title: HIV protease inhibitor ritonavir decreases endothelium-dependent vasorelaxation and increases superoxide in porcine arteries.
abstract: OBJECTIVE
  Although HIV Protease inhibitors significantly reduce the viral load, they are associated with increased risk of cardiovascular disease. The aim of this study was to investigate the effects of HIV protease inhibitor ritonavir on vascular endothelial cell function.
  
  
  METHODS
  Porcine carotid arteries were perfusion-cultured for 24 h as controls or with 15 microM of ritonavir. Vessels were precontracted with norepinephrine followed by endothelium-dependent vasorelaxation with acetylcholine. Rings of vessels were cultured as controls or with ritonavir for 24 h and basal and NADPH-stimulated superoxide levels were determined using lucigenin-enhanced chemiluminescence. Superoxide levels in situ were also examined using dihydroethidium (DHE) staining, and nitrotyrosine levels were examined using a nitrotyrosine antibody.
  
  
  RESULTS
  Endothelium-dependent vasorelaxation was significantly reduced in ritonavir-treated vessels compared to controls. There were significant increases in basal and NADPH-stimulated superoxide production in vessel rings treated with ritonavir compared to control vessels. Dihydroethidium staining and nitrotyrosine staining were also elevated in endothelial cells of ritonavir-treated vessels, indicating increased superoxide production and increased oxidative stress, respectively, in ritonavir-treated vessels compared to controls.
  
  
  CONCLUSIONS
  These data demonstrate that HIV protease inhibitor ritonavir causes a significant reduction in endothelium-dependent vasorelaxation in cultured porcine carotid arteries. Increased oxidative stress may be a possible mechanism of HIV protease inhibitor ritonavir-induced endothelial dysfunction.
authors.affiliation: Michael E. DeBakey Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, Molecular Surgeon Research Center, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Conklin
authors.forename: Weiping
authors.initials: W
authors.lastname: Fu
authors.forename: Peter H
authors.initials: PH
authors.lastname: Lin
authors.forename: Alan B
authors.initials: AB
authors.lastname: Lumsden
authors.forename: Qizhi
authors.initials: Q
authors.lastname: Yao
authors.forename: Changyi
authors.initials: C
authors.lastname: Chen
mesh_terms: D000818:Animals; D001158:Arteries; D042783:Endothelial Cells / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008297:Male; D018384:Oxidative Stress; D010477:Perfusion; D019438:Ritonavir / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism*; D013552:Swine; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
chemical_list: D017320:HIV Protease Inhibitors; D013481:Superoxides; C002744:3-nitrotyrosine; D014443:Tyrosine; D019438:Ritonavir