title: Predominant role of obesity/insulin resistance in oxidative stress development.
abstract: BACKGROUND
  Hyperlipidaemia, hyperglycaemia and hyperinsulinaemia, hallmarks of the postprandial state, have been also associated with increased oxidative stress and lipoprotein oxidation contributing to vascular injury and atherosclerosis. However, the specific links among metabolic disorders, postprandial state, insulin resistance and oxidative stress are still to be clarified. This study aimed at investigating the individual role played by obesity, insulin resistance and type 2 diabetes in the occurrence of fasting and postprandial oxidative stress.
  
  
  METHODS
  Biomarkers of oxidative stress [F2-isoprostanes and circulating oxidized low-density lipoproteins (LDL)], LDL oxidability (conjugated diene kinetic, thiobarbituric acid reactive substances (TBARs) formation and electronegativity increase) and antioxidant vitamins (β-carotene, α-tocopherol and retinol) were evaluated at fasting and 6 h after a standard fat-rich meal in 10 obese diabetic (ObD), 11 obese and 11 normal-weight control men. Insulin sensitivity was evaluated by euglycaemic hyperinsulinaemic clamp.
  
  
  RESULTS
  ObD and obese subjects, characterized by a similar level of adiposity and insulin resistance, showed higher urinary F2-isoprostanes and circulating oxidized LDL, an increased susceptibility to oxidation of plasma LDL (lower lag phase, higher TBARs formation, and higher relative electrophoretic mobility), and lower plasma content of β-carotene and retinol than control subjects, both at fasting and after the test meal.
  
  
  CONCLUSIONS
  Obesity and insulin resistance, more than type 2 diabetes, play the most relevant role in oxidative stress development. The correction of obesity and insulin resistance might be a useful strategy in counteracting systemic oxidative stress.
authors.affiliation: Department of Veterinary Public Health and Food Safety, Italian National Institute of Health, Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: D'Archivio
authors.forename: Giovanni
authors.initials: G
authors.lastname: Annuzzi
authors.forename: Rosaria
authors.initials: R
authors.lastname: Varì
authors.forename: Carmelina
authors.initials: C
authors.lastname: Filesi
authors.forename: Rosalba
authors.initials: R
authors.lastname: Giacco
authors.forename: Beatrice
authors.initials: B
authors.lastname: Scazzocchio
authors.forename: Carmela
authors.initials: C
authors.lastname: Santangelo
authors.forename: Claudio
authors.initials: C
authors.lastname: Giovannini
authors.forename: Angela A
authors.initials: AA
authors.lastname: Rivellese
authors.forename: Roberta
authors.initials: R
authors.lastname: Masella
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000503:physiopathology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D019518:Postprandial Period; D014815:Vitamins / Q000378:metabolism
chemical_list: D000975:Antioxidants; D008077:Lipoproteins, LDL; D014815:Vitamins