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γ‐Tocopherol attenuates hyperglycemia‐induced vascular endothelial dysfunction (VED) in men by decreasing asymmetric dimethylarginine accumulation
Author(s) -
Noh Sang K,
Mah Eunice,
Ballard Kevin D,
Volek Jeff S,
Bruno Richard S
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.218.7
Subject(s) - asymmetric dimethylarginine , postprandial , medicine , endocrinology , glucose homeostasis , endothelial dysfunction , nitric oxide , crossover study , arginine , chemistry , diabetes mellitus , insulin resistance , placebo , biochemistry , alternative medicine , amino acid , pathology
Acute hyperglycemia (AH) increases cardiovascular disease risk by disrupting nitric oxide (NO) homeostasis, possibly by increasing asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase generated from arginine (ARG). We hypothesized that the antioxidant activity of γ‐tocopherol (γ‐T) would attenuate VED by decreasing AH‐mediated accumulation of ADMA. A randomized, crossover study was conducted in healthy men (n = 15; 21.8 ± 0.8 y; 28.2 ± 2.0 kg/m 2 ) who followed their usual diet or were provided γ‐T (500 mg/d, 5 d) prior to a fasting 75 g oral glucose challenge. Brachial artery flow‐mediated dilation (FMD), plasma glucose, vitamin E, ARG, ADMA, and symmetric dimethylarginine (SDMA) were measured at regular intervals for 3 h postprandially. Supplementation increased γ‐T by 3‐fold without affecting α‐T, glucose, ARG, ADMA, or SDMA. Postprandial FMD AUC 0–3 h was greater (P<0.05) following γ‐T supplementation, consistent with greater baseline FMD. AH decreased ARG time‐dependently to a similar extent in both trials. Postprandial ADMA/ARG as well as SDMA/ARG increased time‐dependently in both trials. However, γ‐T decreased postprandial ADMA/ARG AUC 0–3 h without affecting SDMA/ARG AUC 0–3 h . These data suggest that short‐term γ‐T supplementation protects against VED by increasing the availability of ARG for NO synthesis. Support provided by ILSI.