Acute effects of various fast-food meals on vascular function and cardiovascular disease risk markers: the Hamburg Burger Trial.

BACKGROUND: High-fat meals have negative effects on endothelial function, but vitamin-rich side orders may prevent these negative effects. OBJECTIVE: The acute effects of conventional and alternative fast-food meals on vascular function and various cardiovascular biomarkers were investigated. DESIGN: In a crossover study, flow-mediated endothelium-dependent dilatation (FMD) and cardiovascular disease risk markers were investigated in 24 healthy volunteers before and 2 and 4 h after 3 fast-food meals: a conventional beef burger with French fries, ketchup, and carbonated lemon-flavored soda (meal 1); a vegetarian burger with French fries, ketchup, and carbonated lemon-flavored soda (meal 2); and a vegetarian burger with salad, fruit, yogurt, and orange juice (meal 3). RESULTS: FMD decreased after all 3 fast-food meals: the values were 9.7 +/- 2.5%, 7.5 +/- 3.5%, and 6.2 +/- 3.3% for meal 1; 9.2 +/- 3.4%, 7.1 +/- 3.4%, and 6.3 +/- 4.0% for meal 2; and 8.8 +/- 3.3%, 6.2 +/- 4.0%, and 6.8 +/- 4.3% for meal 3 at baseline, 2 h, and 4 h, respectively. There were significant intraindividual differences for time (P < 0.001) but not for type of meal (P = 0.677). A postprandial increase in baseline diameter of the brachial artery was significant for time (P < 0.001) but not for type of meal (P = 0.148). CONCLUSIONS: Against common expectations, a conventional beef burger meal and presumably healthier alternatives with or without vitamin-rich side orders did not differ significantly in their acute effects on vascular reactivity. The frequently reported postprandial decline in FMD may be attributed in part to a postprandial increase in baseline arterial diameter.

High-throughput liquid chromatographic-tandem mass spectrometric determination of arginine and dimethylated arginine derivatives in human and mouse plasma.

The balance between nitric oxide (NO) and vasoconstrictors like endothelin is essential for vascular tone and endothelial function. L-Arginine is converted to NO and L-citrulline by NO synthase (NOS). Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are endogenous inhibitors of NO formation. ADMA is degraded by dimethylamino dimethylhydrolases (DDAHs), while SDMA is exclusively eliminated by the kidney. In the present article we report a LC-tandem MS method for the simultaneous determination of arginine, ADMA, and SDMA in plasma. This method is designed for high sample throughput of only 20-mul aliquots of human or mouse plasma. The analysis time is reduced to 1.6 min by LC-tandem MS electrospray ionisation (ESI) in the positive mode. The mean plasma levels of l-arginine, ADMA, and SDMA were 74+/-19 (SD), 0.46+/-0.09, and 0.37+/-0.07 microM in healthy humans (n=85), respectively, and 44+/-14, 0.72+/-0.23, and 0.19+/-0.06 microM in C57BL/6 mice. Also, the molar ratios of arginine to ADMA were different in man and mice, i.e. 166+/-50 and 85+/-22, respectively.