Effects of Mealtime Insulin Aspart and Bedtime NPH Insulin on Postprandial Inflammation and Endothelial Cell Function in Patients with Type 2 Diabetes

Acute hyperglycaemia exerts deleterious effects on the arterial wall. We suggested that rapid-acting insulin has a beneficial postprandial effect on endothelial dysfunction and inflammation compared with intermediate-acting insulin because of its ability to lower postprandial hyperglycaemia. This was tested in a parallel, controlled study on well-controlled patients with type 2 diabetes randomly assigned to bedtime Neutral Protamine Hagedorn (NPH) insulin (n = 41) or mealtime insulin aspart (n = 37). They were served standard diabetic meals for breakfast (8.00) and lunch (12.00). Blood samples were collected at 7.40 (fasting), 9.30, 11.30, 13.30 and 15.30 and analysed for glucose, insulin, lipids, intercellular adhesion molecules (ICAM), C-reactive protein (CRP), von Willebrand factor (vWF) and fibrinogen. The postprandial glucose response differed significantly between insulin regimens with a postprandial increase on NPH insulin and a decrease on insulin aspart. There was a minor but significant postprandial decrease in ICAM, CRP and vWF on both insulin regimens and a decrease in fibrinogen on NPH insulin. No insulin group differences were observed in postprandial responses for ICAM, CRP, vWF and fibrinogen. The rapid-acting insulin analogue aspart and the intermediate-acting insulin NPH had different effects on postprandial glucose response but similar postprandial effects on markers of inflammation and endothelial dysfunction.