Acute Effect of High-Fat Meal on Endothelial Function in Moderately Dyslipidemic Subjects

Abstract

Objective-Hypercholesterolemia markedly impairs endothelial function. Whether this is the case for hypertriglyceridemia is less clear, however, and limited evidence exists on the effect of an acute increase in triglyceridemia caused by a high-fat meal. Methods and Results-In 16 normotensive subjects with an untreated mild hypertriglyceridemia and dyslipidemia and in 7 normal controls, we measured radial artery diameter and blood flow by an echo-tracking device (NIUS02). Data were obtained at baseline, at the release of a 4-minute ischemia of the hand, which causes an increase in arterial diameter dependent on nitric oxide (NO) secretion, and at the release of a 12-minute exclusion of the arm by an arm cuff to obtain a larger increase in arterial diameter mainly of nonendothelial nature. Measurements were performed before and 6 hours after a high-fat meal (680 kcal/m 2 body surface; 82% lipids). In mild dyslipidemic hypertriglyceridemic subjects, the high-fat meal did not alter baseline blood pressure (beat-to-beat finger measurement), heart rate, radial artery diameter, and blood flow. It also did not alter the increase in blood flow induced by the 4-minute ischemia (ϩ42.7Ϯ10.4 and ϩ43.7Ϯ10.4 mL/min), whereas it markedly attenuated the concomitant increase in arterial diameter (ϩ0.31Ϯ0.06 versus 0.13Ϯ0.06 mm; PϽ0.05). The alteration of the diameter response did not correlate with changes in total cholesterol, but it showed a significant correlation with the increase in serum triglycerides induced by high-fat meal (rϭ0.49, PϽ0.05). This attenuation was not seen in control subjects and in subjects in whom measurements were repeated after a 6-hour observation period. It was also not paralleled by an alteration of the endothelially independent response to a 12-minute ischemia whose larger effects on arterial diameter and blood flow were similar before and after the high-fat meal. Key Words: blood flow Ⅲ vasodilation Ⅲ endothelium Ⅲ triglyceridemia Ⅲ acute triglyceridemia increase S everal studies have shown that an increased level of serum triglycerides can be an independent risk factor for coronary disease, when occurring alone and when occurring on the background of other alterations in lipid profile. [1][2][3][4] This has stimulated research on whether triglycerides cause endothelial dysfunction, which starts the cascade of events that lead to the atherosclerosis, ie, the anatomic lesion responsible for coronary heart disease. [5][6][7][8] Evidence that this is the case is not conclusive, however, because triglycerides were reported both to worsen and to have no measurable effect on endothelial function. 9 -18 Furthermore, little evidence has been obtained on whether triglycerides affect endothelial function in individuals with more complex, yet common, alterations in lipid profile, despite the evidence that under this circumstance the role of triglycerides as a cardiovascular risk factor may be enhanced. [1][2][3][4] Our study was aimed at providing further information on this issue by examining the effect of se...

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