title: Effects of exogenous peripheral-blood-derived endothelial progenitor cells or unfractionated bone-marrow-derived cells on neointimal formation and inflammation in cholesterol-fed, balloon-denuded, and radiated iliac arteries of inbred rabbits.
abstract: BACKGROUND
  Injection of bone marrow cells (BMC) and endothelial progenitor cells (EPC) or application of stem-cell-mobilizing factors has been associated both with reduction or exacerbation of atherosclerosis and with unstable plaque phenotype. The discrepancies may reflect the cell type, dosing, duration, and route of administration of cells in these studies. The aim of this study was to determine the effects of peripheral-blood-derived endothelial progenitor cells (PBEPC) or unfractionated BMC obtained from inbred siblings on neointimal formation and inflammation in cholesterol-fed, balloon-denuded, and radiated rabbit iliac arteries.
  
  
  METHODS
  Rabbits were fed a 1.0% cholesterol diet for 14 days, followed by endothelial denudation in both iliac arteries, and continued on a 0.15% cholesterol diet. On day 42, denuded areas were radiated, and animals were randomized. The first group received PBEPC (n=5), the second group received BMC (n=4), and the third group received heparinized (20 IU) saline (Control; n=3). PBEPC were characterized by flow cytometry. Cells (5x10(6)) or saline was administered twice through the ear vein: the first time at 1 h after radiation and the second time at 2 weeks after radiation. Four weeks after radiation, the animals were sacrificed, and arterial segments were processed for morphometry.
  
  
  RESULTS
  Administration of BMC or PBEPC from inbred siblings had no adverse effect. Lumen area (0.93+/-0.53 mm(2)), neointimal area (0.65+/-0.29 mm(2)), percent stenosis (44+/-21), and macrophage score (0.6+/-0.3) in controls were similar to those in cell-treated groups.
  
  
  CONCLUSIONS
  This study demonstrates that, in the current animal model, either PBEPC or BMC failed to affect neointimal formation or inflammation.
authors.affiliation: Cardiovascular Research Institute, Washington Hospital Center, Washington, DC, USA. ron.waksman@medstar.net
authors.forename: Ron
authors.initials: R
authors.lastname: Waksman
authors.forename: Richard
authors.initials: R
authors.lastname: Baffour
authors.forename: Rajbabu
authors.initials: R
authors.lastname: Pakala
authors.forename: Mickey
authors.initials: M
authors.lastname: Scheinowitz
authors.forename: David
authors.initials: D
authors.lastname: Hellinga
authors.forename: Rufus
authors.initials: R
authors.lastname: Seabron
authors.forename: Rosanna
authors.initials: R
authors.lastname: Chan
authors.forename: Frank
authors.initials: F
authors.lastname: Kolodgie
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani