Acute macrovascular dysfunction in patients with type 2 diabetes induced by ingestion of advanced glycated β-lactoglobulins

Abstract

OBJECTIVE-Recent evidence indicates that heat-enhanced food advanced glycation end products (AGEs) adversely affect vascular function. The aim of this study was to examine the acute effects of an oral load of heat-treated, AGE-modified β-lactoglobulins (AGE-BLG) compared with heat-treated, nonglycated BLG (C-BLG) on vascular function in patients with type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS-In a double-blind, controlled, randomized, crossover study, 19 patients with T2DM received, on two different occasions, beverages containing either AGE-BLG or C-BLG. We measured macrovascular [brachial ultrasound of flowmediated dilatation (FMD)] and microvascular (laser-Doppler measurements of reactive hyperemia in the hand) functions at baseline (T0), 90 (T90), and 180 (T 180) min. RESULTS-Following the AGE-BLG, FMD decreased at T 90 by 80% from baseline and remained decreased by 42% at T 180 (P < 0.05 vs. baseline, P < 0.05 vs. C-BLG at T 90). By comparison, following C-BLG, FMD decreased by 27% at T 90 and 51% at T180 (P < 0.05 vs. baseline at T 180). A significant decrease in nitrite (T180) and nitrate (T90 and T180), as well as a significant increase in N-carboxymethyllisine, accompanied intake of AGE-BLG. There was no change in microvascular function caused by either beverage. CONCLUSIONS-In patients with T2DM, acute oral administration of a single AGE-modified protein class significantly though transiently impaired macrovascular function in concert with decreased nitric oxide bioavailability. These AGE-related changes were independent of heat treatment. © 2013 by the American Diabetes Association.