title: MicroRNA-221 sponge therapy attenuates neointimal hyperplasia and improves blood flows in vein grafts.
abstract: BACKGROUND
  Vein graft failure due to neointimal hyperplasia remains an important and unresolved problem of cardiovascular surgery. MicroRNA-221 (miR-221) has been shown to play a major role in regulating vascular smooth muscle cell (VSMC) proliferation and phenotype transformation. Thus, the purpose of this study is to determine whether adenovirus mediated miR-221 sponge gene therapy could inhibit vein graft neointimal hyperplasia.
  
  
  METHODS
  Adenovirus encoding miR-221 sponge (Ad-miR-221-SP) was used to inhibit VSMC proliferation in vitro and neointimal formation in vivo. Expression of miRNA-221 was evaluated in cultured VSMC and in rat vein graft models following transduction with Ad-miR-221-SP, Ad-Control-SP (without miR-221 antisense binding sites), or Ad-GFP (control). To accelerate the transfer of miR-221 sponge gene to the vein grafts, 20% poloxamer F-127 gel was used to extend virus contact time and 0.25% trypsin to increase virus penetration.
  
  
  RESULTS
  miR-221 sponges can significantly decrease the expression of miR-221 and proliferation in cultured VSMC. Cellular proliferation rates were significantly reduced in miR-221 sponge treated grafts as compared with controls at 6 weeks after bypass surgery (19.8% versus 43.6%, P=0.0028). miR-221 sponge gene transfer reduced the neointimal area (210.75 ± 24.13 versus 67.01 ± 12.02, P<0.0001), neointimal thickness (171.86 ± 27.87 versus 64.13 ± 16.23, P<0.0001) and neointima/media ratio (0.74 ± 0.21 versus 1.95 ± 0.25, P<0.0001) in vein grafts versus controls. miR-21 sponge treatment was also improved hemodynamics in vein grafts. We have further identified that p27 (Kip1) is a potential target gene of miR-221 in vein grafts.
  
  
  CONCLUSIONS
  miR-221 sponge therapy can significantly reduce miR-221 activity and inhibit neointimal hyperplasia in vein grafts. Locally adventitial delivery of adenoviruses mediated miRNA sponges may be promising gene therapies to prevent vein graft failure.
authors.affiliation: Department of Cardiothoracic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China; Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Wang
authors.affiliation: Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: He
authors.affiliation: Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; SBS Core Laboratory, CUHK Shenzhen Research Institute, Shenzhen, China.
authors.forename: Kai-Chuen
authors.initials: KC
authors.lastname: Lee
authors.affiliation: Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Huang
authors.affiliation: Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; SBS Core Laboratory, CUHK Shenzhen Research Institute, Shenzhen, China.
authors.forename: Jia-Biao
authors.initials: JB
authors.lastname: Hu
authors.affiliation: Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.affiliation: Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Xiang
authors.affiliation: Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; SBS Core Laboratory, CUHK Shenzhen Research Institute, Shenzhen, China. Electronic address: fengbo@cuhk.edu.hk.
authors.forename: Bo
authors.initials: B
authors.lastname: Feng
authors.affiliation: Department of Cardiothoracic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China. Electronic address: lzqsurgery@163.com.
authors.forename: Zhi-Qian
authors.initials: ZQ
authors.lastname: Lu
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D002478:Cells, Cultured; D015316:Genetic Therapy / Q000379:methods*; D006965:Hyperplasia / Q000235:genetics / Q000503:physiopathology / Q000628:therapy; D007601:Jugular Veins / Q000502:physiology / Q000637:transplantation*; D008297:Male; D035683:MicroRNAs / Q000008:administration & dosage* / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000502:physiology / Q000637:transplantation; D058426:Neointima / Q000235:genetics / Q000503:physiopathology / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D058017:Vascular Grafting / Q000379:methods*
chemical_list: C576526:MIRN221 microRNA, rat; D035683:MicroRNAs
keywords: Gene therapy; MicroRNA; Neointimal formation; Sponges; Vein graft disease