title: Enhanced efficacy of sirolimus-eluting bioabsorbable magnesium alloy stents in the prevention of restenosis.
abstract: OBJECTIVE
  To determine the efficacy of sirolimus-eluting bioabsorbable magnesium alloy stents (SEBMAS) in restenosis prevention.
  
  
  METHODS
  A balloon-expandable bioabsorbable magnesium alloy stent (BMAS) was created and coated with biodegradable poly(lactic acid-co-trimethylene carbonate) that contained the antiproliferative drug sirolimus (140 ± 40 µg/cm²). Both the uncoated BMAS and the coated SEBMAS were deployed 2 cm apart in balloon-injured infrarenal abdominal aortas of 20 New Zealand white rabbits. The stented aortic segments were removed at 30, 60, 90, and 120 days (5 rabbits per interval) after implantation. The average stent strut sectional area of each group was measured to evaluate the degree of magnesium corrosion and to forecast the biodegradation time profile of the magnesium stent. Histology and histopathology of the sectioned stented aortic segments were performed to evaluate neointima formation, endothelialization, and inflammation.
  
  
  RESULTS
  The SEBMAS degraded gradually after being implanted into the rabbit aorta, and total biocorrosion occurred after ~120 days. In all groups, the lumen area was significantly greater, but the neointimal area was significantly smaller in SEBMAS segments compared with the uncoated BMAS segments (p < 0.05) at all time points. There was no significant difference in the injury or inflammation scores between the groups. Endothelialization was delayed at 30 days in the SEBMAS segments vs. the uncoated BMAS segments.
  
  
  CONCLUSIONS
  SEBMAS further reduces intimal hyperplasia and improves the lumen area when compared to uncoated BMAS; however, it delays vascular healing and endothelialization.
authors.affiliation: Department of Radiology, First Affiliated Hospital of China Medical University, Key Laboratory of Diagnostic Imaging and Interventional Radiology, Liaoning Province.
authors.forename: Haiwei
authors.initials: H
authors.lastname: Li
authors.forename: Hongshan
authors.initials: H
authors.lastname: Zhong
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Ke
authors.initials: K
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Bingchun
authors.initials: B
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Zheng
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Xia
authors.forename: Lili
authors.initials: L
authors.lastname: Tan
authors.forename: Duo
authors.initials: D
authors.lastname: Hong
mesh_terms: D000497:Alloys; D017130:Angioplasty / Q000295:instrumentation*; D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology*; D001018:Aortic Diseases / Q000209:etiology / Q000473:pathology / Q000628:therapy*; D001157:Arterial Occlusive Diseases / Q000209:etiology / Q000473:pathology / Q000628:therapy*; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible; D003251:Constriction, Pathologic; D004146:Dioxanes; D004195:Disease Models, Animal; D054855:Drug-Eluting Stents; D042783:Endothelial Cells / Q000473:pathology; D006965:Hyperplasia; D019344:Lactic Acid; D008274:Magnesium; D008297:Male; D011091:Polyesters; D011108:Polymers; D011474:Prosthesis Design; D011817:Rabbits; D055502:Secondary Prevention; D020123:Sirolimus / Q000008:administration & dosage*; D013997:Time Factors; D014945:Wound Healing
chemical_list: D000497:Alloys; D002317:Cardiovascular Agents; D020099:Coated Materials, Biocompatible; D004146:Dioxanes; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C443643:trimethylene carbonate; C033616:poly(lactide); D008274:Magnesium; D020123:Sirolimus