title: Carvedilol, a new vasodilating beta adrenoceptor blocker antihypertensive drug, protects endothelial cells from damage initiated by xanthine-xanthine oxidase and neutrophils.
abstract: OBJECTIVE
  Oxygen radical mediated endothelial injury plays an important role in cardiovascular disease. Carvedilol, a new beta blocker and antihypertensive agent, has been shown to have antioxidant activity. The aim of this study was to determine whether carvedilol protects oxygen radical induced endothelial injury.
  
  
  METHODS
  Cultured bovine pulmonary artery (BPAEC) and human umbilical vein endothelial cells (HUVEC) were used and oxygen radicals were generated by xanthine-xanthine oxidase or phorbol myristate acetate (PMA) activated human neutrophils. Cell injury was assessed by lactate dehydrogenase (LDH) release and cell death, or 51 Cr release from prelabelled BPAEC. The electron paramagnetic resonance (EPR) spin trapping technique was used to detect the amount of radical spin adducts formed in cell lipids.
  
  
  RESULTS
  Carvedilol dose dependently inhibited xanthine-xanthine oxidase induced LDH release from BPAEC and HUVEC, with IC50 values of 3.8 microM and 2.6 microM, respectively, and significantly reduced cell death by xanthine-xanthine oxidase. Other beta blockers tested (propranolol, labetalol, pindolol, and celiprolol) showed a mild effect or no effect at all. Increasing the time of pretreatment with carvedilol enhanced its cell protective effect against oxidative stress. Carvedilol also protected BPAEC dose dependently from PMA activated, neutrophil induced cell injury. Carvedilol had no effect on xanthine oxidase activity. EPR study confirmed that xanthine-xanthine oxidase induced the formation of lipid derived radicals in cell lipids and carvedilol scavenged free radicals, as indicated by the decreased EPR signal.
  
  
  CONCLUSIONS
  Carvedilol protects endothelial cells against oxygen radical mediated cell injury and death by scavenging free radicals. The prevention of oxidative injury to endothelial cells might potentially contribute to the clinical beneficial effects of carvedilol as an antihypertensive agent.
authors.affiliation: SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406-0939.
authors.forename: T L
authors.initials: TL
authors.lastname: Yue
authors.forename: P J
authors.initials: PJ
authors.lastname: McKenna
authors.forename: J L
authors.initials: JL
authors.lastname: Gu
authors.forename: H Y
authors.initials: HY
authors.lastname: Cheng
authors.forename: R E
authors.initials: RE
authors.lastname: Ruffolo
authors.forename: G Z
authors.initials: GZ
authors.lastname: Feuerstein
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002227:Carbazoles / Q000737:chemistry / Q000494:pharmacology*; D000077261:Carvedilol; D002417:Cattle; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009504:Neutrophils / Q000502:physiology; D011412:Propanolamines / Q000737:chemistry / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism; D014665:Vasodilator Agents / Q000494:pharmacology*; D019820:Xanthine; D014969:Xanthine Oxidase / Q000378:metabolism; D014970:Xanthines / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002227:Carbazoles; D011412:Propanolamines; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D014970:Xanthines; D000077261:Carvedilol; D019820:Xanthine; D007770:L-Lactate Dehydrogenase; D014969:Xanthine Oxidase; D013755:Tetradecanoylphorbol Acetate