title: Impaired endothelial function of the retinal vasculature in hypertensive patients.
abstract: OBJECTIVE
  Arterial hypertension constitutes a central factor in the pathogenesis of stroke. We examined endothelial function of the retinal vasculature as a model of the cerebral circulation.
  
  
  METHODS
  Thirty-eight young subjects (19 hypertensive and 19 normotensive) were treated with the AT1-receptor blocker candesartan cilexetil and placebo, each over 7 days. Retinal capillary flow and blood flow velocity in the central retinal artery were assessed with scanning laser Doppler flowmetry and pulsed Doppler ultrasound, respectively. N(G)-monomethyl-L-arginine (L-NMMA) was infused to inhibit nitric oxide (NO) synthesis. Diffuse luminance flicker was applied to stimulate NO release.
  
  
  RESULTS
  In normotensive subjects, L-NMMA decreased retinal capillary flow by 8.2%+/-13% (P<0.05) and flickering light increased mean blood flow velocity in the central retinal artery by 19%+/-29% (P<0.01). In contrast, no significant change to these provocative tests was seen in hypertensive subjects. Treatment with candesartan cilexetil restored a normal pattern of reactivity in retinal capillaries (l-NMMA: decrease in perfusion by 10%+/-17%, P<0.05) and the central retinal artery (flicker: increase in mean blood flow velocity by 42%+/-31%, P<0.001) in hypertensive patients.
  
  
  CONCLUSIONS
  Endothelial function of the retinal vasculature is impaired in early essential hypertension but can be improved by AT1-receptor blockade.
authors.affiliation: Department of Nephrology, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Delles
authors.forename: Georg
authors.initials: G
authors.lastname: Michelson
authors.forename: Joanna
authors.initials: J
authors.lastname: Harazny
authors.forename: Sebastian
authors.initials: S
authors.lastname: Oehmer
authors.forename: Karl F
authors.initials: KF
authors.lastname: Hilgers
authors.forename: Roland E
authors.initials: RE
authors.lastname: Schmieder
mesh_terms: D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002196:Capillaries / Q000503:physiopathology; D002540:Cerebral Cortex / Q000098:blood supply; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D012161:Retinal Artery / Q000187:drug effects / Q000503:physiopathology*; D013777:Tetrazoles; D014664:Vasodilation / Q000187:drug effects
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D013777:Tetrazoles; C077793:candesartan cilexetil