title: Outside stenting of the vein graft decreases VEGF-A expression and induces significant down-regulation of VEGFR-1 in the intimal and medial layers after the re-endothelialization period.
abstract: BACKGROUND
  Neointimal hyperplasia (NIH) in vein grafts implanted into the arterial system develops after re-endothelialization and is considered a significant risk factor of occlusion. Evidence suggests that VEGF-A expression with VEGFR-2 activation and/or VEGFR-1 down-regulation might be involved in inhibiting NIH formation. The aim was to assess whether a stented vein graft (SV) has an impact on VEGF-A and VEGFR-1 expression compared with non-stented vein grafts.
  
  
  METHODS
  Twelve sheep received a radial vein with an outside stent (SV) and a radial vein (RV) transplanted into their carotid arteries. The covering of the luminal surface of the SV and RV grafts by endothelium was 98.3% and 96.3%, respectively, at 6 weeks. From the 6th to 12th weeks after transplantation, the time course of total VEGF-A expression and VEGFR-1 expression were evaluated separately for the intima and media.
  
  
  RESULTS
  VEGF-A and VEGFR-1 expression were significantly lower in the SV than in the RV group in the intima. In the media the SV grafts were associated with higher VEGF-A and VEGFR-1 expression at 6 and 8 weeks, but lower values were observed at weeks 10 and 12 compared with the RV grafts. Comparing the time courses of VEGF-A and VEGFR-1 expression in the intima and media with intimal/medial thickening in the SV and RV groups, negative correlations for the SV grafts were found.
  
  
  CONCLUSIONS
  These findings indicate that outside stenting of the vein graft decreases VEGF-A expression and induces significant down-regulation of VEGFR-1 in the intima and media after the re-endothelialization.
authors.affiliation: 1st Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Krejca
authors.forename: Andrzej
authors.initials: A
authors.lastname: Plewka
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Szmagala
authors.forename: Danuta
authors.initials: D
authors.lastname: Plewka
authors.forename: Grazyna
authors.initials: G
authors.lastname: Nowaczyk
authors.forename: Janusz
authors.initials: J
authors.lastname: Skarysz
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Bialek
authors.forename: Michal
authors.initials: M
authors.lastname: Guc
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bochenek
mesh_terms: D000818:Animals; D001807:Blood Vessel Prosthesis; D049109:Cell Proliferation; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology*; D008297:Male; D012756:Sheep; D015607:Stents; D013997:Time Factors; D017539:Tunica Intima / Q000378:metabolism / Q000473:pathology*; D017540:Tunica Media / Q000378:metabolism / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism*; D014680:Veins / Q000378:metabolism / Q000473:pathology
chemical_list: D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1