothelialization can be enhanced.
  
  
  RESULTS
  Stainless steel R Stents, with biodegradable SynBiosys polymer coating with sirolimus abluminally applied and surface modified with anti-CD34 antibody were prepared at 2 dosages (low-dose sirolimus [LD-Combo, 2.5 microg sirolimus/mm] and full-dose sirolimus [Combo, 5 microg sirolimus/mm). These Combo stents and the Cypher stent (10 microg sirolimus/mm) were deployed in 98 normal porcine arteries and harvested for pharmacokinetic analysis at 0.25, 1, 3, 7, 14, 28, and 35 days. The LD-Combo stents showed faster early release (50%total dose in 72 hours) than the Combo and Cypher. At 30 days, drug release was near complete with both Combo stents, whereas 20% of drug remained on the Cypher stents. To assess efficacy, a total of 50 stents (Xience V=8, Cypher=8, Genous bioengineered R stent=6, LD-Combo=14, and Combo=14) were implanted in 18 pigs for 14 and 28 days. Optical coherence tomography was performed, and stents were harvested for histology. At 28 days, there was less neointimal thickness with Combo (0.173+/-0.088 mm) compared with Cypher (0.358+/-0.225 mm), LD-Combo (0.316+/-0.228 mm), and Xience V (0.305+/-0.252 mm; P<0.00001). Immunohistochemical analysis of endothelialization showed that Genous bioengineered R stent had the highest degree of platelet endothelial cell adhesion molecule expression (87%) followed by the Combo (75%), LD-Combo (65%), and Cypher (58%).
  
  
  CONCLUSIONS
  Both optical coherence tomography and histology demonstrate that anti-CD34 sirolimus-eluting stents promote endothelialization while reducing neointimal formation and inflammation.
authors.affiliation: Skirball Center for Cardiovascular Research, Cardiovascular Research Foundation, New York, NY, USA. jgranada@crf.org
authors.forename: Juan F
authors.initials: JF
authors.lastname: Granada
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Inami
authors.forename: Michael S
authors.initials: MS
authors.lastname: Aboodi
authors.forename: Armando
authors.initials: A
authors.lastname: Tellez
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Milewski
authors.forename: David
authors.initials: D
authors.lastname: Wallace-Bradley
authors.forename: Sherry
authors.initials: S
authors.lastname: Parker
authors.forename: Steve
authors.initials: S
authors.lastname: Rowland
authors.forename: Gaku
authors.initials: G
authors.lastname: Nakazawa
authors.forename: Marc
authors.initials: M
authors.lastname: Vorpahl
authors.forename: Frank D
authors.initials: FD
authors.lastname: Kolodgie
authors.forename: Greg L
authors.initials: GL
authors.lastname: Kaluza
authors.forename: Martin B
authors.initials: MB
authors.lastname: Leon
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
mesh_terms: D020341:Absorbable Implants; D000418:Albumins / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry; D000792:Angiography; D000818:Animals; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D054855:Drug-Eluting Stents; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D007249:Inflammation / Q000188:drug therapy; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011108:Polymers / Q000737:chemistry; D019919:Prosthesis Implantation / Q000295:instrumentation; D020123:Sirolimus / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics; D013552:Swine
chemical_list: D000418:Albumins; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011108:Polymers; D020123:Sirolimus