Nerla Roberto, Di Monaco Antonio, Sestito Alfonso, Lamendola Priscilla, Di Stasio Enrico, Romitelli Federica, Lanza Gaetano Antonio, Crea Filippo
Dipartimento di Medicina Cardiovascolare, Università Cattolica del Sacro Cuore, Rome, Italy.
Heart Vessels. 2011 Sep;26(5):524-9. doi: 10.1007/s00380-010-0087-z. Epub 2010 Dec 9.
Flow-mediated dilation (FMD) is a widely used tool to investigate endothelial function. However, FMD assessment may cause mechanical damage to the arterial endothelium. In this study we investigated the effect of FMD assessment on endothelial function. We studied 20 healthy subjects (26 ± 6 years; 12 males). FMD was assessed by measuring brachial artery dilation in response to hyperemia after 5 min of forearm cuff inflation. Subjects were studied on 2 subsequent days. On day 1 they underwent two consecutive FMD measures, with the second test (FMD2) performed 15 min after the first test (FMD1). On day 2, the subjects were randomized to receive either placebo (saline) or intravenous L: -arginine (10 g in 20 min). At the end of the infusion, patients underwent two consecutive FMD measures following the same protocol as on day 1. Asymmetric dimethyl-arginine (ADMA) serum levels were assessed on day 2 before FMD1 and FMD2. On day 1, FMD2 was lower than FMD1 in both groups (placebo 6.47 ± 2.1 vs. 7.86 ± 1.8%, P < 0.01; arginine 6.13 ± 2.6 vs. 7.76 ± 2.7%, P < 0.01). On day 2, a significant reduction of FMD was observed during FMD2 compared to FMD1 in the placebo group (5.82 ± 1.7 vs. 7.44 ± 2.2%, P < 0.001), but not in the arginine group (7.19 ± 1.5 vs. 7.27 ± 1.5, P = 0.67). ADMA levels significantly increased compared to baseline after FMD1 (0.59 ± 0.12-0.91 ± 0.64 μmol/l, P = 0.036), with similar changes in the two groups. FMD assessment induces a significant impairment of endothelial function. An increase of endogenous NO synthesis inhibitors seems responsible for the phenomenon that is reversed by L: -arginine administration.
血流介导的血管舒张功能（FMD）是一种广泛用于研究内皮功能的工具。然而，FMD评估可能会对动脉内皮造成机械损伤。在本研究中，我们调查了FMD评估对内皮功能的影响。我们研究了20名健康受试者（26±6岁；12名男性）。通过在前臂袖带充气5分钟后测量肱动脉对充血的舒张反应来评估FMD。受试者在随后的两天接受研究。在第1天，他们连续进行两次FMD测量，第二次测试（FMD2）在第一次测试（FMD1）后15分钟进行。在第2天，受试者被随机分配接受安慰剂（生理盐水）或静脉注射L-精氨酸（20分钟内10克）。在输注结束时，患者按照与第1天相同的方案连续进行两次FMD测量。在FMD1和FMD2之前的第2天评估不对称二甲基精氨酸（ADMA）血清水平。在第1天，两组中FMD2均低于FMD1（安慰剂组6.47±2.1对7.86±1.8%，P<0.01；精氨酸组6.13±2.6对7.76±2.7%，P<0.01）。在第2天，与FMD1相比，安慰剂组在FMD2期间观察到FMD显著降低（5.82±1.7对7.44±2.2%，P<0.001），而精氨酸组未观察到（7.19±1.5对7.27±1.5，P=0.67）。与FMD1后的基线相比，ADMA水平显著升高（0.59±0.12 - 0.91±0.64μmol/l，P=0.036），两组变化相似。FMD评估会导致内皮功能显著受损。内源性一氧化氮合成抑制剂的增加似乎是导致该现象的原因，而L-精氨酸给药可逆转这一现象。
