title: Plasma and aqueous humor angiotensin-converting enzyme levels in patients with diabetic retinopathy.
abstract: OBJECTIVE
  To assess angiotensin-converting enzyme (ACE) levels in aqueous humor and plasma of patients with nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) as another potent ischemia-induced angiogenic factor.
  
  
  METHODS
  The clinical comparative study included 40 patients with diabetic retinopathy and 16 healthy subjects. For all patients, aqueous humors were collected during the cataract surgery or intravitreal injection of triamcinolone acetonide. ACE levels were measured using a solid-phase chemiluminescence immunoassay.
  
  
  RESULTS
  We observed significantly elevated ACE level in aqueous humor of patients with PDR compared with the patients with NPDR and normal subjects (P = 0.023), but no significant difference was detected between nonproliferative diabetics and control group (P = 0.239). There was no significant difference in plasma ACE levels among diabetic and control groups (P = 0.816).
  
  
  CONCLUSIONS
  Elevated ACE level may induce retinal angiogenesis and proliferative retinopathy in patients with DM. We consider that high levels of ACE in aqueous humor can reflect the association between retinal angiogenesis and DM serve as predictor in the progression of diabetic retinopathy.
authors.affiliation: Department of Ophthalmology, Gaziosmanpasa University Faculty of Medicine, Tokat, Turkey. erdincaydin@yahoo.com
authors.forename: Erdinc
authors.initials: E
authors.lastname: Aydin
authors.forename: Helin Deniz
authors.initials: HD
authors.lastname: Demir
authors.forename: Semsettin
authors.initials: S
authors.lastname: Sahin
mesh_terms: D000368:Aged; D001082:Aqueous Humor / Q000201:enzymology*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology; D003930:Diabetic Retinopathy / Q000201:enzymology*; D005260:Female; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000097:blood*
chemical_list: D007703:Peptidyl-Dipeptidase A