title: L-arginine polymer mediated inhibition of graft coronary artery disease after cardiac transplantation.
abstract: BACKGROUND
  Nitric oxide (NO) limits the development of graft coronary artery disease (GCAD) in transplanted hearts. We hypothesized that l-arginine polymers administered to cardiac allografts ex vivo would translocate across vascular cellular membranes, up-regulate inducible nitric oxide synthase (iNOS) production of NO, and inhibit the development of GCAD.
  
  
  METHODS
  Three groups of PVG rat donor hearts were incubated with either 0.8 ml phosphate-buffered saline, (PBS, n=12) or 50 microM L-arginine polymer solutions of length five (R5, n=12) or nine (R9, n=12) prior to heterotopic transplantation into ACI recipients. Graft vessels were scored at POD 60 and 90 for percentage luminal narrowing (%LN), intima to media ratio (I/M), and percentage affected vessels (%AV). Translocation efficiency was determined by treatment with biotinylated polymers. NO production of treated aortic segments was determined in vitro by Griess reaction.
  
  
  RESULTS
  Translocation efficiencies were 89+/-19% (R9), 7+/-10% (R5), and 0+/-0% PBS (ANOVA, P<0.001) which corresponded to NO production in treated aortic segments of 0.175+/-0.17 (R9), 0.120+/-0.006 (R5), and 0.135+/-0.035 microM/mg (PBS), (ANOVA, P=0.002). GCAD scores at POD 60 were: %LN: 3.2+/-3.8% (R9), 12.6+/-6.7% (R5), 11.3+/-4.2% (PBS) (ANOVA, P=0.025); I/M: 0.03+/-0.04 (R9), 0.13+/-0.07 (R5), 0.12+/-0.05 (PBS) (ANOVA, P=0.037); %AV: 7+/-7% (R9), 19+/-7%(R5), 22+/-9%(PBS) (ANOVA, P=0.021). Reduction of GCAD parameters was maintained at POD 90.
  
  
  CONCLUSIONS
  R9 efficiently translocated across cytoplasmic membranes, enhanced vascular NO production, and decreased neointimal hyperplasia. This ex vivo treatment may have a therapeutic role in preventing GCAD.
authors: Stanford University Medical School, Stanford, CA 94305-5247, USA.
authors: M H
authors: MH
authors: Kown
authors: T
authors: T
authors: van Der Steenhoven
authors: S
authors: S
authors: Uemura
authors: C L
authors: CL
authors: Jahncke
authors: G E
authors: GE
authors: Hoyt
authors: J B
authors: JB
authors: Rothbard
authors: R C
authors: RC
authors: Robbins
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D001120:Arginine / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D003327:Coronary Disease / Q000517:prevention & control*; D003331:Coronary Vessels / Q000473:pathology; D016027:Heart Transplantation / Q000009:adverse effects*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology; D009573:Nitrites / Q000378:metabolism; D011108:Polymers / Q000493:pharmacokinetics / Q000627:therapeutic use*; D051381:Rats; D011912:Rats, Inbred ACI; D011919:Rats, Inbred Strains; D017207:Rats, Sprague-Dawley
chemical_list: D009573:Nitrites; D011108:Polymers; D009569:Nitric Oxide; D001120:Arginine