Effects of a single administration of acarbose on postprandial glucose excursion and endothelial dysfunction in type 2 diabetic patients: A randomized crossover study

Context: Postprandial hyperglycemia has been reported to elicit endothelial dysfunction and provoke future cardiovascular complications. A reduction of postprandial blood glucose levels by the alpha-glucosidase inhibitor acarbose was associated with a risk reduction of cardiovascular complications, but effects of acarbose on endothelial function have never been elucidated. Design: This study was aimed to assess the efficacy of acarbose on postprandial metabolic parameters and endothelial function in type 2 diabetic patients. Postprandial peak(glucose) (14.47 +/- 1.27 vs. 8.50 +/- 0.53 mmol/liter), plasma glucose excursion (PPGE), and change in the area under the curve (Delta AUC)(glucose) after a single loading of test meal (total 450 kcal; protein 15.3%; fat 33.3%; carbohydrate 51.4%) were significantly higher in diet-treated type 2 diabetic patients (n=14) than age- and sex-matched controls (n=12). Results: The peak forearm blood flow response and total reactive hyperemic flow (flow debt repayment) during reactive hyperemia, indices of resistance artery endothelial function on strain-gauge plethysmography, were unchanged before and after meal loading in controls. But those of diabetics were significantly decreased 120 and 240 min after the test meal. A prior administration of acarbose decreased postprandial peak(glucose), PPGE, and Delta AUC(glucose). The peak forearm blood flow and flow debt repayment were inversely well correlated with peak(glucose), PPGE, and Delta AUC(glucose) but not with Delta AUC(insulin) or the other lipid parameters. Conclusions: Even a single loading of test meal was shown to impair endothelial function in type 2 diabetic patients, and the postprandial endothelial dysfunction was improved by a prior use of acarbose. Acarbose might reduce macrovascular complication by avoiding endothelial injury in postprandial hyperglycemic status.