title: Possible involvement of endothelin-1 and nitric oxide in the pathogenesis of proliferative diabetic retinopathy.
abstract: BACKGROUND
  Overproduction of endothelin-1 (ET-1) and nitric oxide (NO) in the retina is demonstrated in experimental diabetic animals. To clarify the possible involvement of ET-1 and NO in the pathogenesis of diabetic retinopathy, the authors examined the vitreous levels of these principal endothelium-derived vasoactive substances in patients with proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Vitreous fluid was taken from patients with PDR (ET-1, n = 12; NO, n = 12) and from patients with macular holes as controls (ET-1, n = 10; NO, n = 10) at vitreous surgery. Endothelin-1 and NO metabolites were measured by radioimmunoassay and high-performance liquid chromatography based on the Griess method, respectively.
  
  
  RESULTS
  Endothelin-1 levels (mean +/- SE) were 21.5 +/- 1.7 pg/mL in the vitreous of patients with PDR and 16.7 +/- 0.7 pg/mL in the vitreous of patients with macular hole. There was a significant difference between patients with PDR and controls (P = 0.009, Mann-Whitney). Nitrate (NO3) was 49.8 +/- 5.0 micromol/L in patients with PDR and 24.2 +/- 2.8 micromol/L in patients with macula hole; it was also significantly elevated in patients with PDR (P = 0.004, Mann-Whitney), whereas nitrite (NO2) was not detected in this study.
  
  
  CONCLUSIONS
  These results indicate that ET-1 and NO may be related in the pathogenesis of PDR.
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan. hidehirookku@aol.com
authors.forename: H
authors.initials: H
authors.lastname: Oku
authors.forename: T
authors.initials: T
authors.lastname: Kida
authors.forename: T
authors.initials: T
authors.lastname: Sugiyama
authors.forename: J
authors.initials: J
authors.lastname: Hamada
authors.forename: B
authors.initials: B
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002851:Chromatography, High Pressure Liquid; D003930:Diabetic Retinopathy / Q000209:etiology* / Q000378:metabolism*; D019332:Endothelin-1 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D011863:Radioimmunoassay; D012167:Retinal Perforations / Q000378:metabolism; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide