OBJECTIVE -Diabetes is characterized by marked postprandial endothelial dysfunction induced by hyperglycemia, hypertriglyceridemia, advanced glycation end products (AGEs), and dicarbonyls (e.g., methylglyoxal [MG]). In vitro hyperglycemia-induced MG formation and endothelial dysfunction could be blocked by benfotiamine, but in vivo effects of benfotiamine on postprandial endothelial dysfunction and MG synthesis have not been investigated in humans until now.RESEARCH DESIGN AND METHODS -Thirteen people with type 2 diabetes were given a heat-processed test meal with a high AGE content (HAGE; 15.100 AGE kU, 580 kcal, 54 g protein, 17 g lipids, and 48 g carbohydrates) before and after a 3-day therapy with benfotiamine (1,050 mg/day). Macrovascular flow-mediated dilatation (FMD) and microvascular reactive hyperemia, along with serum markers of endothelial disfunction (E-selectin, vascular cell adhesion molecule-1, and intracellular adhesion molecule-1), oxidative stress, AGE, and MG were measured during both test meal days after an overnight fast and then at 2, 4, and 6 h postprandially.RESULTS -The HAGE induced a maximum reactive hyperemia decrease of Ϫ60.0% after 2 h and a maximum FMD impairment of Ϫ35.1% after 4 h, without affecting endotheliumindependent vasodilatation. The effects of HAGE on both FMD and reactive hyperemia were completely prevented by benfotiamine. Serum markers of endothelial dysfunction and oxidative stress, as well as AGE, increased after HAGE. These effects were significantly reduced by benfotiamine.CONCLUSIONS -Our study confirms micro-and macrovascular endothelial dysfunction accompanied by increased oxidative stress following a real-life, heat-processed, AGE-rich meal in individuals with type 2 diabetes and suggests benfotiamine as a potential treatment.
Diabetes Care 29:2064 -2071, 2006E ndothelial dysfunction is an early marker of atherosclerosis and accompanies states showing a high cardiovascular risk, such as smoking (1), dyslipidemia (2), arterial hypertension (3), obesity (4), coronary artery disease (5), congestive heart failure (6), and type 1 (7) and type 2 (8) diabetes. Postprandial endothelial dysfunction has been proposed as the link between postprandial dysmetabolism and atherosclerosis (9) and occurs not only in patients with cardiovascular disease (10) or diabetes (11) but even in healthy subjects (12). Distinctive and cumulative (11) effects of hyperglycemia (13) and hypertriglyceridemia (14) on postprandial endothelial dysfunction have been shown. Since the postprandial state covers most of our daytime, interventions aimed at reducing postprandial endothelial dysfunction might play a decisive role in prevention of atherosclerosis. Several therapeutic approaches have been suggested for the treatment of postprandial endothelial dysfunction, including insulin, folic acid, tetrahydrobiopterin, vitamins C and E, and statins (11). These approaches aim at reducing postprandial oxidative stress (vitamins C and E, statins, and partly folic acid), postprandial hyperglycemia (insul...