Effect of a single high-fat meal on endothelial function in patients with the metabolic syndrome: Role of tumor necrosis factor-alpha

Background and aims: A single high-fat meal may induce endothelial ac- tivation and dysfunction in both normal subjects and in patients with type 2 diabetes. The aim of this study was to assess the effect of a high-fat meal on endo- thelial function in patients with the metabolic syndrome. Methods and results: Twenty-five patients with the metabolic syndrome (ATP III cri- teria) were matched for sex, age and body mass index with 25 subjects without the metabolic syndrome. All subjects ate under supervision a high fat meal (760 calories) with 59% energy from fat, 12% energy from protein and 29% energy from carbohydrates. Compared with the control group, subjects with the metabolic syndrome had reduced endothelial function, as assessed with the L-arginine test, and higher circulating levels of TNF-a. Following the high-fat meal, both triglycer- ide and TNF-a levels increased more in subjects with the metabolic syndrome than in subjects without, while endothelial function decreased more in subjects with the metabolic syndrome. There was a significant relation between increases in TNF-a levels and decreases in endothelial function score in subjects with the metabolic syndrome (r 1⁄4 ÿ0.39, P 1⁄4 0.03). Conclusion: TNF-a levels are increased in subjects with the metabolic syndrome; moreover, a high-fat meal produces further increase in its levels associated with endothelial dysfunction.