Effect of acute hyperglycaemia, long-term glycaemic control and insulin on endothelial dysfunction and inflammation in Type 1 diabetic patients with different characteristics

Diabet Med. 2010 Aug;27(8):911-7. doi: 10.1111/j.1464-5491.2009.02928.x.

Abstract

Objective: To investigate the possibility of reversing endothelial dysfunction and inflammation by glucose normalization, antioxidants and insulin per se, in different subgroups of Type 1 diabetic patients.

Methods: Three subgroups of Type 1 diabetic patients were studied: patients within 1 month of diagnosis (subgroup 1); patients with approximately 5 years' disease duration and with glycated haemoglobin (HbA(1c)) <or= 7.0% (subgroup 2) or > 7.0% since diagnosis (subgroup 3). Participants underwent four procedures: 2-h hyperglycaemic clamp followed by: (A) 12 h near-normalization of blood glucose, with the addition of vitamin C during the last 6 h; (B) 12-h vitamin C and near-normalization of blood glucose for the last 6 h; (C) both vitamin C and near-normalization of blood glucose for 12 h; (D) hyperglycaemic-hyperinsulinaemic clamp for 12 h, with the addition of vitamin C during the last 6 h.

Results: After 2 h of hyperglycaemia, markers of endothelial dysfunction, nitrotyrosine, 8-iso prostaglandin F2alpha, soluble intercellular adhesion molecule-1, soluble vascular adhesion molecule-1, interleukin (IL)-6 and IL-18 were increased in all the subgroups. Levels were normalized, at all time points, by treatments A, B and C in the subgroups 1 and 2. In the third subgroup, levels were normalized only by the simultaneous normalization of blood glucose and vitamin C treatment. During treatment D, the levels were improved at 6 h in all the subgroups, but normalized at 12 h only after vitamin C in subgroups 1 and 2, but not in subgroup 3.

Conclusions: This study suggests that different subgroups of Type 1 diabetic patients react identically to acute hyperglycaemia and insulin, but differently to glucose normalization.

MeSH terms

  • Ascorbic Acid / therapeutic use
  • Blood Glucose / metabolism
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy
  • Diabetes Mellitus, Type 1 / physiopathology*
  • Diabetic Angiopathies / blood
  • Diabetic Angiopathies / drug therapy
  • Diabetic Angiopathies / physiopathology*
  • Endothelium, Vascular / physiopathology
  • Female
  • Humans
  • Hyperglycemia / blood
  • Hyperglycemia / drug therapy
  • Hyperglycemia / physiopathology*
  • Hypoglycemic Agents / therapeutic use
  • Inflammation / blood*
  • Insulin / therapeutic use
  • Male
  • Oxidative Stress / physiology
  • Young Adult

Substances

  • Blood Glucose
  • Hypoglycemic Agents
  • Insulin
  • Ascorbic Acid