title: Effective silencing of adhesion molecules on venous endothelial cells for protection of venous bypass grafts.
abstract: OBJECTIVE
  The patency of venous conduits after aortocoronary bypass grafting is still not satisfactory and needs to be improved. Atherosclerotic alterations mediated by adhesion molecules triggering the transmigration of leukocytes are regarded as one of the major causes for venous graft failure. This study deals with short interfering RNA (siRNA)-mediated silencing of adhesion molecule expression on venous endothelial cells, which could lead to a new therapeutic strategy, resulting in improved patency rates by inhibiting early graft alterations.
  
  
  METHODS
  Primary human venous endothelial cells (HVECs) were cultured in a newly developed perfusion model and subsequently transfected with specific siRNAs targeting three different adhesion molecules (the E-selectin (ESELE), the intercellular adhesion molecule 1 (ICAM-1), and the vascular adhesion molecule (VCAM-1)), followed by stimulation with tumor necrosis factor-alpha (TNF-α). Isolated leukocytes were perfused under physiological shear stress conditions, and their attachment to HVEC after single and triple transfection was quantified.
  
  
  RESULTS
  siRNA transfection effectively knocks down adhesion molecule expression on venous endothelial cells, which subsequently reduces leukocyte attachment. Leukocyte adhesion to activated HVEC was significantly reduced after transfection by specific siRNAs in each case compared to the controls (p<0.05). Transfection with a mixture of all three siRNA sequences improved this effect even more (p<0.05).
  
  
  CONCLUSIONS
  For the first time, a functional protection of HUEC in a model simulating physiologic vascular conditions by using nonviral transfection of the cells in a setup with high relevance for clinical applicability was demonstrated. Therefore, siRNA transfection of bypass material may develop into a new therapeutic option to improve the quality of venous graft material in the future.
authors.affiliation: Department of Thoracic, Cardiac, and Vascular Surgery, Tuebingen University Hospital, Hoppe Seyler Strasse 3, 72076 Tuebingen, Germany. tobias.walker@med.uni-tuebingen.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Walker
authors.forename: Isabelle
authors.initials: I
authors.lastname: Müller
authors.forename: Claudia
authors.initials: C
authors.lastname: Raabe
authors.forename: Boris
authors.initials: B
authors.lastname: Nohe
authors.forename: Christof
authors.initials: C
authors.lastname: Zanke
authors.forename: Gerhard
authors.initials: G
authors.lastname: Ziemer
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Wendel
mesh_terms: D002448:Cell Adhesion / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D001026:Coronary Artery Bypass / Q000379:methods*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020868:Gene Silencing; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D009504:Neutrophils / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D012501:Saphenous Vein / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014654:Vascular Patency
chemical_list: D015815:Cell Adhesion Molecules; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha