title: Serum markers of oxidative stress and severity of diabetic retinopathy.
abstract: OBJECTIVE
  To compare serum markers of oxidative stress with diabetic retinopathy severity
  
  
  METHODS
  This cross-sectional study compared patients with types 1 and 2 diabetes with control subjects in western New York and Pennsylvania. Retinopathy severity was graded from funduscopic fields based on the Early Treatment of Diabetic Retinopathy Study. Serum samples were analyzed for thiobarbituric acid-reacting substances (TBARS), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, creatinine, HbA1, and triglycerides. Appropriate analysis of covariance models were performed.
  
  
  RESULTS
  TBARS (P = 0.019), triglyceride (P = 0.004), and glucose and HbA1 (both P<0.001) levels were elevated in diabetic patients compared with those in control subjects. SOD (P = 0.003) and GSH-Px (P = 0.046) levels were lower in diabetic patients than in control subjects. No correlation existed between SOD levels and either glucose or HbA1 levels. No significant associations existed between levels of TBARS, SOD, or GSH-Px and severity of diabetic retinopathy There was a significant association between poorer visual acuity and worse retinopathy (P = 0.009), which was only partly explained by macular edema.
  
  
  CONCLUSIONS
  Increased levels of TBARS and decreased levels of SOD and GSH-Px were found in diabetic patients compared with those in control subjects, but no significant associations were found between the levels of these substances and severity of retinopathy When duration and type of diabetes and serum HbA1 levels were taken into account, only visual acuity remained associated with more severe retinopathy.
authors.affiliation: Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts, USA. hartnett@vision.eri.harvard.edu
authors.forename: M E
authors.initials: ME
authors.lastname: Hartnett
authors.forename: R D
authors.initials: RD
authors.lastname: Stratton
authors.forename: R W
authors.initials: RW
authors.lastname: Browne
authors.forename: B A
authors.initials: BA
authors.lastname: Rosner
authors.forename: R J
authors.initials: RJ
authors.lastname: Lanham
authors.forename: D
authors.initials: D
authors.lastname: Armstrong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000097:blood* / Q000145:classification / Q000503:physiopathology*; D005260:Female; D005451:Fluorescein Angiography; D005979:Glutathione Peroxidase / Q000097:blood*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000097:blood*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis*; D014280:Triglycerides / Q000097:blood
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005979:Glutathione Peroxidase; D006442:Glycated Hemoglobin; D013482:Superoxide Dismutase; D017392:Thiobarbituric Acid Reactive Substances; D014280:Triglycerides