title: Nitric oxide proxies and ocular perfusion pressure in primary open angle glaucoma.
abstract: BACKGROUND
  To investigate the levels of nitric oxide (NO) markers in plasma and aqueous humour of patients with primary open angle glaucoma (POAG) and their relation to ocular perfusion pressure.
  
  
  METHODS
  Cyclic guanosine monophosphate (cGMP) and nitrite (NO(2)(-)) were determined in plasma and aqueous humour of 38 patients with POAG and 46 controls. Blood pressure and IOP were measured to calculate ocular perfusion pressure (PP).
  
  
  RESULTS
  cGMP and NO(2)(-) plasma levels were significantly decreased in glaucoma patients compared with controls (p = 0.001 v p = 0.004). In the aqueous humour of subjects with POAG, cGMP and NO(2)(-) concentrations were also lower than in normal eyes (p = 0.0001 v p = 0.001). There was a linear association between cGMP in plasma and aqueous humour in glaucomas and controls (r = 0.514, p = 0.029 and r = 0.558, p = 0.004) and this relation differed in the two groups (p = 0.003). Considering glaucoma patients with controls, a positive correlation was found between cGMP and PP (r = 0.379, p = 0.01) and between NO(2)(-) and PP (r = 0.339, p = 0.040). The cGMP/PP correlation was of borderline statistical significance in controls (p = 0.050), whereas it did not attain statistical significance in POAG, as well as the association between NO(2)(-) and PP when glaucomas and controls were considered separately.
  
  
  CONCLUSIONS
  The authors found alterations of NO markers in the plasma and aqueous humour of glaucoma patients. Primary or secondary impaired NO balance could alter ocular perfusion pressure.
authors.affiliation: Department of Oto-Neuro-Ophthalmological Sciences, University of Florence, Eye Unit II, Florence, Italy. fernando.galassi@unifi.it
authors.forename: F
authors.initials: F
authors.lastname: Galassi
authors.forename: G
authors.initials: G
authors.lastname: Renieri
authors.forename: A
authors.initials: A
authors.lastname: Sodi
authors.forename: F
authors.initials: F
authors.lastname: Ucci
authors.forename: L
authors.initials: L
authors.lastname: Vannozzi
authors.forename: E
authors.initials: E
authors.lastname: Masini
mesh_terms: D000368:Aged; D001082:Aqueous Humor / Q000737:chemistry*; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D016022:Case-Control Studies; D010478:Chemotherapy, Cancer, Regional Perfusion; D006152:Cyclic GMP / Q000032:analysis* / Q000097:blood; D005260:Female; D005902:Glaucoma, Open-Angle / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000032:analysis* / Q000097:blood
chemical_list: D015415:Biomarkers; D009573:Nitrites; D009569:Nitric Oxide; D006152:Cyclic GMP