title: The relationship between endothelial dysfunction and oxidative stress in diabetes and prediabetes.
abstract: OBJECTIVE
  Diabetes mellitus is associated with endothelial dysfunction and oxidative stress (OS). The aim of the present study was to determine whether increased OS and impaired endothelial function, are present in early states of diabetes, such as impaired glucose tolerance (IGT) and impaired fasting glucose (IFG).
  
  
  METHODS
  Brachial artery flow-mediated dilatation (FMD) and nitrate-induced dilatation were measured in 133 subjects with carbohydrate abnormalities (45 IGT, 44 IFG and 44 Type 2 diabetes mellitus) and in 46 subjects with normal glucose tolerance (NGT). Waist circumference, body mass index, blood pressure and fasting lipid profiles were obtained, and glucose and insulin values in response to a 75-g oral glucose load were also measured. Plasma malondialdehyde (MDA) and superoxide dismutase (SOD) activity were determined.
  
  
  RESULTS
  Patients with diabetes and prediabetes had a higher plasma MDA concentration, but a lower plasma SOD activity than the NGT group (p = 0.006) and SOD activity was positively associated with FMD (p = 0.039). FMD were significantly reduced in the groups of subjects with abnormal carbohydrate metabolism compared with the NGT group (p = 0.035). Among the subjects with diabetes and prediabetes, FMD showed a negative correlation with fasting glucose and/or plasma glucose level at 120 min after oral glucose tolerance test (p = 0.028).
  
  
  CONCLUSIONS
  The results showed that endothelial dysfunction and increased OS were present in subjects with IGT and IFG, indicating endothelial damage in these stages.
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Su
authors.forename: X-M
authors.initials: XM
authors.lastname: Liu
authors.forename: Y-M
authors.initials: YM
authors.lastname: Sun
authors.forename: H-B
authors.initials: HB
authors.lastname: Jin
authors.forename: R
authors.initials: R
authors.lastname: Fu
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Luan
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D001916:Brachial Artery / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D018149:Glucose Intolerance; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D011236:Prediabetic State / Q000503:physiopathology*