title: The role of gene therapy for intimal hyperplasia of bypass grafts.
abstract: BACKGROUND
  Proliferation of the intima is an early lesion of saphenous vein graft disease. Early patency rates of radial artery grafts are acceptable, but little is known about their risk of intimal hyperplasia.
  
  
  RESULTS
  To develop a model of intimal hyperplasia, we incubated human saphenous veins, internal mammary arteries, and radial arteries (n=6, 8, and 10, respectively) in an organ culture with Roswell Park Memorial Institute 1640 (30% serum) for 0, 4, 7, 10, and 14 days. Quantitative histological studies were performed, and the average intimal-to-medial (I/M) ratio was calculated for each incubation interval. After 10 and 14 days of culture, the I/M ratio increased in the saphenous veins (P=0. 03, P=0.04 versus 0 day, respectively). No significant increase occurred in the I/M ratio in either the internal mammary or radial arteries. Next, the ability of adenoviral gene transfers to inhibit intimal hyperplasia in the saphenous veins was evaluated. Adenoviral-mediated gene transfer of nitric oxide synthase significantly reduced the I/M ratio at 14 days compared with vehicle (P=0.001) and virus (P=0.004) controls.
  
  
  CONCLUSIONS
  The human saphenous vein has a greater propensity for intimal hyperplasia than arterial grafts; the human radial artery behaves similarly to the internal mammary artery. In the future, gene therapy may augment nitric oxide synthase, limiting vein graft disease.
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Cable
authors.forename: J A
authors.initials: JA
authors.lastname: Caccitolo
authors.forename: N
authors.initials: N
authors.lastname: Caplice
authors.forename: T
authors.initials: T
authors.lastname: O'Brien
authors.forename: R D
authors.initials: RD
authors.lastname: Simari
authors.forename: R C
authors.initials: RC
authors.lastname: Daly
authors.forename: J A
authors.initials: JA
authors.lastname: Dearani
authors.forename: C J
authors.initials: CJ
authors.lastname: Mullany
authors.forename: T A
authors.initials: TA
authors.lastname: Orszulak
authors.forename: H V
authors.initials: HV
authors.lastname: Schaff
mesh_terms: D000256:Adenoviridae; D002315:Cardiopulmonary Bypass; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D006965:Hyperplasia / Q000235:genetics / Q000628:therapy; D008323:Mammary Arteries / Q000473:pathology; D009569:Nitric Oxide / Q000502:physiology*; D009924:Organ Culture Techniques; D017534:Radial Artery / Q000473:pathology; D012501:Saphenous Vein / Q000473:pathology; D017540:Tunica Media / Q000473:pathology*
chemical_list: D009569:Nitric Oxide