title: Effects of antioxidants on postprandial oxidative stress and endothelial dysfunction in subjects with impaired glucose tolerance and type 2 diabetes.
abstract: OBJECTIVE
  To compare changes in the oxidation-reduction balance and endothelial function before and after meal in patients with type 2 diabetes or impaired glucose tolerance and determine the effects of standard antioxidant supplementation.
  
  
  METHODS
  Forty diabetics and 40 subjects with impaired glucose tolerance were compared with a control group. We assessed before and after a test meal (homogenized milkshake containing 80 g of saturated fat, amounting to 1,480 kcal), some reactive oxygen species, inflammation markers and flow-mediated vascular dilatation. These parameters were then reassessed after standard antioxidant treatment.
  
  
  RESULTS
  After the meal, diabetics, subjects with impaired glucose tolerance and controls had higher levels of oxidant compounds compared to fasting levels. In subjects with diabetes and impaired glucose tolerance (IGT), Vascular Adhesion Molecule-1 and CRP were higher after the meal--diabetic subjects exhibited lower fasting flow-mediated dilatation, which deteriorated significantly after the meal. Antioxidant administration significantly improved the parameters investigated in all subjects.
  
  
  CONCLUSIONS
  In diabetic subjects, altered glycaemia and lipaemia are closely correlated with markers of systemic oxidative stress. Our results show that the abnormal changes in oxidative-reductive balance parameters are paralleled by similar changes in markers of endothelial dysfunction and inflammation at 4 h after ingestion of a fatty meal. Supplementation with a pool of antioxidants can reduce oxidative stress and inflammation in healthy subjects and, more importantly, in IGT patients. This previous aspect suggests that the timing of antioxidant supplementation has an important role in endothelium protection in healthy and pre-diabetic subjects, and along with prompt antioxidant treatment before irreversible endothelial damage has occurred, may have an important protective role in subjects with IGT-patients who require administration of adequate dietary antioxidants.
authors.affiliation: Department of Internal Medicine and Systemic Disease, University of Catania, Catania, Italy. sergio.neri4@tin.it
authors.forename: S
authors.initials: S
authors.lastname: Neri
authors.forename: S
authors.initials: S
authors.lastname: Calvagno
authors.forename: B
authors.initials: B
authors.lastname: Mauceri
authors.forename: M
authors.initials: M
authors.lastname: Misseri
authors.forename: A
authors.initials: A
authors.lastname: Tsami
authors.forename: C
authors.initials: C
authors.lastname: Vecchio
authors.forename: G
authors.initials: G
authors.lastname: Mastrosimone
authors.forename: A
authors.initials: A
authors.lastname: Di Pino
authors.forename: D
authors.initials: D
authors.lastname: Maiorca
authors.forename: A
authors.initials: A
authors.lastname: Judica
authors.forename: G
authors.initials: G
authors.lastname: Romano
authors.forename: A
authors.initials: A
authors.lastname: Rizzotto
authors.forename: S S
authors.initials: SS
authors.lastname: Signorelli
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D003924:Diabetes Mellitus, Type 2 / Q000517:prevention & control / Q000628:therapy*; D019587:Dietary Supplements; D004727:Endothelium / Q000378:metabolism; D005260:Female; D018149:Glucose Intolerance / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D019518:Postprandial Period; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species