Menzies Research Inst., Univ. of Tasmania, Medical Science 1 Bldg., Liverpool St., Hobart, 7000, Australia.
Am J Physiol Heart Circ Physiol. 2011 Jul;301(1):H123-8. doi: 10.1152/ajpheart.00102.2011. Epub 2011 Apr 13.
Acute elevation of circulating lipids, such as the postprandial state, contributes to increased cardiovascular risk. However, the effect of acutely elevated triglycerides on arterial and left ventricular function is not completely understood. We aimed to assess whether an acute increase in triglycerides affects ventricular-vascular interaction. Fifteen healthy men (age, 49 ± 8 yr) underwent blinded, randomized infusion of saline and intravenous fat emulsion to acutely raise plasma triglycerides. All subjects underwent both randomization trials, in random order on two separate days. Ventricular-vascular interaction measures were recorded by tonometry (central blood pressure) and echocardiography (left ventricular volumes, strain, and strain rate) at baseline and after 1 h infusion. Net ventricular-vascular interaction was defined by the effective arterial elastance (E(A))-to-left ventricular end-systolic elastance (E(LV)) ratio (E(A)/E(LV)). When compared with saline, the infusion of intravenous fat emulsion increased triglycerides and free fatty acids (ΔP < 0.001 for both) and improved left ventricular contractility (ΔE(LV), end-systolic volume and strain rate; P < 0.05 for all). However, arterial function was unchanged (ΔE(A), brachial and central blood pressure; P > 0.05 for all). Overall, E(A)/E(LV) was decreased by an infusion of intravenous fat emulsion (P = 0.004) but not saline (P > 0.05, P = 0.001 for Δ between trials). We conclude that intravenous fat emulsion and acute elevation of blood lipids (including triglycerides and free fatty acids) alter ventricular-vascular interaction by increasing left ventricular contractility without affecting arterial load. These findings may have implications for cardiovascular responses to parenteral nutrition.
循环脂质（如餐后状态）的急性升高会增加心血管风险。然而，急性升高的甘油三酯对动脉和左心室功能的影响尚不完全清楚。我们旨在评估甘油三酯的急性升高是否会影响心室-血管相互作用。15 名健康男性（年龄 49 ± 8 岁）接受了盲法、随机的生理盐水和静脉内脂肪乳剂输注，以急性升高血浆甘油三酯。所有受试者均在两天内的两个不同日子分别进行了两次随机试验。在基线和输注后 1 小时通过张力测量法（中心血压）和超声心动图（左心室容积、应变和应变率）记录心室-血管相互作用测量值。有效动脉弹性（E(A)）与左心室收缩末期弹性（E(LV)）的比值（E(A)/E(LV)）定义为净心室-血管相互作用。与生理盐水相比，静脉内脂肪乳剂的输注增加了甘油三酯和游离脂肪酸（两者均为 ΔP < 0.001），并改善了左心室收缩性（ΔE(LV)、收缩末期容积和应变率；所有均为 P < 0.05）。然而，动脉功能保持不变（ΔE(A)、肱动脉和中心血压；所有均为 P > 0.05）。总的来说，静脉内脂肪乳剂的输注降低了 E(A)/E(LV)（P = 0.004），但生理盐水输注未降低（P > 0.05，P = 0.001，试验间差异）。我们的结论是，静脉内脂肪乳剂和血液脂质（包括甘油三酯和游离脂肪酸）的急性升高通过增加左心室收缩性而改变心室-血管相互作用，而不影响动脉负荷。这些发现可能对肠外营养的心血管反应有影响。
