Acute hypertriglyceridemia is associated with peripheral vasodilation and increased basal plow in healthy young adults

Prior studies suggest that acute elevations in plasma triglycerides alter v ascular tone and impair endothelial function. To investigate the relation b etween acute hypertriglyceridemia and vascular function, we examined the ef fects of high- and low-fat meals on brachial artery reactivity in 14 health y volunteers, Flow-mediated dilation declined from 14.7 +/- 8.3% to 10.6 +/ - 6.2% after the high-felt meal only (p < 0.001), and this decline wets ass ociated with a 6% increase in baseline brachial artery diameter (3.50 +/- 0 .74 mm to 3.70 +/- 0.81 mm, p < 0.001), but not a decrease in the arterial diameter during hyperemia, The high-fat meal increased serum triglycerides and insulin by 94% and 438%, respectively, To investigate the effects of tr iglyceride elevation in isolation from hyperinsulinemia, we examined vascul ar responses to an intravenous infusion of a triglyceride emulsion in 28 su bjects, Triglyceride emulsion increased serum triglycerides 197% but had no effect on serum insulin. Brachial artery diameter increased 4%, from 3.68 +/- 0.51 mm to 3.81 +/- 0.56 mm (p < 0.05), and forearm flow increased 36%, reflecting vasodilation of forearm resistance vessels. Flow-mediated dilat ion and nitroglycerin-mediated dilation were unaffected. The triglyceride e mulsion had no direct dilator effect on rabbit aortic tissue in vitro. In c onclusion, acute hypertriglyceridemia is associated with vasodilation of co nduit and resistance vessels in the arm and does not impair endothelial vas odilator function per se. The dilator effect is not insulin-dependent and d oes not appear to be a direct effect of triglycerides on vascular tissue. ( C) 2001 by Excerpta Medico, Inc.